EPA-600/3-77-095
August 1977
Ecological Research Series
Roberts. Kerr
74820
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RESEARCH REPORTING SERIES
Research reports of the Office of Research and Development, U.S. Environmental
Protection Agency, have been grouped into nine series. These nine broad cate-
gories were established to facilitate further development and application of en-
vironmental technology. Elimination of traditional grouping was consciously
planned to foster technology transfer and a maximum interface in related fields.
The nine series are.
1 Environmental Health Effects Research
2. Environmental Protection Technology
3. Ecological Research
4. Environmental Monitoring
5 Socioeconomic Environmental Studies
6. Scientific and Technical Assessment Reports (STAR)
7. Interagency Energy-Environment Research and Development
8. "Special" Reports
9. Miscellaneous Reports
This report has been assigned to the ECOLOGICAL RESEARCH series. This series
describes research on the effects of pollution on humans, plant and animal spe-
cies, and materials. Problems are assessed for their long- and short-term influ-
ences. Investigations include formation, transport, and pathway studies to deter-
mine the fate of pollutants and their effects. This work provides the technical basis
for setting standards to minimize undesirable changes in living organisms in the
aquatic, terrestrial, and atmospheric environments.
This document is available to the public through the National Technical Informa-
tion Service, Springfield, Virginia 22161.
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EPA-600/3-77-095
August 1977
IMPACT OF ABANDONED WELLS
ON GROUND WATER
by
Tyler E. Gass, Jay H. Lehr, and Harold W. Heiss, Jr.
National Water Well Association
Worthington, Ohio 43085
Grant No. R-803889
Project Officer
Jack W. Keeley
Ground Water Research Branch
Robert S. Kerr Environmental Research Laboratory
Ada, Oklahoma 74820
ROBERT S. KERR ENVIRONMENTAL RESEARCH LABORATORY
OFFICE OF RESEARCH AND DEVELOPMENT
U.S. ENVIRONMENTAL PROTECTION AGENCY
ADA, OKLAHOMA 74820
Environjnantal Protection Agency
Region V% Librery
230 South Dearbcrn Street
Chicago» Illinois 6080**
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DISCLAIMER
This report has been reviewed by the Robert S. Kerr Environmental
Research Laboratory of the U.S. Environmental Protection Agency, and
approved for publication. Approval does not signify that the contents
necessarily reflect the views and policies of the U.S. Environmental
Protection Agency, nor does mention of trade names or commercial products
constitute endorsement or recommendation for use.
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FOREWORD
The Environmental Protection Agency was established to coordinate
administration of the major Federal programs designed to protect the
quality of our environment.
An important part of the Agency's effort involves the search for
information about environmental problems, management techniques, and new
technologies through which optimum use of the Nation's land and water
resources can be assured and the threat pollution poses to the welfare
of the American people can be minimized.
EPA's Office of Research and Development conducts this search through
a nationwide network of research facilities.
As one of these facilities, the Robert S. Kerr Environmental Research
Laboratory is responsible for the management of programs to: (a) investi-
gate the nature, transport, fate, and management of pollutants in ground
water; (b) develop and demonstrate methods for treating wastewaters with
soil and other natural systems; (c) develop and demonstrate pollution con-
trol technologies for irrigation return flows; (d) develop and demonstrate
pollution control technologies for animal production wastes; (e) develop
and demonstrate technologies to prevent, control or abate pollution from
the petroleum refining and petrochemical industries; and (f) develop and
demonstrate technologies to manage pollution resulting from combinations
of industrial wastewaters or industrial/municipal wastewaters.
This report contributes to that knowledge which is essential in order
for EPA to establish and enforce pollution control standards which are
reasonable, cost effective, and provide adequate environmental protection
for the American public.
William C. Galegar
Director
Robert S. Kerr Environmental Research Laboratory
m
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ABSTRACT
Unplugged abandoned wells are a hazard to our nation's potable ground
water supplies. Today, millions of dollars of damage can be directly attrib-
uted to the contamination of ground water by improperly abandoned wells. The
total impact of the hazard, however, is not fully understood, nor apparent.
A review of case histories of ground water pollution caused by unplugged,
leaking wells reveals the potential magnitude of the problem.
A survey of state laws concerning well abandonment procedures exposes a
disparity in the regulations in and among different states. The laws in the
traditional oil producing states are generally up-to-date and effective in
dealing with abandoned wells. In the remainder of the states, well abandon-
ment laws are ineffective or non-existent. Model legislation on abandoned
wells is presented to contrast ineffective legislation with that which would
give effective control. By examining the model legislation guidelines, state
and local authorities can gain technical insight and legislative perspective,
which will enable them to formulate and enact effective laws to protect their
state's ground water supplies.
This report is submitted in partial fulfillment of Federal Grant
No. R-803889 by the National Water Well Association under the sponsorship
of the U.S. Environmental Protection Agency. Work was completed as of
April 1, 1977.
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CONTENTS
Foreword iii
Abstract iv
Figures vi
1. INTRODUCTION 1
2. CONCLUSIONS 4
3. RECOMMENDATIONS 6
4. CASE HISTORIES OF GROUND WATER POLLUTION CAUSED
BY WELL ABANDONMENT 9
5. STATE WELL ABANDONMENT REGULATION SURVEY 18
Bibliography 38
Appendices 40
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FIGURES
Number Page
1 Permanent Bridge Seals 43
2 Intermediate Seals 45
3 Uppermost Aquifer 46
VI
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SECTION 1
INTRODUCTION
Properly constructed water wells, oil and gas wells, and liquid waste
disposal wells are not normally sources of ground water contamination, but
when they are in a state of disuse and disrepair, casings and screens begin
to corrode and the wells can become conduits through which contaminants can
travel vertically through the boreholes.
An abandoned well's potential for adversely affecting ground water qua-
lity will depend on its original use, the local geology, the hydraulic charac-
teristics of the subsurface fluids, and the type of well construction. When
a well is abandoned, it is often covered by a board or by a sheet of metal
that may or may not be welded to the top, in a feeble attempt to insure that
the well does not become a public hazard. Unfortunately, such procedures fail
to take into account the fact that the mere existence of an unplugged, aban-
doned well represents a great hazard to ground water quality. If left unplug-
ged, the well endangers area water supplies and may, in fact, indirectly cause
sickness or death to persons using that water for drinking.
An abandoned well frequently becomes a convenient receptacle for the
disposal of wastes. People will throw anything into a well that will fit,
including dead animals, automobile batteries, household garbage and a variety
of liquid wastes.
The presence of unrecorded abandoned wells in areas subject to occasion-
al or permanent flooding, such as the flood plains of streams, coastal areas
undergoing subsidence, or areas flooded by artificial reservoir impoundments,
permit the entrance of poor quality surface water into aquifers. The addition
of a reservoir operating head can cause high inflows with an attendant danger
of continuous contamination.
When wells penetrate saline or other aquifers under higher artesian
head, deterioration of the casing results and the well becomes a conduit for
the movement of poor quality water, or potentially hazardous fluids, into
potable aquifers.
In addition to abandoned water, oil and gas wells, there are literally
hundreds of thousands of abandoned mineral exploration wells, test borings,
and seismic shot holes. These open holes permit water to migrate freely from
one aquifer to another. A fresh water aquifer may thus be joined with a pol-
luted aquifer or a deeper saline aquifer, or polluted surface water may drain
into fresh water zones.
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Many state regulations governing well abandonment are not comprehensive
enough to insure adequate plugging of an abandoned well, and few states are
capable of enforcing any regulations which may exist. Furthermore, since
regulations vary greatly from state to state, particular states are reluctant
to improve their regulations, when surrounding states call for less stringent
well abandonment requirements. Listed below are some examples of this type
of variability (U.S. EPA, 1976):
Oregon requires that any well that is to be permanently
abandoned shall be filled in a manner so as to prevent the well
from being a channel allowing the vertical movement of water
and a possible source of contamination of the ground water supply.
The Texas regulation specifies that the well be filled with
cement to the land surface, but also specifies alternatives de-
pending upon whether there is undesirable water above or below
the fresh water zone.
The North Carolina regulations contain several specific re-
quirements, including the specific stipulation that in the case
of gravel packed wells in which casing and screens have not been
removed, the casing shall be perforated opposite the gravel pack
at intervals not exceeding 3 meters (10 feet). It specifically
allows casing and screen to be salvaged. It requires that bored
wells be completely filled; for wells in unconsolidated forma-
tions, it requires that this filling be done by introducing
cement grout through a pipe extending to the bottom of the well
which can be raised as the well is filled.
A regulation of the San Joaquin Local Health District,
California (in that state regulations are local, adopted under
state recommended standards), requires "destruction" of any
well that no longer serves a useful purpose, or has fallen into
such a state of disuse or disrepair that it may become a source
of impairment to ground water quality. The regulation is thor-
ough, requiring that the interior of the casing first be cleaned
to eliminate obstructions that might interfere with sealing pro-
cedures. It specifies filling of the well with the following
additional requirement:
If there is no annular seal or if occurrence
is unknown, the casing shall be perforated
upward beginning just above the filler material
for a distance of approximately 1.5 meters (5
feet). Grout shall be applied above the
filler material in such a manner that the grout
will be forced out of the holes, forming a bar-
rier to the vertical movement of water.
The regulation also requires, for protection of the seal
and to facilitate future use of the land site, that a three
foot hole be excavated around the well casing, the casing
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cut off 15 centimeters (6 inches) above the bottom of the hole,
and that during sealing operations, grout used to fill the well
be allowed to spill over into the excavation and fill it for a
thickness of 30 centimeters (1 foot) to form a cap which has
a diameter of at least 30 centimeters (1 foot) greater than the
diameter of the originally drilled hole. The excavation is then
filled with soil.
A San Joaquin County ordinance authorizes the district
health officer to destroy any well that is polluted or so lo-
cated as to become polluted or is a safety hazard, and to re-
cover the cost of destruction from the owner of the property
on which the well is located.
The National Water Well Association and American Water Works Association
have prepared recommended water well abandonment standards. It is the inten-
tion of these two agencies that each state consider these recommended stan-
dards as a minimum necessary requirement for proper well abandonment (Appen-
dices A & B).
Ground water contamination caused by abandoned wells could be practically
eliminated through education of state and federal regulatory agencies, and the
general public. Increased awareness of the problem should lead to new regu-
lations and more stringent enforcement of these regulations.
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SECTION 2
CONCLUSIONS
The leakage of contaminated or highly mineralized water through aban-
doned wells and unplugged exploration holes has led to insidious ground water
pollution problems. The scientific community and the state regulatory agen-
cies have only recently realized the potential magnitude of the problems cre-
ated by improperly abandoned water, gas, and oil wells. It is likely that the
full impact of improperly abandoned wells in the United States will not be
entirely recognized for years to come.
Areas where ground water contamination has resulted from improper well
abandonment are subject to the economic and social hardships related to the
loss or impairment of the groundwater resource.
It is neither technically nor economically feasible to plug all existing
abandoned wells and exploration holes. Steps must be taken, however, to in-
sure that wells and exploration holes abandoned in the future will be properly
plugged.
Administrative controls are needed for the drilling of exploration holes.
Unsealed, abandoned wells and exploration holes constitute a hazard to
public health, safety, and welfare, and to the preservation of ground water
resources. The sealing of such wells presents a number of problems, the
character of which depends upon the construction of the well, the geologic
formations encountered, and the hydrologic conditions.
Any permanently abandoned well should be completely filled in such a
manner that vertical movement of water within the well bore, including ver-
tical movement of water within the annular space surrounding the well casing,
is effectively and permanently prohibited and the water is permanently con-
fined to the specific strata in which it was originally encountered.
A well should always be checked before it is sealed in order to insure
that there are no obstructions which could interfere with effective plugging
operations. Removal of casing from some wells may be necessary to assure
placement of an effective seal. If casing opposite water bearing zones can-
not be removed, it should be split with a casing ripper to assure proper seal-
ing of these zones. At least the upper portion of the casing should be re-
moved to prevent surface water from entering the water bearing strata by flow-
ing down the casing. This operation is not necessary if the annular space
around the outside of the casing was cemented when the well was completed.
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Grout of any type, when used as a sealing material below the water level
in the well, should be placed from the bottom up by methods that will preclude
segregation or dilution of material.
Every effort should be made to disinfect wells prior to abandonment.
All materials, such as water, sand, and gravel, to be used in the abandonment
process, should be disinfected.
The best way to reduce or eliminate the detrimental effect abandoned
wells can have on ground water is to create an awareness of the problem through
education of state and federal agencies, of water well contractors and of the
general public. This educational program must also include instruction in the
technology necessary to properly seal abandoned wells.
If those states that have had the worst problems associated with aban-
doned wells can successfully eliminate ground water contamination due to these
wells, then it is a worthwhile goal for all states to strive toward elimina-
tion of ground water pollution resulting from well abandonment.
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SECTION 3
RECOMMENDATIONS
RECOMMENDED REGULATIONS FOR WELL ABANDONMENT
Nationwide uniformity of well abandonment regulations and procedures is
probably unattainable and undesirable. However, each state should adopt mini-
mum regulations to assure the protection of ground water quality.
