Class VI Permit Application Outline

This document provides an overview of the items and the associated activities an applicant may complete during the development of an application to inject
carbon dioxide (CO2) for geologic sequestration (GS) under the UIC Class VI program. It functions as a detailed index to multiple EPA Class VI guidance documents
that steer the development of the information needed for a complete Class VI application. Please note, the permit application items and activities listed herein
reflect EPA's recommendations for complying with the federal Class VI rule requirements. It should also be noted that the elements listed below are not inclusive
of every activity nor are they at the detail that is needed to meet the permit application requirements of the Federal Class VI Rule and demonstrate that
underground sources of drinking water (USDWs) will not be endangered. Prospective permit applicants are encouraged to consult early with their UIC permitting
authority about the specific needs for their project and review the Class VI Rule and the EPA guidance documents, which are available on EPA's web site in order
to gain a full understanding of the Class VI permit application process.

Item

Activity and Purpose

Guidance Reference

Characterize the geologic setting of the proposed GS site to demonstrate that the Class VI well will be sited in an area with a suitable geologic system,
consisting of an injection zone with sufficient capacity to receive the C02 and a confining zone that is free of transmissive faults or fractures. This information
will satisfy the requirements of 40 CFR 146.82(a)(2),(3),(5), and (6). For additional information, see the Class VI Well Geologic Site Characterization Guidance.

• Regional geology and
geologic structure

Summarize information on lithology, the sequence of geologic units (i.e., the injection and
confining zones and USDWs), the thicknesses and lateral extent of formations, and
correlation of units near the project site to place the GS project in a regional context.

Sections 2.1, 2.3.1, and 2.3.10 of
the Geologic Site
Characterization Guidance

• Faults and fractures

Identify and characterize faults and fractures to demonstrate that there are no transmissive
faults or fractures in the confining zone(s) so that injection at proposed maximum
pressures and volumes can occur without initiating or propagating fractures in the
confining zone(s).

Sections 2.1, 2.2, and 2.3.2 of the
Geologic Site Characterization
Guidance

• Injection and confining
zone characteristics

Provide information about the depth, extent, porosity, permeability, and capillary pressure
of the injection and confining zones to show that the site can confine C02; support
estimations of CO2 storage capacity and injectivity; and support the development of a site-
specific area of review (AoR) delineation model.

Sections 2.3.3, 2.3.4, and 2.3.5 of
the Geologic Site
Characterization Guidance

• Hydrologic and
hydrogeologic
information

Describe the relationship between the proposed injection formation and any USDWs,
springs, and water wells within the AoR to support an understanding of the water resources
near the proposed well.

Section 2.3.8 of the Geologic Site
Characterization Guidance

• Geochemical data

Provide water chemistry data on all water-bearing formations to identify USDWs, confirm
that the injection zone is not a USDW, and establish baseline water quality in any
formations for which injection and post-injection phase ground water monitoring is
planned for comparison with future monitoring results. Provide geochemical information
on solids and fluids to identify potential interactions that could affect injectivity or mobilize
trace elements; assess the compatibility of the C02 stream with fluids and minerals in the
injection and confining zones; and inform C02 storage capacity estimates.

Sections 2.3.4 and 2.3.9 of the
Geologic Site Characterization
Guidance

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Item

Activity and Purpose

Guidance Reference

• Geomechanical and
petrophysical
information

Characterize the geomechanical properties of the confining zone (e.g., fractures, stress,
ductility, rock strength, and in situ fluid pressures) to demonstrate the integrity of the
confining zone and set safe operational parameters.

Sections 2.3.5 and 2.3.6 of the
Geologic Site Characterization
Guidance

• Injection & confining
zone mineralogy,
petrology, and lithology

Provide information on the mineralogy, petrology, and lithologies of the injection and
confining zones to help identify any geochemical reactions that could change porosity,
permeability, or injectivity and potentially affect the storage and containment of injected
C02 or mobilize trace elements.

