Texas Railroad Commission Chairwoman Christi Craddick said she expects testing at five disposal wells near last week’s 4.0-magnitude earthquake to be completed by early next week.
During an appearance on an Austin public affairs program, Craddick said the agency, which regulates the oil and gas industry, hopes to “get everybody back up and running by the end of the week, the first of next week,” unless the testing uncovers problems.
Craddick said the agency is still “actively engaged.”
The earthquake, which occurred around 6 p.m. last Thursday, was centered about 6 miles south of Mansfield and about 3 miles northwest of Venus, according to the U.S. Geological Survey.
The temblor was the most powerful of more than 50 quakes that have rumbled through North Texas over the past 18 months, officials said.
A recently released study linked oil and gas activity to a rash of earthquakes near Azle and Reno from November 2013 to January 2014.
As a result, the Railroad Commission sent four teams of inspectors to the area after the quake. They found no immediate problems, but regulators asked that five disposal wells within 100 square miles of the estimated epicenter be shut down so pressure tests could be run.
The operators, Bosque Disposal Systems, EOG Resources, Metro Saltwater Disposal and Pinnergy, voluntarily did so.
Commissioner Ryan Sitton, a mechanical engineer, toured several of the well pad sites. He said the operators are being asked to send monitors down the wells to determine the pressure at the bottom of the subsurface rock formation and how quickly that pressure dissipates.
“We want to get more data,” he said.
The closer to an earthquake, the better, he said. “That is good data for us to have.”
Craddick, talking about the string of earthquakes northwest of Fort Worth, cautioned against automatically linking any seismic activity to drilling.
“I think the fallacy we need to remember is that not all seismic activity is oil- and gas-related, so it needs to be a broader perspective,” she said.
Lawmakers are already discussing spending about $4.4 million to buy seismology equipment and to conduct a statewide study on earthquakes. Also being discussed is having the commission hire another seismologist. It hired its first seismologist last year after the series of quakes near Azle.
A second seismologist would cost an estimated $60,000 to $80,000 a year.
Max B. Baker, 817-390-7714