The National Water Well Association recommends that the states incorpor-
ate the following provisions in any well abandonment legislation:
1) A listing of well abandonment procedures should be written for the
different hydrogeological environments and types of wells that may be encoun-
tered in the state. One single well abandonment method will not be suitable
for all wells and may be too much of an economic burden to be considered by
a well owner or by a water well contractor.
2) States should make provisions for plugging of all existing abandoned
wells. This includes wells that were abandoned before passage of regulations.
Without some type of retroactive recourse, vast numbers of wells would remain
a potential channel for ground water degradation.
The state could provide funding through which the agency in charge of
well abandonment may trace all abandoned wells and either compel the owner to
seal the wells, or permit state funds to be used to seal the wells.
3) All abandoned wells and the equipment and materials used to aban-
don wells should be disinfected to protect aquifers from bacteriological con-
tamination, as is required during well construction.
4) Manpower and funding must be provided for proper enforcement of
well abandonment regulations. Penalties must be established and used if
responsible parties fail to comply with state regulations.
5) Well owners should be required to obtain prior approval from the
regulatory agency of the drilling method and design and construction features
of the well before a drilling permit is issued. When work on the well is
finished, a driller's log and completion report should be filed with the
proper state agency. This will aid in defining the procedures required to
plug the well when it is abandoned.
6) Authority should be provided for the respective state agencies
to trespass and to inspect the workmanship during or after the plugging
of an abandoned wel1.
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7) If a well is to be abandoned ei'ther temporarily or permanently, the
owner should be required to notify the responsible state agencies. Such noti-
fication may simplify the work of a state agency if ground water contamination
should develop in the area around the inactive well.
8) The state regulatory agency governing well abandonment should have
the right to plug an abandoned well and assess the owner for the costs. In
addition, a state fund should be established to permit plugging of abandoned
wells where legal ownership cannot be ascertained.
9) State well abandonment regulations should be applicable to most subsur-
face excavations including, but not limited to water wells, gas and oil wells,
seismic test holes, core borings and test holes, geothermal wells, and all
kinds of injection wells. The goal of the regulations should be to provide
for the restoration, as nearly as possible, of those subsurface and surface
conditions that existed prior to drilling, boring, digging or augering. The
purpose of the regulation is to prevent contamination of aquifers by surface
waters and the interchange of fluids between aquifers.
The regulations should include procedures for abandoning wells, require
inspection of the well during or after abandonment, and provide for enforce-
ment and for penalties if the responsible person or agency fails to comply
with the regulations. These penalties should be clearly delineated in the
regulations.
10) Persons who drill holes, wells, or excavations to be used for the ex-
ploration of underground resources should be licensed by the state regulatory
agency. Failure of the contractor to comply with any state well construction
or abandonment regulations would jeopardize his right to work in that state.
State regulations should require that the owner of the well inform the
proper state agency of any intention to abandon the well. Upon completion of
the abandonment, the contractor who has done the work should file a report
with the state certifying the methods used to abandon the well. No one but
a well contractor should be permitted to seal a well.
The contractor would be responsible for the way the well is sealed, and
should be held legally accountable for any damage to persons or to the envi-
ronment that may occur because of improper sealing techniques.
11) Appendix A consists of the recommended procedures for well abandonment
written by the National Water Well Association for the U. S. Environmental
Protection Agency. These procedures represent the recommended minimum re-
quirements for all states.
12) Every person intending to drill, bore, or in any manner excavate an
opening in the earth for the purpose of evaluation of underground resources,
including, but not limited to, metallic and non-metallic deposits, oil and
gas, coal, water, and brine, should be required to obtain a permit from the
proper regulatory agency. The permit application would describe the location
of the hole or block of holes, their purpose, estimated depth, type and amount
of casing, if any, hole diameter, water level, type of well, permeability,
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thickness and quality of water in the aquifers that have been encountered,
and proposed plugging procedures. Such information would simplify the pro-
cess of locating the well if it is abandoned, of determining if it may be
causing aquifer contamination, and of choosing the proper abandonment tech-
nology.
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SECTION 4
CASE HISTORIES OF GROUND WATER POLLUTION CAUSED BY WELL ABANDONMENT
Disuse of a well leads to its rapid deterioration and increases the po-
tential for ground water contamination.
Although most states require that an abandoned well be plugged to insure
that it does not constitute a public hazard, most abandonment statutes are
less than ideal.
As rural areas increase in population, the local populace is encouraged
to give up the individual domestic supply well in exchange for a public water
supply. The public water supply sometimes takes the form of a surface water
impoundment. When the reservoir begins to fill with water, hundreds of un-
plugged abandoned wells may be submerged. When the water level reaches higher
levels, hydraulic pressure will cause flow of water into the aquifers tapped
by the submerged wells. The introduction of surface water directly into the
abandoned well bores increases the danger of contamination to the aquifer.
Properly constructed water wells, oil and gas wells, and liquid disposal
wells are not normally sources of ground water contamination. However, where
a casing has been corroded or ruptured, where well screens or the open bore-
hole interconnects two separate aquifers, or where the surface casing is not
adequately sealed, wells can serve as a means for transmission of pollutants
from one aquifer to another or from the land surface to the aquifer.
The factors leading to well deterioration and consequent ground water
contamination, discussed in the preceding paragraph, are most typical of
wells that are no longer being used or properly maintained.
Surface drainage into a well usually can be easily remedied. However,
if an abandoned well has deteriorated at depth, the problems and causes of
ground water contamination become difficult to detect, much less correct.
Of concern are wells that penetrate saline or other aquifers under high
artesian heads. When a well is abandoned, deterioration of the casing results
in the well becoming a conduit for movement of poor quality water or poten-
tially hazardous fluids into potable aquifers.
Ground water contamination can occur whenever a hole is drilled from
the surface into one or more aquifers. Thus, test borings, seismic shot holes,
abandoned observation wells, and test wells also represent potential sources
of ground water contamination.
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Most states are not fully aware of the problems associated with aban-
doned wells. Except for an occasional water quality deterioration complaint
from a well owner, it is likely that most states remain unaware of the impact
of abandoned wells on ground water. Typically, a homeowner may complain of
the smell of oil or hydrogen sulfide in his water. A public health official
checking the problem may find that the only potential source of such contam-
ination is an abandoned oil well nearby that has possibly penetrated a coal
seam or a depleted oil reservoir. The well casing has probably corroded, al-
lowing high pressure fluids to rise upward from great depth and to enter the
aquifer that had previously provided potable water.
Case histories of known ground water quality degradation from abandoned
wells are not as readily available as might be suspected even though there are
an estimated 2,000,000 abandoned wells in this country. Most occurrences have
gone unrecorded because many abandoned wells are found in remote rural areas,
and the area contaminated is usually very localized.
ABANDONED WATER WELLS
When it was discovered that the quality of water furnished by a munici-
pal well in Avon, South Dakota, was markedly different from the quality of
water obtained from nearby wells tapping the same aquifer, the United States
Geological Survey state office investigated the phenomenon (Jorgensen, 1968).
An aquifer test and analysis of water samples showed that the anomalous water
quality of the municipal well in Avon was caused by leakage from a nearby
abandoned well that tapped another aquifer.
During an investigation of the ground water supplies of the Atlantic
City region of New Jersey, Thompson (1928) noted that some production wells
in the study area were contaminated with chlorides. The cause of the high
chloride content was discovered to be improperly plugged abandoned wells that
permitted interaquifer transfer of water between fresh and saline aquifers.
Sayre (1937) reported that the ground water of Pliocene Sands in Texas
was locally contaminated by chlorides. He theorized that the localized con-
tamination was the result of casing corrosion in active and abandoned water
wells, which permitted highly mineralized water from shallow strata to flow
into the deeper Pliocene aquifer.
In two studies of the ground water resources in the Baltimore, Maryland,
area, Bennett and Meyer (1952) reported that from 1850 to 1950 an estimated
1,500 wells had been drilled. By 1945 approximately 1,250 wells had been
abandoned, but only 150 wells, or 12 percent, had been plugged. As many as
1,140 of these abandoned wells are no longer accessible because they are cov-
ered by buildings, highways and other structures. It is possible that this
construction may have damaged well casing, increasing the chance of a well
becoming a point of contamination. Nonetheless, it cannot be assumed that
all these unplugged wells are sources of ground water contamination. Many of
the wells do not penetrate more than one aquifer, or do not encounter saline wa>
ter. In addition, it is probable that some abandoned wells have collapsed
and that their boreholes are filled with formation materials.
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In 1956, the American Brass Company constructed three high-capacity
water wells at their plant in Terre Haute, Indiana (Johnson National Drillers
Journal, May-June, 1957).
The engineers were rudely surprised when the water
pumped from each of the wells proved to be contam-
inated with salt. The water was unusually hard
and contained 10 to 30 times more chloride than
the ground water pumped by other industries in
the general area. The wells were completed in
glacial outwash material.
A systematic investigation revealed the presence of an unplugged aban-
doned test hole about 606.6 meters (2,000 feet) from the new water supply
wells. The test hole had been drilled at an earlier date during a period of
oil exploration. The test bore contained water with 8,600 ppm chlorides and
a static water level 8.5 meters (28 feet) higher than the static level of the
fresh water in the glacial formation. This abandoned test hole had never
been plugged. It proved to be the source of the contamination.
The Florida Department of Environmental Regulation has made reference
to a number of known cases on ground water contamination. (Craig L. Helping,
Written Communication, 1976):
1) A conservative estimate would indicate that there are
about 4,000 abandoned wells in Florida with more being
abandoned each year. The state requires notification
for any well which is to be abandoned; however, this
has largely been neglected and very little accurate
information is available. In addition, most of the
information on hand is of recent vintage. Older
records of abandoned wells are generally non-existent.
2) One particular situation which has created special
problems is that of abandoned artesian wells. Large
portions of Florida are underlain by a series of lime-
stone aquifers under sufficient artesian head to cause
wells to flow at the land surface during a portion of
the year. In general, these separate producing zones
are sealed from each other by rather effective aqui-
cludes.
Each aquifer has a different water quality and artesian
head. Where this type of hydrologic system exists, both
artesian pressure and total dissolved solids increase
with depth. This increases the potential of interaquifer
mixing and contamination in instances of improper well
design and deteriorated well casing.
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3) Water table seepage around well casings or via the well
borehole provides the potential for ground water contam-
ination from above.
4) One special problem has been encountered in this state
with regard to abandoned wells. Some flowing wells
which have been abandoned and allowed to deteriorate
have created ponds which pose severe problems in regu-
lation. Other artesian wells have been cut off below
ground level, capped, and then a building or even a
roadway has been constructed on top of them. Once the
casing and cap deteriorate sufficiently, the well be-
gins flowing wildly again, creating significant prob-
lems which are most difficult and expensive to correct.
5) Abandoned wells have been found in every area of the
state, many in remote or inaccessible areas. The loca-
tion of these wells is hindered by the lush, semi-tropic
vegetation and marshlands. Location, of course, is only
the first step toward implementing regulations. Quite
often, once a well is located, it proves to be impossible
to get logging equipment and well plugging equipment to
the site. In such cases, it is difficult to enforce
remedial regulation.
An illustration of this type of problem involves a
number of flowing artesian wells which are submerged
in the Gulf of Mexico off the west coast of Florida.
There are approximately 50 submerged, flowing wells
along the 83 kilometers (52 miles) of coastline of
Managee and Sarasota Counties. These wells, typi-
cally 5 to 9 centimeters (2 to 6 inches) in diameter
and 45 to 243 meters (150 to 800 feet) deep, were
originally drilled to provide domestic water supplies
to residents of the various barrier islands.
Sections of the barrier islands have been eroded
during severe storm and hurricane activity. De-
pending upon the amount of erosion, some wells are
now located from within a few feet of the present
shoreline to a distance of about 152 meters (500
feet) out into the Gulf.
Having been subjected to electrolysis and naturally
corrosive conditions, the majority of these wells
have deteriorated to a point where they are sub-
merged at all times, and no longer are equipped with
valves or caps to prevent the loss of fresh water.
Salt water may also enter an abandoned well and di-
rectly contaminate portions of the fresh water aquifer
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when the artesian pressure declines to a point where the
flow is overcome by the pressure of the salt water above.
The wells which are located beyond the mean high water
line legally become the property of the State of Florida
and should be brought into compliance with state regula-
tions. Locating these wells has become a problem of ma-
jor proportions. Since the majority of the wells are
submerged, it is impossible to locate them by conventional
means. Scuba diving is also impractical since the search
area has 152 meters (500 feet) by 83 kilometers (52 miles)
dimensions.
Discussions of the problem with the National Aeronautics
and Space Administration (NASA) has led to a joint re-
search and development project by NASA and the Florida
Department of Environmental Regulation. The objective
of the experiment has been to use airborne thermal scan-
ner imagery in an attempt to locate the wells by detect-
ing temperature differentials caused by the flowing wells
on the surface of the Gulf of Mexico.
The majority of artesian wells in the project area, de-
pending upon depth, flow water of approximately 26° - 28°C
(80° - 83° F), year round. By conducting the flight mis-
sions during the winter months when the temperature of
the Gulf of Mexico is suppressed to 14° - 16° C (58° -
60° F), the state is assured to the best possibility of
detecting the surface thermal anomalies which submerged,
flowing wells may cause. The thermal imagery gathered
during this experiment is now being analyzed to determine
and map all signatures which may indicate a well. Exten-
sive field checking will then be done to precisely locate
all of the wells. After the location and verification
aspects are completed, the wells will be plugged accord-
ing to specifications.
