Under Pressure: Decomposing and Predicting Methane Emissions Variability in U.S. Oil and Gas Basins

Abstract

Methane is a molecule with unique properties that provide a powerful opportunity to take near-term action on climate change and strengthen today’s economy. This is due to methane’s warming power of 28x carbon dioxide, short atmospheric lifespan of 12 years, and methane being the primary component of natural gas: a key U.S. resource. The challenge with mitigation is that methane comes from a large number of spread out and non-uniform sources. I investigate the largest industrial source of U.S. methane emissions - oil and gas infrastructure - across five major basins, and find a strong seasonal trend as well as significant week-to-week variation. I find that this variability can be explained with weather, natural gas infrastructure, and economic variables through both econometrics and simple machine learning approaches. These approaches preserve variable interpretability and indicate that the primary drivers of methane emissions differ significantly between basins. Within each basin, variables related to human and operational behaviors are more strongly tied to emissions variability than weather, and across basins the composition of underground hydrocarbons is a major differentiator. Basins with associated gas - where economics are driven by oil - had 6 times higher methane emissions per unit of gas production than primarily natural gas basins. I also find that spatial concentration is an immensely important factor in methane emissions mitigation. An area 5% of the Permian Basin contributed 25.2% of total emissions from the region during the 5.5 years of available data. The Haynesville, Eagle Ford, Anadarko, and Barnett Basins also exhibited strong spatial concentration with at least 40% of emissions in each region coming from an area of less than 100 square miles. The Permian Basin is the key region for methane mitigation in the southern US, contributing 67% of total oil and gas emissions in the period of this study. These results on the sources and trends of methane emissions aim to inform mitigation efforts, make the most of available detection resources, and convey the importance of this topic to the non-academic community.