The Efficacy of Methane Leak Detection and Repair (LDAR) Programs in Practice.

Periodic leak detection and repair (LDAR) surveys are a key part of most modern oil and gas sector methane regulations, however their effectiveness in real-world practice has been difficult to assess. This study analyzes three years of reported data from regulated LDAR surveys in British Columbia, Canada, which suggest that 3×/year optical gas imaging (OGI)-based LDAR surveys reduce detected emissions by half at fully compliant sites. However, independent source-resolved aerial surveys at an identical subset of sites find 12 times more methane emissions overall, and four times more emissions after conservatively excluding potential combustion-related and intentional vent sources not targeted by OGI LDAR surveys. This demonstrates that regulated OGI-based LDAR surveys only capture a small portion of total emissions in practice, raising concerns about overestimated mitigation impacts and potentially misguided expectations when assessing alternative technologies. Further analysis reveals the two methods find complementary subsets of sources, with aerial detections comprising a range of larger combustion, vent, and fugitive sources and LDAR detections dominated by numerous smaller leaks from connectors and valves. This underscores the importance of integrating complementary measurement approaches to capture the full distribution of emissions and the necessity of independent verification frameworks such as OGMP 2.0.