Plugging Abandoned Oil & Gas Wells

Abandoned oil and gas wells are wells that are no longer producing and that do not have an operator responsible for their remediation. In the US, these wells collectively emit an estimated 6.6 million MTCO₂e-worth of methane each year, though there is a dearth of empirical measurements at wellheads and this number may actually be significantly higher. The EPA estimates the number of abandoned, unplugged wells in the US to be between 2.3 and 3.2 million.

There is still great uncertainty around the typical emissions from an average abandoned well. We are working to better understand and predict methane emissions from wells across the US, to better prioritize remediation efforts at high-emitting wells and encourage innovation to reduce the carbon intensity of the plugging process.

Abandoned Wells Timeline

Our initial efforts aim to better understand methane emissions from abandoned wells. Very few emissions measurements have been taken at wells across the US. We are supporting measurement at a wider scale, followed by the development of a model which can be used to predict which wells will emit the most methane. The model can be used to map high-priority wells for plugging.

investigation

Literature review and outreach

experimentation

Collaboration with researchers to map wells in regions of interest

experimentation

Field measurements of methane emissions

implementation

Analysis of results and publication of findings and conclusions

implementation

Update well plugging procedures and measurement protocols based upon prior research findings

Currently

Collaborating with the Kentucky Geological Survey

In states with historical oil and gas production, the number of abandoned oil and gas wells exceeds the state’s plugging capacity by several orders of magnitude, even with robust federal funding. The CC Lab is collaborating with the Kentucky Geological Survey (KGS) to develop a prioritization tool which assesses the potential environmental hazard presented by abandoned wells, and provides guidelines on which wells to plug first. Once developed and proved, this model may be adapted for use by other states.

Rig at a well plugging site. CC Lab 2022.

Expand

Identifying High-Priority Wells

This collaboration leverages expertise in geospatial analysis and carbon containment at the CC Lab with a rich well completion database and geological expertise at KGS. Analysis and development of a scoring tool for plugging prioritization is being developed in three pilot areas in western, central, and eastern Kentucky. Evaluated inputs will include engineering and geologic attributes specific to the abandoned wells and, importantly, the geospatial setting of the wells relative to societal and natural resource features. Moreover, results of the work will serve as a guide to select wells for further measurement of methane emissions.

Abandoned wellhead. CC Lab, 2022.

Expand

Designing Better Plugging Methods

Current regulations require wells to be plugged with concrete to protect groundwater resources, prevent surface pollution, and stop methane emissions. This is an expensive – an average well can cost between $30,000 to $170,000 to plug – and carbon-intensive process. It is also challenging to access some well sites located deep in wooded or rugged terrain. Research is needed to innovate and improve these well plugging techniques, lower the cost, and to better characterize and quantify methane emissions from abandoned wells.

Well site pre-plugging in Montana. CC Lab, 2022.

Expand

Risks & Project Challenges

Methane measurement

There are few direct methane emissions measurements from abandoned oil and gas wells. Subsequently, there is high uncertainty over the average amount of methane emitted by a typical well. It is likely that some wells may emit many tons, while others emit little to none.

Aerial survey techniques are improving, but still not sensitive enough capture low-emitting sources such as abandoned wells, necessitating ground measurements and surveys. Given the challenge and expense associated with overland surveys, it is possible survey techniques in certain regions may miss high-emitting wells, while overrepresenting low-emitting ones.

Adoption and implementation

Well plugging programs are currently organized at the state level. Protocols or approaches adopted by one state, may not necessarily be adopted by others.

We aim to ensure findings from our research can be generalized and applied across various regions in US and inform policy beyond the initial research area.

Partners

Kentucky Geological Survey

We are partnering with the Kentucky Geological Survey to develop a prioritization tool for well plugging which will be used across the state of Kentucky.

Partner with us

Your full name ^*

Your email address ^*

Area of Expertise ^*

Your message