The Texas Railroad Commission agreed Tuesday that two wastewater injection wells northwest of Fort Worth did not cause a rash of earthquakes more than a year ago.
Commissioners unanimously agreed with hearing examiners that there was notenough evidence to support findings that wells controlled by EnerVest Operating and XTO Energy near Reno and Azle contributed to seismic activity.
The commissioners agreed with the examiners that EnerVest and XTO should be able to maintain their permits for the wells.
State examiners found that scientific data indicated a “weak” temporal connection between the injection wells and seismic activity
This year, the hearing examiners discounted a peer-reviewed study released in the spring by Southern Methodist University researchers that linked the oil and gas process to the flurry of earthquakes that hit the Azle and Reno area from November 2013 to January 2014.
The SMU study “is a commendable first-order investigation” but it “presents data indicating a weak temporal correlation between injection and seismic activities — too small, however, to imply a causal relationship without further corroborating evidence,” the examiners wrote.
Energy companies use disposal wells to store large volumes of water used as part of oil and gas drilling. The Railroad Commission’s final orders say that the wells by XTO and EnerVest were properly built and operated and that the evidence does not support a finding that fluids are escaping and contributing to seismic activity.
State seismologist Craig Pearson said earlier that he didn’t see any “substantial proof” that the temblors northwest of Fort Worth were linked to oil and gas activity.
Officials with EnerVest and XTO were pleased with the commission’s vote.
In this case, the data we had and the assumptions that were made did not link the injection wells to seismic activity. Railroad Commissioner Ryan Sitton
“As we have said from Day One we believe there was no connection between our well and the seismic activity,” EnerVest spokesman Ron Whitmire said. “We appreciate the diligent work of the hearing examiners and the commissioners throughout this process.”
Suann Guthrie, a spokeswoman for Fort Worth-based XTO, said the commission’s final order “accurately reflects the conclusions that should have been drawn from the evidence XTO presented at the show cause hearing in June.”
Not a rubber stamp
Railroad Commissioner Ryan Sitton said he went into the review thinking that there might be a connection between oil and gas activity and the earthquakes. But Sitton said the state hearing examiner simply found that the SMU study was too limited and in scope and capability.
The SMU seismology team stands by the conclusions presented in the peer-reviewed study of the Azle earthquakes published April 21, 2015 in Nature Communications. SMU spokeswoman Kim Cobb
“In this case the data we had and the assumptions that were made did not link the injection wells to seismic activity,” Sitton said.
But Sitton said this doesn’t mean the agency is not interested in the subject of earthquakes and oil and gas drilling. This was not a rubber stamp of a hearing examiner’s report, he said.
“We’re very engaged in this,” Sitton said. “We’re staying on this. There is a lot of work going on to understand what is happening. … We are working on this daily and weekly.”
SMU spokeswoman Kim Cobb said the school’s seismology team “stands by the conclusions” presented in the study of the Azle earthquakes published April 21 in Nature Communications.
The rash of earthquakes near Reno and Azle have contributed to interest across the state to determine what may be causing the ground to shake in North Texas and elsewhere.
Researchers from the University of Texas at Austin’s Bureau of Economic Geology have been working on a $4.5 million comprehensive earthquake study approved by Texas lawmakers this year. The TexNet system will include 22 permanent seismograph stations and 36 portable ones.
Lawmakers approved money for the study after a rash of earthquakes plagued North Texas residents in recent years, the largest one a 4.0-magnitude temblor near Venus and Mansfield in May.
Scientists don’t necessarily believe that earthquakes in Irving and west Dallas are being caused by drilling. Earthquakes numbered 97 from January 2013 to October 2015 in an area stretching from Reno to Dallas Love Field and from Alliance Airport to Interstate 30, the U.S. Geological Survey reported. The earthquakes were 1.6 to 3.6 in magnitude.