An introduction to plugging of orphan oil and gas wells

Introduction

Calyx Global is excited to announce our first rating of credits from a project that plugs orphan oil and gas wells to prevent methane (CH4) emissions in the U.S. The “Heartland Methane Abatement and Lands Restoration – Packard & Kottke Ranch Project” has been issued just over 80,000 credits under ACR’s “Methodology for The Quantification, Monitoring, Reporting and Verification of Greenhouse Gas Emissions Reductions and Removals From Plugging Orphan Oil And Gas Wells in the U.S. and Canada.”

Background — What are orphan wells?

Research into oil and gas wells that are marginally producing or non-producing is active and ongoing, and a variety of terminology is in use across the literature. In general, an orphan well refers to an oil or gas well that is no longer operating and lacks an owner or operator responsible for its maintenance and monitoring. These wells can date back several decades and were often left behind due to bankruptcy, company closures or inadequate regulations. In many cases, the responsibility of the well has fallen to the states, provinces, federal agencies or Tribes.

An image of an oil pump that is no longer in use[1]

Risks associated with orphan wells, including methane vents

Unsealed wells can become pathways for pollutants to enter the air, groundwater and soil. In particular, many of these wells leak methane, which can be a concern for local communities and is also a highly potent greenhouse gas.

Regulatory requirements for the plugging of orphan wells

Existing regulations typically require oil and gas operators to plug and formally abandon wells, with practices certified by the overseeing government agency. However, orphan wells no longer have solvent owners. They can be of an age that predates plugging requirements, or they may have been plugged decades ago in a manner that does not prevent methane emissions. Several states and provinces operate well-plugging programs, and while research indicates the number of orphan wells may be beyond the amount of funding available for these programs, the proportion of orphan wells that leak methane and in what quantities continues to be an active area of study.

Methane emissions and climate change

It is estimated that methane is responsible for approximately 30% of the rise in global temperatures since the Industrial Revolution, and there is consensus that rapid and sustained reductions in methane emissions are key to limiting near-term warming. Methane has a shorter atmospheric lifetime than carbon dioxide (CO2) — approximately 12 years compared with centuries — but absorbs much more energy while it exists in the atmosphere. As a result the warming potential of methane is over 25 times greater than carbon dioxide over a 100-year period.

The Environmental Defense Fund, McGill University and others conducting research in this area estimate there are hundreds of thousands of orphan oil and gas wells — many of which are known to be leaking some amount of methane — across the U.S. and Canada. A commonly cited figure from the U.S. Environmental Protection Agency estimates between 7-20 million tonnes of carbon dioxide equivalent (CO2e) is emitted from non-producing, unplugged oil and gas wells each year (of which orphan wells are a portion).

Map by the Environmental Defense Fund[2] of a portion of the documented orphan wells across the United States

Plugging technology for orphan oil wells

Plugging orphan oil and gas wells involves removing any materials that may be present and pouring cement into the well, which can range from tens to hundreds of meters in depth. Other practices exist, and in addition to cement, plugging materials can include bentonite and various types of sealants. The plugging aims to prevent the release of methane into the atmosphere and costs can range from below $20,000 to over $1 million, according to the accessibility of the well, the time and expertise necessary to remove materials from the well, and its depth.

Image depicting plugging of orphan well Anderson #7 by Well Done Foundation[3]

Overview of projects in the voluntary carbon market 

To date, 13 projects plugging orphan oil and gas wells are listed with ACR. One of these is complete and has issued credits, while the others have a status of 'listed' with ACR.

Calyx Global ratings of oil well-plugging projects

Calyx Global has developed a rating framework to assess the GHG integrity of well-plugging projects. If you’re interested in viewing our first rating, contact us about a subscription to the Calyx Global Platform.

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Citations

[1] Strange Happenings (November 9, 2022). Rusted Pumpjack in the Desert, Pexels. Accessed July 2024 https://www.pexels.com/photo/rusted-pumpjack-in-the-desert-14377363/
[2] Nick Trotter Maps and Alan Bucknam / Notchcode Creative (October 14, 2021). Plugging orphan wells across the United States, Environmental Defense Fund (EDF). Accessed July 2024 
[3] Well Done Foundation (December 1, 2020). The Well Done Foundation team plugging Anderson #7. Grist.org Accessed July 2024 The government can’t keep up with abandoned oil wells. Can these industry insiders help? | Grist