June 2018 Inventory of U.S. Greenhouse Gas Emissions and Sinks 1990-2017: Updates Under Consideration for Well-Related Activity Data In supporting documentation associated with the development of EPA's 2018 Inventory of U.S. Greenhouse Gas Emissions and Sinks (GHGI), EPA stated plans to assess options to increase consistency and improve activity data for a number of sources and activities related to onshore oil and gas wells. This memo summarizes current methodologies and updates under consideration to increase consistency and accuracy for certain emission source estimates that rely on well-related activity data. Note, this memo references a memo under concurrent development, Inventory of U.S. Greenhouse Gas Emissions and Sinks 1990-2017: Updates Under Consideration for Incorporating GHGRP Data1, which focuses on incorporating GHGRP data into the 2019 GHGI and includes a dedicated section on hydraulically fractured (HF) oil well completions and workovers. 1 Current GHGI Methodologies Table 1 below summarizes the data sources that are currently used to develop activity data for emission sources that directly rely on counts of wells or well-related activities. Appendix A provides a table that shows all well- related activity data over the time series as used in the 2018 GHGI (as well as data elements from updates under consideration, as discussed in Section 3). Note that several existing GHGI methodologies documented in Table 1 (e.g., developing counts of active wells) rely on EPA's analysis of Drillinglnfo's subscription-based digital Dl Desktop raw data feed2; this data set is referred to throughout this memo as "Drillinglnfo data." Table 1. 2018 GHGI Well-Related Activity Data Summary Emission Source/Activity Data Element Activity Basis Data Source/Basis Natural Gas Systems Non-associated gas wells (less HF wells) Wellheads Drillinglnfo data analysis; active wells with GOR>100 mcf/bbl Gas wells with hydraulic fracturing Wellheads Drillinglnfo data analysis; subset of non-associated gas wells located in unconventional formation and/or horizontally drilled Non-HF gas well completions Events 400 completions/year for all gas wells in 1992 (GRI/EPA 19963), scaled in future years Non-HF gas well workovers Events 4.35% of non-HF gas wells (GRI/EPA 1996) HF gas well completions (four control categories) Events GHGRP direct counts (if higher than Drillinglnfo data analysis; count of newly spud or newly producing gas wells located in unconventional formation and/or horizontally drilled) HF gas well workovers (four control categories) Events 1% of HF gas wells are worked-over annually 1 https://www.epa.gov/ghgemissions/stakeholder-process-natural-gas-and-petroleum-systems-1990-2017-inventory 2 https://info.drillinginfo.com/products/di-plus/ 3 Methane Emissions from the Natural Gas Industry. Prepared by Harrison, M., T. Shires, J. Wessels, and R. Cowgill, eds., Radian International LLC for National Risk Management Research Laboratory, Air Pollution Prevention and Control Division, Research Triangle Park, NC. EPA-600/R-96-080a. Page 1 of 10 ------- June 2018 Emission Source/Activity Data Element Activity Basis Data Source/Basis Gas well drilling Events EIA - gas wells and fraction of dry wells drilled (data set last updated in 2010) Petroleum Systems Producing oil wells Wellheads Drillinglnfo data analysis; active wells with GOR<100 mcf/bbl Heavy crude wells population fraction Fraction 7.05% of all oil wells (EPA/ICF 19994) Non-HF oil well completions Events EIA crude oil wells drilled, less HF oil well completions Oil well workovers Events 7.5% of producing oil wells (Radian 19995) HF oil well completions (two control categories) Events Drillinglnfo data analysis; count of newly spud or newly producing oil wells located in unconventional formation and/or horizontally drilled Oil well drilling Events EIA - oil wells and fraction of dry wells drilled (data set last updated in 2010) 2 Updates Under Consideration EPA is considering implementing methodological updates focused on five general areas, to increase consistency and accuracy of activity data for certain emission sources shown in Table 1: • Well drilling: The U.S. Department of Energy's Energy Information Administration (EIA) no longer maintains the well drilling activity data set within its Monthly Energy Review publication that was used to develop well drilling activity inputs in past GHGIs (most recent estimates cover through 2010), so the GHGI requires a new data source for the entire time series, or at least 2011 forward. • Well