No link between Texas quake and oil waste disposal, railroad commission says

The Railroad Commission of Texas (RRC) has found no conclusive evidence that a 4.0 magnitude earthquake that occurred in northern Texas last month was caused by injecting oil-drilling-related waste into underground disposal wells, the commission announced late last week.

The tests were ordered after the quake struck May 7 in Johnson County. Five wells were tested within 100 square miles of the quake's estimated epicenter.

The commission's staff seismologist, geologists and petroleum engineers concluded the tests results do not indicate any bounding faults in the immediate vicinity of the wells tested, RCC officials said in a press release.

The tests were conducted to help determine the effect of injection operations on pressures within subsurface rock formations. The wells' operators, who cooperated with the commission's tests, were Bosque Disposal System LLC, EOG Resources Inc., MetroSaltwater Disposal Inc. and Pinnergy Ltd.

“While we can’t say at this time there is a connection, this is the beginning of the process, not the end in analyzing and understanding whether there is any correlation and what, if any action by the commission may be necessary in the future to protect public safety and our natural resources," said Craig Pearson, the RCC's seismologist.

The commission's staff will continue to work with seismic researchers and the industry to analyze various data to determine if there is a link between seismic activity and oil and gas operations, RCC officials said.

Last year, the RCC adopted comprehensive rules on collecting data and other information on oil and gas operations relating to seismic events.