Methane emissions from shale gas production sites in Sichuan, China

We performed ground-based methane emission measurements (downwind OTM33A method, on site methane measurements) from shale gas production sites in Sichuan province, China (Changning-Weiyuan region, 18 facilities with 81 wells). The mountainous geological location of the sites, and the limited road access has guaranteed only 2 to 3 downwind OTM-33A measurements. A backpack type high-sensitivity methane analyzer was applied to identify methane emissions and map the atmospheric methane distribution inside the gas facilities. The results showed that: the methane level along the fence line of the 16 facilities kept stable at background concentration, with the other 2 enhanced by less than 2 ppm. Inside the 10 facilities putting into production after 2016, pneumatic controllers from the three-phase separator showed no emission since they were running on electricity. Flowback water tanks were the major methane sources with concentration around 354 to 500ppm. Occasionally, the loose venting outlet of the actuator had leakage with methane concentration around 45 ppm. The application of high-sensitivity methane analyzer inside the facility has provided more detailed emission characteristics which could not be found by infrared camera before. This study could provide insights to the emission behavior from components and the distribution patterns of methane inside the shale gas facilities in Sichuan, China. For sites with a non-favored conditions for downwind measurements, other detection methods such as drone-based might be better to implement.