Under the same rules, one plugged well can be issued 37 carbon credits or 989, depending on the leak rate assumed for it [1]. For a seller that number is the revenue, and for a buyer it is the risk of paying for methane that never escaped. The American Carbon Registry (ACR), a carbon crediting program and nonprofit enterprise of Winrock International, made its plugging methodology inactive in May 2025 [2]. The version 2.0 that new projects must use was still listed as in development on 4 November 2026 [3].
A carbon credit is a serialised registry unit representing one metric tonne of carbon dioxide equivalent reduced or removed against a baseline [4]. Carbon dioxide (CO2) equivalent restates another gas as the tonnes of CO2 that would trap as much energy, using that gas’s global warming potential (GWP) [5]. A GWP measures how much energy one tonne of a gas absorbs over a set period, usually 100 years, relative to one tonne of CO2 [5]. GWP values come from the Assessment Reports of the Intergovernmental Panel on Climate Change, such as the Fifth (AR5), and differ between editions [6].
Oil and gas methane carbon credits are credits earned by keeping methane from oil and gas wells and equipment out of the atmosphere. Two project types are covered here: plugging orphaned or marginal wells, and repairing leaks at producing assets [7]. Both are avoidance rather than removal, meaning gas that would have escaped and did not. A credit is the difference between a source’s baseline, what it would have emitted without the work, and what it emits afterwards.
Published leak rates for unplugged wells span more than an order of magnitude, so the assumed baseline decides the volume [1]. The credit count is set by the baseline estimate, which some methodologies take from a field measurement and others model from a decline rate [7]. In order, the post covers the two project types and their rules today, what one avoided leak is worth, and why the baseline decides volume. It is written for operators, plugging developers and credit buyers who are new to carbon markets.
Quick Answer: Oil and gas methane credits include those from plugging orphaned or marginal wells and from leak repair at producing assets [7]. One credit equals one metric tonne of CO2 equivalent [4]. Fossil methane converts at a 100-year GWP of 30 under AR5 [6]. Under ACR’s inactive version 1.0, avoided annual emissions were multiplied by a 20-year crediting period and issued when the well was plugged [8]. Published leak rates run from 7.5 grams an hour, which most abandoned wells fall below, to a 198 gram U.S. mean for unplugged wells [1].
Two Project Types Produce Oil and Gas Methane Credits
The oil and gas methane crediting reviewed here splits into stopping a well venting and stopping equipment leaking. The two are accounted for differently, but neither is guaranteed permanent: a repair can fail, and a plugged well can start leaking again [7]. Earlier studies, using small-sample emission factors, put methane from roughly 3.6 million U.S. abandoned wells at 0.23 to 2.6 teragrams a year [1]. Only part of that range is the market’s supply side, because the abandoned-well count includes wells already plugged and wells with a solvent operator.
The American Carbon Registry (ACR) published a dedicated methodology in May 2023, covering the United States and Canada [8]. The registry made that version inactive on 9 May 2025, to update requirements to ensure consistent application across diverse sites [8].
Version 2.0 remains in development, and ACR still gives 2026 as the publication target [9]. The update had not opened for public comment or entered scientific peer review by 9 September 2026 [9]. ACR continues to accept project listings until version 2.0 publishes, and those projects must validate against the new version [2].
The Climate Action Reserve is separately developing an early plugging protocol for marginal wells in the United States [10]. Its public comment draft was released on 14 September 2026, with comments open through 14 October 2026 [10].
Where the Plugging Rules Stand in November 2026
Since September two standards, the Climate Action Reserve and Isometric, have opened plugging drafts, and none of the new rules is final yet.
| Date | Registry action |
|---|---|
| 24 May 2023 | ACR publishes version 1.0, which ACR calls the world’s first methodology focused on plugging orphaned wells in the United States and Canada |
| 9 May 2025 | ACR makes version 1.0 inactive; verified projects and issued credits are unaffected |
| 14 Sep to 14 Oct 2026 | Climate Action Reserve takes public comment on its U.S. early plugging protocol |
| 15 Oct to 14 Nov 2026 | Isometric consults on a draft Orphaned Well Plugging Protocol for the United States and Canada |
| 4 Nov 2026 | ACR version 2.0 is still in development, planned for 2026, with no comment date posted |
The Reserve’s page did not report board approval of its protocol as of 4 November 2026 [10]. Isometric’s draft requires a direct, on-site measurement of each well’s leak before plugging [11]. It projects the avoided emissions over a 20-year crediting period [11]. Both choices put the pre-plugging measurement at the centre of the credit count.
