The Yates Oil Field in the Delaware Basin. Credit: Jan Buchholtz. |
Since 2009, earthquakes have been rapidly rising in the Delaware Basin – a prolific oil-producing region in West Texas and New Mexico. According to a study led by researchers at The University of Texas at Austin, the majority of them can be linked to oil and gas production.
The researchers looked back on data that tracked seismicity and oil and gas production in the region from 2017 to 2020 and found that 68% of earthquakes above magnitude 1.5 were highly associated with one or more of the following oil and gas production activities: hydraulic fracturing or the disposal of produced formation water into either shallow or deep geologic formations. Formation water is found in all subsurface reservoirs and produced with oil and gas. Companies dispose of produced water by injecting it into geologic formations that are separate from oil and gas reservoirs.
All of these production activities are known to increase subsurface pore pressure, which is a mechanism for triggering earthquakes, said the study’s co-author, Alexandros Savvaidis, a researcher at the UT Bureau of Economic Geology and the principal investigator of Texas’ state seismic monitoring network and seismicity research TexNet, which is overseen by the bureau. By using a combination of statistical analysis and physics-based modeling, the study was able to disentangle which activities have a connection to past earthquakes.
“This paper shows that we now know a lot about how oil and gas activities and seismic activity are connected,” Savvaidis said. “The modeling techniques could help oil and gas producers and regulators identify potential risks and adjust production and disposal activity to decrease them.”
The study was published in Seismological Research Letters.