Oil and gas operations were blamed for causing earthquakes in the Permian Basin throughout southeast New Mexico and West Texas via new research from the University of Texas at Austin, which warned increased production could spell disaster for the region’s geologic stability.
The study, published by the university’s Jackson School of Geosciences, cited both wastewater injection wells and hydraulic fracturing, known as fracking, as contributors to recent increased seismicity in both states.
Production across the basin grew in as fracking was increasingly used to target deeper and harder-to-reach shale deposits of crude oil and natural gas.
In the years since, the region became the most productive for fossil fuel in the U.S., boasting the most oil and gas rigs among the nation’s major producing-basins with 350 rigs as of July 8, per the latest data from Baker Hughes.
The next most active region was the Haynesville Shale in the southeast U.S. with just 49 rigs – about 14 percent of the Permian’s rig count.
But all those operations could lead to an increase in earthquakes and geological instability, the UT-Austin report said, with seismicity gradually rising since 2009, primarily in the western Delaware sub-basin of the Permian which straddles the New Mexico-Texas border.
Researchers studied regional seismicity and oil and gas operations between 2017 and 2020, considered boom years in the area, finding 68 percent of earthquakes at a magnitude (M) of 1.5 or greater resulted from fracking or disposal injection.
The fracking process uses a mixture of water, sand and chemicals pumped underground to break up underground rocks known as shale, so that oil and gas can be extracted and pumped to the surface.
While the process allows operators to better target hydrocarbon deposits, it also produces a significant amount of wastewater.
For every barrel of oil produced in the Permian, up to 10 barrels – about 42 gallons – of wastewater, known as produced water in industry terms, is brought to the surface.
It’s a combination of flowback from the initial frack and formation water from within the same shale deposits oil and gas is extracted from
Produced water is high in brine, metals and other toxic component and is unfit for human use.
Traditionally, this water was disposed of through injection wells that pump it back to the subterranean formations it came from.
That process was the main contributor to an uptick in earthquakes, the study read, by increasing subsurface pressure.
Researcher Alexandros Savvaidis, a co-author of the study said the work proves that oil and gas is linked to seismicity occurring near extraction activities and could help the industry better identify the risks stemming from their operations.
“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.”
About 5,000 quakes within an about 3 square-mile area of the Delaware along the state border were studied in the research.
About 43 percent of the quakes were tied to water injection above the depth associated with fracking, while 12 percent were linked to depths below the fracking depth.
The study pointed to an M 5.0 earthquake reported near Mentone, Texas last year, one the largest in the region’s history, as “strongly associated” with deep injection of produced water.
M 5 earthquakes are known to cause damage and risk injury to people, while M 4 quakes are often felt with some damage reported, and M 3 quakes rarely cause damage, per the Richter Scale.
M 1 and 2 quakes are rarely felt, but an increase in the smaller events, experts warned, could indicate growing seismicity in a region leading to larger incidents.
Lason Grigoratos, post-doctoral researcher and lead author of the study said the information gleaned from the Permian Basin could be used in other oil-producing regions to prevent associated induced seismicity.
“We believe the framework presented in this study is applicable to other regions around the world that might be experiencing seismicity linked to subsurface fluid injection operations,” Grigoratos said.
Work was underway by New Mexico regulators since last year to curb the volume of water injected underground, and promote produced water recycling, in hopes of seeing the quakes decline.
The State’s Oil Conservation Division announced new policies last year that would reduce the allowed volumes injected based on a well’s proximity to a quake.
If there are two M 2.5 quakes within a 10-mile radius, well operators are required to increase volume reporting to weekly from monthly.
If an M 3 occurs, all wells within a radius of up to 3 miles must reduce injection volumes by 50 percent, and all wells between 3 and 6 miles away must cut injections by 25 percent.
After an M 3.5 is reported, wells within 3 miles must be shut in and volumes are reduced for those up to 6 miles away.
Division Director Adrienne Sandoval said this policy appeared to be successful as the state has not seen a quake larger than M 4 since last year – the largest since was an M 3.2.
“Generally, we have not seen increasing seismic activity in that area,” Sandoval said of the Delaware Basin region.
“We’ve had some increase in certain areas, but they were less than the 4.0 and we have taken action. Where we’ve taken action, we’ve seen a reduction in seismicity, and we think that’s a good sign.”
She said the State also encouraged the industry to recycle more of its produced water so it can be reused in subsequent fracking operations, an act that could also reduce pressure on freshwater sources in the arid state.
“The more recycling the better,” she said. “I think we’ve seen increased numbers in produced water and we hope that trend continues.”
Regulations imposed in New Mexico and in Texas by the Texas Railroad Commission, which designated three seismic response areas (SRAs)since last year where injection volumes are similarly reduced, increased demand for services like recycling and transportation of water around the area, said Jason Jennaro, chief executive officer with Breakwater Midstream.
The company recently announced an expansion of its water management network focused on its Big Spring Recycling System in the Texas side of the Permian.
Breakwater reported the system recycles up to 4 million barrels of produced water a month, at about 300,000 barrels recycled per day.
It connects operators producing the wastewater with operators who may be able to use it after recycling via a series of pipelines throughout the region.
In total, the company’s 14 recycling facilities have a daily recycling capacity of about 500,000 barrels of produced water.
Jennaro said the UT-Austin study further validated the need to grow the water sector of the Permian Basin’s oil and gas industry.
“These data validate those efforts and the need for improved stewardship over the water supply chain,” he said. “Operators are looking for more sustainable alternatives to high pressure wastewater injection within seismically sensitive areas.”
Adrian Hedden can be reached at 575-628-5516, [email protected] or @AdrianHedden on Twitter.