completions and workovers: The non-HF gas well completion activity data methodology is based on industry characteristics in base year 1992 (from the 1996 GRI/EPA study). An updated data source should account for changing trends over time. Non-HF oil well completions are sometimes zero in recent time series years, due to limitations of the current data sources and methodologies for both oil well drilling and HF oil well completion counts. For HF gas well completions, the GHGRP reported counts are higher than those obtained from the Drillinglnfo data analysis; due to the reporting threshold, GHGRP counts should represent a subset of national activity, so Drillinglnfo counts should be equal to, or greater than, GHGRP direct counts. For HF oil well completions, EPA is beginning to review newly reported GHGRP activity data in comparison to existing activity developed from the Drillinglnfo data analysis (refer to companion memo on incorporating GHGRP data into the 2019 GHGI). The current assumptions for workover rates have not been updated in recent years, and there is no current estimate representing HF oil well workovers. • Definition of oil versus gas well: The current methodology estimates the count of active gas wells in a given year as any well in the Drillinglnfo data set with a gas-to-oil ratio (GOR) > 100 mcf/bbl in that year, and active oil wells as those with GOR < 100 mcf/bbl. Other industry data sets (e.g., those published by EIA) use different thresholds for defining oil versus gas wells. A value of 6 mcf/bbl is another common threshold. EPA reviewed available data reported under GHGRP subpart W to evaluate how reported GOR values compare to the current GHGI methodology. • Heavy versus light crude equipment service: The fractions used to split counts of wellheads, headers, and separators between heavy and light crude service were developed in the 1990s and applied for all time series years. An updated data source should account for changing trends over time. • Identification of HF wells: The current methodology identifies HF gas or oil wells as those horizontally drilled (based on Drillinglnfo data) and/or located in a shale, low permeability, or coalbed formation. 4 Estimates of Methane Emissions from the U.S. Oil Industry (Draft Report). Prepared by ICF International. Office of Air and Radiation, U.S. Environmental Protection Agency. October 1999. 5 EPA/Radian (1999) Methane Emissions from the U.S. Petroleum Industry. Prepared by Radian International. U.S. Environmental Protection Agency. February 1999. Page 2 of 10 ------- June 2018 Potential GHGI updates to address these priority areas are discussed in more detail in the subsections below. Appendix A provides a table that shows all well-related activity data over the time series as used in the 2018 GHGI, as well as data elements from updates under consideration, as discussed below. After these priority areas are addressed, EPA might investigate updated methodology and/or data sources to potentially improve estimates for other well-related activity data elements. 2.1 Well Drilling As described above, EIA no longer maintains the Monthly Energy Review well drilling activity data set that was used to develop well drilling activity inputs in past GHGIs (most recent estimates cover through 2010), so the GHGI requires a new data source for the entire time series, or at least 2011 forward. EPA is evaluating two general options to estimate well drilling counts over the time series: 1. Identify another data set published by EIA. 2. Develop methodology for querying Drillinglnfo data set. EPA is in the process of reviewing available EIA data that could provide updated well drilling activity. EPA is reviewing ElA's Drilling Productivity Report6 which provides counts of wells drilled, wells completed, and wells drilled but uncompleted; but the public data are not comprehensive (covers years 2014 forward, covers seven production regions (not all U.S. onshore), and does not include conventional wells). EPA is also reviewing data underlying a recently published EIA analysis of HF wells on its Today in Energy website7, which includes coverage of non-HF well drilling and completions. The Today in Energy drilling activity estimates, which are presented in graphical form on the website, are generally lower than those published in ElA's Monthly Energy Review over comparable time periods; this is due to exclusion of dry wells, which are included in current GHGI activity estimates. At the same time, EPA is developing a methodology for querying the