ABANDONED OIL AND GAS WELLS
The leakage of contaminated or highly mineralized water through abandoned
oil and gas wells and unplugged exploration holes has led to insidious ground
water pollution problems.
In Michigan, thousands of holes were drilled for exploration of oil,
gas, and coal resources before the turn of the century. Leakage over the
past 80 to 100 years of billions of liters of highly mineralized solutions
through these open abandoned holes has created widespread problems.
Leakage of acid mine drainage through old oil and gas test wells and
other open holes has caused extensive ground water pollution in the coal
fields of Pennsylvania and elsewhere in Appalachia.
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Regulations of the Kentucky Water Pollution Control
Commission in October, 1958, required disposal wells
to inject brines at depths of 53 meters (175 feet)
or more below the local drainage. Pressure disposal
into porous zones below the New Albany Shale of De-
vonian age was permissible from March, 1959, to
March, 1960. The Louisville Limestone of Silurian
age underlying the New Albany Shale became a major
brine disposal zone at this time. This formation
was previously penetrated, however, by several
abandoned gas and oil test wells drilled in the
1920's and 1930's, which allowed the brines to
move upward and contaminate the fresh-water zones
above. The brines changed the potable ground wa-
ter from a calcium bicarbonate type containing
moderate amounts of magnesium and sulfate to a so-
dium chloride type. Chloride concentrations prior
to oil production generally were less than 60 mg/1;
after oil production, chloride concentrations were
as high as 51,000 mg/1.
Abandoned, unplugged wells from frantic wildcat
drilling in Taylor County, Kentucky, hampered brine
disposal through injection wells. When brines were
injected under pressure, the abandoned wells in the
area also begin to flow brine.
During the development of the Greensburg oil field in the fall of 1958,
many wells and springs formerly yielding fresh water were reported to have
"gone salty." Brines discharged from oil wells in the Greensburg oil field
were the probable source for the increased salinity. The ground water con-
tamination was concentrated in the areas of heavy brine production in Green
and Taylor Counties, but was noticeable as far away as Brownsville, about 161
kilometers (100 miles) downstream.
Highly mineralized water in the Jamestown, New York, area is believed
to be moving upward from deep beds of salt underlying the western and south-
ern portion of the area at depths ranging from 457 to 610 meters (1,500 to
2,000 feet) below mean sea level. These salt deposits were penetrated by
deep test wells drilled for oil and natural gas. Several of the test wells
also penetrated zones containing very salty water at much shallower depths
than the rock salt. The mineralized water results from deep circulation
of fresh ground water down to the salt beds. Most of the upward movement
may be along natural breaks in the rocks. However, some of the water is mov-
ing upward through abandoned oil and gas test wells that have not been ade-
quately plugged (Grain, 1966).
In Chemung County in western New York, adjacent to the Pennsylvania
border, the concentrations of chloride and total dissolved solids have been
increasing. The upper bedrock of Chemung County is composed of a sequence of
sandstone and shale, overlain by glacial drift. Within the major stream val-
leys, the sand and gravel deposits are productive aquifers. Elsewhere, the
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bedrock aquifer is utilized. Salt beds and zones of highly mineralized water
are known to underlie the area at depth. Although never a highly productive
petroleum area, a number of gas wells were drilled and later abandoned. Many
of these old wells are conduits for the upward migration of the mineralized
water. Natural chloride content of the shallow fresh-water aquifers in the
county is less than 10 mg/1; concentrations of this constituent in water from
domestic wells contaminated by brine from the deeper gas strata range from
100 to 500 mg/1. Analyses of water from domestic, industrial and municipal
wells in the Susquehanna River Basin in New York indicate similar conditions
(Miller et. al., 1974).
A classic example of problems that can arise from aban-
doned wells has occurred in Colorado. In 1915, an oil
test hole was drilled in west-central Colorado to a
depth of 560m. (1,837 ft.). This well encountered
warm, mineralized water. Fifty-three years later, on
May 9, 1968, the well was found to be discharging
7,338 cu m/d (1,350 gpm) of brackish water with a con-
centration of 19,200 mg/1 dissolved solids. It was
estimated that this flow contributed 52,000 metric
tons (57,000 tons) of dissolved solids per year to
the White River. The well was subsequently plugged,
after which the hydrostatic pressure built up, caus-
ing other non-flowing wells in the area to flow, and
creating saline seeps in the vicinity of these wells.
(Miller, et. al., 1974).
Wait and McCollum (1963) report that an abandoned, unplugged oil test
well in Glynn County, Georgia, yields salt water with a chloride content as
high as 7,780 mg/1. The 140 meter (4,615 foot) well penetrates both fresh-
water and salt-water aquifers. The well bore serves as a conduit to connect
the salt-water and fresh-water aquifers. Because the pressure is greater in
the deep salt-water aquifers than in the shallower fresh-water aquifers, the
salt water flows upward into the fresh-water aquifer.
Unplugged wells and artesian brine have resulted in reported flowing
salt water wells in Know, Hopkins, and Young Counties, Texas. In Hopkins
County, one abandoned oil test well was flowing between 100 and 125 barrels
per day of brine water before it was plugged (Scalf, et. al., 1973).
Fink (1965) reported to the Texas Water Commission that ground and sur-
face-water contamination near Harrold, Texas, may have been caused by any or
all of three potential sources:
1) Brine injection wells where corrosion of the casing has
taken place;
2) Injected brine that may be entering inadequately plugged,
abandoned oil wells;
3) Brine discharge into unlined surface pits.
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Fink indicates that the majority of the abandoned oil wells in the area
were inadequately plugged, thereby increasing the chances for contamination
from the second source.
In a 1962 study, Burnitt suggests that an improperly plugged oil well
may be permitting gas and brine fluids to contaminate the near surface aquifer.
Burnitt suspects that deterioration of the surface casing remaining in the
well in question has resulted in creating an open bore from the surface down
to the top of the cement around a poorly placed plug.
OTHER TYPES OF ABANDONED WELLS
A study (Bond, 1975) of the influence of seismic shotholes on ground
water quality was done in Montana. It showed that little if any contamination
occurred. Since the shotholes were typically less than 60 meters (200 feet)
in depth, few if any artesian aquifers were encountered, reducing the possi-
bility of inter-aquifer transfer of water. In addition, it appeared that all
shotholes sealed themselves within a year, as a result of the collapse of
sand, clay or silt in the borehole. However, the Montana findings may not
apply elsewhere.
Rold (1971) points out that in many areas, shotholes are 90 meters (300
feet) or deeper and can provide a ready admixing of salt and fresh water aqui-
fers. These holes can deplete the pressures of shallow artesian aquifers and
allow shallow polluted waters or alkaline waters to enter deeper potable aqui-
fers.
Underground gas storage is defined as storage in rock of synthetic or
natural gas. The gas may be stored in gaseous or liquid form, and is often
injected into depleted oil or gas reservoirs or in aquifers.
Undergound gas storage fields present a potential for
contamination of usable ground water by leakage of gas
through the confining beds, through improperly plugged
wells . . . (U.S. EPA, 1973)
Deep well injection is a method commonly used to dispose of oil field
brines.
Payne (1966) discussed how brine injection coupled with local abandoned
wells can represent a hazard to fresh ground water in Texas. Other authors,
Burnitt, et. al . (1962), Fish (1965), and Preston (1969), had similar exper-
iences with brine injection and abandoned wells.
The Herscher underground natural gas storage field, located one mile
south of the Village of Herscher in Kankakee County, Illinois, was the site
of ground water pollution by natural gas. Although no conclusive evidence
was developed to prove how gas escapes from the underground storage formation,
abandoned oil wells were suspected.
The Herscher reservoir structure underlies approximately 60.7
(15,000 acres) of rural land. Geologically the storage structure is a closed
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anticline or dome. It is shaped like an inverted saucer that provides the
geologic trap necessary for large-scale storage of natural gas. Five hundred
and thirty-three meters (1,750 feet) below the ground surface is the apex of
a very porous and permeable bed of sandstone (the Galesville Formation) which
forms the reservoir for the storage field.
The existence of the structure had been known for many years. Follow-
ing the turn of the century, approximately 20 oil wells had been drilled to
an average depth of 60 meters (200 feet) where oil and a small amount of gas
had been encountered. After a short period of fruitless pumping, these wells
were abandoned. No attempt to plug the wells was made. The casing was cut
off below the ground surface and farming was continued on the site.
During August, 1953, after gas had been injected for 4 months, a total
of 33 village water wells became active with gas. It has been postulated
that one or more of the old oil wells had actually been drilled into the
Galesville Formation, thereby allowing natural gas to escape into the over-
lying strata.
Although it was not conclusively proved that abandoned wells were the
prime cause of contamination, the chances are good that they were.
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SECTION 5
STATE WELL ABANDONMENT REGULATION SURVEY
The degree to which state agencies understand the potential impact of
abandoned wells on ground water quality is reflected in their well abandon-
ment regulations. Alaska, Indiana, Iowa, New Hampshire, Connecticut, Ken-
tucky, Massachusetts, Mississippi, and the District of Columbia claim that
their states have no problems with abandoned wells, or that abandoned wells
do not exist within their boundaries. Therefore, these states have no regu-
lations to deal with well abandonment. Louisiana and Texas have long realized
the effect that abandoned wells can have on potable ground water. Both of
these states have thousands of abandoned water, oil, gas and exploration wells,
seismic shotholes, and brine and liquid waste disposal wells. Louisiana and
Texas economies are closely tied to their subsurface natural resources, such
as oil, gas, and water, and depletion of any of these resources could result
in economic disaster. Consequently, these two states have formulated extreme-
ly detailed and comprehensive well abandonment regulations which fully describe
the procedures to be used for each type of well and for wells that penetrate
different hydrogeological environments.
The majority of states do have regulations to deal with the hazards of
well abandonment, but they are not uniform in content. In some states, the
regulations are useless and only require that all wells be filled to prevent
injury or death to people and animals who might fall into one; other states
have regulations that exceed suitable well abandonment requirements. The
variability of these laws is indicative of the lack of understanding of the
problems associated with well abandonment.
Well abandonment regulations are only as good as their enforcement, and
enforcement is a problem that confronts most states. Only Louisiana, Florida,
Hawaii, Missouri, New Jersey, Texas, Utah, West Virginia and Wisconsin have
provisions for enforcement of well abandonment procedures. Some states leave
enforcement up to county or local agencies. Other states simply do not have
the manpower to carry out inspection and enforcement at any level.
In states where well owners are responsible for paying the costs of well,
abandonment, one finds that owners are less than enthusiastic about reporting
an abandoned well. Usually, state regulatory agencies do not find out about
an abandoned well until they are asked to evaluate the cause of some localized
ground water contamination.
The problem with owner abandonment is becoming most evident in regions
where rural water supply districts have been created. After a homeowner,
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farmer, or small business has been assessed for a hook-up to public water,
they are generally reluctant to bear the additional expense of proper well
abandonment.
A further obstacle to the proper sealing of an abandoned well is that
some states permit the owner to seal or plug the well. The procedures of
well abandonment should be carried out only by drilling contractors who have
a complete understanding of the difficulties of properly plugging a well,
the reasons for plugging, and the equipment necessary.
One of the best ways to analyze the practicality of well abandonment
regulations is to review those of each state. To assist the reader in eval-
uation, there is a general commentary on the different regulations at the end
of the review. When a particular regulation is worthy of commendation or
criticism, a brief comment immediately follows.
ALABAMA
"All wells shall be permanently abandoned in the following manner:
The well will be filled with a puddled clay material containing 50 mg/1 of
chlorine to within 6 meters (20 feet) of the top of the well. The top 6
meters (20 feet) shall be filled with cement grout or concrete."
ALASKA
No specific well abandonment regulations.
ARIZONA
"Abandoned wells and test wells should be sealed by restoring the
controlling geological conditions which existed before the wells were drilled.
Whenever feasible, the wells should be completely filled with concrete."
Comments: Regulations in Arizona and Alabama fail to describe
specific procedures for well abandonment, to require inspection
and notification of well abandonment, and to enforce the regu-
lations.
ARKANSAS
"Wells drilled for water and then abandoned for any reason shall be
properly protected to maintain the original quality of the ground water source.
The abandoned well must be grouted to a minimum depth of 3 meters (10 feet)
below ground surface. It is the contractor's responsibility to seal out any
and all contamination, such as surface water or seepage, by placing the grout
to the necessary depth. The enactment and enforcement of the regulation is
the responsibility of the Arkansas Committee on Water Well Construction."
CALIFORNIA
The purpose of well abandonment in California is to assure that the
ground water supply is protected and preserved for future use, and to elimin-
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ate the potential physical hazard that exists. All abandoned wells shall be
destroyed in such a way that they will not produce water or act as a channel
for the interchange of water.
