MARFA, Texas (CN) – Researchers at the University of Texas say a cluster of earthquakes near the small West Texas town of Pecos grew considerably in recent years during a dramatic boost in oil and gas production in the area.
The Delaware Basin, a subset of the broader Permian Basin oilfield, has skyrocketed to prominence in the energy industry as companies have rushed to get their hands on the more than 46 billion barrels of oil the U.S. Interior Department identified in the region in late 2018.
Monday’s study, published in the Journal of Geophysical Research: Solid Earth, stopped short of directly linking that boom to the growth in earthquakes, but it did acknowledge that such a connection is likely.
“Petroleum production and related activities in the Delaware Basin probably induce this seismicity but the exact mechanism is uncertain,” the study said.
Previous studies in Texas have shown that the underground disposal of wastewater used in the hydraulic fracturing process can trigger earthquakes. Just last month, researchers went a step further by linking some earthquakes in West Texas directly to the fracking process.
The study published Monday attempts to fill in a gap in scientists’ understanding of earthquakes in the Delaware Basin, which were not tracked closely before the launch of a statewide seismic monitoring program called TexNet in 2017.
The researchers found that the Pecos area saw little to no seismic activity before 2009, when several earthquakes were recorded.
“Subsequently activity rates have increased considerably, with more than 2,000 earthquakes occurring in 2017,” the study said.
The growth in earthquakes coincided with the growth in Texas oil production, which exploded from about 399 million barrels in 2009 to more than 1.2 billion barrels in 2017, according to figures from the Energy Information Administration.
To analyze the Pecos earthquakes, the researchers gathered historical seismic data from a monitor located about 150 miles away in the Texas border town of Lajitas. The monitor was able to pick up signs of far-away earthquakes in part because the mostly empty lands near Lajitas are more remote and “seismically very quiet,” the University of Texas’ Jackson School of Geosciences said in a press release.
While the researchers noted that other parts of the region have not experienced the same type of increase in earthquakes alongside growing oil production, they discovered that around Pecos, earthquakes declined at times when fracking activity slowed.
“The increasing rates of seismic activity in the Pecos Cluster were interrupted by two notable periods of decreasing activity, the first occurring early in 2013, and the second in the last half of 2015 and first half of 2016,” the study said. “Both time periods coincide roughly with decreases in wastewater disposal volumes following decreases in hydraulic fracture fluid volumes.”
Regulators at the Texas Railroad Commission have historically expressed skepticism about the science linking earthquakes and oilfield activity, though the commission did adopt stricter rules on wastewater disposal to address the issue in 2014.
“Commission staff work closely with academic researchers and industry professionals to ensure RRC policies and procedures are based upon the best available science,” the commission’s staff seismologist Aaron Velasco said in a statement. “This science is evolving rapidly thanks to the Texas Legislature’s commitment of millions of dollars to set up and maintain TexNet, Texas’ first statewide network of seismometers to detect and record seismic activity, which is providing an enormous amount of data for analysis and understanding.”
A commission spokesperson said since the 2014 rules went into effect, regulators have forced oil and gas companies to limit and/or more closely monitor wastewater disposal for almost half of the 657 disposal permit applications filed in earthquake-prone parts of the state. Other permits have been rejected or withdrawn, while more than 150 are still pending.
Peter Hennings, a co-author on the new study, said in a statement the research will factor into the broader, ongoing work his team at the Center for Integrated Seismicity Research is involved with.
“The obvious next step is exactly what the University of Texas is doing — conducting these careful studies on the relationship between earthquakes and their human and natural causes to build an integrated understanding,” he said.
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