Drillinglnfo data set to develop estimates of wells drilled. EPA is considering the following approach: • Count all wells drilled in time series year N with: o Onshore location -and- o Spud date within year N -or- spud date not reported, but date of first production within year N+l • Apportion counts between oil, gas, and dry production types o Dry or temporarily inactive (TIA) wells drilled: spud date within year N, but no production is reported in year N+l o Gas wells drilled: GOR in year N+l >100 mcf/bbl o Oil wells drilled: GOR in year N+l < 100 mcf/bbl • Apportion dry/TIA counts to natural gas and petroleum systems according to the year-specific split between gas wells drilled and oil wells drilled. For a Drillinglnfo-based methodology, EPA seeks feedback on a few additional considerations. First, whether this approach adequately accounts for dry wells (which are spud but do not achieve reportable production levels). Based on preliminary analysis of results, this approach does appear to sufficiently represent dry wells at comparable levels to the EIA data set; on average, dry wells (not including TIA wells which report production after year N+l) contribute 10% of total wells drilled. Second, whether this approach is overly inclusive of wells that may not be drilled for oil and gas production purposes but are present in the Drillinglnfo data set. Second, how to account for time series coverage issues. For states without recently released data, EPA might develop a surrogate methodology wherein an early year's data are assigned to recent years to fill state-level data gaps, similar to the existing approach for counts of active wells. Additionally, total wells drilled in most recent time series year cannot 6 https://www.eia.gov/petroleum/drilling/ 7 https://www.eia.gov/todayinenergy/detail.php?id=34732 Page 3 of 10 ------- June 2018 be fully estimated by the current approach (i.e., GOR in year N+l is not available); EPA is considering a surrogate approach such as using the previous year's estimate. Appendix A shows well drilling counts across the time series in the 2018 GHGI, as well as relevant publicly available data from ElA's Monthly Energy Review publication and preliminary estimates by the Drillinglnfo data analysis approach described above. EPA seeks stakeholder feedback on these approaches under consideration, or other data sets or methodologies to consider for well drilling activity data in the 2019 GHGI; see Section 3 for specific stakeholder feedback requests. 2.2 Well Completions and Workovers As described above, the current methodology for well completion and workover event counts involves a mix of Drill ingl nfo data analyses, GHGRP data analyses, and historical assumptions. EPA is investigating the use of Drillinglnfo data and GHGRP data to update current activity data methodologies, including allocation across control categories. Specifically: • Non-HF gas well completion counts: Currently based on industry characteristics in base year 1992 (from the 1996 GRI/EPA study). Drill inglnfo data might offer an update to total activity across all time series years, and GHGRP data might be used to check/supplement Drill inglnfo data and provide updated control assumptions in recent years. • Non-HF oil well completion counts: Are sometimes zero in recent time series years, due to limitations of the current data sources and methodologies for both oil well drilling and HF oil well completion counts. Drillinglnfo data might offer an update to total activity across all time series years. • HF gas well completions: GHGRP reported counts are higher than those obtained from the Drillinglnfo data analysis; due to the reporting threshold, GHGRP counts should represent a subset of national activity, so Drillinglnfo counts should be equal to, or greater than, GHGRP direct counts. EPA is continuing to review Drillinglnfo and GHGRP data to assess whether updates can be made to ensure that activity data for this source represents national coverage. • HF oil well completions: EPA is beginning to review newly reported GHGRP activity data (refer to companion memo on incorporating GHGRP data into the 2019 GHGI) in comparison to existing activity developed from the Drillinglnfo data analysis. • Workover rates: Have not been updated in recent years, and there is no current estimate representing HF oil well workovers. EPA is beginning to review GHGRP activity data to ensure that activity data for workovers reflects trends overtime and represents national coverage. EPA has conducted a preliminary