Texas Tribune
Originally Posted: June 12, 2015
Regulators: No Evidence Wells Caused 4.0 Quake
After wrapping up a round of testing, Texas regulators say they have found no evidence that injecting oilfield waste into five disposal wells triggered the largest recorded earthquake in North Texas’ history.
“At this time, there is no conclusive evidence the disposal wells tested were a causal factor in the May 7 seismic event,” the Texas Railroad Commission said Friday in a news release.
Last month, a 4.0-magnitude earthquake hit Johnson County, leading to a few reports of minor damage. It was the most powerful ever recorded in the Barnett Shale region, including more than 50 quakes that have struck since November 2013 — a surge that has coincided with the proliferation of disposal wells, deep resting places for liquid oil and gas waste injected underground at high pressures.
Under rules adopted last year, the Railroad Commission ordered testing at five disposal wells, which the four companies that operate them voluntarily shut down. On Friday, the commission said its analysis of “fall-off pressure”– tests to determine the effects of injections at the well sites – turned up no fault patterns nearby that could have been related to the earthquakes. READ MORE