Section 2.3.4 of the Geologic Site
Characterization Guidance

• Seismic history, seismic
sources, and seismic risk

Provide information on seismic history and the presence and depths of seismic sources and
seismic risk to understand the potential for seismicity, inform a seismic monitoring
program, and support the development of an Emergency and Remedial Response Plan that
is appropriate to the potential frequency and magnitude of seismic events in the region.

Section 2.3.7 of the Geologic Site
Characterization Guidance

• Surface air and/or soil
gas monitoring data

Provide data on C02 concentrations and fluxes (if required by the UIC Program Director) to
serve as a baseline for comparison to C02 levels during and after the operational phase of
the project in order to detect any potential leakage.

Section 2.3.11 of the Geologic
Site Characterization Guidance

• Fades changes in the
injection or confining
zone

Evaluate facies changes in the injection or confining zone to inform an understanding of the
storage and confinement of C02 and support the development of a geologic conceptual
model.

Section 3.1 of the Geologic Site
Characterization Guidance

• Structure of the

injection and confining
zones

Provide information on the geologic structure of the injection and confining zones to
demonstrate that local and regional geologic structures are conducive to GS and form an
adequate confining system.

Section 3.2 of the Geologic Site
Characterization Guidance

• Compatibility of the C02
with subsurface fluids
and minerals

Describe the results of evaluations of the compatibility of the C02 stream with subsurface
fluids and minerals to identify potential chemical reactions that could mobilize
contaminants and potentially endanger USDWs.

Section 3.3 of the Geologic Site
Characterization Guidance

• Injection zone storage
capacity

Estimate the storage capacity of the injection zone to demonstrate that it is of sufficient
areal extent, thickness, porosity, and permeability to receive the total anticipated volume
of C02 to be injected.

Section 3.4 of the Geologic Site
Characterization Guidance

• Confining zone integrity

Demonstrate that the confining zone(s) can contain the C02 and not allow migration of C02,
or other fluids either through interconnected pore spaces across the thickness of the seal
or along faults or fractures to prevent fluid movement that could endanger USDWs.

Section 3.5 of the Geologic Site
Characterization Guidance

Prepare a proposed AoR Delineation and Corrective Action Plan to demonstrate that the AoR, as modeled, represents the area in which USDWs may be
endangered by the injection operation and ensure that all artificial penetrations that may allow fluid movement into USDWs are identified and appropriately
addressed. This information will satisfy the requirements of 40 CFR 146.82(a)(4), (13) and 146.84(b). For additional information, see the Class VI AoR
Evaluation and Corrective Action Guidance and the Class VI Project Plan Development Guidance.

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Item

Activity and Purpose

Guidance Reference

• Conceptual site model

Develop a conceptual site model, which is a representation of the proposed GS project that
includes all major geologic elements present in the flow system and any relevant physical
processes (as informed by the geologic site characterization) and operational conditions.
The conceptual site model illustrates the inputs for the computational AoR model.

Sections 3.3.1 and 3.3.2 of the
AoR Evaluation and Corrective
Action Guidance

• Computational AoR
delineation model

Delineate the AoR using a multi-phase computational model that estimates the extent and
migration of the separate-phase C02 plume and changes in fluid pressures within the
injection zone overtime. The model (at an appropriate spatial extent, discretization, and
boundary conditions, and timeframe) will help ensure that the extent of the C02 plume and
pressure front is well-understood and support monitoring of the site over the duration of
the project.

Sections 3.3.3 and 3.3.4 of the
AoR Evaluation and Corrective
Action Guidance

• Artificial penetrations
within the AoR

Identify and characterize all artificial penetrations within the delineated AoR that penetrate
the confining zone to identify any improperly plugged and abandoned wells that could
provide flow conduits out of the injection zone that could potentially endanger USDWs.

Section 4 of the AoR Evaluation
and Corrective Action Guidance

• AoR and Corrective
Action Plan

Develop a proposed AoR Evaluation and Corrective Action Plan that will ensure that a site-
specific strategy is in place to delineate the AoR (initially and throughout the duration of
the project) and ensure that all deficient artificial penetrations within the AoR will be
addressed through appropriate and timely corrective action methods.

