Oklahoma's oil regulator to shut some disposal wells following large quake

Jan 31 (Reuters) - Oklahoma's oil and gas regulator said on Monday it would shut deep saltwater disposal wells and restrict others near where a large earthquake earlier in the day rattled homes and businesses in the northern part of the state.

The quake had a magnitude of 4.5 on the Richter scale, regulator Oklahoma Corporation Commission said in a revised estimate. No damage had been reported, according to an official with the Grant County Sheriff Department.

The tremor occurred near Medford, Oklahoma, in the north-central part of the state and home to oil and gas drilling.

The OCC is ordering shut three disposal within six miles of the quake's epicenter and that other water disposal wells within 10 miles of the epicenter would be restricted to accepting an average volume of 500 barrels per day.

Several years ago, Oklahoma suffered a sharp uptick in earthquakes tied to the disposal of saltwater, a natural byproduct of oil and gas production. The tremors had largely subsided in recent years after the OCC took measures to limit water disposal in quake-prone areas.

Monday's quake occurred in an area where the OCC had previously shut down disposal due to an increase in quakes.

West Texas is now grappling with a similar issue in its Permian Basin, the largest U.S. shale field. The state's Railroad Commission, which regulates its oil and gas industry, has taken steps in recent months to curb the frequency of earthquakes, including shutting some disposal wells. read more

Texas Railroad Commissioner Jim Wright on Monday published a public letter addressing the increase in earthquakes in the Permian Basin. In it, he touted the benefits of recycling water and also said the RRC is working with operators to expedite the approval of additional shallow disposal wells, which are less likely to induce seismic activity.

Reporting by Liz Hampton in Denver Editing by Matthew Lewis

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