Disposal well near Oklahoma's biggest earthquake was drilled too deep, into granite 'basement'

An oil wastewater disposal well near Oklahoma's biggest earthquake ever recorded was drilled too deep, "a mistake some think can lead to earthquakes," Mike Soraghan writes for Energy Wire. New Dominion LLC, which owns the well, has received permission to make it more shallow, but says that doesn't mean the well caused the November 2011 quake.

"New Dominion LLC categorically and expressly denies that its Wilzetta salt water disposal well had anything at all to do with the Prague earthquake in 2011," company attorney Fred Buxton said in an email.

However, state officials and seismologists say that drilling into granite rock makes a path for wastewater that's injected into disposal wells to get to faults, causing earthquakes. The Oklahoma Corporation Commission, "which regulates oil and gas activity including dispoal, has been moving to make sure wells in earthquake-prone areas aren't injecting into basement rock," Soraghan reports.

Corporate commission officials say wells were never allowed in the "basement," or granite rock, but they focused primarily on inspection for groundwater contamination. Now they plan to pay special attention to whether wells are drilled too deep. (Read more)