The question of whether oilfield “fracking” and wastewater injection wells are causing or contributing to the spate of earthquakes making Oklahoma shake, rattle and roll will be addressed in an interim legislative study this fall, state Rep. Cory Williams said Thursday.
Williams’ request for an interim study on the probable subterranean effects of oilfield activity will be combined with another legislator’s proposal for a study of Oklahoma Corporation Commission injection well data monitoring.
House Speaker Jeff Hickman approved both requests and assigned the consolidated study to the House Committee on Utility and Environmental Regulation. Interim studies can begin on Aug. 5and must be completed by Nov. 12, Hickman decreed recently.
“We have been having a swarm of earthquakes in our area, and I’m fielding a lot of inquiries from constituents who want to know what, if anything, the State of Oklahoma is doing about,” said Williams, D-Stillwater.
By 5 p.m. Tuesday, the Oklahoma Geological Survey had logged 20 earthquakes in the Stillwater area during the preceding 30 days, and 209 tremors in the surrounding area this year – or more than one per day, on average.
The OGS counted all temblors recorded in an area extending 12 miles east and west of Stillwater, and eight miles north and south of the Payne County community, including Glencoe and Ripley, according to Amberlee Darold, a research seismologist with the Oklahoma Geological Survey.
Payne County has 40 injection wells and 260 active oil and gas wells, Corporation Commission records reflect.
Oklahoma has experienced nearly 250 small-to-medium earthquakes since January, the U.S. Geological Survey reported this week. That’s almost half of all magnitude-3 or higher earthquakes recorded this year in the continental U.S.
Austin Holland, a research seismologist with the OGS, said Oklahoma is experiencing unprecedented earthquake activity, and said his agency is monitoring the activity to determine whether the earthquakes are a natural phenomenon or are manmade.
No deaths or injuries have been reported, but varying degrees of property damage have been blamed on the quakes.
The OGS counted 2,270 earthquakes in Oklahoma as ofJune 6; eight of those ranged in magnitude from 4.0 to 4.5 and all occurred in Logan County. In comparison, 2,848 earthquakes were recorded in Oklahoma in all of 2013, 980 in 2012, 1,470 in 2011, and 1,047 in 2010.
The USGS statistically analyzed the recent earthquake rate changes and found that “they do not seem to be due to typical, random fluctuations in natural seismicity rates.” The agency’s analysis suggests that “a likely contributing factor to the increase in earthquakes” is wastewater injected into deep geological formations.
Seismologists also contend that hydraulic fracturing – “fracking,” which entails blasting water, sand and chemicals deep into underground rock formations to liberate trapped oil and gas – can cause microquakes that are rarely strong enough to register on monitoring equipment.
To more accurately determine the locations and magnitudes of earthquakes in the Sooner State, the OGS has increased the number of monitoring stations and now operates a seismograph network of 15 permanent and 17 temporary stations.
One point of contention is whether some injection well operators are pumping too much wastewater into the ground, or pumping it at exceedingly high pressures.
The Oklahoma Independent Petroleum Association reports that water emerges from the wellbore, along with oil and natural gas, in some areas. Such wells typically produce 10 times as much water as hydrocarbons, the OIPA claims.
Regulators said Oklahoma producers injected more than a billion gallons of oilfield wastewater underground in 2012.