Second of two parts. Read part one here.
PRAGUE, Okla. -- Seismologists have simple advice for oil and gas companies to avoid unleashing an earthquake -- don't inject millions of gallons of wastewater near active faults.
That's advice Oklahoma's drilling industry and regulators have chosen to ignore.
It's not an academic debate in this rural crossroads, halfway between Tulsa and Oklahoma City. People here learned they live above an active fault only after it jolted them Nov. 5, 2011, with the state's largest recorded earthquake. The magnitude-5.6 convulsion injured at least two people and damaged as many as 200 homes and businesses.
A number of seismologists, along with many of the people who live around here, think the injection wells are connected to the earthquake (EnergyWire, July 24). Others dispute any connection.
What is not disputed, however, is that two oil companies have continued injecting millions of gallons of wastewater -- with the state's blessing -- into wells within two and a half miles of the quake's epicenter, which is just northwest of Prague's city limits.
That risks another damaging earthquake, scientists say, possibly even a bigger one.
"Bad idea," Stanford University professor Mark Zoback said simply when asked last month about the continuing wastewater injection.
Zoback is no crusader against hydraulic fracturing. In addition to teaching at Stanford, he became a senior adviser to Baker-Hughes after the multinational well services firm bought the consulting firm where he was chairman in 2008. Zoback started his career as a geophysicist at Amoco Production Co., and before working at Stanford, he was chief of the Tectonophysics Branch of the U.S. Geological Survey Earthquake Hazards Reduction Program.
Zoback wrote in the April edition of Earth Magazine that man-made quakes -- or "induced seismicity" -- are manageable, as long as certain steps are taken.
"First, it is important to avoid injection into active faults," he wrote.
Regulators, he wrote, must be prepared to halt drilling if they find a previously unknown fault. The article doesn't contemplate the idea of continuing to inject into a known fault.
In his brief interview with EnergyWire, Zoback said he wasn't familiar with reports from fellow scientists that the magnitude-5.6 quake was linked to drilling activities.
Still, Zoback said, no one should be drilling near active, known faults. In the Senate hearing on man-made earthquakes that preceded the brief interview last month, he had an exchange with Sen. Lisa Murkowski of Alaska. Zoback said avoiding faults when injecting seemed like a "no-brainer." Murkowski, the top Republican on the Senate Energy and Natural Resources Committee, agreed, calling it "pretty obvious."
Prague, the city closest to the quake's epicenter, is an oil patch town. Still, there is unease about injecting fluid deep in the earth so close to the center of last year's upheaval.
"It's probably not a good idea to inject into a known fault," said Prague City Manager Jim Greff, pondering the situation in an interview in the former bank building that serves as City Hall. But he added, "Oil and gas is big in Oklahoma."
Oil and gas drilling here is regulated by the Oklahoma Corporation Commission, a three-member elected panel whose members get more campaign contributions from oil and gas than from any other industry (Greenwire, Dec. 9, 2011).
Since the earthquake, the commission hasn't put any restrictions on drilling or injection. The commission is awaiting findings from the Oklahoma Geological Survey, which has criticized the work of other geologists linking the earthquake to drilling activities as "premature." The state is also getting data from seismic testing done in the area after the earthquake by a company looking for oil.
"We don't really have any substantiation that the injection wells in that area were responsible for this," said Dana Murphy, the corporation commissioner who currently chairs the panel. "In the scientific community, there's very much a diversity of opinion on this."
Murphy cited a section of Zoback's Earth Magazine article that noted "speculation" that the Oklahoma quake might have been triggered by drilling activities but said "no linkage" has been established. It was published before an April conference of the Seismological Society of America, during which scientists presented evidence of a "compelling" link and warned that continued injection could cause another damaging earthquake (EnergyWire, April 19). Murphy indicated she was not familiar with the explicit warning not to inject into active faults.
Murphy also said campaign contributions play no role in her decisionmaking.
"I'm not anybody's commissioner," she said. "I'm for the state of Oklahoma."
Oklahoma Geological Survey seismologist Austin Holland said injection should "absolutely" continue because of the knowledge that can be gained by continuing to study the interaction between injection and the fault.
"We can actually learn what's going on," he said, "and perhaps mitigate these things in the future."
State regulators in Arkansas, he said, missed a chance to gain such knowledge when they shut down drilling last year amid a "swarm" of earthquakes in the north-central part of the state.
But University of Memphis seismologist Steve Horton -- whose research was part of the basis for the moratorium in Arkansas -- warned in a scientific report in April that continuing to inject brine into the Wilzetta Fault risks another damaging earthquake (EnergyWire, April 19).
In an email earlier this year to U.S. EPA officials who oversee injection wells as part of the agency's "Underground Injection Control" (UIC) program, Horton urged them to press Oklahoma officials harder for information.
"This fault should be capable of a [magnitude] 6 earthquake if it were to rupture as a single event. It is presumably capable of more [magnitude] 5.6 events," Horton wrote in an email obtained by EnergyWire through the Freedom of Information Act. "Continued injection at those wells could possibly trigger more damaging earthquakes. Not to put too fine a point on it, but you guys are supposed to be coming up with guidelines for UIC wells and induced/triggered earthquakes. Can't you ask for information?"
In Ohio earlier this year, state officials moved quickly to get an injection well operator to agree to shut down its well, months before they issued a final report linking earthquakes to the well.
"Our top priority is the health and safety of the public and the protection of Ohio's natural resources," Ohio Department of Natural Resources Director James Zehringer said at the time.
EPA oversees state regulation of underground injection wells, but there are no federal requirements banning injection into faults, nor are there penalties for causing earthquakes. Oil and gas injection wells are exempt from the federal environmental laws requiring tests before drilling such wells to ensure they won't unleash quakes.
But a recent report from the National Research Council suggests that in areas susceptible to man-made earthquakes, state officials could add seismic provisions to their permit approvals (Greenwire, June 15). Few states have done so, though some have shut down wells after earthquakes.
The National Research Council's report also suggests injection could be scaled back if it is tied to earthquakes and could even be stopped if it becomes a broader concern for public health and safety. But Oklahoma Geological Survey's Holland notes, even that isn't a guarantee.
"If you avoid faults, you may avoid the possibility of large earthquakes, but you may not," he said. "There can be other faults."