Glossary:Abandoned well

Definition depends on jurisdiction. In Canada, abandoned wells have been plugged but where the site has not been fully reclaimed (similar to a plugged well in the United States). In the U.S., abandoned wells are unproductive wells with a known operator but are often confused with orphaned wells. Due to the confusion and multiple definitions, we recommend avoiding use of the term ‘abandoned’ unless in a specific regulatory context.

Recent studies have investigated methane leakage from abandoned wells in the U.S. The term "abandoned wells" as typically used in published scientific articles and this memo encompasses various types of wells:

• Wells with no recent production, and not plugged. Common terms (such as those used in state databases) might include: inactive, temporarily abandoned, shut-in, dormant, idle.
• Wells with no recent production and no responsible operator. Common terms might include: orphaned, deserted, long-term idle, abandoned.
• Wells that have been plugged to prevent migration of gas or fluids.

Emissions from abandoned oil and gas wells were not included in previous GHGIs. Commenters on previous GHGIs supported including this source, but noted that the current data were limited, and suggested reviewing data that will become available in the future.

According to a recent paper from Stuart Riddick from the CSU Energy Institute uses this classification method: “The term abandoned describes a range of well types including:

1. wells with no recent production, and not plugged (inactive, temporarily abandoned, shut-in, dormant, idle);
2. wells with no recent production and no responsible operator (orphaned, deserted, long-term idle); and
3. well that have been plugged to prevent migration of gas or fluids.”

References

Methane Emissions from Abandoned Oil and Gas Wells in Colorado,” Riddick, Mbua, Santos, Emmerson, Cheptonui. Hartzell and Zimmerle, 2023