The objective of California's regulations is to restore as nearly as
possible the subsurface conditions in existence before the well was construct-
ed. To accomplish this objective, the borehole first must be cleared of all
obstacles and, if possible, the casing shall be removed. In unconsolidated
materials, in an unconfined aquifer where ground water is within 15 meters
(50 feet) of the surface, the upper 6 meters (20 feet) of the well shall be
sealed with impervious material and the remainder of the well filled with
sand, clay, or other suitable inorganic material. Where wells penetrate sev-
eral producing zones, sand or clay can be placed opposite the producing zones,
but an impervious plug a minimum of 3 meters (10 feet) in length must be
placed between the zones to prevent the vertical movement of water. Where
wells penetrate creviced or fractured formations, cement or concrete shall be
placed opposite the formation. Where neat cement, cement grout, or concrete
is used, it must be poured in one continuous operation. Where artesian flow
is present, special methods will be used during sealing operations. To as-
sure that the well is filled and that there has been no jamming or "bridging"
of the material, verification shall be made that the volume of material placed
in the well at least equals the volume of the empty hole.
The regulation also describes sealing and fill materials.
Enactment and enforcement of the regulation is up to the counties and
cities of the state. Twenty-nine of 58 counties have enacted these regula-
tions, while 118 of the 411 incorporated cities have adopted the well aban-
donment ordinances. How well these regulations are enforced is unknown, but
can be assumed to vary greatly from county to county, and city to city.
Comments: There is a vast difference in the detail of the
Arkansas and California ordinances for well abandonment as
compared to those of Alabama or Arizona. Most noteworthy
is the fact that procedures for well abandonment are des-
cribed, and that they vary for different subsurface en-
vironments.
COLORADO
Small diameter wells in unconfined materials can be filled with sand
and gravel up to the static water level, then with inert material to within
3 meters (10 feet) of the surface. The top 3 meters (10 feet) shall be filled
with concrete, neat cement, or other approved material. Requirements for
large diameter wells in unconfined aquifers is similar except that inert
fill material shall be used from the water table to the surface, and a per-
manent cover shall be placed on top of the casing.
Water wells completed in confined formations shall be plugged with
concrete, neat cement, or other approved material at the first impervious
strata above each zone and cement grout from the surface to a depth of 3
meters (10 feet).
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The Colorado ordinance permits either a contractor or well owner to
plug an abandoned well.
Comments: When a licensed water well contractor is hired to
plug an abandoned well, the result is generally more satis-
factory than when a well is plugged by an owner who does not
know the proper abandonment procedures. Once a well is filled
or plugged incorrectly, it is difficult to get the owner to
dig it up and plug it properly.
CONNECTICUT
No regulations.
DELAWARE
All wells must be abandoned by a licensed water well contractor. Noti-
fication of an abandoned well must be sent to the Water and Air Resources Com-
mission, who under unusual circumstances may specify special techniques for
well abandonment. In other cases, wells must be filled and sealed with pud-
dled clay or concrete.
DISTRICT OF COLUMBIA
No well abandonment regulations.
FLORIDA
Florida's ordinances are on a par with those of California and Arkansas.
The state specifically designates procedures to be used for abandoning arte-
sian and non-artesian wells. The regulations shall be administered and en-
forced by the Department of Natural Resources and the five Water Management
Districts. During and after abandonment, the enforcing agents can inspect
the well site to insure that proper procedure is or has been followed.
GEORGIA
Abandoned wells must be plugged at the owner's expense. The contractor
must notify the Environmental Protection Division of the State Department of
Natural Resources within 30 days of plugging.
GUAM
A permit is required to abandon a well. The purpose of proper well
abandonment shall be to prevent the interchange of water in different aquifers
and to protect the ground water quality of potable aquifers. All obstacles,
including casing when possible, will be removed before plugging. Where the
well casing cannot be removed, it shall be perforated to permit cement to
enter and form an adequate seal in the annular space. The regulations of Guam
are nearly identical to those of California.
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HAWAII
It is up to the well owner to have a well sealed after it is abandoned
to protect ground water resources against wastage and contamination. In-
spection shall be conducted by persons from the Department of Land and Nat-
ural Resources. All wells shall be abandoned by filling from bottom to top
with neat cement grout. Violation of these regulations is a misdemeanor, and
thus punishable as prescribed by law.
Comment: Hawaii is one of the few states that clearly describes
penalties for failing to comply with state regulations. The
request to have a well filled entirely with neat cement may be
unjustifiable because of economics. In this case, Hawaii would
be better off providing alternative methods of plugging for dif-
ferent conditions encountered.
IDAHO
Wells constructed under Idaho Minimum Well Construction Standards,
where the casing and seal are intact, must, at a minimum, have a 6 millimeter
(0.25 inch) thick steel water-tight plate covering the top of the casing and
welded to the casing. Water wells which have had the casing removed or which
were not constructed in accordance with minimum well construction standards,
upon abandonment shall be filled with cement grout, concrete, or puddled clay.
If the well is artesian, a cement grout, concrete plug, or packer, ap-
proved by the Director, should be placed in the confining stratum overlying
the artesian zone to prevent subsurface leakage from the artesian zone. The
remainder of the well must be filled with cement grout, concrete, or puddled
clay.
Abandoned waste disposal and injection wells constructed in accordance
with Idaho Minimum Well Construction Standards and where the casing and seal
remain intact must, at a minimum, have a steel, water-tight plate fully cov-
ering the top of the casing and welded to the casing. Abandonment procedures
will be specified by the Director at the time authority is requested to aban-
don the disposal well.
ILLINOIS
Water well abandonment regulations are administered by the Illinois
Department of Mines and Minerals. There are separate regulations for aban-
doned water wells and abandoned oil, gas, and salt water disposal wells.
The water well regulations call for removal or tearing of the casing. Neat
cement shall be used from the bottom to the top of the water table; clay shall
then be used to the top of the well. Abandonment is to be done by a certified
contractor.
In unconsolidated formations, sand and gravel shall be used opposite
water yielding zones. Creviced rock formation wells shall be entirely filled
with neat cement. Noncreviced rock formations shall be filled with sand or
gravel with 3 meters (10 feet) of cement or clay at the top. Wells penetrat-
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ing more than one aquifer shall be sealed in such a way that inter-aquifer ex-
change is prohibited. A cement plug not less than 9 meters (30 feet) in length
shall be placed opposite each aquifer. Artesian wells may have to be grouted
under pressure. The state describes recommended procedures for different sit-
uations encountered. After sealing the well, the owner must sign an affidavit
stating that the well has been sealed.
INDIANA
No well abandonment regulations.
IOWA
No state statutes regulating the abandonment of wells.
KANSAS
Kansas provides three different procedures for abandoning wells based
on whether they penetrate confined or unconfined aquifers, or whether they
are test wells.
A well which penetrates an unconfined aquifer shall have its casing
cut off one meter ( 3 feet) below the ground surface. The hole shall then be
filled with natural earth materials to the static water level, and from there
with inert material to within one meter (3 feet) of the surface. The top of
the casing shall be sealed with a concrete or steel plate.
Wells completed in confined and unconfined aquifers shall be abandoned
by cutting off the casing one meter (3 feet) below the land surface, then
plugging with concrete, neat cement or other material to the first impervious
strata above each aquifer, and cement grout from a point one meter (3 feet)
below the surface for a depth of at least 3 meters (10 feet). Natural earth
materials can be used between the plugs.
Test holes shall be plugged within three days after testing with natur-
al earth materials, neat cement, or concrete from bottom to top. Holes pene-
trating two or more aquifers shall be plugged in accordance with the preced-
ing paragraph.
KENTUCKY
Kentucky has no statutes to regulate abandonment of wells.
LOUISIANA
To assure that wells are properly abandoned, their existence must be
reported to the state, and abandonment work must be approved by the state.
Inspection by the Louisiana Department of Public Works can be ordered at any
time to determine if the work has been completed satisfactorily. The con-
tractor in charge is obligated to file a completion form when abandonment
work is finished. To assure that the well is properly sealed and that there
is no bridging of material, it is recommended that the contractor make veri-
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fication calculations and measurements to check that the volume of the mater-
ial placed in the hole at least equals the volume of the casing or the hole
to be filled.
The state can consider a well abandoned if a year or more has passed
since the well has been used, or if the well is seemingly in a state of dis-
repair. A well can be left inactive if properly maintained.
An "abandoned hole" is a borehole that has not been cased. A hole
will be considered abandoned if it has not been used in 30 days.
The well owner is responsible for well abandonment. Failure to comply
with well abandonment procedures will result in action of the Police Jury of
the Parish, which can then have the Department of Public Works notify the
owner that he must have his well properly plugged within 30 days. If the
work order is not followed, then the Department of Public Works can have the
well plugged at the owner's expense.
The well or hole must be plugged by an experienced contractor. The well
shall first be inspected so that the borehole or casing is free of obstacles.
All plugging material shall be implaced under pressure or by circulation.
The surface plug shall be at least 9 meters (30 feet) in length. The well
shall be plugged form bottom to top.
A well less than 15 meters (50 feet) deep shall be plugged completely
with cement slurry, neat cement, or fill material in sufficient amount to
plug the hole and seal the annular space.
If a well is greater than 15 meters (50 feet) in depth and in an area
where one or more fresh water aquifers are penetrated, then either: 1) the
entire well shall be filled from the bottom to the top of the casing with
cement, slurry, or 2) fill material shall be placed in the screen or in the
open hole oppostie the producing aquifer. A bridge plug not less than 15
meters (50 feet) in length shall be set above the top of the screen. The
remainder of the casing below the upper 9 meters (30 feet) shall be filled
with fill material, above which a surface plug will be set.
If one or more saline aquifers are penetrated, the entire well casing
and screen shall be sealed with cement slurry.
Additional but similar special provisions are made for wells which
have had all or part of their casing removed, gravel packed wells, wells in
which multiple zones have been screened, and of augered, bored or dug wells.
Seismic shot holes, cathodic-protection wells, saline-water wells
associated with secondary recovery operation, brine wells, oil and gas wells,
geothermal and geopressured wells, waste disposal wells, and holes and exca-
vations used in the development and/or exploration of mineral resources are
exempt from the preceding regulations. However, owners of such excavations
are still legally responsible for the contamination of potable ground water
resources due to their negligence or if their wells in any way endanger
the health and welfare of the general public.
24
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Comments: Louisiana has one of the nation's most comprehensive
well abandonment regulations. Louisiana Department of Public
Works officials report that contamination from abandoned wells
has been virtually eliminated because of strict enforcement
legislation.
MAINE
The state requires that abandoned wells be filled to prevent accident
or injury to people or animals.
MARYLAND
Maryland requires that abandoned wells be plugged to prevent the inter-
aquifer exchange of water of varying quality. The abandonment of wells is
only permitted by a licensed contractor.
The first step in well abandonment is the removal of all obstacles from
the well, including the casing. If the casing cannot be withdrawn it shall
be perforated to permit the sealing of the annular space. Shallow, small
diameter wells shall be entirely sealed. Sealing involves the use of con-
crete, neat cement, or bentonite clay. Wells in unconsolidated formations
shall have the upper 12 meters (40 feet) sealed; the remainder of the well
shall be filled. The process of filling involves the installation of material
such as clay, silt, and gravel that has been thoroughly disinfected.
If a well penetrates several aquifers, sand or fill shall be placed op-
posite the producing zones and seal material shall be placed opposite the
confining layers. Where a well penetrates creviced or cavernous rock, course
material shall be used to fill the cavity, but sealing material shall extend
from the top of the more competent rock units. A minimum of 3 meters (10
feet) of sealing material is required. Wells in non-creviced consolidated
formations shall have 6 meters (20 feet) of sealing material in the non-cre-
viced formation, and the rest of the well shall be plugged with fill material.
The state requires that all material be placed from the bottom up.
Where cement or concrete is used, its placement should be continuous. After
completion of the plugging, the contractor has 30 days in which to file a
completion form.
Maryland has been unable to suitably enforce these regulations.
MASSACHUSETTS
Massachusetts has no statutes for the regulation of well abandonment.
MICHIGAN
Michigan requires that an abandoned well be filled and sealed by one
of the following methods in accordance with the geological formations pene-
trated. It shall be done in a manner as to prevent the well from acting as
a channel for pollution, or to prevent the escape of subterranean gases.
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A report of the method of sealing shall then be filed with the health
officer.
A well in unconsolidated deposits shall be filled with clean puddled
clay, neat cement grout, or concrete grout.
The section of a well in a cavernous or creviced rock (such as caver-
nous limestone or basalt lava rock, creviced granite, etc.) shall be filled
with concrete or neat cement grout or alternate layers of concrete or neat
cement grout, gravel or stone aggregate. The filling shall be completed at
the top by a layer of neat cement grout or concrete grout extending at least
6 meters (20 feet) above the top of the cavernous rock or to the ground sur-
face.
The section of a well in a sandstone strata shall be filled with neat
cement grout, concrete grout or sand. The filling shall be completed at the
top of the formation by a layer of neat cement grout or concrete grout ex-
tending at least 6 meters (20 feet) above the top of the sandstone or to the
ground surface.
The flow in a flowing well shall be confined and the well filled in
accordance with preceding paragraphs, or the well shall be sealed by pressure
grouting.
Abandonment of wells containing subterranean gases requires special pre-
cautions, and a casing in such a well shall be sealed with neat cement grout
or concrete grout.
Debris or obstructions that may interfere with sealing operations shall
be removed from the we!1.