analysis to assess how workover rates reflected in the subpart W data compare to current GHGI assumptions. The subpart W data reporting structure and requirements limit the level of detail for such an analysis, due to: (1) there is not a specific reporting element indicating whether reported wells are HF or non-HF; and (2) non-HF oil well workovers are not reported. EPA analyzed the overall gas well workover rate, as summarized in Table 2. For gas wells reported under subpart W, the overall workover rate is 5-6% in recent years (compared to the current GHGI assumption of 4.35% for non-HF gas wells and 1% for HF gas wells). Table 2. Subpart W Gas Well Workover Data and Calculated Workover Rate Subpart W Data Element 2015 2016 # Gas wells reported (Introduction3 table AA.l.ii) 309,132 284,112 # Gas well workovers with HF reported 263 103 # Gas well workovers without HF reported 18,031 14,957 Calculated: Gas well workover rate 6% 5% a - Reported under 40 CFR 98.236(aa). Number of producing wells at the end of the calendar year. Data element "ii" refers to count from the "Sub-basin characterization" table. Page 4 of 10 ------- June 2018 Appendix A shows completion and workover counts across the time series in the 2018 GHGI. EPA seeks stakeholder feedback on improving the current methodology in the 2019 GHGI; see Section 3 for specific stakeholder feedback requests. 2.3 Definition of Oil versus Gas Well The current methodology estimates the count of active gas wells in a given year as all wells in the Drillinglnfo data set with a gas-to-oil ratio (GOR) > 100 mcf/bbl in that year, and active oil wells as those with GOR < 100 mcf/bbl. By this definition, oil wells include associated gas wells. Other data sets (e.g., those published by EIA) use different GOR thresholds for defining oil versus gas wells and might have different underlying assumptions regarding whether associated gas wells are a subset of oil wells. A value of 6 mcf/bbl is another common definition threshold, based on the oil and gas energy equivalence factor (6 mcf gas provides roughly the same amount of energy as 1 bbl oil equivalent (BOE); BOE is commonly used in financial statements to combine oil and gas production into a single measure). EPA is beginning to review available data reported under GHGRP subpart W to evaluate how reported GOR values compare to the current GHGI methodology and consider whether the current production type delineation threshold of 100 mcf/bbl is appropriate. Reporters have been providing GOR data for oil wells under GHGRP subpart W since 2011, as summarized below. Per subpart W, oil wells are defined as producing from an oil formation, not defined by a specific GOR thresholds. • RY2011-2014, summary data (Envirofacts table W_SUB_BASIN) o Average GOR for all oil wells operated by a company within a given sub-basin (i.e., county) o Well counts not directly reported • RY2015-2016, summary data (Envirofacts table EF_W_FACILITY_OVERVIEW) o Average GOR for all oil wells operated by a company within a given sub-basin (i.e., county) o Associated counts of active wells as of the end of the calendar year are also reported o Available data cover over 400,000 wells • RY2016, well-level data (Envirofacts table EF_W_ONSHORE_WELLS) o Well-level GOR, but only for oil wells that use measured data for calculating emissions from HF completions and workovers o Available data cover less than 160 wells Table 3 below summarizes reported GOR data based on EPA's review of subpart W RY2015-2016 summary data (Envirofacts table EF_W_FACILITY_OVERVIEW, containing data for over 400,000 wells reported to the EPA as of August 5, 2017). For most oil wells reported under subpart W (73%), the sub-basin level average GOR falls within the current GHGI definition (<100 mcf/bbl); while a significant fraction (27%) have higher average GORs. At a lower delineation threshold (e.g., 6 mcf/bbl), an even higher fraction of subpart W oil wells (roughly 50%) would be considered gas wells. Therefore, based on this analysis, EPA finds support for the current approach to delineating oil versus gas wells, but seeks stakeholder feedback (see Section 3 for specific requests on this topic). Table 3. 