Section 2 of the Project Plan
Development Guidance

Provide evidence of financial responsibility to demonstrate that sufficient resources are available for all needed corrective action, injection well plugging,
post-injection site care (PISC) and site closure, and emergency and remedial response. This information will satisfy the requirements of 40 CFR 146.82(a)(14)
and 146.85(a). For additional information, see the Class VI Financial Responsibility Guidance.

• Cost estimates

Provide estimates of the cost for contracting an independent third party to carry out
corrective action, injection well plugging, PISC and site closure, and emergency and
remedial response to prevent the general public from bearing the costs of abandoned GS
projects.

Sections 3 and 4 of the Financial
Responsibility Guidance

• Financial instruments

Describe proposed financial responsibility instruments that are secure and meet the UIC
requirements to facilitate enforceability and prevent gaps in financial coverage over the
duration of the project.

Section 6 of the Financial
Responsibility Guidance

Submit proposed well construction schematics and procedures for the injection well to demonstrate that it will be constructed in a manner that is
appropriate to planned operations, is compatible with the C02 stream and subsurface chemistry (as informed by baseline geochemical data), and will maintain
mechanical integrity. This information will satisfy the requirements of 40 CFR 146.82(a)(ll), (12) and 146.86. For additional information, see the Class VI
Injection Well Construction Guidance.

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Item

Activity and Purpose

Guidance Reference

• Injection well casing

Design and describe casing strings that are appropriate to the geology and planned
operations to ensure that the surface casing will protect all USDWs and the long-string
casing will extend into the injection zone; and that they are made of materials that can
withstand contact with formation fluids, the injected C02 stream, the product of mixing
formation and injection fluids, and the down-hole stresses they will encounter so that they
won't experience degradation during injection operations.

Sections 2.1 to 2.4 of the Well
Construction Guidance

• Cementing procedures

Design and describe the cement/additives and a cementing program to demonstrate that
the cement will be properly emplaced and provide a continuous sheath of cement from the
bottom of each casing string to the surface to prevent C02 or other fluids from entering a
permeable zone or potentially migrate into a USDW.

Section 2.5 of the Well
Construction Guidance

• Tubing and packer

Design and describe tubing and packer that are properly placed and compatible with the
C02 stream, the formation fluids, and/or the product of mixing formation and injection
fluids that may be encountered so that they can resist corrosion for the duration of the
project.

Section 2.6 of the Well
Construction Guidance

• Continuous monitoring
devices

Design and describe continuous monitoring and shutoff devices and automatic alarms and
surface shut-off systems that are appropriate to planned operational limits and will shut-in
when injection or annulus pressures exceed limits to prevent fracturing of the confining
zone or damaging to the well.

Section 2.8 of the Well
Construction Guidance

Prepare a Pre-Operational Testing Plan to demonstrate that information will be collected to address any uncertainties about subsurface formations and fluid
geochemistry that were identified during the geologic site characterization and verify that the well is properly constructed. This information will satisfy the
requirements of 40 CFR 146.82(a)(8) and 146.87. For additional information, see the Class VI Injection Well Construction Guidance, the Class VI Well Geologic
Site Characterization Guidance, and the Class VI Reporting, Recordkeeping, and Data Management Guidance.

• Tests during well
drilling/construction

Describe logs and tests to be performed during the construction of the injection well to
determine or verify the depth, thickness, porosity, permeability, lithology, and formation
fluid salinity in all relevant geologic formations and demonstrate that the well was
appropriately constructed and has mechanical integrity.

Section 2.2 of the Well
Construction Guidance and
Section 4.1 of the Geologic Site
Characterization Guidance

• Injection and confining
zone core sampling

Describe plans to collect and analyze core samples within the injection and confining zones
to refine site characterization data and provide information to support stratigraphic
correlation, interpretation of depositional environments, and wireline log calibration.

