Wastewater disposal at injection well halted for 20 days
By Summit Voice
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FRISCO — Colorado regulators this week halted the disposal of fracking wastewater into a Weld County injection well as they try to fully understand the link between injection and recent earthquake activity in the area.
A magnitude 3.4 earthquake rattled Greely on May 31, and University of Colorado geologists have detected more low-level seismic activity, including a 2.6 temblor earlier this week. As a result, the Colorado Oil and Gas Conservation Commission directed High Sierra Water Services to halt injections for 20 days.
The Colorado action comes just a couple of weeks after federal and state geologists in Oklahoma warned of increased risk for a damaging quakes after string of trenors rattled the Oklahoma City area.
“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,” said COGCC director Matt Lepore.
Deep injection of wastewater into deep geological formations can increase pressure underground and even lubricate faults, in a well-known process called injection-induced seismicity. Much of this wastewater is a byproduct of oil and gas production and is routinely disposed of by injection into wells specifically designed and approved for this purpose.
The COGCC will undertake several actions over the shutdown period to include: evaluation of baseline, historical seismic activity; continued coordination with the CU team; coordination with the U.S. Geological Survey and Colorado Geological Survey; evaluation of other disposal wells in the area; and a detailed review of data associated with the well in question, including further examination of injection rates, pressures and volumes.
The company immediately agreed to COGCC’s request, and shut the well down on Monday.
The well, labeled by the company as C4A, is located east of the Greeley-Weld County Airport. It was permitted by COGCC in March 2013 and injection began in April of 2013.
The COGCC has delegated authority by the U.S. Environmental Protection Agency, to regulate Underground Injection Control wells for oil and gas wastewater (known as Class II UIC wells). Such wells must be analyzed for a variety of geologic factors before permits are issued; disposal of the wastewater must also occur at the proper rate and pressure to ensure it is safely deposited in the formation.
A history and overview of underground injection wells and seismicity in Colorado is available at the COGCC’s website under the LIBRARY tab on the left hand side of the page. Scroll down to “Underground Injection Control and Seismicity.”