2018 GHGI Well-Related Activity Data Summary # Oil Wells with Specified GOR (mcf/bbl) Reporting Year GOR <10 10< GOR <100 100< GOR <1,000 GOR >1,000 2015 123,446 28,104 11,674 48,091 [58%] [13%] [6%] [23%] 2016 117,538 33,346 21,068 32,781 [57%] [16%] [10%] [16%] Combined 240,984 61,450 32,742 80,872 [58%] [15%] [8%] [19%] Page 5 of 10 ------- June 2018 2.4 Heavy versus Light Crude Equipment Service Heavy crude is defined as oil with lower than 20° API gravity. The GHGI uses separate EFs and activity data for wellheads, separators, and headers in heavy versus light crude service. Currently, the total counts of wellheads and headers are split into heavy versus light crude categories using an assumed split between heavy crude wells (7.05% of all oil wells) and light crude wells (92.95%). As documented in the 1999 EPA/ICF report8, this assumption, and its extension to wellhead and header activity, was developed for a 1995 base year; this split is currently applied to calculate equipment counts in all time series years. The split between heavy and light crude separators in base year 1995 is also documented in the 1999 EPA/ICF report: EPA assumed 90.1% of separators are in light crude service, and 9.9% in heavy crude service, and applied this split to all time series years. EPA has identified multiple data sources that might facilitate improvement to the current methodology by allowing calculation of the heavy versus light crude equipment splits in recent years. GHGRP subpart W collects API gravity data associated with production in all oil sub-basins. Based on an analysis of RY2015 and RY2016 data, 19% and 18%, respectively, of oil wells reporting to GHGRP produce heavy crude. This value is higher than the current assumption of 7.05% of wells producing heavy crude (and subsequent assumption that 7.05% of wellheads and headers are in heavy crude service). To follow the existing methodology which assumes that per well equipment counts are the same for heavy crude and light crude wells (with the exception of separators, where on average over the time series each heavy crude well has 0.47 separators while each light crude well has 0.32 separators), EPA might analyze subpart W data specifically for facilities that produce heavy crude versus light crude. For this approach, however, only a subset of onshore production facility data can be analyzed—those with either all heavy crude sub-basin formation types or all light crude sub-basin formation types—since equipment counts (e.g., separators) are reported at a basin level. Table 4 summarizes the data availability and preliminary estimates of separator activity factors based on this approach. EPA might use subpart W data to update the equipment count splits in recent years and reflect updated industry trends. Table 4. Subpart W Equipment Counts3 Count of Separators/ Number of Data Separators Count of Wellheads Wellhead Points (Facilities) Data Set 2015 2016 2015 2016 2015 2016 2015 2016 Notes/Methodology All onshore oil prod Counts from records classified 76,690 86,890 213,380 221,326 0.36 0.39 319 315 in Table R.4 as "Crude oil production equipment"15 Counts from records in Table Heavy R.4 - from facilities that crude-only 1,818 345 40,894 40,063 0.04 0.01 14 14 produce only heavy crude (all facilities sub-basins are oil with API gravity <20 in Table AA.l.ii) Counts from records in Table Light crude- R.4 - from facilities that only 22,153 23,048 54,098 51,428 0.41 0.45 102 103 produce only light crude (all facilities sub-basins are oil with API gravity >20 in Table AA.l.ii) a - Data reported as of August 5, 2017. b - For this approach, data from all facilities reporting presence of crude oil production equipment for equipment leak calculations can be used (ignoring the reported sub-basin formation type(s)). Alternatively, EPA might use the methodology documented in the 1999 Radian report which was the basis for the 1999 EPA/ICF report estimates. The 1999 Radian report methodology analyzed state-level reported heavy oil 8 Estimates of Methane Emissions from the U.S. Oil Industry (Draft Report). Prepared by ICF International. Office of Air and Radiation, U.S. Environmental Protection Agency. October 1999. Page 6 of 10 ------- June 2018 production as a fraction of total oil production, then applied that fraction to state-level oil well counts to estimate heavy oil well counts in each state, and finally summed heavy oil well counts to estimate the national population fraction. The EIA data set described above provides oil production data by API gravity range for many states in years 2015 and 2016; EPA might pair this data set with state-level well counts from Drillinglnfo to estimate the current national fraction of heavy oil wells in recent years. This approach would not facilitate development of a heavy versus light split for equipment other than wellheads (e.g., a specific split for separators as in the current methodology). EPA seeks stakeholder feedback on the data sources and approaches described above, or other methodologies to consider for improving this aspect of the oil production segment major equipment activity estimates; see Section 3 for specific stakeholder feedback requests on this topic. 