The Colorado Oil and Gas Conservation Commission has ordered a 20-day halt to wastewater injection in a Weld County well following a 2.6 magnitude earthquake in the Greeley area June 23.
The decision follows a 3.4 magnitude earthquake that hit Greeley at the end of May. In other parts of the country, injection wells have been linked to earthquakes. Such wells are different from wells that produce energy, and often hold wastewater produced from oil and gas wells.
After May's quake, the first in the area since 1969, researchers from the University of Colorado set up a network of monitors to watch for further seismic activity.
Anne Sheehan, a scientist at the University of Colorado Boulder whose team set up the network, said Monday that the researchers have tracked 30 or so aftershocks, all too small to be felt.
"The events do not seem to be tapering off or decreasing in size, though," Sheehan said.
COGCC director Matt Lepore said the 20 days will be used to analyze data without injection happening to see if there is a change.
“I want to be clear that while we think it is the prudent thing to do to stop injection at this well and do the next steps, we are not making yet a causative determination," Lepore said. "We want to continue to gather information.”
Lepore said the COGCC will coordinate with the U.S. Geological Survey and Colorado Geological Survey – which also recorded Monday’s earthquake – to study the data.
The injection well belongs to High Sierra Water Services, and is located east of the Greeley-Weld County Airport. It was permitted by COGCC in March 2013 and injection began in April of 2013.
For reference, a super handy, understandable Colorado Geological Survey white paper on human-induced earthquakes: http://t.co/AQ71Mbji27
— Luke Runyon (@LukeRunyon) June 24, 2014