Public Money Is Already Plugging These Wells at Scale
Federal money now funds plugging at national scale [12]. The Interior Department reports 6,433 jobs supported in federal fiscal year 2022 (FY22) and 780 in FY23 [12]. Economic contribution over the two years came to $934.5 million [12]. A federal fiscal year begins on 1 October and ends on 30 September [13].
Section 40601 of the Bipartisan Infrastructure Law provides 4.677 billion dollars for orphaned well plugging, remediation and restoration [12]. Of that, 4.275 billion dollars goes to states for wells on state and private land [12].
The program is well past pilot scale [12]. States and federal bureaus reported 9,002 orphaned wells plugged with those funds through 30 June 2024 [12]. The work continues against an inventory of 141,959 documented orphan wells reported by 29 states as of 31 December 2023 [12].
The undocumented population is estimated to be larger than the documented one [12]. The Interstate Oil and Gas Compact Commission estimates a further 250,000 to 740,000 undocumented orphaned wells [12]. Undocumented wells cannot be credited until they are located, because a project has to identify the source it is abating.
What Additionality Requires When a Grant Would Have Paid
Under the Integrity Council’s additionality principle, a credit has to fund a reduction that would not have occurred without carbon credit revenue [14]. A well already scheduled for plugging under a state grant is hard to call additional, though ACR version 1.0 passed every eligible orphaned well. The federal program’s size could therefore narrow the crediting pool, though ACR version 1.0 treated orphaned wells as highly unlikely to be remediated soon.
The remaining pool is the wells public money is not reaching. That is a smaller and less well characterised set than the headline well count suggests.
Leak repair at producing assets sits on firmer ground with buyers. The Integrity Council for the Voluntary Carbon Market lists AM0023 version 4.0, a leak repair methodology, as approved under its high-integrity Core Carbon Principles (CCP) [15]. That methodology covers leak detection and repair in gas production, processing, transmission, storage and distribution systems and in refinery facilities [15]. Well plugging sits a step behind: no plugging methodology holds the CCP label, and three new plugging rules were still unfinished in November 2026.
How Many Credits One Avoided Leak Is Worth
The arithmetic starts short: a leak rate times hours of operation, converted from methane mass to carbon dioxide equivalent. A well leaking 13 grams of methane an hour releases about 114 kilograms a year [1]. At a global warming potential of 30, that is roughly 3.4 tonnes of CO2 equivalent a year [6].
Which Global Warming Potential Applies to Vented Methane
The Greenhouse Gas Protocol says fossil fugitive methane, such as from oil and gas systems, should take the fossil value, not the non-fossil one [6]. EPA’s Greenhouse Gas Reporting Program uses 28 for methane, the AR5 value without the fossil adjustment [16]. The fossil figure includes extra radiative forcing from carbon dioxide formed when that methane oxidises [6]. The table gives Greenhouse Gas Protocol values from the Intergovernmental Panel on Climate Change’s Fourth (AR4), Fifth (AR5) and Sixth (AR6) Assessment Reports [6].
| 100-year GWP | AR4 | AR5 | AR6 |
|---|---|---|---|
| Methane, non-fossil | 25 | 28 | 27.0 |
| Methane, fossil | not given | 30 | 29.8 |
Moving one project from AR4 to AR5 fossil raises its credit count by a fifth [6]. No molecule changed.