2.5 Identification of HF Wells Appendix A shows current GHGI estimates of HF gas and oil well counts. There are limited public data estimating national total counts comparable to the GHGI; Appendix A shows year 2016 estimates from ElA's Today in Energy website. EPA seeks stakeholder feedback on data sources and methodologies that might be used to update the current approach for identifying HF gas and oil wells within the Drillinglnfo data set. EPA might retain the current assumption that all horizontally drilled wells are hydraulically fractured but update the methodology for identifying wells that do not report horizontal drill type but would be expected to be hydraulically fractured based on location in an unconventional formation. EPA is considering reviewing subpart W sub-basin-level (county-level) data to assess whether a crosswalk of location and HF indication might be constructed from or verified using reporting data, in order to estimate total national HF well counts (at least for recent time series years). 3 Requests for Stakeholder Feedback Well Drilling (Section 2.1) 1. EPA seeks stakeholder feedback on data available to improve annual national activity estimates for well drilling across the time series. EPA seeks feedback on the most appropriate data source for updating the GHGI, whether it is highlighted in Section 2.1 (i.e., EIA or Drillinglnfo) or another source that should be considered. 2. EPA seeks feedback on how to ensure time series consistency, given the current EIA data source provides annual activity through 2010. Should a new data source cover only recent years, or be used to entirely replace current estimates? 3. As EPA further considers developing annual well drilling activity estimates from Drillinglnfo data, feedback is sought on the specific methodology and other considerations outlined in Section 2.1. Specifically: a. Whether this approach adequately accounts for dry wells (which are spud but do not achieve reportable production levels). Based on preliminary analysis of results, this approach does appear to sufficiently represent dry wells at comparable levels to the EIA data set; on average, dry wells (not including TIA wells which report production after year N+l) contribute 10% of total wells drilled. b. Whether this approach is overly inclusive of wells that may not be drilled for oil and gas production purposes but are present in the Drillinglnfo data set (e.g., wells drilled specifically for injection). EPA expects a minor contribution from such wells, since estimates developed from the Drillinglnfo approach under consideration are comparable with EIA estimates for the overlapping time frame (1990-2010), as shown in Appendix A. EPA estimates that that injection wells might contribute approximately 2-4% to total counts; it is difficult to identify such wells in the Page 7 of 10 ------- June 2018 Drillinglnfo data set due to the presence of hundreds of reported production types. EPA seeks feedback on how the Drillinglnfo-based methodology might take this issue into account. c. How to account for time series coverage issues (due to states with lagging reporting and therefore not fully represented in the Drillinglnfo data set in recent years). Well Completions and Workovers (Section 2.2) 4. EPA seeks stakeholder feedback on how to use available data to improve national activity estimates for well completion and workover events—specifically, how Drillinglnfo and subpart W data sets might be used in conjunction, or if one data set should be used to develop estimates and the other to verify estimates. Definition of Oil vs. Gas Well (Section 2.3) 5. EPA seeks stakeholder feedback on whether the current methodology for counting and allocating active well counts between oil and gas should be updated, and if so, how. Heavy vs. Light Crude Equipment Service (Section 2.4) 6. Based on RY2015 and RY2016 subpart W data, 19% and 18%, respectively, of oil wells in that data set produce heavy crude (API gravity less than 20), compared to the current GHGI basis of 7.05%. This updated heavy crude fraction is based on reported data for approximately 210,000 active oil wells (out of approximately 580,000 active oil wells nationwide). EPA seeks stakeholder