Characterization Of A Point Source Methane Plume With An Innovative Aerial Technique

Abstract

In this study, and unmanned aerial vehicle, mounted with a custom laser-based methane sensor, was deployed to measure methane emissions from a natural gas compressor station in Barnett Shale, Texas. Experimental flights were designed to follow an approximately spiral pattern above and around the station, allowing measurements to be taken at various altitudes. This provided the capability of observing a full downwind cross-section of the emissions from the station, allowing estimation of the total methane flux and the capture of individual methane plumes. Eleven flights produced analyzable datasets. from which it is concluded that the average leakage from the station is 13.92 g/s. which represents an approximate loss of 0.026% of total natural gas throughput. Throughout these eleven flights. significant variability was observed in the methane flux, with values as low as 4 g/s and as high as 26 g/s. In eight of the flights, individual plumes were clearly defined, with diameters of 10 m to 60 m, captured at altitudes ranging from 10 m to 100 m, with plume fluxes of 0.52 g/s to 10.75 g/s. The observed variability of plume characteristics and methane flux suggests that some conventional measurement techniques may not be capable of adequately capturing a source's methane emissions. This study demonstrates that this innovative aerial measurement technique is a valuable tool for measuring source-specific emissions, with many promising future applications.