How Many Years a Plugged Well Is Credited For
Under the American Carbon Registry’s version 1.0, a plugged well was credited for two decades at once, not year by year [8]. Under the inactive version 1.0, the American Carbon Registry set a single non-renewable crediting period of twenty years [8]. Credits corresponding to twenty years of avoided emissions are eligible for issuance in the year the well is plugged [8]. The methodology’s Equation 2 multiplies the annual avoided emissions by 20 directly [8].
| Methodology | Crediting period | Baseline treatment |
|---|---|---|
| American Carbon Registry (v1.0, inactive) | 20 years | Measured rate held flat |
| CarbonPath | 50 years | Measured rate held flat |
| BCarbon | 20 years | Declines from a starting point set by the well’s production history |
| Open Carbon Protocol | 20 years | Declines at a rate set by emitter class |
The American Carbon Registry row is from its own methodology; the other three rows are as characterised in the Payne Institute’s review. [17] CarbonPath sets the longer period against a lower starting rate, because it credits a measured current leak rate rather than a leak potential [17]. BCarbon instead forecasts from at least 42 months of the well’s production history and takes a probability-weighted average of two leak scenarios [17]. Open Carbon Protocol assigns its decline rate by emitter class rather than well by well [17].
That version also applied a haircut: projects had to take a 5 per cent uncertainty deduction from quantified reductions [8]. Eligibility separately requires sampling precision within 10 per cent of the mean at 90 per cent confidence [8]. The estimator below applies the deduction to a rate you supply and states the precision requirement alongside it.
The Baseline Estimate Decides the Credit Volume
Baseline choice moves credit volumes further than any other input in a methane project. RMI, an independent clean-energy nonprofit, identifies four approaches in use across methodologies in its technical explainer [7]. They are flat-rate extrapolation of a current measurement, terminal decline, decline curve modelling, and volumetric analysis [7]. Its verdict is that there is no market consensus on which of them is most appropriate, and it lists a drawback for each [7].
A Payne Institute study of 14,000 wells put terminal decline rates between 2.9 and 9.4 per cent [17]. The band is a 20th-to-80th percentile spread around a 6.4 per cent average, not an absolute range [17]. Open Carbon Protocol assigns 4.9 to 7.3 per cent by emitter class, and BCarbon sets the rate well by well [17].
A Single Visit Cannot Pin a Rate That Moves
The measurements feeding those baselines are less stable than a single number suggests. A 2025 study measured one orphaned well near Hobbs, New Mexico at 9.00 kilograms of methane an hour during a controlled venting operation [1]. That was 71 per cent above the 5.3 kilograms measured at the same well seven months earlier [1].
Venting this well also gave an opportunity to calculate its leak rate under American Carbon Registry guidance [1]. The 9.00 figure is therefore a crediting input rather than the rate the well leaks when left alone. That same well’s persistent leak, through its surface casing, was 0.43 to 0.67 kilograms an hour [1]. A baseline drawn from the vent is more than an order of magnitude above the one drawn from the leak.
The authors conclude that wells need periodic revisits for accurate annual estimates [1]. Under ACR version 1.0, one visit could not have set the baseline [8]. The method required two measurement series at least 30 days apart and made a well ineligible if its rates did not stabilise [8]. Two afternoons of fieldwork a month apart would have priced two decades of the asset.
Population averages are a poor guide to any one well, because the distribution they average is skewed. Most abandoned wells emit under 7.5 grams of methane an hour [1]. The commonly cited average is about 13 grams, and the estimated United States mean is 198 [1]. Those three assumptions turn one plugged well into 37, 65 or 989 issued credits [1].
A 26-fold spread on the headline product is not a rounding problem. It argues for well-specific measurement, which ACR version 1.0 and Isometric’s draft protocol both require before plugging. Background on how these wells are identified sits in Abandoned Gas Wells: What They Are and Where to Find Them.
Figure 1. Credits one plugged well would earn over 20 years at three published population leak rates (7.5, 13 and 198 grams of methane an hour), computed by TetraSoft from rates cited in Follansbee et al. (2025) [1].
Method matters as well as frequency. At one well, the 2025 study reports 15 per cent accuracy, within two standard deviations, using on-site dispersion parameters instead of an assumed stability class [1].
A baseline is more than a measurement. It is a claim about what a source would have emitted: a measurement can anchor it, but a projection carries it forward.
Read the registry’s two numbers together. The registry’s own eligibility bar is a sampled mean good to 10 per cent at 90 per cent confidence [8]. The well near Hobbs read 71 per cent higher on a return visit seven months later, likely from gas pressure building up [1]. One visit cannot demonstrate that precision on a source that moves that far, which is why version 1.0 required two measurement series.
