ORPHANED WELL PLUGGING PRIORITIZATION SYSTEMS IN THE UNITED STATES

Unplugged oil and gas wells that do not have a responsible, solvent owner are typically referred to as orphaned wells. The lack of a responsible owner makes these wells more likely to have negative impacts on the environment and surrounding communities. Thus, these wells come under the jurisdiction of regulatory agencies in the United States (U.S.). More than 100,000 known orphaned wells are scattered across 30 states in the U.S. Regulatory agencies typically do not have enough resources to plug and remediate all of their orphaned wells and hence prioritize them. In 2021, the Bipartisan Infrastructure Law allocated $4.7 billion to orphaned well plugging in the U.S. To receive these funds, regulatory agencies were required to have well plugging prioritization systems in place. Each regulatory agency has their own prioritization system aligned with their goals and unique considerations of their jurisdiction. We gathered and analyzed the prioritization systems published by 15 U.S. state and federal regulatory agencies. We summarized the respective prioritization systems, identified commonalities and differences, and evaluated the systems against a risk-based approach. Most jurisdictions have straightforward systems that facilitate the rapid prioritization of orphaned wells with readily available data. Most assign the highest weight to the proximity of sensitive receptors like population centers, water resources, etc., and the leaking status of the well. Few jurisdictions account for environmental justice metrics to account for community impacts. On average, prioritization systems are also consistent with a risk-based prioritization approach except for orphaned wells with a large amount of missing information. This study will aid regulatory agencies seeking to improve their prioritization systems, and other stakeholders working to locate high-priority orphaned wells. Information from this study will also be useful for devising methods to optimally deploy finite resources to maximize benefits from plugging.

Prepared by LLNL under Contract DE-AC52-07NA27344. Funded by the Undocumented Orphaned Wells Research program, Office of Fossil Energy and Carbon Management, U.S. Department of Energy.