Section 4.2 of the Geologic Site
Characterization Guidance

• Injection zone
characterization

Describe plans to gather information on the fluid temperature, pH, conductivity, reservoir
pressure, and static fluid level of the injection zone(s).

Sections 4.3 and 4.4 of the
Geologic Site Characterization
Guidance

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Item

Activity and Purpose

Guidance Reference

• Fracture pressure, fluid
characteristics, and
downhoie conditions

Describe a plan to determine or calculate the confining zone fracture pressure (to inform
injection pressure limits) and to determine the physical chemical characteristics of the
injection and confining zones and characterize formation fluids in the injection zone (to
evaluate the compatibility of the injectate with the formation fluids).

Sections 4.3 and 4.4 of the
Geologic Site Characterization
Guidance

• Injection and confining
zone formation testing

Describe planned pre-operational formation tests/logging (i.e., pressure fall-off test, pump
test, or injectivity tests) that will provide needed data on the geologic and hydrogeologic
properties of subsurface formations.

Section 4.5 of the Geologic Site
Characterization Guidance

• Quality Assurance
Surveillance Plan
(QASP)

Describe quality assurance/quality control (QA/QC) procedures for required logs and tests,
such as equipment calibration information and sample QA, to ensure that pre-operational
testing and monitoring will provide accurate information about the site.

Section 4.4 of the Reporting,
Recordkeeping, and Data
Management Guidance

Describe the proposed operating conditions to demonstrate that the planned injection rate, pressure, and volume are appropriate to the site geology (as
informed by the geologic site characterization) and the well's construction. This information will satisfy the requirements of 40 CFR 146.82(a)(7),(9),(10) and
146.88. For additional information, see the Class VI Well Geologic Site Characterization Guidance, the Class VI Well Testing and Monitoring Guidance, and the
Class VI Injection Well Construction Guidance.

• Injection rate

Describe a proposed injection rate that is appropriate to the site geology (i.e., the
properties of the injection zone) and the well's construction.

Section 3.4 of the Geologic Site
Characterization Guidance

• Maximum injection
pressure

Describe the proposed injection pressure that is no more than 90 percent of the injection
zone fracture pressure to prevent the injection zone from being fractured and reduce the
potential for fracturing the confining zone.

Section 4.1 of the Well
Construction Guidance and
Section 3.3 of the Testing and
Monitoring Guidance

• C02 volume

Propose a total volume of C02 to be injected throughout the life of the GS project that the
injection zone can receive and contain without endangering USDWs.

Section 3.4 of the Geologic Site
Characterization Guidance

• Annulus pressure

Provide information to demonstrate that the proposed maximum annular pressure will be
greater than the injection pressure or propose an alternative annular pressure and
demonstrate that it will be appropriate and protective.

Section 4.2 of the Well
Construction Guidance

• Well stimulation
procedures

If well stimulation is planned, describe the stimulation fluids and procedures to ensure that
stimulation will not fracture the confining zone, affect well integrity, or otherwise allow
injection or formation fluids to endanger USDWs.

Section 4.1 of the Well
Construction Guidance

• C02 stream
characteristics

Describe the physical and chemical characteristics of the C02 stream to ensure that (1)
interactions among the C02, fluids, and solids will not affect permeability, porosity, or
injectivity; (2) trace elements will not be liberated from subsurface solids; and (3) no
interactions among the fluid, C02, and cement will deteriorate the well cement.

Section 3.3 of the Geologic Site
Characterization Guidance

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Item

Activity and Purpose

Guidance Reference

Prepare a proposed Testing and Monitoring Plan to demonstrate that planned testing and monitoring of the injectate, the well, and the geologic
environment will be appropriate to planned operations, the well's construction, and site-specific geologic conditions. This information will satisfy the
requirements of 40 CFR 146.82(a)(15), 146.89, and 146.90. For additional information, see the Class VI Well Testing and Monitoring Guidance and the Class VI
Reporting, Recordkeeping, and Data Management Guidance.

