Spatiotemporal Variability of Methane Emissions at Oil and Natural Gas Operations in the Eagle Ford Basin

Abstract

Methane emissions from oil and gas facilities can exhibit operation-dependent temporal variability; however, this variability has yet to be fully characterized. A field campaign was conducted in June 2014 in the Eagle Ford basin, Texas, to examine spatiotemporal variability of methane emissions using four methods. Clusters of methane-emitting sources were estimated from 14 aerial surveys of two ("East" or "West") 35 × 35 km grids, two aircraft-based mass balance methods measured emissions repeatedly at five gathering facilities and three flares, and emitting equipment source-types were identified via helicopter-based infrared camera at 13 production and gathering facilities. Significant daily variability was observed in the location, number (East: 44 ± 20% relative standard deviation (RSD), N = 7; West: 37 ± 30% RSD, N = 7), and emission rates (36% of repeat measurements deviate from mean emissions by at least ±50%) of clusters of emitting sources. Emission rates of high emitters varied from 150-250 to 880-1470 kg/h and regional aggregate emissions of large sources (>15 kg/h) varied up to a factor of ∼3 between surveys. The aircraft-based mass balance results revealed comparable variability. Equipment source-type changed between surveys and alterations in operational-mode significantly influenced emissions. Results indicate that understanding temporal emission variability will promote improved mitigation strategies and additional analysis is needed to fully characterize its causes.

Quantifying Methane and Ethane Emissions to the Atmosphere From Central and Western U.S. Oil and Natural Gas Production Regions

“…Lavoie et al () used CH 4 measurements from small aircraft in June 2014 to determine emissions from large point sources in the eastern Eagle Ford region. They found aggregate emissions from large sources as a percentage of natural gas produced of 0.9 ± 0.3% and 1.3 ± 0.5% from their two study regions, which combine to average 1.1 ± 0.4%.…”

“…The mass balance technique (White et al, ) used here to quantify emissions has been extensively used to estimate CH 4 and C 2 H 6 emissions from O&NG‐producing regions in the United States, including the Uinta Basin of Utah (Karion et al, ), the Denver Basin of northeastern Colorado (Pétron et al, ), the Marcellus shale region of northeastern Pennsylvania (Barkley et al, ; Peischl et al, ), the Fayetteville shale region of Arkansas (Peischl et al, ; Schwietzke et al, ), the Haynesville shale region of northwestern Louisiana and eastern Texas (Peischl et al, ), the Barnett shale region of Texas (Karion et al, ; Smith et al, ), the Bakken shale region of North Dakota (Kort et al, ; Peischl et al, ), and the San Juan region of New Mexico and Colorado (Smith et al, ). A similar mass balance technique has been used to quantify CH 4 and other emissions from portions of O&NG‐producing regions and from large point sources (Caulton et al, ; Conley et al, ; Lavoie et al, ). The analysis and technique presented here expand upon the work of Peischl et al () and are summarized in Text S2.…”

Methane emissions from oil and gas production sites in Alberta, Canada

“…Thus mitigating emissions effectively requires frequent monitoring with the time between inspections short enough to minimize the duration of spatio-temporally dynamic super-emitting sites (Lyon et al, 2016;Lavoie et al, 2017).…”

“…On top of the relationship between age, gas production and emissions, our model suggests that oil producing sites tend to have higher emissions than sites without oil production: higher emissions are expected at sites with higher oil production (e.g., venting from condensate tanks (Lyon et al, 2016;Lavoie et al, 2017)). …”

Methane Emissions from the Marcellus Shale in Southwestern Pennsylvania and Northern West Virginia Based on Airborne Measurements

“…The validity of the study by Allen et al (2013) is still an ongoing point of contention (Alvarez et al, 2016(Alvarez et al, , 2018Guglielmi, 2018). It is noteworthy that there is considerable temporal variability in CH 4 emission rates in shale gas production regions, which could lead to variability in these estimates (Lavoie et al, 2017). Given the current low cost of natural gas, a purely economic driver to reduce the atmospheric release of CH 4 does not exist.…”