Investigation Continues Into Greeley Quake, Wastewater Injection Well
DENVER (CBS4) - The commission investigating seismic activity near wastewater disposal sites in Weld County is meeting this afternoon to discuss developments since it ordered an injection well temporarily shut down.
The Colorado Oil and Gas Conservation Commission on Monday directed High Sierra Water Services, the owner of the injection site, to halt the disposal of wastewater into the well east of the Greeley-Weld County Airport. The company agreed to stop injection for 20 days so COGCC can study data to determine if a 2.6-magtitude earthquake was related.
Representatives from COGCC, High Sierra and University of Colorado seismologists were expected to attend the meeting. The CU scientists, who tracked the small quake on Monday, also picked up a larger 3.4-magnitude quake near Greeley on May 31.
“In light of the findings of CU’s team, we think it’s important we review additional data, bring in additional expertise and closely review the history of injection at this site in order to more fully understand any potential link to seismicity and use of this disposal well,” COGCC director Matt Lepore said.
Companies use wastewater injection wells to dispose of some of the water used in the drilling process, which extracts oil and gas from below the earth’s surface. When water doesn’t stay in rock layers and flows to the surface, companies must dispose of that water properly. One option is to re-inject the water back into the ground through a Class II UIC injection well, the Colorado Geological Survey says.
There are 309 of those wells in Colorado, and approximately 145,000 in the United States, according to August 2013 CGS numbers. COGCC administers the wells.
COGCC said the well — labeled by High Sierra as C4A — was permitted in March 2013. Injection began a month later. Wells are analyzed for geologic factors, including proximity to water supplies, before permits are issued.
Small earthquakes aren’t just rattling Colorado.
According to the Associated Press, Oklahoma has experienced more than 230 quakes this year with a magnitude of 3.0 or greater. Prior to 2008, the state averaged just more than one annually. Now, it’s one per day. The state is investigating whether fracking or wastewater injection is connected.
The Oklahoma Geological Survey keeps real-time data of seismic activity in the state. By 1 p.m. Friday, six quakes had struck, with magnitudes between 2.3 and 4.1. It’s unclear if they had any relation to injection sites.
In Edmond recently, hundreds of residents gathered at a local church to discuss the quakes.
“The risk is all taken on the homeowners. It’s our lives. It’s our property,” a woman said.
But an oil and gas advocacy group, Energy in Depth, told CBS News that “the best science available to us right now suggests strongly that (fracking) has nothing at all to do with these small seismic events.”
Austin Holland, with the Oklahoma Geological Survey, says he’s linked only a small percentage of recent quakes to fracking: “We can’t explain the entire sequence through man’s activity.”
In Texas, quakes in magnitudes weaker than 3.0 have struck northwest of Fort Worth. The city of Azle, along with oil and gas companies, has asked seismologists from Southern Methodist University to study the activity.
ExxonMobil, the parent company of the driller in charge of the wastewater injection wells in Azle, told the AP in a statement: “The study will help inform and educate all parties on exactly where these events are taking place and possible causes.”
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