• C02 stream analysis

Prepare an injectate (C02 stream) analysis plan to demonstrate that the parameters for
which the C02 stream will be analyzed—and the associated analytical procedures—are
appropriate to characterize the C02 stream.

Section 3.1 of the Testing and
Monitoring Guidance

• Mechanical integrity
and corrosion testing

Describe planned methods for corrosion monitoring; continuous recording of injection
pressure, rate, and volume; and annual external MITs that will provide early detection of
potential or actual damage to the well that could compromise well integrity and provide a
conduit for fluid movement that could endanger USDWs.

Sections 2, 3.2, 3.3, and 3.4 of
the Testing and Monitoring
Guidance

• Pressure fall-off testing

Describe planned fall-off testing to monitor for changes in the near-well bore environment
that could affect injectivity and increase pressure.

Section 3.5 of the Testing and
Monitoring Guidance

• Groundwater quality
monitoring

Develop and describe a groundwater monitoring plan (i.e., with appropriate monitoring
locations, sampling frequencies, and analytical parameters) to identify potential C02
migration and/or native fluid displacement from the injection zone or other water quality
changes that may lead to endangerment of USDWs.

Section 4 of the Testing and
Monitoring Guidance

• C02 plume and

pressure front tracking

Develop a plan to track the plume and pressure front to identify potential risks to USDWs,
verify modeled predictions of the project behavior, and inform reevaluations of the AoR.

Section 5 of the Testing and
Monitoring Guidance

• Surface air and/or soil
gas monitoring

Develop an air and/or soil gas monitoring plan (if applicable) to provide an additional line of
evidence of whether C02 has leaked from the injection zone and could endanger USDWs.

Section 6 of the Testing and
Monitoring Guidance

• Testing and monitoring
plan QASP

Describe QA/QC procedures to ensure that all testing and monitoring provides accurate
results that meet the requirements of 40 CFR 146.90.

Section 3.1.6 of the Reporting,
Recordkeeping, and Data
Management Guidance

Prepare a proposed Injection Well Plugging Plan to demonstrate that the materials and procedures proposed for injection well plugging are appropriate to
the well's construction and the site's geology and geochemistry so that the well will not serve as a conduit for fluid movement that could endanger USDWs
following cessation of injection. This information will satisfy the requirements of 40 CFR 146.82(a)(16) and 146.92. For additional information, see the Class VI
Well Plugging, Post-lniection Site Care, and Site Closure Guidance and the Class VI Project Plan Development Guidance.

• Injection Well Plugging
Plan

Prepare an Injection Well Plugging Plan that describes the procedures for properly plugging
the Class VI well to prevent fluid movement that could endanger USDWs following the
cessation of injection.

Section 2 of the Well Plugging,
Post-Injection Site Care, and Site
Closure Guidance and Section 4
of the Project Plan Development
Guidance

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Item

Activity and Purpose

Guidance Reference

Prepare a proposed Post-Injection Site Care and Site Closure Plan to demonstrate that post-injection monitoring strategies will ensure non-endangerment of
USDWs throughout the PISC phase and the site will be properly closed. This information will satisfy the requirements of 40 CFR 146.82(a)(17),(18) and 146.93.
For additional information, see the Class VI Well Plugging, Post-lniection Site Care, and Site Closure Guidance.

• Pressure differential
and position of the C02
plume and pressure
front

Predict and present the pre- and post-injection pressure differential and the predicted
position of the C02 plume and pressure front at site closure to demonstrate that the
predicted pressure decline and fluid movement on which the PISC and Site Closure Plan are
based are consistent with the results of AoR delineation modeling.

Section 3.2 of the Well Plugging,
Post-Injection Site Care, and Site
Closure Guidance

• Post-injection phase
monitoring plan

Develop a plan to monitor the site (e.g., groundwater quality and the C02 plume and
pressure front) to ensure that any unforeseen USDW endangerment during the post-
injection phase is identified and mitigated and to collect data to inform the non-
endangerment demonstration. This monitoring will be an extension of some components
of the injection-phase Testing and Monitoring Plan.

