Challenges with Developing a Measurement-Based Basin Methane Intensity Estimate: A Case Study from the Haynesville

Kristian D. Hajny , Bailey K. Fosdick, Zachary Weller, Ellie Martinez, Hon Xing Wong, Abigail Corbett, Chris Moore

Methane intensity, the emissions relative to production, has been a focus in global regulations on oil and gas production and imports, given the climate benefits of methane emission reductions. Methodological frameworks to create annual measurement-based emissions inventory estimates and calculate methane intensity using snapshot measurements have been developed. However, there are still multiple decision points within these frameworks whose impact may be underappreciated. These include uncertainty in the underlying facility population and associated production in purview. In this work, we discuss the development of a comprehensive measurement-based inventory for the dry gas Haynesville Basin located in the U.S. States of Texas and Louisiana using Bridger Photonics LiDAR data. From a measurement dataset covering 8% of all facilities, we estimate annual basin total methane emissions of 760 [610, 940] Gg/year and a methane intensity of 0.79% [0.63%, 0.98%] (95% confidence intervals), in agreement with previous measurement-based studies in the region. We then show that different methodological choices can result in a difference of more than a factor of two in the estimated methane intensity for the subset of choices considered in this work. As such, this work demonstrates the importance of considering all aspects of the methodology to produce comparable methane intensity estimates.