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Orphaned wells, meaning unplugged and non-producing wells lacking responsible owners, pose a significant and undersampled environmental challenge due to their vast number and unknown associated emissions. We propose, develop and test an alternative method for estimating emissions from orphaned wells using a forced advection sampling technique (FAST) that can overcome many of the limitations in current methods (cost, accuracy, safety). In contrast to existing ambient Gaussian plume methods, our approach uses a fan-generated flow to force advection between the emission source and a point methane (CH4) sensor. The fan flow field is characterized using a colocated sonic anemometer to measure the 3D wind profile generated by the fan. Using time-series measurements of CH4 concentration and wind, a simple estimate of the CH4 emission rate of the source can be inferred. The method was calibrated using outdoor controlled-release experiments and then tested on four orphaned wells in Lufkin, TX, and Osage County, OK. Our results suggest that the FAST method can provide a low-cost, portable, fast and safe alternative to existing methods with reasonable estimates of orphaned well emissions over a range of leak rates below 40 g h−1 and within certain geometric and atmospheric constraints.
Details
; Moyes, Andrew B 2 ; Reichl, Ken 2 ; Lee, James E 3
; Dubey, Manvendra K 3
; LeYhuelic, Corentin 4 ; Variano, Evan 1 ; Follansbee, Emily 3
; Chow, Fotini K 1
; Biraud, Sébastien C 2
1 Department of Environmental Engineering, University of California, Berkeley, CA 94720, USA
2 Climate Sciences Department, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
3 Earth and Environmental Sciences Division, Los Alamos National Laboratory, Los Alamos, NM 87545, USA
4 Department of Physics, École Normale Supérieure Paris Saclay, Paris, France