Why a Population Average Cannot Set a Baseline
Pre-plugging tests at 1,446 of 9,002 federally funded plugged wells found most barely leaking; about a quarter with detectable methane averaged 296 grams an hour [12]. Methane detection tests were made at 1,446 wells before plugging, and about a quarter produced detectable quantities [12].
Roughly 85 per cent were leaking less than 1 gram of methane an hour [12]. Roughly 90 per cent were leaking less than 10 grams an hour [12].
The averages sit nowhere near those figures [12]. Wells with detectable methane averaged about 296 grams an hour [12]. Across the whole 1,446-well dataset the average was about 70 grams an hour [12].
An average of 70 against a majority under 1 is the shape of the problem. The mean describes a population where about 85 per cent of tested wells sat below 1 gram an hour, at least seventy times under it.
Figure 2. About 85 per cent of tested wells emit less than 1 gram an hour; the averages are set by the minority that emit more. [12]
A skewed distribution makes the average the wrong statistic to credit against. Applying 70 grams an hour to a well leaking under 1 would issue credits for far more abatement than its measured leak supports. Applying it to a 296 gram well would under-issue against real abatement.
Well-specific measurement, repeated rather than taken once, is one route that survives either direction. It is also what the registries have been moving toward.
What clears the bar is a distribution rather than a single number. TetraSoft MAES, the Mechanistic Air Emissions Simulator, is a physics-based simulator that estimates emissions facility by facility [18]. TetraSoft MAES is built to simulate operating oil and gas facilities, not orphaned wells, so the plugging case is not its job. It models producing facilities, where this market’s other project type, leak repair, takes place.
The model was developed at Colorado State University and the University of Texas at Austin [18]. TetraSoft uses it through a partnership with Colorado State University [18]. It generates an expected emission range for operating equipment [19].
A Measurement-Informed Inventory anchors that range to field measurement [19]. Neither half produces one alone. Your 989-credit well and your 37-credit well may be the same well [1]. The difference is which baseline you can defend when a validator asks.
Frequently Asked Questions
Why is the crediting period twenty years?
The American Carbon Registry set a single non-renewable period of twenty years [8]. That length reflects Enverus oilfield data showing that wells states currently classify as orphaned last produced 17 years ago on average [8]. The registry says it will update the methodology as data on well degradation and decline curves improves [8].
Can an operator sell credits for methane it is already required to control?
No. Registry methodologies such as the American Carbon Registry’s apply a regulatory surplus test, which excludes reductions that law already compels. A repair mandated by a federal or state rule is not additional, so it cannot be credited. The same abatement can still appear in an emissions inventory, because reporting and issuance are separate systems.
Do carbon credits count toward GHGRP or OGMP 2.0 reporting?
No: under the Integrity Council’s Core Carbon Principles, a registry issues carbon credits after independent third-party validation and verification [15]. Selling a credit does not change the inventory figure, and reporting an inventory does not create a credit.
Under the Greenhouse Gas Reporting Program (GHGRP), the federal Environmental Protection Agency (EPA) collects emissions data from large greenhouse gas sources [20]. OGMP 2.0, the Oil and Gas Methane Partnership, is the United Nations Environment Programme’s flagship oil and gas methane reporting programme [21]. The reporting side is covered in OGMP 2.0 Level 4 and Level 5 Reporting Explained.
What happens to credits already issued under a methodology that is later withdrawn?
They remain valid. When the American Carbon Registry made its orphaned well methodology inactive, it said issued credits were unaffected [2]. Projects holding approved Methane Measurement Method Approval Forms could complete verification under the inactive version 1.0 [2]. ACR’s inactivation closed version 1.0 to new projects rather than reversing past issuance.
Does a plugged well need monitoring after the credits are issued?
That is the permanence question: version 1.0 required post-plugging monitoring to demonstrate plug integrity [8]. It also applied its 5 per cent uncertainty deduction partly because the long-term integrity of well plugs is still being researched [8]. Under version 1.0 the American Carbon Registry issued all twenty years of credits at once, upon verification of the plugging [7]. Issuing decades of credits at once puts the weight on the pre-plugging measurement; later monitoring tests the well for leakage rather than re-measuring the baseline.
This post is for informational purposes only and does not constitute legal or compliance advice. Consult qualified legal counsel or a compliance professional for guidance specific to your operations and jurisdiction.
