Basin-Wide Top-Down Estimates for CH4 Emissions from Oil and Gas Extraction using Aircraft Observations

While significant advances in oil and natural gas drilling technology has enabled producers in the US to access previously inaccessible reservoirs of natural gas, thus offering a possible reduced impact on air quality compared to oil and coal usage due to the high efficiency and relative purity of natural gas at the point-of-use, recent work has suggested that emissions from the point-of-extraction to the point-of-use may have a significant negative impact on climate and air quality that has not been properly quantified in current inventory-based estimates. The goal of this project is to produce aircraft-based flux estimates of CH4 emissions from the San Juan basin in New Mexico, which is the largest coal bed methane production region in the world. Observations will be made from the NOAA Twin Otter aircraft equipped with continuous measurements of methane (CH4), ethane (C2H6), carbon monoxide (CO), carbon dioxide (CO2), wind, temperature and relative humidity along with discrete flask measurements of these trace gases and 40 other species, including isotopes of CH4, to understand the origin of the measured CH4 emissions. These measurements will provide decisive information about the presence of fossil vs. non-fossil CH4 sources, and also clearly distinguish CH4 emissions associated primarily with oil production (high C2H6) from those associated primarily with gas production (low C2H6).