The operator of a new Love County disposal well has shut in operations after the Oklahoma Geological Survey indicated the well might be the cause of a series of earthquakes in the area over the past several weeks.
The Oklahoma Corporation Commission last week ordered the well operation reduced to less than 5 percent of its designed capacity. The operator then shut in the well because it was not economic at the reduced rates, commission spokesman Matt Skinner said.
The geological survey has installed five seismometers in the area and is continuing its investigation.
“We certainly want to understand this better,” said Austin Holland, a seismologist at the Oklahoma Geological Survey and author of the Love County report. “The challenge is navigating the complex scenario in the most responsible way.
“There are states where at this point the well would have been shut in. But we know earthquakes occur naturally in Oklahoma. We need to rule out natural occurrences as a possibility.”
The Love County Disposal Well No. 1 was completed Aug 14. An initial test was conducted Aug. 13, and the well entered full operation Sept. 9.
The Oklahoma Geological Survey on Sept. 17 began observing seismic activity in Love County after local residents complained to the Oklahoma Corporation Commission about small quakes.
The geological survey has recorded at least 18 earthquakes in the area with a magnitude 2.0 or greater, including a 3.2 and a 3.4 on Sept. 23, Holland said.
“The largest of these caused significant damage to local residents,” the report stated. “This damage includes damage to unreinforced masonry, including damage to chimneys, columns and brick facade, as well as broken windows and fallen objects from walls and cabinets.”
Such significant damage from a 3.4 quake “suggests a shallow focal depth for the earthquake,” the report stated.
Disposal wells are used to pump saltwater and other unwanted materials from oil and natural gas drilling deep underground. Disposal wells in Ohio and other parts of the country have been linked to earthquakes near the well sites.
The Oklahoma Geological Survey is in the midst of similar ongoing investigations in other parts of the state.
“There have been a number of specific cases where the potential of induced seismicity has been suggested in and near Oklahoma over the past few years involving both hydraulic fracturing and disposal well activities,” the report stated.
Dueling reports from two University of Oklahoma seismologists this spring reached different conclusions about whether the magnitude 5.7 earthquake that struck central Oklahoma in 2011 was caused by disposal well activity.
Oklahoma is dotted with 393 active commercial injection wells, including 18 new wells permitted within the past six months.
Injection wells have been used throughout Oklahoma for much of the state's history. Holland said the state has experienced a significant increase in seismic activity over the past four years, but that it is still unclear what has caused the change.
“There are researchers that say all of the earthquakes we've had recently have to be due to oil and gas injection. I don't think it can be that simple,” he said. “I don't think we can explain it all through changes in our oil and gas activity or that somehow we've hit the tipping point for the state. It's an interesting question and something I spend a lot of time thinking about.
“I think there's probably something going on in the natural environment changing the rate we're having earthquakes, which could make it more likely to trigger earthquakes from these wells. But that's all speculation.”
There are researchers that say all of the earthquakes we've had recently have to be due to oil and gas injection. I don't think it can be that simple.”
A seismologist at the Oklahoma Geological Survey