Screening the well population is where a plugging project starts. TetraSoft Atlas, a subscription data platform, maps 3,095 New Mexico wells with open plugging liability from state records: orphaned, temporarily abandoned, shut-in, or plugged-but-unreleased [22]. That regulator is the Oil Conservation Division (NMOCD), which regulates oil and gas activity in New Mexico [23].
Of those, 497 carry a Reclamation Fund status (485 approved, 12 pending), the category Atlas maps as orphan [22]. Each well carries its status and its operator, so a candidate list can be filtered before anyone drives out [22]. Contact us to see the inventory behind a candidate list.
Disclosure: Arthur Santos, the author of this post, is a co-author of the Follansbee et al. (2025) study and lead author of the Santos et al. (2025) study cited here.
References
- Follansbee, E., Lee, J. E., Dubey, M. L., Dooley, J. F., Shuck, C., Minschwaner, K., Santos, A., Biraud, S. C., and Dubey, M. K. “Orphaned oil and gas well methane emission rates quantified using Gaussian plume inversions of ambient observations.” Atmospheric Measurement Techniques, 18, 4527-4542, 2025. https://doi.org/10.5194/amt-18-4527-2025
- American Carbon Registry. Update about Plugging Orphaned Oil and Gas Wells Methodology v1.0. 16 May 2025. https://acrcarbon.org/news/plugging-orphaned-oil-and-gas-wells-methodology-v1-0-made-inactive/
- American Carbon Registry. Plugging Orphaned Oil and Gas Wells, Version 2.0 (in development). https://acrcarbon.org/methodology/plugging-orphaned-oil-and-gas-wells-2/. Accessed 4 November 2026.
- Integrity Council for the Voluntary Carbon Market. Core Carbon Principles, Assessment Framework and Assessment Procedure, Version 1.1, January 2024. Glossary definition of “carbon credit”. https://icvcm.org/wp-content/uploads/2024/02/CCP-Book-V1.1-FINAL-LowRes-15May24.pdf
- U.S. Environmental Protection Agency. Understanding Global Warming Potentials. https://www.epa.gov/ghgemissions/understanding-global-warming-potentials
- Greenhouse Gas Protocol. Global Warming Potential Values. August 2024. https://ghgprotocol.org/sites/default/files/2024-08/Global-Warming-Potential-Values%20%28August%202024%29.pdf
- RMI. Technical Explainer: Orphaned Oil and Gas Well Carbon Credits. 31 March 2026. https://rmi.org/resources/technical-explainer-orphaned-oil-and-gas-well-carbon-credits/
- American Carbon Registry. Methodology for the Quantification, Monitoring, Reporting and Verification of Greenhouse Gas Emission Reductions and Removals from Plugging Orphaned Oil and Gas Wells in the US and Canada, Version 1.0. Published 24 May 2023; made inactive 9 May 2025. https://acrcarbon.org/wp-content/uploads/2023/05/ACR-OOG-v1.0-2024-04-19.pdf
- American Carbon Registry. Plugging Orphaned Oil and Gas Wells, Version 2.0 (in development). https://acrcarbon.org/methodology/plugging-orphaned-oil-and-gas-wells-2/. Accessed 9 September 2026.
- Climate Action Reserve. U.S. Early Plugging of Marginal Oil and Gas Wells Protocol (in development). https://climateactionreserve.org/how/protocols/waste/early-plugging-of-marginal-oil-and-gas-wells/dev/. Accessed 4 November 2026.
