GREELEY, Colo. - Colorado regulators have ordered the temporary shutdown of an oil and gas wastewater disposal well east of Greeley after seismologists detected two earthquakes in the area in less than a month.
The Colorado Oil and Gas Conservation Commission directed High Sierra Water Services to stop injecting water into the well after a team of University of Colorado seismologists recorded a 2.6-magnitute earthquake Monday afternoon. The team began monitoring the region after a 3.4-magnitude earthquake shook the Greeley area on May 31.
The company agreed Monday to halt wastewater injection at the site for 20 days as a precaution.
"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.
The COGCC said it plans to evaluate the area's baseline, historical seismic activity and evaluate other disposal wells in the area.
Wastewater disposal must occur at the proper rate and pressure to ensure it is safely deposited in the formation.
Injection wells are used to dispose of wastewater byproducts from traditional oil and gas drilling and fracking.
Dr. William L. Ellsworth with the U.S. Geological Survey said that scientist have known since the 1960s that injection wells can trigger earthquakes.
A 2013 article Ellsworth wrote states, "The RMA earthquakes demonstrate how the diffusion of pore pressure within an ancient fault system can initiate earthquakes many kilometers from the injection point, delayed by months or even years after injection ceased."