Screens on nonflowing wells which terminate in the glacial drift shall
be pulled and the casing filled with puddled clay or other approved material
from bottom to top. If the casing is to be pulled, the hole shall be kept
full of the grouting material while the casing is being pulled, adding more
grout from time to time during the process. A few days after the casing is
removed, a visit shall be made to the location to refill the hole after
settling occurs, before final abandonment.
In plugging flowing wells in the drift, the difficulty is inversely
proportional to the depth. In a deep well, a quantity of puddled clay shall
be introduced heavy enough to overcome the flow, then cement shall be placed
on top of the clay. In a shallow well, however, the column of clay fluid is
occasionally not heavy enough to reverse the flow. In that case, a mud pump
shall be used to pump in a high-density mud fluid through a swedged nipple
on the top of the casing. Sometimes in shallow wells with very high heads,
it is necessary to pump in cement mixed with enough chloride or other hard-
ener to set up immediately.
The best way to insure a satisfactory plugging job is to leave the
drive pipe in the hole and fill it with clay, neat cement grout or cement
grout. If water is flowing up the outside of the casing, it is necessary
26
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to "squeeze" cement up around the outside of the casing by pumping it down
the inside. The casing shall remain in the hole when the well is plugged
and be completely filled with grouting material. The casing is filled with
grouting material to reduce corrosion.
Michigan requires that the well owner and contractor share the respon-
sibility for proper abandonment.
MINNESOTA
Minnesota requires that the borehole of an abandoned well be filled in
such a manner as to prevent contaminating materials from entering the water-
bearing formations. All obstacles, debris and, if possible, casing shall be
removed from the borehole. If the casing cannot be removed, it shall be per-
forated. Concrete or cement grout shall be used for sealing material; how-
ever, if the well is so large that the use of these materials is not practi-
cal, the filling materials shall be selected to restore natural conditions
without exceeding the original permeability of the formation. The casing
remaining in the hole shall be cut off 0.6 meters (2 feet) below the surface.
The uppermost 3 meters (10 feet) of casing must be filled with cement or con-
crete grout. The remaining top 0.6 meters (2 feet) of the hole shall be
filled with native top soil. Where concrete, cement grout, puddled clay or
heavy drilling fluid is used for sealing, it shall be inserted in the well
through a grout pipe from the bottom of the well upward to the surface under
pressure, in one continuous operation. Special provision is made for the
sealing of cavernous or creviced rock.
Comments: While Minnesota recommends filling nearly all the
borehole with cement or concrete, it realizes that this pro-
cedure is unfeasible in some cases and provides for filling
some sections with other inorganic material . This is in con-
trast to the state of Hawaii which requires grouting of the
entire well.
MISSISSIPPI
No state statutes regulating well abandonment.
MISSOURI
The state requires that whenever any well is abandoned, it shall be
plugged or sealed as necessary to prevent pollution of subsurface waters.
An affidavit setting forth in detail the significant data in connection
with the well and the procedure of plugging, signed by a qualified witness
to the plugging and duly notarized, shall be filed in duplicate with the
agency within 15 days after plugging is completed, except that upon applica-
tion to and approval by the agency when a number of test holes of any one
person are involved and drilling is on a continuing basis, reports may be
submitted quarterly setting forth the significant hole data and plugging pro-
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cedure. Unless prohibited by the Missouri Clean Water Law, such reports,
upon written request, will be held confidential for one year. The agency
may require the well owner or operator to replug any well where the plugging
was not effective.
Any test hole which is drilled for underground exploration, and which
penetrates into or through any aquifer which is, or may be used for a potable
water supply, shall be plugged. Test holes which do not encounter the potable
water aquifer may be refilled with the same material taken from the hole, or
other non-polluting fill material, except that those drilled just preceding
such active mining in the area, (example, coal mining, limestone quarry, etc.),
do not have to be refilled or plugged until after such active mining has
ceased.
MONTANA
The state of Montana has no statutes to regulate abandoned wells, but
recommends procedures for well abandonment suggested by the Department of
Health and Earth Sciences and the Montana Water Well Driller's Association.
NEBRASKA
The owner of a well is required to make certain that the well is aban-
doned in accordance with the rules and regulations of the Department of Wa-
ter Resources. Written notice of well abandonment shall be provided to the
Department within 60 days.
Wells abandoned previous to the effective date of the regulations are
encouraged, but need not comply with regulations.
Before the borehole is filled, the well shall be checked to see if it
is clear of obstructions. Where applicable, the casing shall be perforated
or otherwise punctured to insure that sealing material fills not only the
well casing, but the annular space and surrounding voids as well.
Wells in an unconfined aquifer shall be abandoned by filling the well
with clean sand or gravel to at least the top of the aquifer. Inert material
shall be implaced in the borehole from the top of the aquifer to within 1.5
meters (5 feet) of the surface. The remaining 1.5 meters (5 feet) shall be
abandoned by:
1) Removing the top 1.5 meters (5 feet) of the casing, capping
the well 1.5 meters (5 feet) below the surface with concrete
at least 10 centimeters (4 inches) thick and filling the re-
mainder of the hole with native soil;
2) Filling the remainder of the cavity with inert material and
installing a permanent water-tight cover at the top of the
casing;
3) Filling the entire borehole with concrete, neat cement, or
other impervious material.
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Where a well penetrates a confined aquifer, the impervious strata shall
be plugged with concrete, neat cement or other approved material. The plug
shall not be less than 1.5 meters (5 feet) in length. The top of the well
shall be filled and capped as described in the preceding paragraphs.
NEVADA
The abandonment of oil, gas or water wells, dry holes and seismic ex-
ploration wells in the state of Nevada is directed by the "Nevada Oil and Gas
Conservation Law and General Rules and Regulations." A notice of intention
must be filed with the Oil and Gas Conservation Commission and approval must
be obtained before work shall commence. The abandoned well shall be plugged
in a manner which will confine all gas, oil and water in the separable strata
originally containing them. Upon completion, a form stating that the work
has been terminated must be filed with the Commission.
NEW HAMPSHIRE
New Hampshire has no state laws regarding well abandonment. It does
require that open wells be fenced or protected to prohibit the danger of in-
jury to people and animals.
NEW JERSEY
The owner of any well in the state shall, upon abandonment of said well
or test hole, notify the Division of Water Resources, Department of Environ-
mental Protection, and they shall effectively seal and fill such wells. The
Division of Water Resources also has the power to order the sealing of any
abandoned well when, in its judgment, the condition of the well endangers or
threatens to endanger the subsurface or percolating waters by intrusion of
salt water or from other causes, or endangers life. The owner of any aban-
doned well who shall fail or refuse to seal it in the time or manner ordered
by the Division shall be subject to a penalty of five hundred dollars for
each violation and fifty dollars per day for each day the violation shall
continue.
To engage in sealing a well, the contractor must be approved by the
Bureau of Water Control of the Division of Water Resources and the operation
must be under the immediate supervision of a licensed New Jersey well driller.
Detailed information is presented pertaining to the procedures to be
followed for abandoning rock wells and wells in unconsolidated formations.
After filling with gravel or concrete, the remaining space at the top of the
well shall then be filled with concrete and the top formed to create a con-
crete slab at least 15 centimeters (6 inches) thick above the top of the cas-
ing with a diameter at least 0.6 meters (2 feet) greater than the outer cas-
ing.
NEW MEXICO
The state requires that in order to plug a shallow well, it shall be
filled to the ground surface or, if the casing is not to be removed, a steel
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plate or cap shall be welded to the casing. Artesian wells and exploration
wells can only be plugged under the supervision of the State Engineer or his
representative, who shall designate the amount of cement to be used and the
depths at which cement plugs snail be set.
Comments: By requiring that only a steel plate or cap be
placed on an abandoned well with casing, New Mexico is ig-
noring the fact that the casing will at sometime in the
future corrode. Thereafter the well may serve as a conduit
for contaminants to enter the aquifer.
NEW YORK
The New York State Department of Environmental Conservation has been
delegated the authority to regulate the abandonment of wells. Only Long Island
is required to abide by these regulations. The regulations that have been
adopted are based on the American Water Works Association Standard for Deep
Wells No. A 100-66 (See Appendix B).
NORTH CAROLINA
The well shall be inspected and all obstacles inside shall be removed.
Prior to sealing, the well will be chlorinated. Bored wells shall be complete-
ly filled with cement grout or dry clay. Wells drilled in unconsolidated for-
mations shall be completely filled with cement grout. Wells constructed in con-
solidated formations may be filled with sand or gravel opposite the zones of
consolidated rock. The top of the sand and gravel shall be at least 1.5 meters
(5 feet) below the top of the consolidated rock. The remainder of the well
shall be filled with cement grout. The owner of the well shall be responsible
for abandonment except when agreed upon in a written contract with a driller,
or when abandonment is the result of drilling in an improper location, or the
driller fails to comply with the provisions of the contract between he and the
owner.
Comments: North Carolina requires that the well be disinfected
before sealing. This is an extremely valuable requirement that
is often neglected in state well abandonment regulations. Un-
fortunately, the statute is still not thorough enough. Not only
should the well be disinfected before sealing, but all materials
placed in the well and all tools used in the abandonment process
should be sterilized.
NORTH DAKOTA
The state requires that all abandoned wells shall be sealed by restoring
as far as possible the geological conditions that existed before the well was
drilled. Requirements and procedures for well abandonment have been adopted
from the American Water Works Association Standard No. A 100-66 (See Appendix B).
OHIO
The Ohio Environmental Protection Agency is charged with the authority to
write legislation and enforce abandoned well regulations. All abandoned wells
and test holes shall be either completely filled with grout or such other mater-
ials as will prevent contaminants from entering ground water, or shall be main-
tained in strict compliance with all applicable requirements of Ohio EPA "Modi-
fication and Maintenance of Wells." The enforcement of well abandonment regu-
lations is handled on a request or complaint basis through Ohio EPA, or is
covered under various county regulations,
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OKLAHOMA
The owner of a well is responsible for its abandonment. Notification
of well abandonment is required and plugging shall be supervised by a state
representative. The well shall be plugged in a manner that will prevent the
migration of fluids between formations. All liquids shall be displaced from
the well and the well shall be filled with drilling mud. Any uncovered hole
below the shoe of any casing to be left in the well shall be filled with ce-
ment to a depth of at least 15 meters (50 feet) above the shoe of the casing.
The well bore shall be filled with cement from the base of the screen or liner
to a point at least 15 meters (50 feet) above the liner or screen. All fresh
water zones encountered in the well shall be sealed off and protected by ade-
quate casing extending from a point at least 15 meters (50 feet) below the
base of the lowest fresh water zone to within one meter (3 feet) of the top
of the well bore and by completely filling the annular space behind such cas-
ing with cement.
If the surface or other casing in the well meets these requirements, a
cement plug may be set at least 15 meters (50 feet) below the shoe of the
casing to extend at least 15 meters (50 feet) above the shoe of the casing.
If the casing and cement behind the casing do not meet the requirements of
this subsection, the well bore shall be filled with cement from a point 15
meters (50 feet) below the base of the lowest fresh water zone to a point 15
meters (50 feet) above the shoe of the casing. The well bore shall, in all
events, be filled with cement from a point one meter (3 feet) below ground
surface to a point 10 meters (33 feet) below ground surface. All intervals
between cement plugs in the well bore shall be filled with mud. Any "rat" or
"mouse" hole used in the drilling of a well with rotary tools shall be filled
with mud to a point 2.5 meters (8 feet) below ground level and with cement
from such a point to a point one meter (3 feet) below ground level and then
shall be filled in with earth above the top of the cement. The top of the
plug of any plugged well shall show clearly by permanent markings, whether
inscribed in the cement or on a steel plate embedded in the cement, the well
number and date of plugging.
Within 15 days after a well has been plugged, the owner or operator
shall file a plugging record in duplicate with the Board. If a complete and
correct log of the well is not on file with the Board, then the owner at the
time of plugging shall furnish and file a complete and correct log thereof
or the best information available. The well bond will be released only when
the requirements of this rule have been met.
OREGON
Oregon's Water Resources Department has adopted the well abandonment
procedures contained in the Manual of Recommended Water Well Construction
Standards, prepared by the National Water Well Association for the Environ-
mental Protection Agency (See Appendix A).
Comments: Oregon has found that policing and enforcement of
the well construction standards is very difficult, particularly
in the placement of adequate casing seals. Usually, it is not
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possible to have the well inspector available at the drilling
site at the precise moment when the casing and well grouting
procedures are performed.
PENNSYLVANIA
The Commonwealth of Pennsylvania has revised their well abandonment
regulations to conform to the recommended procedures described by the National
Water Well Association for the Environmental Protection Agency (See Appendix
A).
RHODE ISLAND
The Rhode Island Department of Health requires that only public supply
wells be abandoned following American Water Works Association Standard No.
A 100-66 (See Appendix B).
SOUTH CAROLINA
South Carolina has no regulations governing abandonment of wells. How-
ever, when a ground water contamination problem results from an abandoned
well, the department of Health and Environmental Control recommends that the
procedures be utilized as outlined in the Manual of Recommended Water Well
Construction Standards, as prepared by the National Water Well Association in
conjunction with the Environmental Protection Agency (See Appendix A).
