Examining Daily Temporal Characteristics of Oil and Gas Methane
Emissions in the Delaware Basin Using Continuous Tower Observations
Abstract
Top-down studies have found consistent underestimations in the United
States Environmental Protection Agency (EPA) methane emissions inventory
from the oil and gas (O&G) sector. Many of these studies use
observations that bias towards hours when worktime activity occurs. In
this study we analyze over two years of methane measurements from a
tower network in the Delaware basin to analyze hourly temporal emission
patterns. Inversion results suggest a range in emissions from 134 Mg/hr
at night to 196 Mg/hr during the day, present during both weekdays and
weekends. If these results are applicable to other basins,
daytime-influenced methodologies may overestimate daily emission rates
by up to 27%. This bias does not reconcile the more than 200%
difference between the EPA inventory and top-down estimates in the
Delaware basin. This study demonstrates how continuous measurement
networks can be combined with detailed activity data to improve
bottom-up inventories.