posted on 2024-02-02, 06:03authored byColette Schissel, David Allen, Howard Dieter
Methane emission
estimates for oil and gas facilities are typically
based on estimates at a subpopulation of facilities, and these emission
estimates are then extrapolated to a larger region or basin. Basin-level
emission estimates are then frequently compared with basin-level observations.
Methane emissions from oil and gas systems are inherently variable
and intermittent, which make it difficult to determine whether a sample
population is sufficiently large to be representative of a larger
region. This work develops a framework for extrapolation of emission
estimates using the case study of an operator in the Green River Basin.
This work also identifies a new metric, the capture ratio, which quantifies
the extent to which sources are represented in the sample population,
based on the skewness of emissions for each source. There is a strong
correlation between the capture ratio and extrapolation error, which
suggests that understanding source-level emissions distributions can
mitigate error when sample populations are selected and extrapolating
measurements. The framework and results from this work can inform
the selection and extrapolation of site measurements when developing
methane emission inventories and establishing uncertainty bounds to
assess whether inventory estimates are consistent with independent
large spatial-scale observations.