SOUTH DAKOTA
Abandoned wells will be plugged using methods and material specified by
the Water Rights Commission. Each abandoned well is handled on an individual
basis so there are no written plugging procedures. An abandoned well is to
be plugged in a manner that will prohibit leaking of its water underground or
over the surface, and inhibit inter-aquifer exchange.
TEXAS
The Texas Water Development Board has the authority to regulate and en-
force well abandonment. The Board requires that the landowner or person hav-
ing the well drilled shall be charged with the responsibility of having the
well sealed.
In the event undesirable water is encountered in a zone overlying a
fresh-water zone, the well shall be filled with cement to the land surface; or
cement shall be placed opposite the fresh-water zone to some distance above
the uppermost fresh-water zone and the remainder of the hole filled with
heavy mud to form a base for a cement plug, which shall extend from some dis-
tance below the undesirable water zone to the land surface or some distance
above the undesirable water zone, and the remainder of the hole filled with
heavy mud. The method used to plug the hole shall be selected based on the
condition of the borehole, lithology of the section penetrated, or the hydro-
static pressures in the aquifers.
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In the event undesirable water is encountered in a zone underlying a
zone of fresh water, the well shall be filled with cement to the land surface;
or the lower part of the well shall be filled with find sand, clay or heavy
mud to form a base for a cement plug which shall be placed opposite the fresh-
water zone, extending from below the fresh-water zone to the land surface or
extending from below to some distance above the fresh-water zone and the re-
mainder of the hole filled with heavy mud; or cement shall be placed opposite
the undesirable water zone and extending upward to the base of the lowermost
fresh-water zone, or to some distance above the undesirable water zone and
the remainder of the hole filled with heavy mud. The method used to plug the
well shall be selected based on the condition of the well bore, lithology of
the section penetrated, or the hydrostatic pressures in the aquifers.
When an existing water well is deepened and encounters undesirable water,
the zone contributing undesirable water to the deepened well shall be isolated
from the well bore by cement extending to the land surface, or to the base of
the lowermost fresh-water zone, or to some distance above the undesirable wa-
ter zone. The method selected shall be based on the condition of the well-
bore, lithology of the section penetrated or the hydrostatic pressures in the
aquifers.
In the event that the use of a well penetrating an undesirable water
zone is permanently discontinued, all of the casing shall be removed from the
well and the well plugged in accordance with Water Development Board Rules
discussed in the three preceding paragraphs; or the casing below, opposite
and above the undesirable water zone perforated and squeeze-cemented, to con-
fine the undesirable water to its zone of origin and the well filled with
heavy mud; or all porous zones encountered in the drilling of the well shall
be squeeze-cemented and the entire well bore filled with heavy mud.
All sand point wells drilled or driven for the purpose of producing
fresh water which encounter undesirable water shall be filled from total depth
to the land surface with cement or heavy mud.
In the event an uncased well is plugged in such a manner that cement
does not extend to the land surface, the uncemented part of the well bore shall
be filled with mud and the well capped with a cement plug at or near the land
surface in such a manner as to prevent the entrance of surface water, or other
materials and objects, into the well. The capped part of the well shall be
capable of supporting a static weight of 226.8 kilograms (500 pounds).
In the event a well equipped with casing at the land surface is plugged
in such a manner that cement does not extend to the land surface, the outer-
most casing shall be fitted with a water-tight cap, at or near the land sur-
face and the annular space between the casing and the wall of the borehole
filled with cement in such a manner as to prevent the entrance of surface wa-
ter, or other materials and objects, into the well. The well so capped must
be capable of supporting a static weight of 226.8 kilograms (500 pounds).
Comments: The Texas Water Development Board is in charge of
enforcing the well abandonment regulations. When the Board
receives a request to have a well abandoned, it will make
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recommendations on how the well shall be plugged on an
individual basis. Recommendations are based on information
furnished in the Board's files or information furnished by
the well owner. The well construction data is then exam-
ined with the available geological and hydrological infor-
mation. If such data is not present or is not sufficient,
then field investigations are conducted in order to make
proper recommendations to prevent pollution of the water.
By considering each well abandonment case individually,
coupled with an excellent outline of well abandonment
procedures, the state has been effective in reducing po-
tential ground water contamination from abandoned wells.
TENNESSEE
The state of Tennessee requires that test wells and ground water sources
which are not in use shall be sealed by methods which will restore the control-
ling geological conditions that existed before the wells were constructed.
The purpose of sealing the wells is to prevent exchange of water from one
geologic strata to another. The well should be filled with material which
shall prevent contamination of the ground water. Concrete is the preferred
fill material.
UTAH
The Office of the State Engineer regulates well abandonment. The state
requires that the abandoned well shall be filled in a manner to prevent the
well from becoming a channel through which fluids can migrate vertically and
become a possible source of contamination to fresh ground water supplies.
The well casing shall be removed during abandonment. As the casing is
being withdrawn, the well shall be plugged with cement grout, concrete or pud-
dled clay. All gravel-packed wells shall be pressure-grouted throughout the
perforated sections of the well casing. The remainder of the well shall be
filled with cement grout, concrete or puddled clay. Procedures for abandon-
ment of drilled and jetted wells is similar to that of gravel-packed wells.
Abandonment of artesian wells should be done by placing cement grout or con-
crete plugs in the confining stratum overlying the artesian zone to prevent
subsurface leakage from the artesian zone. The remainder of the well shall
be filled with cement grout, concrete, or puddled clay. A contractor who
fails to abide by state regulations may have his license revoked.
VIRGINIA
The Virginia Department of Health and the Virginia State Water Control
Board require that abandoned wells be sealed by methods which will restore the
controlling geological conditions that existed before the construction. All
abandoned wells shall be sealed to prevent exchange of water from one geologi-
cal strata to another. The abandoned wells shall be filled with material
which will prevent contamination of ground water. Concrete is the preferred
material.
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WASHINGTON
The state requires that all abandonment procedures be recorded and re-
ported to the state. The remainder of the state's regulations are nearly
identical to that of the state of Utah.
WEST VIRGINIA
West Virginia requires that only abandoned oil and gas wells be plugged.
There is no legislation regulating water wells or boreholes.
Before an oil or gas well can be plugged or abandoned, the owner must
acquire a permit or verbal permission from the Division of Oil and Gas of the
Department of Mines. In addition, a bond or approved security must be filed
before a plugging operation can begin.
The state requires all oil and gas wells be abandoned in a manner that
will prevent migration of oil, gas, water (fresh or salt) or any injected li-
quid or gas to any strata other than the stratum or strata in which they oc-
cur or have been placed. Only non-porous materials shall be used as plugs.
Upon completion of the plugging operation, a report of the procedure must be
filed with the Division of Oil and Gas.
WISCONSIN
The state of Wisconsin, Department of Natural Resources, requires that
when a well is permanently abandoned, the owner must fill and seal the well
in such a manner as to prevent it from acting as a channel for contamination
or vertical movement of water by one of the following methods:
1) Wells in drift or unconsolidated formations shall be filled with
concrete or clean puddled clay in which case at least a 6 meter (20 foot)
plug of concrete shall be poured at the top of the well. If possible, the
inner well casing shall be removed. The top 2 meters (7 feet) of curbing in
dug wells shall be removed prior to plugging.
2) In limestone strata, wells shall be filled entirely with concrete.
As an alternative, layers of concrete and gravel or stone aggregate can be
used, except for the top 6 meters (20 feet) of the well, which must be filled
with concrete. An exception to this may be made where the well casing is set
in rock and sealed in place with cement grout, in which case a concrete plug
shall be placed extending at least 6 meters (20) feet above and below the bot-
tom of the casing. The remainder of the cased portion up to 6 meters (20
feet) shall also be filled with concrete.
3) Sandstone formations shall be filled with concrete. As an alterna-
tive, disinfected sand or pea gravel may be used except that the top 6 meters
(20 feet) of the formation, and the entire cased portion, shall likewise be
filled with concrete.
4) Shale rock, granite and quartzite formation wells use the same pro-
cedure as with limestone formation wells.
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5) Where formations are variable, the limestone, sandstone, shale,
granite and quartzite strata shall be filled in compliance with preceding
sections, providing concrete or concrete grout plugs at least 12.2 meters
(40 feet) in depth, extending at least 6 meters (20 feet) above and below
the point of surface contact between every recognized different geologic
formation—where the alternative methods to filling the well entirely with
concrete are selected.
6) Procedures for plugging flowing wells are the same as above for the
same strata except that all cement grouts must be emplaced under pressure.
A report shall be made to the department by the owner of every well
which has been permanently abandoned or temporarily removed from service.
Such reports shall include a detailed description of location, construction
and geologic features, and method of sealing. Wisconsin has penalties to deal
with contractors who fail to comply with teh above regulations, but there is
no inspection program.
WYOMING
The state of Wyoming has the following provisions in its regulations for
water well abandonment.
1) It is the responsibility of the well owner to properly care for a
well when it is not being used to supply water for beneficial use. It is the
responsibility of the driller to properly fill and seal (destroy) any test
well not converted into a permanent water well.
2) When a well is temporarily removed from service, it shall be kept
in a state of good repair. The top of the well shall be sealed with a water-
tight cap or seal to prevent the entrance of pollutants.
3) When any well, including any test well, is to be permanently removed
from service, it shall be destroyed, to prevent the well from becoming a chan-
nel that allows vertical movement of water or that allows contamination of the
ground water supply. An uncased well shall be destroyed by filling it com-
pletely with grout, cement or concrete grout, drilling mud, or bentonite.
4) A cased well in unconsolidated formations shall be destroyed by
placing cement or concrete plugs opposite all perforations or screens. The
rest of the well shall be filled with grout, cement or concrete grout, drill-
ing mud, or bentonite.
5) A well in consolidated formations shall be destroyed by filling it
with grout, cement or concrete grout, drilling mud, or bentonite. Any section
of the well intersecting cavernous or creviced rock shall be filled with con-
crete or cement grout, or alternate layers of cement grout and gravel or stone
aggregate. A concrete or cement plug shall extend to at least 3 meters (10
feet) above the cavernous zone and 3 meters (10 feet) below the cavernous
zone or to the bottom of the well, whichever distance is less.
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6) An artesian well shall be destroyed in such a manner that a cement
or concrete plug completely seals the artesian aquifer and extends above the
artesian zone for a minimum of 3 meters (10 feet). This seal shall also ex-
tend 3 meters (10 feet) below the artesian zone or to the bottom of the well,
whichever distance is less. If necessary to stop surface or subsurface leak-
age from the artesian zone, the entire zone shall be pressure-grouted. The
remainder of the well shall be filled with grout, cement or concrete grout,
drilling mud, or bentonite.
7) A gravel packed well shall be destroyed by pressure-grouting the
entire perforated or screened section of the casing. The remainder of the
well shall be filled with grout, cement or concrete grout, drilling mud, or
bentonite.
Any hole drilled for mineral exploration shall be capped upon abandon-
ment. In addition, all such holes shall be located to the nearest 61 meters
(200 feet) and their existence shall be made known to the state engineer.
The plugging of an abandoned mineral exploration hole shall be done in
a manner similar to the procedure for water wells. Any person or company who
fails to comply with Wyoming regulations is guilty of a misdemeanor punishable
by not more than 90 days in jail or a fine of not more than $5,000 or both.
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BIBLIOGRAPHY
Bennett, R. R. and Meyer, R. R. "Geology and Ground Water Resources of
the Baltimore Area." Maryland Natural Resources, Department of Geology.
Mines and Water Resources Bulletin 4. 1952.
Bond, E. W. "A Study of the Influence of Seismic Shotholes on Ground Water
and Aquifers in Eastern Montana." Bureau of Mines and Geology, Special
Publication 67. 1975. 87 pp.
Burnitt, S. C., et. al. "Reconnaissance Survey of Salt Water Disposal in
the Mexia, Negro Creek, and Cedar Creek Oil Fields, Limestone County,
Texas." Texas Water Commission Memorandum Report 62-02. 1962. 27 pp.
Burnitt, S. C. "Reconnaissance of Soil Damage and Ground Water Quality,
Fisher, County, Texas." Texas Water Commission Memorandum Report 63-02.
1963. 49 pp.
Crain, J. "Ground Water Pollution from Natural Gas and Oil Production in
New York." New York State Water Resources Commission Report of Investi-
gaion No. RI-5. 1969. 15 pp.
Fink, B. E. "Investigation of Ground-and Surface-Water Contamination near
Harrold, Willbayer County, Texas." Texas Water Commission Report LD-
0365. 1965. 23 pp.
Hopkins, H. T. "The Effect of Oilfield Brines on the Pothole Ground Water in
the Upper Big Pitman Creelo Basin, Kentucky." Kentucky Geological Sur-
vey Report of Investigation 4. Section X. 1963. 36 pp.
Jorgensin, D. G. "An Aquifer Test Used to Investigate a Quality of Water Ano-
maly." Ground Water. Vol. 6, No. 6. Nov. - Dec. pp. 18-20.
Miller, D. W., DeLuca F. A., and Tessier, T. L. "Ground Water Contamination
in the Northeast States." U. S. Environmental Protection Agency. EPA-
600/2-74-056. 1974. 325 pp.
Payne, R. D. "Saltwater Pollution Problems in Texas." Journal of Petroleum
Technology. Vol. 8. October, pp. 1401-1407.