feedback on incorporating this updated fraction into the GHGI time series. a. Should EPA consider developing geographic-specific (e.g., NEMS region-level) estimates of heavy crude well fractions? b. Should EPA retain the estimate of 7.05% of oil wells producing heavy crude (developed for base year 1995) for early years of the time series, and interpolate to the updated fraction based on subpart W data? Or is a different approach more appropriate—for example, where the heavy crude fraction is more tailored to the specific time period, rather than a set or linearly increasing value? EPA seeks information on data sources that might offer information to implement a more tailored approach. 7. How should EPA use API gravity data in conjunction with equipment count data reported under subpart W to improve oil production segment major equipment activity estimates? For example, Table 4 above presents activity factors for separators per oil well developed specifically for heavy and light crude populations. a. Should EPA retain the current approach of extending the heavy/light crude well count split to wellhead and header activity data (for example, 19% of oil wells produce heavy crude, therefore 19% of headers are in heavy crude service)? b. Should EPA retain the current approach of developing specific activity factors for separators in heavy versus light crude service, as shown in Table 4? Identification of HF Wells (Section 2.5) 8. EPA seeks stakeholder feedback on whether it is reasonable to retain the current assumption that all wells with horizontal drill type according to the Drillinglnfo data set are hydraulically fractured, or if there are recommendations for improving this assumption. 9. EPA seeks input on publicly available data sources and methodologies that might be used to identify wells that do not report horizontal drill type in the Drillinglnfo data set but would be expected to be hydraulically fractured based on location in an unconventional formation (i.e., used to create a new formation type crosswalk). a. EPA specifically seeks feedback on how GHGRP subpart W data might be used in this step to construct or verify such a crosswalk. Page 8 of 10 ------- June 2018 Appendix A. Well-Related Activity Data 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 Well counts 2018 GHGI Non-HF gas wells 135,552 141,052 139,823 140,834 142,127 142,245 144,501 144,082 148,078 148,112 144,545 156,621 157,696 162,506 167,595 168,855 175,567 178,970 187,366 186,667 187,098 187,153 182,776 179,300 179,305 173,544 168,151 HF gas wells 62,074 78,538 76,875 82,527 88,242 90,423 99,399 103,820 108,880 113,260 122,364 135,526 142,815 154,003 162,832 179,615 195,683 207,348 227,138 234,576 242,301 248,162 250,614 248,528 252,141 252,107 248,730 Total active gas wells 197,626 219,590 216,698 223,361 230,369 232,668 243,900 247,902 256,958 261,372 266,909 292,147 300,511 316,509 330,427 348,470 371,250 386,318 414,504 421,243 429,399 435,315 433,390 427,828 431,446 425,651 416,881 Non-HF oil wells * 469,317 467,760 454,605 446,499 432,774 423,199 418,579 419,582 401,394 381,938 382,314 379,071 375,274 372,953 372,994 374,960 379,859 380,541 391,513 387,949 389,226 393,598 401,244 404,373 405,284 398,424 373,608 HF oil wells* 84,582 88,843 86,070 87,745 87,088 84,442 86,754 87,650 84,935 82,132 84,785 86,243 86,547 88,223 91,457 94,672 98,627 97,217 112,992 113,657 123,494 135,121 151,260 165,297 184,166 191,593 188,356 Total active oil wells 553,899 556,603 540,675 534,244 519,862 507,641 505,333 507,232 486,329 464,070 467,099 465,314 461,821 461,176 464,451 469,632 478,486 477,758 504,505 501,606 512,720 528,719 552,504 569,670 589,450 590,017 561,964 Total HF wells * 146,656 167,381 162,945 170,272 175,330 174,865 186,153 191,470 193,815 195,392 207,149 221,769 229,362 242,226 254,289 274,287 294,310 304,565 340,130 348,233 365,795 383,283 401,874 413,825 436,307 443,700 437,086 Total active wells 751,525 776,193 757,373 757,605 750,231 740,309 749,233 755,134 743,287 725,442 734,008 757,461 762,332 777,685 794,878 818,102 849,736 864,076 919,009 922,849 942,119 964,034 985,894 997,498 1,020,896 1,015,668 978,845 EIA Today in Energy Total HF wells NPA NPA NPA NPA NPA NPA NPA NPA NPA NPA NPA NPA NPA NPA NPA NPA NPA NPA NPA NPA NPA NPA NPA NPA NPA NPA 670,000 Total active wells NPA NPA NPA NPA NPA NPA NPA NPA NPA NPA NPA NPA NPA NPA NPA NPA NPA NPA NPA NPA NPA NPA NPA NPA NPA NPA 977,000 Drilling event counts 2018 GHGI Gas wells drilled (incl. fraction of dry) 15,096 13,066 10,887 13,047 12,232 