Section 3.3 of the Well Plugging,
Post-Injection Site Care, and Site
Closure Guidance

• Alternative PISC
timeframe

If approval of a shorter PISC timeframe than the 50-year default is sought, provide site-
specific data and evidence to show that the project will no longer pose a risk of
endangerment to USDWs at the end of the proposed PISC timeframe.

Section 3.2.2 of the Well
Plugging, Post-Injection Site Care,
and Site Closure Guidance

• Non-endangerment
demonstration criteria

Describe the criteria on which the non-endangerment demonstration will be based; this
optional step will allow the applicant and the permitting authority to agree early in the
project on the criteria that will need to be met prior to authorization for site closure.

Section 3.4 of the Well Plugging,
Post-Injection Site Care, and Site
Closure Guidance

• Monitoring well
plugging and site
closure plan

Describe how all monitoring wells will be plugged and site closure and site restoration
activities will be performed so that the project will not pose a risk of endangerment to
USDWs after closure.

Sections 2 and 4 of the Well
Plugging, Post-Injection Site Care,
and Site Closure Guidance

Prepare a proposed Emergency and Remedial Response Plan to demonstrate that appropriate and timely responses will be taken to protect USDWs from
endangerment should an emergency event occur during the construction, operation, and post-injection phases of the project. This information will satisfy the
requirements of 40 CFR 146.82(a)(19) and 146.94. For additional information, see the Class VI Project Plan Development Guidance.

• Emergency and
Remedial Response
Plan

Prepare a proposed Emergency and Remedial Response Plan that describes the actions that
would be taken in the unlikely event of an emergency in order to expeditiously mitigate any
emergency situations and protect USDWs from endangerment. The Plan should consider
the geologic setting, planned operations, and the well's construction.

Section 6.0 of the Project Plan
Development Guidance

Prepare an Injection Depth Waiver Application, if appropriate, to demonstrate that USDWs above and below the injection zone are protected from
endangerment if injection into non-USDWs that are located above or between USDWs is planned. This information will satisfy the requirements of 40 CFR
146.82(d) and 146.95(a). For additional information, see the Class VI Reporting, Recordkeeping, and Data Management Guidance.

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Item

Activity and Purpose

Guidance Reference

• Injection depth waiver
application

Provide information on the upper and lower confining zones; the injection zone; drinking
water resources and water supply needs and plans for securing alternative water resources
or treating USDWs; and hydrocarbon or mineral resource exploitation to demonstrate that
USDWs will not be endangered if the project operates under an injection depth waiver.

Section 3.2 of the Reporting,
Recordkeeping, and Data
Management Guidance

Apply to expand the areal extent of an existing Class II aquifer exemption, if appropriate, to demonstrate that an appropriately sized area is exempted such
that the C02 plume and pressure front remain within the approved exempted area. Note that no new aquifer exemptions will be approved for Class VI
injection activities (only expansions of existing aquifer exemptions). This information will satisfy the requirements of 40 CFR 144.7(d)(1) and 40 CFR 146.4(d).
For additional information, see the Class VI Reporting, Recordkeeping, and Data Management Guidance.

• Aquifer exemption
expansion area

Delineate and describe the proposed areal extent of a requested expansion to an existing
Class II aquifer exemption based on the predicted extent of the injected C02 plume and any
mobilized fluids (as informed by computational modeling of the AoR) to demonstrate that
the project will not allow these fluids to move into a USDW over the lifetime of the project.

Section 3.3 of the Reporting,
Recordkeeping, and Data
Management Guidance

• Demonstration that the
aquifer is not a USDW

Demonstrate that the proposed area of the expanded aquifer exemption (1) does not
currently serve as a source of drinking water; (2) has a TDS content of more than 3,000
mg/L and less than 10,000 mg/L; and (3) is not reasonably expected to supply a public
water system.

Section 3.3 of the Reporting,
Recordkeeping, and Data
Management Guidance

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