Measurements of methane emissions from natural gas gathering facilities and processing plants: measurement methods

摘要

Increased natural gas production in recent years has spurred intenseinterest in methane (CH₄) emissions associated with its production,gathering, processing, transmission, and distribution. Gathering andprocessing facilities (G&P facilities) are unique in that the wide rangeof gas sources (shale, coal-bed, tight gas, conventional, etc.) results in awide range of gas compositions, which in turn requires an array oftechnologies to prepare the gas for pipeline transmission and distribution.We present an overview and detailed description of the measurement methodand analysis approach used during a 20-week field campaign studying CH₄emissions from the natural gas G&P facilities between October 2013 andApril 2014. Dual-tracer flux measurements and on-site observations were usedto address the magnitude and origins of CH₄ emissions from thesefacilities. The use of a second tracer as an internal standard revealedplume-specific uncertainties in the measured emission rates of 20–47%,depending upon plume classification. Combining downwind methane, ethane(C₂H₆), carbon monoxide (CO), carbon dioxide (CO₂), andtracer gas measurements with on-site tracer gas release allows forquantification of facility emissions and in some cases a more detailedpicture of source locations.