10,465 11,498 14,473 14,507 14,564 19,863 25,350 20,041 23,582 27,180 31,969 36,536 36,255 35,824 20,266 18,837 18,837 18,837 18,837 18,837 18,837 18,837 Oil wells drilled (incl. fraction of dry) 17,234 16,796 12,540 11,744 9,587 10,679 11,255 14,105 9,575 5,818 9,424 10,208 7,830 9,251 9,877 12,053 14,893 14,816 18,478 12,537 17,774 17,774 17,774 17,774 17,774 17,774 17,774 Total wells drilled 32,330 29,862 23,427 24,791 21,819 21,144 22,753 28,578 24,082 20,382 29,287 35,558 27,871 32,833 37,057 44,022 51,429 51,071 54,302 32,803 36,611 36,611 36,611 36,611 36,611 36,611 36,611 EIA Monthly Energy Review (basis of 2018 GHGI) Gas (EIA) 11,246 9,793 8,163 9,839 9,375 8,082 9,027 11,498 11,639 12,027 17,051 22,072 17,342 20,722 24,186 28,590 32,838 32,719 32,246 18,088 16,696 NE NE NE NE NE NE Oil (EIA) 12,839 12,588 9,402 8,856 7,348 8,248 8,836 11,206 7,682 4,805 8,090 8,888 6,775 8,129 8,789 10,779 13,385 13,371 16,633 11,190 15,753 NE NE NE NE NE NE Dry (EIA) 8,245 7,481 5,862 6,096 5,096 4,814 4,890 5,874 4,761 3,550 4,146 4,598 3,754 3,982 4,082 4,653 5,206 4,981 5,423 3,525 4,162 NE NE NE NE NE NE Total wells drilled 32,330 29,862 23,427 24,791 21,819 21,144 22,753 28,578 24,082 20,382 29,287 35,558 27,871 32,833 37,057 44,022 51,429 51,071 54,302 32,803 36,611 NE NE NE NE NE NE Preliminary Drillinglnfo Data Analysis (described in Section 2.1)a Gas 13,417 6,719 7,464 6,794 7,208 7,648 16,608 9,557 9,089 10,507 14,449 17,131 14,390 17,237 20,018 23,060 24,733 24,964 23,600 11,636 12,172 9,206 5,512 4,725 4,385 2,580 1,550 Oil 15,013 11,030 11,854 10,720 9,145 10,210 18,925 12,636 7,746 8,447 10,981 11,232 9,558 11,570 13,498 15,553 16,951 18,820 18,633 12,566 20,697 25,874 29,953 30,422 30,209 14,049 8,246 Dry/TIA 7,971 5,650 5,220 4,641 4,249 3,909 4,228 4,601 3,898 3,601 5,095 6,782 4,875 5,549 6,477 6,872 9,190 7,631 9,232 4,773 5,614 6,271 5,781 5,304 7,037 3,861 1,964 Gas wells drilled (incl. fraction of dry/TIA) 17,179 8,858 9,481 8,594 9,081 9,322 18,584 11,538 11,193 12,503 17,344 21,227 17,319 20,557 23,886 27,164 30,186 29,315 28,759 13,931 14,251 10,852 6,410 5,438 5,277 3,179 1,861 Oil wells drilled (incl. fraction of dry/TIA) 19,222 14,541 15,057 13,561 11,521 12,445 21,177 15,256 9,540 10,052 13,181 13,918 11,504 13,799 16,107 18,321 20,688 22,100 22,706 15,044 24,232 30,499 34,836 35,013 36,354 17,311 9,899 Total wells drilled 36,401 23,399 24,538 22,155 20,602 21,767 39,761 26,794 20,733 22,555 30,525 35,145 28,823 34,356 39,993 45,485 50,874 51,415 51,465 28,975 38,483 41,351 41,246 40,451 41,631 20,490 11,760 Page 9 of 10 ------- June 2018 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 Completion event counts 2018 GHGI Gas well non-HF completions 365 405 400 412 425 429 450 458 474 482 493 539 555 584 610 643 685 713 765 778 793 804 800 790 796 786 770 Gas well HF completions 3,769 3,630 2,630 3,425 3,322 3,034 4,057 5,352 4,785 4,583 6,881 8,675 7,536 8,911 10,459 12,866 14,176 14,206 15,223 8,811 8,691 9,749 7,665 7,382 7,141 5,272 3,105 Oil well non-HF completions 9,764 9,644 6,395 5,916 4,742 5,855 6,203 7,671 5,359 3,476 5,844 5,791 4,285 4,618 5,046 6,185 7,369 7,142 8,305 6,117 7,565 3,252 0 0 0 3,315 3,315 Oil well HF completions 3,075 2,944 3,007 2,940 2,606 2,393 2,633 3,535 2,323 1,329 2,246 3,097 2,490 3,511 3,743 4,594 6,016 6,229 8,328 5,073 8,188 12,501 16,335 17,332 19,154 12,438 12,438 Workover event counts 2018 GHGI Gas well non-HF workovers 5,897 6,136 6,082 6,126 6,183 6,188 6,286 6,268 6,441 6,443 6,288 6,813 6,860 7,069 7,290 7,345 7,637 7,785 8,150 8,120 8,139 8,141 7,951 7,800 7,800 7,549 7,315 Gas well HF workovers 621 785 769 825 882 904 994 1,038 1,089 1,133 1,224 1,355 1,428 1,540 1,628 1,796 1,957 2,073 2,271 2,346 2,423 2,482 2,506 2,485 2,521 2,521 2,487 Oil well workovers 41,542 41,745 40,551 40,068 38,990 38,073 37,900 38,042 36,475 34,805 35,032 34,899 34,637 34,588 34,834 35,222 35,886 35,832 37,838 37,620 38,454 39,654 41,438 42,725 44,209 44,251 42,147 * Values not published in the 2018 GHGI, but underlie the current estimates of HF oil well completion event counts N/A - Not applicable NPA - Not publicly available NE - Not estimated a - Results of preliminary approach discussed in Section 2.1. This does not include state-level adjustments to account for lagging reporting that EPA implements for other well-related data elements that are based on Drillinglnfo data. After adjustments that would be implemented in a final methodology, estimates in recent years (e.g., 2015 forward) will likely increase. Page 10 of 10 ------- |