In a groundbreaking study, NETL researchers and their collaborators compiled and analyzed an unprecedented amount of regulatory data that describes the integrity of oil and gas wells in multiple states. The study results will be valuable for industry operators and regulatory agencies as they seek to prevent well leakage and ensure the success of carbon storage, oil and gas production, natural gas storage, and hydrogen storage operations.

Findings are presented in a research article titled “Public data from three U.S. states provide new insights into well integrity” published in the Proceedings of the National Academy of Sciences of the United States of America.

While more than 900,000 oil and gas wells are currently active in the U.S., estimates of the percentage of these wells that have experienced an integrity issue and leaked during their lifetime have been limited by data availability. In this study, NETL researchers address this issue by using advanced computational techniques to gather and extract data from over 470,000 regulatory records that describe the results of well leakage tests performed in Colorado, New Mexico, and Pennsylvania on more than 100,000 wells prior to 2018. The data extracted from these records represents the largest and most complete record yet assembled to review the integrity of U.S. oil and gas wells.

NETL researchers focused on estimating the percentage of oil and gas wells that have exhibited pressures and flows indicative of an internal well integrity issue. Testing records from Pennsylvania showed that 14.1% of wells tested prior to 2018 have potentially experienced an integrity issue. Data from different hydrocarbon-producing regions within Colorado and New Mexico revealed that wells experienced integrity issues with a wider range of frequencies (0.3%-26.5%) than previously reported, which highlights the need to better understand regional and basinal trends in well integrity.

Directional wells were more likely to exhibit integrity issues than vertical wells in Colorado and Pennsylvania. Most wells with integrity issues experienced leakage internal to the well system that did not escape into groundwater. Testing around wells for indicators of gas leakage into groundwater is not a widespread practice, but 3.0% of Colorado wells tested and 0.1% of New Mexico wells tested exhibited characteristics that made them susceptible to leakage outside the well.

Study findings demonstrate the value of statewide well testing programs, highlight the challenges of interpreting disparate inter-jurisdictional well testing data, and suggest the need for a comprehensive standardized well testing protocol. Researchers recommended the adoption of a comprehensive, standardized testing protocol to “ensure the compatibility of testing results from different jurisdictions, enable the establishment of a uniform criteria for identifying well integrity issues, and ease the compilation of test results.”

“Beyond their use for the public, these datasets have the potential to become a critical reference for researchers, industry operators, and regulatory agencies seeking to prioritize the remediation, abandonment or potential reuse of wells,” the study stated. It was recommended that future research should continue to aggregate and analyze this type of data, to better inform stakeholder decision-making.

The U.S. Department of Energy’s National Energy Technology Laboratory develops and commercializes advanced technologies that provide clean energy while safeguarding the environment. NETL’s work supports DOE’s mission to ensure America’s security and prosperity by addressing its energy and environmental challenges through transformative science and technology solutions.