Seismic monitoring continues around a deep fracking wastewater well in Ohio after a magnitude-4.0 earthquake and 10 other earthquakes were tentatively linked to activity at the well.
Scientists from Columbia University’s Lamont-Doherty Earth Observatory said that seismic monitoring will continue at least for a few more weeks around the Youngstown, Ohio, Class II disposal well, about 1.7 miles deep.
That monitoring, which includes four seismometers in the area, led the Ohio Dept. of Natural Resources to shut down the injection well on Dec. 30 following a magnitude-2.7 earthquake near the well on Dec. 24. A week later, a magnitude-4.0 quake shook the area. The well, owned by Northstar Disposal Services, Youngstown, has been tentatively linked to 11 earthquakes since it began operating in 2010. Northstar did not return a call seeking comment. DNR also shut down activity at five other nearby wells, which were not receiving waste.
Scientists, including Won-Young Kim at the Lamont-Doherty observatory, have been quoted as saying that activity at the injection well is likely linked to the earthquakes. But in e-mail correspondence with Engineering News-Record, Kim said the observatory “cannot conclusively link the earthquakes to the injection wells” and that the Ohio Dept. of Natural Resources (DNR) would have to make that determination. The Ohio DNR expects to issue a study about the possible link within 30 days, says Heidi Hetzel-Evans, a spokeswoman for the DNR's oil and gas division.
On Dec. 30, Ohio DNR Director James Zehinger, when announcing the shutdown of the well, said, “Our top priority is the health and safety of the public and the protection of Ohio’s natural resources. We are going to make sure this process is done right and won’t hesitate to stop operation of disposal sites if we have concerns. And while our research doesn’t point to a clear and direct correlation to drilling at this site and seismic activity, we will never gamble when safety is a factor.”
But Anthony Ingraffea, a Cornell University professor in civil and environmental engineering who has studied hydraulic fracturing for years, says the quake is “incontrovertibly” linked to the injection of waste from hydraulic fracturing into the well.
“My guess is that they pumped too much fluid into that well and mobilized a fault system,” says Ingraffea, who has been outspoken in trying to promote better practices in hydraulic fracturing. “The pressure became so great that fracturing in that well occurred.”
Injection of the waste occurs under pressure, but it was unclear whether the well was pressurized when the quakes occurred. Hetzel-Evans says there is no volume capacity limit to the injection wells, but that the maximum allowable pressure for the well was 2500 psi. She says the company operating the wells had not gone above that level.
While hydraulic fracturing purposely fractures deep shale formations to extract natural gas, the injection of the waste fluid is not intended to fracture rock formations.
Yet, injection of fracking fluid into deep wells has been tentatively linked to small earthquakes in Arkansas, Texas, Oklahoma and British Columbia.
Thomas Stewart, executive vice president of the Ohio Oil and Gas Association, said in a statement that the quakes involving the Youngstown well “should not cast doubt about the effectiveness or usage of Class II injection wells, which have been used safely and reliably as a disposal method for wastewater from oil and gas operations in the U.S. since the 1930s and is the preferred method for oil-field waste management under the Safe Drinking Water Act.”
Ohio DNR says there are 177 Class II wells in the state. However, this particular well could be disturbing a fault system below it, Ingraffea says. “Either they didn’t know the fault system was down there, or they assumed that the injection into that system would not further lubricate the system,” Stewart says.
Hetzel-Evans says the well in question and nearby wells are the only wells in the state in which injection is occurring in the Precambrian rock layers.
The overall problem, Ingraffea says, stems from the fact that there are not enough disposal wells to handle the millions of gallons of hydraulic fracturing fluid being used in the process. Pennsylvania, which has dozens of operators fracturing shale in search of natural gas, has only seven permitted disposal wells. Ingraffea says that while some operators recycle their fluid, others ship it over state lines for disposal in injection wells in Ohio and West Virginia.
The class II injection wells are regulated by the Environmental Protection Agency, but the EPA can choose to cede regulation to the states. The EPA regulates the wells in Pennsylvania, but Ohio DNR regulates the wells in Ohio.
Ingraffea says, historically, drilling fluid and wastes are injected into abandoned oil and gas wells after they have been inspected for casing and cement competency, among other check-list items. But the shale-rock wells now being drilled, he says, aren’t suitable to hold the waste fracking fluid because of the composition of shale.
U.S. Senator Frank R. Lautenberg (D-N.J.) on Jan. 9 called for the U.S. Geological Survey to further study the link between the fracking fluid disposal and earthquakes.
Rick Groll, an industrial seismologist, says the link between the quakes and the deepwater wells are “nebulous.” But the owners of the well need to determine quickly whether there is a link, he adds. They should “stay out ahead” of the problem by using permanently installed seismographs. “If this starts happening elsewhere,” Groll says, “[the industry] is going to get driven into the ground with lawsuits.”