Wednesday, November 04, 2015

Rash of earthquakes in rural North Texas not caused by injection wells, state officials rule

No link exists between wastewater disposal wells and a rash of earthquakes in 2013 and 2014 in two North Texas towns, despite research that suggests otherwise, state officials ruled on Tuesday, Jim Malewitz reports for The Texas Tribune. The three-member Republican panel of the Texas Railroad Commission unanimously cleared Houston-based EnerVest and ExxonMobil subsidiary XTO Energy from any responsibility for the more than two dozen earthquakes in the rural towns of Reno and Azle (Best Places map) in the Barnett Shale region. The ruling clears the companies to continue their usual business.

The Texas Railroad Commission "ordered hearings after a team of researchers led by Southern Methodist University concluded that industry activity 'most likely' unleashed the earthquakes," Malewitz writes. "The peer-reviewed research, published in April, linked the earthquakes to wells operated by XTO Energy and EnerVest. The SMU study said the operators’ withdrawal of brine—naturally salty water removed during oil and gas drilling—and the high-pressure injection of huge volumes of wastewater from gas wells likely spurred the quakes."

"In two rulings, commission examiners sided with the energy companies, writing that 'natural tectonic processes' surprised North Texans unaccustomed to shaky ground," Malewitz writes. "The SMU study is a 'commendable first-order investigation' of the issue, the examiners wrote in both decisions, but 'presents data indicating a weak temporal correlation between injection and seismic activities—too small, however, to imply a causal relationship without further corroborating evidence.'” (Read more)

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