Preston, R. D. "Occurrence and Quality of Groundwater in Shakelford County,
Texas." Texas Water Development Board Report 100. 1969. 48 pp.
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Rold, J. W. "Pollution Problems in the 'Oil Patch1." American Association
Petroleum Geologists Bulletin. Vol. 55, No. 6. June, 1971. pp. 807-
809.
Sayre, A. N. "Geology and Ground Water Resources of Duval County, Texas."
U.S.G.S. Water Supply Paper 776. 1937. 116 pp.
Scalf, M. R., Keeley, J. W., and LaFevers, C. J. "Ground Water Pollution in
the South Central States." EPA R2-73-268. June, 1973. 181 pp.
Thompson, D. G. "Ground Water Supplies of the Atlantic City Region." New
Jersey Department of Conservation and Development Bulletin 30. 1928.
U.S. Department of Health, Education, and Welfare. "Proceedings of 1961
Symposium, Ground Water Contamination." Technical Report W61-5. 1961.
U.S. Environmental Protection Agency. "Ground Water Pollution from Subsur-
face Excavations." EPA-430/9-73-012. 1973. 217 pp.
U.S. Environmental Protection Agency. Manual of Water Well Construction
Practices. EPA-570/9-75-001. 1975. 156 pp.
U.S. Environmental Protection Agency. A Manual of Laws, Regulations, and
Institutions for Control of Ground Water Pollution. EPA-440/9-76-006.
1976. 316 pp.
Wait, R. L., and McCollum, M. J. "Contamination of Fresh Water Aquifers
Through an Unplugged Oil-Test Well in Glynn County, Georgia." Georgia
Geological Survey Mineral Newsletter. Vol. 16, No. 3-4. 1963. pp. 74-
80.
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APPENDIX A
PERMANENT WELL AND TEST HOLE ABANDONMENT
From: Manual of Water Well Construction Practices, U. S. Environmental
Protection Agency, Office of Water Supply, EPA-570/9-75-001
PREAMBLE
Unsealed abandoned wells constitute a hazard to public health, safety,
welfare, and to the preservation of the ground water resource. The sealing
of such wells presents a number of problems, the character of which depends
upon the construction of the well, the geological formations encountered, and
the hydrologic conditions. To seal an abandoned water well properly, several
things must be accomplished: 1) elimination of a physical hazard; 2) pre-
vention of ground water contamination; 3) conservation of yield and mainte-
nance of hydrostatic head of aquifers; and 4) prevention of the intermingling
of desirable and undesirable waters.
The basic concept governing the proper sealing of abandoned wells is
the restoration, as far as feasible, of the hydrogeologic conditions that
existed before the well was drilled and constructed, for an improperly aban-
doned well might serve as an uncontrolled invasion point for contaminated and
polluted water. Any well that is to be permanently abandoned should be com-
pletely filled in such a manner that vertical movement of water within the
well bore, including vertical movement of water within the annular space sur-
rounding the well casing, is effectively and permanently prevented and the
water is permanently confined to the specific zone in which it originally
occurred. If all these objectives can be accomplished, all the rules for
sealing wells heretofore presented will be fulfilled.
To seal an abandoned well properly, the character of the ground water
must be considered. If the ground water occurs under unconfined or water-
table conditions, the chief problem is that of sealing the well with imper-
meable material so as to prevent the percolation of surface water through the
original well opening, or along the outside of the casing, to the water table.
If the ground water occurs under confined or artesian conditions, the sealing
operation must confine the water to the aquifer in which it occurs -- thereby
preventing loss of artesian pressure by circulation of water to the surface,
to a formation containing no water, or to one containing water under a lower
head than that in the aquifer which is to be sealed.
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Preparation for Abandonment
Strong efforts should be made to remove all materials from a well which
may hinder its proper abandonment. This is especially important where speci-
fied zones must be sealed.
If a screen has been installed in the well by telescoping, its recovery
is usually possible by installing a string or fishing casing from the top of
the well to a sand hitch placed close to the bottom of the screen. Following
the setting of the sand hitch, a lifting force, applied either by mechanical
or hydraulic jacks, or multiple pulling lines from the casing reel of the
drilling machine, will usually withdraw the screen from the well.
In recovering steel casings extending to the surface, the least expen-
sive and least hazardous method is to apply a lifting force to the casing by
the use of jacks, or with the drilling machine, or with the two in combination.
Still more effective is the use of a jarring head applied at the top of the
casing string and used in combination with lifting devices.
Maximum recovery is usually obtained by using a trip-type casing spear
actuated by a fishing cable tool string and used in combination with lifting
devices. The trip spear is usually limited in its use to recently drilled
wells or to those in which the casing is known to be in sound condition. The
risk of failure associated with the use of a casing spear increases with the
age of the well and the depth at which it is to be used.
It is always good practice to probe the well with a swage of the same
diameter as the spear prior to inserting the latter.
The order of descent into the casing for a trip spear string of tools
is: 1) trip spear; 2) fishing jars; 3) sinker bar of drill stem; 4) rope
socket, which is attached to the drilling line. The swage would replace the
spear in the above string of tools.
Abandonment
Borehole Bridging --
To reduce cost of unnecessary backfilling of long sections of borehole,
it is often desirable to establish a temporary bridge in the borehole upon
which a permanent cement-based bridge can be placed. No organic materials
should be used in either the temporary or permanent bridge—except that spe-
cially manufactured devices such as cement plugging tools in which neoprene
rubber or plastics are used, are acceptable and those greatly facilitate the
work. Some of these devices permit establishing the permanent bridge without
first having to set a temporary one.
Abandonment of Flowing Artesian Wells --
The flowing artesian well with improperly sealed casing and with water
escaping around the outside of the casing either to the surface or to another
formation presents a special problem. A necessary first step in bringing the
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flow under control is to establish a permanent cement seal between the casing
and the point or points from which the water is escaping.
In order to place this seal effectively, the flow must be stopped and
the water level lowered in the well. This can be accomplished by several
methods. Some of these are: 1) pumping the problem well, thereby producing
the necessary drawdown; 2) pumping nearby wells, producing the same effect;
and 3) introducing high specific gravity fluids at the bottom of the borehole
and filling the hole with the fluid until all flow ceases. The method or
methods used will depend in part on the shut-in pressure of the well and the
depth to which the water level must be lowered.
The sealing of abandoned wells that have a large movement of water be-
tween aquifers or to the surface requires special attention. The movement of
water may be sufficient to make the sealing with ordinary metarials and by the
usual methods impractical. In such wells, large stone aggregates (not more
than 1/3 of the diameter of the hole), lead wool, steel shaving, a well pack-
er, or cast lead plug or bridge should be used to restrict the flow thereby
permitting the placement of appropriate sealing material. If preshaped or
precast plugs are used, they should be several times larger than the diameter
of the well to prevent tilting. The flow of artesian wells to be abandoned
can best be stopped with neat cement or sand-and-cement grout piped under pres-
sure or, in some instances, by the use of a suitable well packer or cast lead
plug placed at the bottom of the confining formation immediately overlying the
artesian water-bearing zone.
In wells in which the hydrostatic head producing the flow is low and in
which there is no escape of water below ground, the movement of water can be
arrested by extending the well casing to an elevation above the artesian pres-
sure surface. This permits the placement of sealants and fill materials, af-
ter which the casing may be cut off at or below ground level.
Abandonment of Other Borings and Holes ~
Mineral exploration holes, solution or "in situ" mining wells, dewater-
ing wells, temporary service wells, construction water wells, process wells,
and/or other structures that affect the withdrawal from or quality of water
in the ground water reservoir, regardless of location or intended life of the
structure or hole, should be abandoned as described herein for water supply
wells.
Functions of Seals --
Three basic types of seals -- distinguished by their functions -- may
be used in a properly abandoned well. They are:
A. Permanent Bridge-Seal: The deepest cement seal to be placed
in the well, this seal serves two purposes: it forms a per-
manent bridge below which a considerable volume of unfilled
hole may remain and upon which fill material may be safely
deposited; and it seals upper aquifers from any aquifer(s)
which may exist below the point of sealing (See Fig. 1).
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CD
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B. Intermediate Seal: This seal is placed between water-bearing
formations which have, or are believed to have, different
static heads. Its function is to prevent the inter-aquifer
transfer of water (See Fig. 2).
C. Seal at Uppermost Aquifer: This seal is placed immediately
above the uppermost aquifer penetrated by the bore hole.
Its function is to seal out water from the surface and from
shallower formations. In flowing artesian wells, it is de-
signed to prevent the escape of water to the surface, or to
shallower formations (See Fig. 3).
Each abandonment effort should be considered an individual problem, and
methods and materials should be selected only after detailed study of both
construction and hydrogeology. Whenever there is doubt about either the con-
struction or the hydrogeology involved, the choices of materials and procedures
should be those affording the greatest probability for successful sealing.
AQUIFER SEALING CRITERIA
56.100-000-000 Aquifer Sealing Criteria: Aquifers shall be filled with
disinfected, dimensionally stable materials, compacted mechanically if neces-
sary to avoid later settlement. (Cement, cement-and-sand, and concrete do
not require disinfectionT)
Disinfection of aquifer fill materials shall be accomplished by using
chlorine compounds such as sodium hypochlorite or calcium hypochlorite. Aqui-
fer fill materials shall be clean (relatively free of clays and organic mater-
ials) before placement in the well. Disinfection shall be accomplished by
dissolving sufficient chlorine compound to produce a calculated concentration
of at least 100 mg/1 available chlorine in double the volume of water in the
well. The fill material shall be placed in the well after the water in the
well has been so treated.
PERMANENT BRIDGES
56.010-000-000 Permanent Bridges: Permanent bridges may be used to avoid hav-
ing to fill very deep holes below the deepest point at which a permanent seal
is required. Permanent bridges shall be composed only of cement or cement-
bearing minerals. The cement shall be allowed to harden for at least 24 hours,
if Type I cement is used, or for at least 12 hours if Type III (highly early
strength) cement is used, before backfilling is continued. Temporary bridges
used to provide a base for the permanent bridge shall consist only of inor-
ganic materials--except those patented devices containing expandable neoprene,
plastic, and other elastomers, which are specifically designed and accepted
for use in well construction.
PLACEMENT OF GROUT
56.001-000-000 Placement Operations: Concrete, sand-and-cement grout, or cem-
ent grout used as a sealing material in abandonment operations shall be intro-
duced at the bottom of the well or interval to be sealed (or filled) and
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DISINFECTED SAND AND GRAVEL
(OR SAND-ANO-CEMENT) BACKFILL
CASING RIPPED AT LEAST 10FT. QM.l
POR NEAT CEMENT SEAL
Figure 2. Intermediate Seals.
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placed progressively upward to the top of the well. All such sealing materials
shall be placed by the use of grout pipe, tremie, cement bucket or dump bailer,
in such a way as to avoid segregation or dilution of the sealing materials.
Dumping grout material from the top shall not be permitted.
Seals intended to prevent vertical movement of water in the well or
bore hole shall be composed of cement, sand-and-cement, or concrete — except
that where such seals must be placed within casings or liners, only neat ce-
ment or grout may be used. The cement-water ratio shall be that specified
in Article 48.100-000-000. Cement seals shall be placed by means of pumping
through drop-pipe or by use of a dump-bailer, with placement beginning at the
bottom and continuing upward. The minimum cement seal length, wherever dimen-
sions permit, shall be 3 meters (10 feet).
56.002-000-000 Intermediate Seals: Intermediate seals of cement, sand-and-
cement, or concrete shall be placed in impermeable strata between aquifers
which are identifiable as, or are suspected of being, hydraulically separated
under natural, undisturbed conditions. Once the required cement seal has been
installed, the remainder of the impermeable zone or non-producing zone between
aquifers shall be filled with sand, sand and gravel, or cement-bearing mineral
material.
56.003-000-000 Seal at Uppermost Aquifer: A cement, sand-and-cement, or con-
crete seal shall be installed in the least permeable zone immediately above
the uppermost water-producing zone. Such seals shall be placed only in quies-
cent (non-flowing) water. [See Preamble (56.) for instructions on how to seal
flowing wells.]
56.004-000-000 Seals Placed Within Casing, Liners. Filters, etc.: Seals which
must be placed in casing, liners, or filters require special attention. The
material between the well and the face of the bore hole shall be thoroughly
perforated, ripped, or otherwise disintegrated as the necessary first step.
Neat cement only, or neat cement with a maximum of 5 percent by weight of com-
mercially processed bentonite clay, shall be used as the seal. Either of two
methods may be used.
1) The calculated amount of grout required to fill the well interval
plus the annular space outside the lining shall be placed within
the space to be cemented, running the cement through a special
cementing packer manufactured for this purpose and installed im-
mediately above the perforated or ripped zone. The cement shall
be injected at a pressure calculated to be at least 3.5 Kg/cm^
(50 psi) greater than the normal hydrostatic pressure within the
well at the point of injection.
2) The calculated amount of cement grout required to fill the casing
interval plus the annular space outside the lining, plus suffi-
cient cement grout to fill an additional 3 meters (10 feet) of
the lining, shall be introduced at the bottom of the interval
to be cemented.
