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Researchers dig deeper into link between oilfield activity and earthquakes in West Texas

Researchers are increasingly linking oilfield activity and seismic activity, with a new report from the University of Texas at Austin linking the two in the Delaware Basin.

Researchers investigating increased seismic activity in Delaware since 2009 studied data that tracked seismicity and oil and gas production in the basin from 2017 to 2020. They found that 68% of tremors Earthquakes greater than magnitude 1.5 were strongly associated with hydraulic fracturing and/or product removal from water in shallow or deep geologic formations.

“They identify a definitive link between sewage injection and earthquake frequency,” Jason Jennaro, chief executive of Breakwater Energy Partners, told The Reporter-Telegram via email. “But interestingly, they also identify a strong statistical relationship between sewage injection and earthquake intensity, which is particularly relevant to population centers.”

Jennaro noted that the report identified sewage injection into shallow and deep geological formations as the primary cause of more than 5,000 earthquakes in West Texas and New Mexico. The largest of these earthquakes, such as a magnitude 5 quake near Mentone in 2020, was strongly linked to deep storage, he added.

As a result, Jennaro added, operators have focused their 2022 water management programs on recycling and moving wastewater out of seismically active areas, especially seismic response zones.

“These data validate these efforts and the need for better water supply chain management,” he wrote.

Alexandros Savvaidis, a researcher in UT’s Office of Economic Geology and principal investigator of the Texas State Earthquake Monitoring Network and TexNet Seismicity Research, told The Reporter-Telegram via email that the work presents a framework that can assess the causal link between industry operations and seismicity.

The paper shows that researchers know a lot about how oil and gas activity and seismic activity are linked, Savvaidis said, and modeling techniques can help producers and regulators identify potential risks and adjust. production and disposal activities to reduce these risks.

“Using current information, we provide a model that links operations to seismicity and this model can be used to mitigate risk,” he wrote. “Additionally, when we have the expected underground fluid injection data – projection of underground fluids based on expected production – we can use the model to perform a retrospective simulation of seismicity. This way we can take measurements proactive to protect the environment and industry investment.”

The paper’s lead author, Iason Grigoratos, developed the model as a postdoctoral researcher at UT Jackson School of Geosciences, where the office is a research unit. The model was first applied in a 2020 study that found a link between produced water disposal and seismicity in Oklahoma.

The model was developed using a combination of statistical analysis and physics-based modeling to determine which activities are related to past earthquakes.

More importantly, Savvaidis noted, this framework can be used in other parts of the state and around the world.

The plan, he continued, is to apply the developed methodology to other areas and turn the methodology into an accessible outlet for stakeholders. Improving earthquake, oil and gas data, he said researchers plan to use the methodology on a smaller scale – less than 5 kilometers – and also develop additional methods for assessment. causality of seismicity and risk mitigation.

The researchers analyzed about 5,000 earthquakes, selecting the magnitude 1.5 threshold above. Forty-three percent of earthquakes greater than magnitude 1.5 were related to injection into shallow sedimentary formations above hydraulic fracturing depth; 12% was related to injection into deep sedimentary formations above bedrock and below hydraulic fracturing depth. The 2020 magnitude 5.0 earthquake in Mentone occurred in an area where seismicity was strongly associated with deep produced water injection. Hydraulic fracturing was linked to only 13% of earthquakes. However, this was higher than expected.