UT-led study links quakes, fracking
Previous research had blamed tremors on disposal wells
A new study from the University of Texas at Austin blames hydraulic fracturing for causing some earthquakes in the Permian Basin of West Texas, dispelling the widely held view that oilfield wastewater disposal wells were solely responsible for the man-made tremors.
In a study released Tuesday afternoon, scientists with the TexNet Seismic Monitoring Program at UT-Austin reported that some earthquakes in Reeves, Pecos and Culberson counties may have been caused by fracking, the process of pumping water, sand and chemicals at high pressures deep underground to crack shale rock and unlock and oil natural gas.
Previous studies had blamed the earthquakes in oil-producing regions across on disposal wells, into which wastewater from drilling, hydraulic fracturing and production activities is injected.
“The research done through this new study in West Texas, using a statistical approach to associate (earthquakes) with oil and gas operations, suggests that some (earthquakes are) more likely related to hydraulic fracturing than saltwater disposal,” Alexandros Savvaidis, a research scientist and manager of the TexNet Seismic Monitoring Program,
said in a statement.
TexNet was created by the Texas Legislature in 2015 to study the growing number of earthquakes around the state and their relation to oil and gas drilling. TexNet, funded by the state and housed at UT-Austin, has nearly 60 seismographs deployed across the state. Its research arm, the Center for Integrated Seismicity Research, or CISR, is funded by the state in partnership with companies such as Chevron, Exxon Mobil and Shell.
So far this year, TexNet seismographs have recorded 209 earthquakes across the state above a 2.0-magnitude, which the U.S. Geological Survey reports are not generally felt. The strongest of this year’s quakes was recorded near Synder on Oct. 1. — a 3.8-magnitude tremor, strong enough to be felt by some people on the ground and those in the upper floors of buildings.
The number of earthquakes recorded this year have already outpaced the 192 recorded by TexNet last year when the strongest one recorded was on Oct. 20, 2018, near Amarillo — a 4.2magnitude earthquake that should have been strong enough to be felt by people indoors in addition to rattling dishes, windows and doors.
Sharon Wilson, an anti-fracking activist and Dallas organizer for the environmental group Earthworks, said the study confirmed what she and others have been saying for years — that hydraulic fracturing can cause earthquakes.
While previous studies from Southern Methodist University, the U.S. Geological Survey and other sources blamed earthquakes in North Texas on saltwater disposal activity, Wilson and others insisted on calling the tremors “frackquakes.”
“It’s no surprise to communities affected by these quakes that science confirms they’re fracking-related,” Wilson told the Houston Chronicle. “But there’s a gap between what the science repeatedly shows and what Texas regulators require to protect the public. And that’s a chasm that Texas families and their homes have fallen into for years.”
Following a string of earthquakes in Azle and other towns in the Barnett Shale of North Texas in 2013, the Railroad Commission of Texas, the state agency that regulates the oil and gas industry, hired a seismologist and adopted stricter regulations for saltwater disposal wells in November 2014.
Over the last five years, the agency has received 657 disposal well applications in areas where earthquakes have occurred historically. Of those proposed projects, 302 permits were issued with special conditions that include reducing maximum daily injection volumes and pressures.
Applications for 91 disposal sites were returned or withdrawn. Another 82 applications were sent to hearing while 25 permits were issued without special conditions and 157 applications are pending technical review
It remains to be seen how or if the new study will lead the Railroad Commission to consider new regulations. Railroad Commission seismologist Aaron Velasco, who serves as a technical advisor to TexNet, said the agency and its procedures are based on the best available science at the time.
“This science is evolving rapidly and 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,” Veslasco said.
Steve Everley, a spokesman for the industry-funded group Texans For Natural Gas, said the industry supported and participated in the regulatory changes that the Railroad Commission adopted in 2014.
Although the industry welcomes further studies on the topic, Everley noted that the majority of the earthquakes listed in the TexNet study were not strong enough to cause any damage or be felt by casual observers at the surface.
In a statement, Todd Staples, president of the Texas Oil & Gas Association, an Austin-based trade group, said members of the industry work closely with scientists at TexNet and its research center.
“The oil and natural gas industry continues to work collaboratively and extensively with industry peers, TexNet and CISR to monitor and share data, and gather information that guides industry practices,” Staples said. “We will continue to work with academia and others to ensure continued safe operations.”