Field Trial of Methane-Emission Quantification Technologies
This paper presents a field trial that compares multiple methane detection and quantification methods and compares the measurements with engineering estimates of emissions.
The drone measurements and on-site sampling report emissions at the scale of individual sources and the emission estimates have time resolution of one to several minutes. The emission estimates based on downwind measurements are site totals, and each emission estimate is typically a minute in duration. Often multiple approximately minute-long estimates are performed at each site. The results from these detection and quantification methods will be compared with one another and to high-time-resolution engineering estimates of methane emissions.
Governments in the US, Canada, Europe, and other countries have promulgated methane-mitigation regulations, and many companies have undertaken voluntary programs beyond regulatory requirements. As programs expand, emerging-technology developers have responded with the development of multiple monitoring, detection, and quantification systems for methane emissions. Methane detection and quantification systems operate at multiple spatial and temporal scales, and, when these methods are compared against one another and against inventories of methane emissions, analyses must carefully match spatial and temporal scales. This field trial compares multiple methane detection and quantification methods and compares the measurements with engineering estimates of emissions.
Engineering estimates of the detailed temporal patterns of methane emissions at oil and gas production sites reveal the challenges of comparing measurements of individual sources that are not exactly synchronized. Because some detection and quantification methods can interfere with one another, most intercomparisons are based on asynchronous measurements and approaches for intercomparing ensembles of measuements are suggested.
Detection and quantification of methane emissions at oil and gas production sites occurs at a variety of spatial and temporal scales. The spatial scales of measurements can range from individual sources (on the order of meters) to measurements of emissions for entire production regions (on the order of 102 to 103 kilometers); the temporal scales can range from instantaneous snapshots of emission rates (seconds to minutes) to emission estimates averaged over periods of months to years. Methane emissions from oil and gas production sites have complex spatial and temporal patterns, and the design of emission surveys and the analysis of methane detection and quantification data should account for these complex emission patterns.
This work compares emission detection and quantification methods deployed in a dry gas production region of east Texas using a drone-mounted in-situ infrared sensor, a downwind mobile detection and quantification system and emission detection, and measurement performed on-site using optical gas imaging and an emission quantification sampler.