Technologies and Practices for Plugging and Remediating Orphan Oil and Gas Wells (2026)
Chapter: Appendix C: Questionnaire to State and Tribal Agency Representatives
Appendix C
Questionnaire to State and Tribal Agency Representatives
The following questionnaire was sent to state officials before a planned meeting after the Interstate Oil & Gas Compact Commission Annual Business Meeting, May 21–22, Oklahoma City, Oklahoma. Anonymized responses are stored in the consensus study’s public access file.
GENERAL QUESTIONS
Are there important well plugging technology challenges or opportunities that your agency/organization would like to see addressed by the research community?
What component of your state orphaned well program is most challenging (i.e. contracting process, technical factors, others)? Please describe the challenge.
Looking at the consensus study statement of task, what is the most important area(s) of focus for your state?
- - Examine current and emerging plugging and abandonment technologies, best practices, equipment, and materials for well characterization, wellbore plugging and barrier placement, wellbore integrity and verification, and durability and lifespan. Information from the National Academies workshop on “Practices and Standards for Plugging Orphaned and Abandoned Hydrocarbon Wells” will be considered in this examination.
- - Evaluate unexpected or unique circumstances that necessitate varying criteria and standards, including engineering design, cost, logistics, or technical management.
- - Assess available data on potential causes, frequency, consequences, and remediation of plug failures.
- - Examine post-plugging monitoring techniques, approaches, and technology that are or will be important for the long-term protection of the environment and
-
public health and safety. Include any identified post-plugging risk management best practices to ensure the long-term protection of groundwater and prevention of methane emissions as well as relevant economic considerations.
- - Identify technology, materials, or policies that warrant further research and that may contribute to the success of well-plugging and abandonment efforts carried out by industry, states, tribes, and federal agencies.
DATA ON PLUGGED WELLS AND ORPHANED WELLS
Do you collect or have data on plugging failures from previously plugged wells?
Plugged well failure means any well that was previously plugged with intentions of being permanently abandoned (i.e. not returning to the site) and has exhibited a loss of containment of wellbore fluids that has impacted surface or subsurface (e.g. groundwater) requiring the previously plugged well to be re-entered and remediated.
If Yes, please respond to the below questions.
If No, please provide any information you are able or willing to share with the study committee (especially related to root causes for well leakages post plugging). If none, please note “NA”
(If Yes) What is the total number of plugged and abandoned wells in your state on record as of March 31, 2025? If approximate, please note.
(If Yes) What is the total number of previously plugged and abandoned wells in your state that were reported to have leaked (surface or subsurface), post plugging and abandonment? If approximate, please note.
(If Yes) Provide any available information on well age and root causes for leakages (e.g. not plugged to current regulation or standard, cement plug failure, annulus cement failure, etc.). Specifically, please note the following categories if possible:
- − Well ID
- − Well age
- − Well plug date/well plug age
- − Root cause for leakages post plugging
Where records are too extensive to list out entirely, please provide a few examples as you see fit and note any summarizing data or additional information you would like the committee to know. Furthermore, where records are publicly available, please note where they can be accessed.
REQUIREMENTS AND MONITORING
What are the requirements for pulling well casing during plugging in your jurisdiction?
What are the post plugging monitoring requirements in your jurisdiction? If possible, please note what is monitored, for how long, and at what intervals.
What definition of “protected waters” do you consider when plugging? Is it consistent with the USDW (underground sources of drinking water) definition copied below? “A USDW is defined in the Code of Federal Regulations (40 CFR 144.3) as:
an aquifer or its portion: (a)(1) Which supplies any public water system; or (2) Which contains a sufficient quantity of ground water to supply a public water system; and (i) Currently supplies drinking water for human consumption; or (ii) Contains fewer than 10,000 mg/l total dissolved solids; and (b) Which is not an exempted aquifer.”
Source: https://www.epa.gov/uic/general-information-about-injection-wells#USDW_defined
If possible, please provide additional information on whether the definition used in your jurisdiction is consistent across state agencies/organizations (e.g., oil and gas regulator, department of water resources); approximately how long has the current definition been in use; has it changed over time?
How are protected waters delineated (e.g. by TDS or salinity)? When were they last delineated?
