How to identify earthquake damage
The Kansas Corporation Commission has launched an investigation to determine what’s causing a spate of earthquakes in the Hutchinson area, focused on the underground disposal of oilfield waste that’s been blamed for quakes elsewhere in southern Kansas, officials said Wednesday.
The regulatory agency took that action after a cluster of 17 earthquakes hit Reno County over five days from Aug. 15 to Sunday.
“Amid damage reports and a concern for public safety, the KCC is conducting an investigation and will evaluate whether additional action is needed to safeguard Kansans,” KCC spokeswoman Linda Berry said in a written statement announcing the investigation.
Investigators will collect data and analyze recent oilfield injection well activity in a 15-mile radius of where the earthquakes have been occurring, said Ryan Hoffman, director of the KCC’s Conservation Division that regulates oil and gas drilling.
The study in Reno County will focus specifically on wells in the Arbuckle Formation, which has been problematic before.
Geologically placid for decades, southern Kansas began to be rocked by earthquakes in 2013, corresponding to an increase in “fracking,” an oil industry term for using high-pressure liquid to fracture subsurface rock to free trapped pockets of oil and gas.
Seismologists have ruled out fracking as a direct cause of the quakes, but the increased production it made possible generated millions of barrels of wastewater that are blamed for the increase in seismic activity.
The wastewater, trapped underground for ages, is so polluted with oil and salt that it can’t be disposed of at the surface. So operators pump it back underground, which can upset the balance of forces in deep-rock formations and cause quakes.
The average Kansas well generates 16 barrels of wastewater for every barrel of oil recovered.
Hoffman said somewhat paradoxically, wastewater disposal in the 15-mile circle around the Reno County quakes is actually lower today than in was in 2015, when oil prices and production were booming.
Injection peaked in 2015 at almost 16 million barrels. Since then, it’s fluctuated in the 14.5 to 14.8 million barrel range.
“There has been an increase (in 2018), but to put it in the larger context, it’s still a decrease,” Hoffman said.
Hoffman said Reno County wasn’t part of a study that led to KCC-ordered limits on wastewater disposal in 2015 and 2016. That action has been credited with calming seismic activity in Barber, Harper, Kingman, Sedgwick and Sumner counties.
At the time, seismologists noted that quake activity appeared to be moving to the north and forecast that the trend could continue.
The swarm of 17 earthquakes over five days in the same area of Reno County started with two the morning of Aug. 14, a 2.8 and a 2.0, according to Kansas Geological Survey reports. A magnitude 4.2 hit just before 8 a.m. Friday with seven aftershocks in the next seven hours. The strongest was a 3.3 magnitude.
Two more earthquakes shook the ground Friday night, and four more struck Saturday morning before dawn. The strongest was a 3.0. Then early Sunday morning, a second 4.2 magnitude earthquake shook the ground.