Extension of Methane Emission Rate Distribution for Permian Basin Oil and Gas Production Infrastructure by Aerial LiDAR

Aerial LiDAR measurements at 7474 oil and gas production
facilities
in the Permian Basin yield a measured methane emission rate distribution
extending to the detection sensitivity of the method, 2 kg/h at 90%
probability of detection (POD). Emissions are found at 38.3% of facilities
scanned, a significantly higher proportion than reported in lower-sensitivity
campaigns. LiDAR measurements are analyzed in combination with measurements
of the heavy tail portion of the distribution (>600 kg/h) obtained
from an airborne solar infrared imaging spectrometry campaign by Carbon
Mapper (CM). A joint distribution is found by fitting the aligned
LiDAR and CM data. By comparing the aerial samples to the joint distribution,
the practical detection sensitivity of the CM 2019 campaign is found
to be 280 kg/h [256, 309] (95% confidence) at 50% POD for facility-sized
emission sources. With respect to the joint model distribution and
its confidence interval, the LiDAR campaign is found to have measured
103.6% [93.5, 114.2%] of the total emission rate predicted by the
model for equipment-sized emission sources (∼2 m diameter)
with emission rates above 3 kg/h, whereas the CM 2019 campaign is
found to have measured 39.7% [34.6, 45.1%] of the same quantity for
facility-sized sources (150 m diameter) above 10 kg/h. The analysis
is repeated with data from CM 2020–21 campaigns with similar
results. The combined distributions represent a more comprehensive
view of the emission rate distribution in the survey area, revealing
the significance of previously underreported emission sources at rates
below the detection sensitivity of some emissions monitoring campaigns.