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PLACEMENT OF FILL
56.000-100-000 Non-Producing Zones; Non-producing zones below the top of the
uppermost aquifer shall be filled with dimensionally stable materials such as
sand, sand-and-gravel, cement, cement-and-sand, or concrete. Non-producing
zones above the uppermost aquifer seal shall be filled with materials less
permeable than the surrounding undisturbed formations. The uppermost 1.5 me-
ers (5 feet) of the bore hole (at land surface) shall be filled with a material
appropriate to the intended use of the land.
SPECIAL CONDITIONS
56.000-010-000 Pre-Existing Contamination: An abandoned well which has already
been affected by salt water intrusion or any other contaminants shall be con-
sidered a special case, and the method of filling and sealing such wells shall
be subject to individual review and written approval by the regulatory agency
involved.
In the sealing of a double or multiple cased well, the CONTRACTOR shall
submit a drawing thereof with a description of the proposed procedure and
materials to be used, for prior approval by the regulatory agency involved.
Mineral exploration holes, solution or "in situ" mining wells, dewater-
ing wells, temporary service wells, construction water wells, process wells,
and/or other structures which affect the withdrawal or quality of ground wa-
ter, or the elevation of the water table, regardless of location or intended
length of life of the structure, shall be abandoned according to standards and
minimums as described herein for water supply wells.
WELL ABANDONMENT RECORDS
56.000-001-000 Recording Location of Abandoned Well or Bore Hole: Before
equipment is removed from the site, the exact location of the abandoned well
or hole shall be determined and recorded, "tying in" the location with per-
manent reference points, or as prescribed by the state or local regulatory
agency. All information relative to the abandonment procedures'and the loca-
tion of the abandoned well shall be prepared and assembled as prescribed by
the state or local regulatory agency, with copies supplied to the respective
agency and the owner of the land.
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APPENDIX B
From: American Water Works Association Standard for Deep Wells
American Water Works Association Standard No. Al00-66
Section Al-13: Sealing Abandoned Wells
Section A1-13.1 - General: Unsealed abandoned wells constitute a hazard to
public health and welfare. The sealing of such wells presents a number of
problems, the character of which depends upon the construction of the well,
the geologic formations encountered, and the hydrologic conditions. To seal
an abandoned water well properly, several factors must be considered: 1) eli-
minating physical hazard; 2) preventing contamination of ground water; 3) con-
serving yield and hydrostatic head of aquifers; and 4) preventing intermingl-
ing of desirable and undesirable waters.
The guiding principle to be followed in the sealing of abandoned wells
is the restoration, as far as feasible, of the controlling geological condi-
tions that existed before the well was drilled or constructed. If this re-
storation can be accomplished, all the objectives of sealing wells heretofore
presented will be adequately fulfilled.
To seal an abandoned well properly, the ground water conditions at the
particular well to be sealed must be recognized and evaluated. Thus, if the
ground water occurs under water table conditions, the well must be sealed with
impermeable material to prevent the percolation of surface water through the
original well opening or along the outside of the casing to the water table.
If the ground water occurs under artesian conditions, the driller should be
equipped to remove obstructions interfering with sealing operations and to
provide for placing the sealing materials in the most effective manner. The
sealing operations must confine the water to the aquifer in which it occurs--
thereby preventing loss of artesian pressure by circulation of water to the
surface--to a formation containing no water, or to one containing water under
a lower head than that of the aquifer being sealed.
Usually a well should be checked before it is sealed, to insure freedom
from obstructions that may interfere with effective sealing operations. This
check is especially important in wells that may conduct contaminated or other-
wise objectionable water into aquifers yielding potable waters. Removal of
liner pipe from some wells may be necessary to assure placement of an effect-
ive seal. If liners or casings opposite water-bearing zones cannot be read-
ily removed, they should be split with a casing ripper to assure the proper
sealing of water-bearing zones with the sealing material. At least the upper
portion of the casing should be removed to prevent surface water from enter-
ing the water-bearing strata by following down the casing. This operation is
not always essential if the annular space around the outside of the casing
was cemented when the well was drilled.
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Concrete, cement grout, or neat cement, when used as a sealing material
below the water level in the well, should be placed from the bottom up by
methods that will avoid segregation or dilution of material. Piping cementing
materials directly to the point of application or placement by means of a dump
bailer or tremie is recommended. Other sealing materials referred to here-
after, except mud-laden or special clay fluids, can, as a rule, be gradually
introduced into the top of the well.
Employment of a competent well driller to accomplish sealing of a deep
or flowing well or one in a creviced formation is usually advisable. His
knowledge of well construction and the geologic conditions of the region will
be valuable in the proper abandonment of a well, just as it is in the construc-
tion of a new well. It may be advantageous to call in a consulting engineer
or a representative of the state health department or other department having
jurisdiction.
The recommendations contained herein pertain to wells in consolidated
and unconsolidated formations, to those of small or large diameter, to test
wells, and to so-called "stovepipe wells." Each sealing job should be con-
sidered as an individual problem, and methods and materials should be deter-
mined only after carefully considering the objectives outlined in the first
paragraph of this section.
Section A1-13.2 - Wells in Unconsolidated Formations: Normally, abandoned
wells extending only into unconsolidated formations near the surface and con-
taining water under water table conditions can be adequately sealed by filling
with concrete, grout, neat cement, clay, or clay and sand. In the event that
the water-bearing formation consists of coarse gravel, and producing wells are
located nearby, care must be taken to select sealing materials that will not
affect the producing wells. Concrete may be used if the producing wells can
be shut down for a sufficient time to allow the concrete to set. Clean, dis-
infected sand or gravel may also be used as fill material opposite the water-
bearing formation. The remainder of the well, especially the upper portion,
should be filled with clay, concrete, grout, or neat cement to exclude surface
water. The latter method, using clay as the upper sealing material, is espe-
cially applicable to large-diameter abandoned wells.
In gravel-packed, gravel envelope, or other wells in which coarse mater-
ial has been added around the inner casing to within 6-9 meters (20-30 feet)
of the surface, sealing outside the casing is very important. Sometimes this
sealing may require removal of the gravel or perforation of the casing.
Section Al-13.3 - Wells Extending Into Creviced Rock Formations: Abandoned
wells that penetrate limestone or other creviced or channelized rock forma-
tions lying immediately below the surface deposit should preferably be filled
with concrete, grout, or neat cement to assure permanence of the seal. The
use of clay or sand in such wells is not desirable because fine-grained fill
material may be displaced by flow of water through crevices of channels. Al-
ternate layers of coarse stone and concrete may be used for fill material
through the water-producing horizon if limited vertical movement of water in
the formation will not affect the quality or quantity of water in the produc-
ing wells. Only concrete, neat cement, or grout should be used in this type
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of well. The portion of the well between a point 3-6 meters (10-20 feet)
below and a point above the bottom of the casing should be sealed and a plug
formed of sealing material above the creviced formation. Clay or sand may be
used to fill the upper part of the well.
Section Al-13.4 - Nells Extending Into Noncreviced Rock Formations: Abandoned
wells encountering noncreviced sandstone or other water-bearing consolidated
formations below the surface deposits may be satisfactorily sealed by filling
the entire depth with clay, provided there is no movement of water in the well.
Clean sand, disinfected if other producing wells are nearby, may also be used
through the sandstone up to a point 3-6 meters (10-20 feet) below the bottom
of the casing. The upper portion of this type of well should be filled with
concrete, neat cement, grout, or clay to provide an effective seal against en-
trance of surface water. If there is an appreciable amount of upward flow,
pressure cementing or mudding may be advisable.
Section Al-13.5 - Wells Extending Into More Than One Aquifer: Some special
problems may develop in sealing wells extending into more than one aquifer.
These wells should be filled and sealed in such a way that exchange of water
from one aquifer to another is prevented. If no appreciable movement of wa-
ter is encountered, filling with concrete, neat cement, grout, or alternate
layers of these materials and sand will prove satisfactory. When velocities
are high, the procedures outlined in Sec. Al-13.6 are recommended. If alter-
nate concrete plugs or bridges are used, they should be placed in known non-
producing horizons, or, if location of the non-producing horizons is not
known, at frequent intervals. Sometimes, when the casing is not grouted or
the formation is noncaving, it may be necessary to break or slit the casing to
fill any annular space on the outside.
Section Al-13.6 - Wells With Artesian Flow: The sealing of abandoned wells
that have a large movement of water between aquifers or to the surface re-
quires special attention. Frequently the movement of water may be sufficient
to make sealing by gravity placement of concrete, cement grout, neat cement,
clay or sand impractical. In such wells, large stone aggregate (not more than
one-third of the diameter of the hole), lead wool, steel shavings, a well
packer, or a wood or cast-lead plug or bridge will be needed to restrict the
flow and thereby permit the gravity placement of sealing material above the
formation producing the flow. If preshaped or precast plugs are used, they
should be several times longer than the diameter of the well. This will pre-
vent tilting.
Inasmuch as it is very important in wells of this type to prevent cir-
culation between formations or loss of water to the surface or to the annular
space outside the casing, it is recommended that pressure cementing with neat
cement using the minimum quantity of water that will permit handling be em-
ployed. The use of pressure mudding instead of this process is sometimes per-
missible.
In wells in which the hydrostatic head-producing flow to the surface is
low, the movement of water may be arrested by extending the well casing to an
elevation above the artesian pressure surface. Previously described sealing
methods suitable to the geologic conditions can then be used.
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Section A1-13.7 - Sealing Methods^ A number of materials for sealing wells
satisfactorily, including concrete, cement grout, neat cement, clay, sand,
or combinations of these materials, are mentioned herein. Each material has
certain characteristics and distinctive properties; accordingly, one material
may be especially suited for doing a particular job. The selection of the
material must therefore be based on the construction of the well, the nature
of the formations penetrated, the material and equipment available, the loca-
tion of the well with respect to possible sources of contamination, and the
cost of doing the work.
Concrete is generally used for filling the upper part of the well or
water-bearing formation, for plugging short sections of casings, or for filling
large-diameter wells. Its use is cheaper than neat cement or grout, and it
makes a stronger plug or seal. But concrete will not penetrate seams, cre-
vices, or interstices. Furthermore, if not properly placed, the aggregate is
apt to separate from the cement.
Cement grout or neat cement and water are far superior for sealing small
openings, for penetrating any annular space outside of casings, and for filling
voids in the surrounding formation. When applied under pressure, it is strong-
ly favored for sealing wells under artesian pressure or those encountering more
than one aquifer. Neat cement is generally prefereed to grout as it avoids
the danger of separation.
Clay, as a heavy mud-laden or special clay fluid applied under pressure,
particularly for sealing artesian wells, is considered adequate by many com-
petent authorities, although others feel that it may, under some conditions,
eventually be carried away into the surrounding formations.
Clay in a relatively dry state, clay and sand, or sand alone may be used
advantageously, particularly under water table conditions where diameters are
large, depths are great, formations are caving, and there is no need of achiev-
ing penetration of openings in casings, liners, or formations, or of obtaining
a watertight seal at any given spot.
Frequently combinations of these materials are necessary. The more ex-
pensive materials are used where strength, penetration, or watertightness
are needed. The less expensive materials are used for the remainder of the
well. Cement grout or neat cement is now being mixed with specially processed
clays and with various aggregates. Superior results and economies are claimed
for such mixtures.
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TECHNICAL REPORT DATA
(Please read Instructions on the reverse before completing)
1. REPORT NO.
EPA-600/3-77-095
3. RECIPIENT'S ACCESSION-NO.
4. TITLE AND SUBTITLE
IMPACT OF ABANDONED WELLS ON GROUND WATER
5. REPORT DATE
August 1977
issuing date
6. PERFORMING ORGANIZATION CODE
7. AUTHOR(S)
Tyler E. Gass, Jay H. Lehr, and Harold W. Heiss, Jr.
8. PERFORMING ORGANIZATION REPORT NO.
9. PERFORMING ORGANIZATION NAME AND ADDRESS
National Water Well Association
500 West Wilson Bridge Road
Worthington, Ohio 43085
10. PROGRAM ELEMENT NO.
1BA609
11. CONTRACT/GRANT NO.
Grant No. R-803889
12. SPONSORING AGENCY NAME AND ADDRESS
Robert S. Kerr Environmental Research Lab.
Office of Research & Development
U.S. Environmental Protection Agency
Ada, Oklahoma 74820
- Ada, OK
13. TYPE OF REPORT AND PERIOD COVERED
Final 1Q75-1977
14. SPONSORING AGENCY CODE
EPA/600/15
15. SUPPLEMENTARY NOTES
16. ABSTRACT
The impact of unplugged wells on ground-water resources is
discussed, including a review of case histories and a survey of
state laws concerning well abandonment procedures. Model regula-
tions are suggested to guide those states where existing regulations
are ineffective or non-existent.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b.lDENTIFIERS/OPEN ENDED TERMS C. COS AT I Field/Group
Ground Water
Resources
Waste Disposal
Wells
Abandonment
Case Histories
State Regulations
Model Regulations
13/B
13. DISTRIBUTION STATEMENT
Release to Public,
19. SECURITY CLASS. (This Report)
Unclassified
21. NO. OF PAGES
59
20. SECURITY CLASS (This page)
Unclassified
22. PRICE
EPA Form 2220-1 (9-73)
53
S. GOVERNMENT PRINTING OFFICE: 1977-757-056/6530 Region No. 5-II
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