- Isometric. A new protocol for Orphaned Well Plugging. 15 October 2026. https://isometric.com/writing-articles/a-new-protocol-for-orphaned-well-plugging
- U.S. Department of the Interior, Orphaned Wells Program Annual Report to Congress, November 2024. Orphaned Wells Program Office, Bipartisan Infrastructure Law Section 40601. https://www.doi.gov/sites/default/files/documents/2024-11/fy-2024-owpo-annual-congressional-reportfinal-publishing.pdf
- U.S. Department of the Treasury. Accounting & Budget FAQs. https://home.treasury.gov/subfooter/faqs/accounting-budget-faqs
- Integrity Council for the Voluntary Carbon Market. Core Carbon Principles, Assessment Framework and Assessment Procedure, Version 1.1, January 2024. Core Carbon Principle 5, Additionality. https://icvcm.org/wp-content/uploads/2024/02/CCP-Book-V1.1-FINAL-LowRes-15May24.pdf
- Integrity Council for the Voluntary Carbon Market. Core Carbon Principles and CCP Assessment Status. https://icvcm.org/assessment-status/
- U.S. Code of Federal Regulations. 40 CFR Part 98, Subpart A, Table A-1, Global Warming Potentials, 100-Year Time Horizon. https://www.ecfr.gov/current/title-40/chapter-I/subchapter-C/part-98/subpart-A/appendix-Table%20A-1%20to%20Subpart%20A%20of%20Part%2098
- Handler, B. Orphan Well Carbon Crediting Methodologies: A Review of Quantification Practices and Proposal to Incorporate Leak Forecasting. Payne Institute for Public Policy, Colorado School of Mines, Commentary, 25 June 2026. https://payneinstitute.mines.edu/orphan-well-carbon-crediting-methodologies-a-review-of-quantification-practices-and-proposal-to-incorporate-leak-forecasting-2/
- TetraSoft. MAES landing page. https://www.tetrasoftco.com/maes-platform/maes-landing.html
- Santos, A., Mollel, W., Duggan, G. P., Hodshire, A., Vora, P., and Zimmerle, D. “Using Measurement-Informed Inventory to Assess Emissions in the Denver-Julesburg Basin.” ACS ES&T Air, 2025, 2 (8), 1598-1611. https://doi.org/10.1021/acsestair.5c00089
- U.S. Environmental Protection Agency. Greenhouse Gas Reporting Program (GHGRP). https://www.epa.gov/ghgreporting
- Oil and Gas Methane Partnership 2.0. OGMP 2.0 home page. https://ogmpartnership.org/
- TetraSoft Atlas, New Mexico orphaned and abandoned well inventory, from EMNRD OCD (NMOCD) records. https://www.tetrasoftco.com/atlas
- New Mexico Energy, Minerals and Natural Resources Department. Oil Conservation Division. https://www.emnrd.nm.gov/ocd/
- Climate Action Reserve. U.S. Early Plugging of Marginal Oil and Gas Wells Protocol (in development). https://climateactionreserve.org/how/protocols/waste/early-plugging-of-marginal-oil-and-gas-wells/dev/. Accessed 9 September 2026.
- Verra. AM0023: Leak Detection and Repair in Gas Production, Processing, Transmission, Storage and Distribution Systems and in Refinery Facilities. https://verra.org/methodologies/leak-detection-and-repair-in-gas-production-processing-transmission-storage-and-distribution-systems-and-in-refinery-facilities/
Interactive tool
Methane abatement credit estimator
Enter a measured leak rate. The three settings beside it are conventions, not measurements, and they move the result further than the plugging work does.
Credits issued
65
tonnes CO2e over 20 credited years
Enter a leak rate above zero and a whole number of wells.
The same settings, applied to three published population rates
| Baseline rate | Basis | Credits |
|---|---|---|
| 7.5 g/h | Most abandoned wells below | 37 |
| 13 g/h | Commonly cited average | 65 |
| 198 g/h | Higher recent estimate | 989 |
Follansbee et al., Atmospheric Measurement Techniques 2025, 18, 4527-4542
What this estimate assumes
- Emissions after plugging are taken as zero, the PP term in the registry's Equation 2. A leaking plug is a permanence question, not a baseline one. American Carbon Registry, Plugging Orphaned Oil and Gas Wells Methodology v1.0
- The leak rate is held flat across the whole crediting period, which is how the flat-rate methodologies treat it. A decline method returns less. American Carbon Registry, Plugging Orphaned Oil and Gas Wells Methodology v1.0
- Vented well gas is fossil methane, so it takes the fossil GWP row rather than the more familiar non-fossil value. Greenhouse Gas Protocol, Global Warming Potential Values, August 2024
- Eligibility separately requires sampling precision within 10% of the mean at 90% confidence. That is a gate on the measurement, not a factor in this arithmetic. American Carbon Registry, Plugging Orphaned Oil and Gas Wells Methodology v1.0
An estimate of issuance under a flat-rate methodology, not a project valuation and not a verification. A registry, a validator and a buyer each apply their own tests. Nothing leaves your browser.
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