In Oklahoma, water, fracking - and a swarm of quakes

Reuters

By Carey Gillam

NORMAN, Okla., Nov 19 (Reuters) - Seismologist AustinHolland wants to start an earthquake.

From his office a few feet below the earth's surface - abasement at the University of Oklahoma in Norman - Holland, whotracks quakes for the Oklahoma Geological Survey, is digginginto a complex riddle: Is a dramatic rise in the size and numberof quakes in his state related to oil and gas productionactivity? And, if so, what can be done to stop it?

As part of his wide-ranging research, Holland is proposingto inject pressurized water into porous rock in an area alreadyknown to be earthquake-prone, to see whether injections of oilindustry wastewater are contributing to a "swarm" of earthquakesrocking the state.

"This is a dramatic new rate of seismicity," Holland said inan interview. "We can't guarantee the earthquakes aren't acoincidence (unrelated to oil and gas work)," he said. "But itwould be a pretty remarkable coincidence."

Experts say billions of dollars could be at stake, aspotential new regulations could affect the oil and gasindustry's profits and as lawsuits by property owners withearthquake-related claims make their way through the legalsystem.

Oklahoma, the nation's fifth-largest oil-producing state, recorded 238 earthquakes through Nov. 18. More than 100 of thosewere at least a magnitude 3.0 on the Richter scale, tremorslarge enough to shake shelves and shred nerves.

One series of quakes in September near a newly openedinjection well in the southern part of the state damaged severalhomes.

The quake activity is a far cry from four years ago when thestate had but 20 rumblers of 3.0 and above. And from 1991 to2008 there were no more than three quakes a year of that size inthe state.

Since 2009, the volume of wastewater from oil and gas workinjected deep into underground disposal wells has also risen, upabout 50 percent in 2012 from the level seen during most of thefirst decade of the century, with the last couple of yearsshowing the biggest jumps.

Most earthquakes occur naturally, but the increases infrequency and magnitude are distinct new elements, researcherssay. While there are already many studies linking work atinjection wells to earthquakes, Holland and other scientists arefocusing on how the quakes are triggered and on measures tomitigate seismic activity.

The concern is not unique to Oklahoma. Since 2001 theaverage annual number of earthquakes of magnitude 3.0 or greaterhas jumped "significantly" across the midsection of the country,including not just Oklahoma but also Ohio, Arkansas and Texas,according to the U.S. Department of Interior.

In Arkansas, a group of homeowners who filed lawsuitsagainst well operators alleged that their properties weredamaged by a swarm of earthquakes that hit the central part ofthat state in 2010 and 2011. Scientists there blamed disposalwells for touching off more than 1,000 quakes in those years.

"Potentially billions of dollars are involved, from profitsto class action lawsuits," oil industry analyst John Daly notedto clients recently. "Given the stakes, Holland's research willbe closely watched not only by Oklahoma's oil and gas industrybut producers throughout the U.S. as well."

The increasing number of large quakes has given freshurgency to questions about whether the seismic activity is beinginduced by oil and gas production activities. Along withHolland, earthquake experts in Oklahoma, Texas, California,Arkansas and elsewhere are examining the issue. The federalgovernment and the oil industry are funding some of theresearch.

Most earthquakes occur naturally. But scientists have longlinked some small earthquakes to oil and gas work underground,which can alter pressure points and cause shifts in the earth.

Oil and gas exploration has increased in recent years acrossthe country, spurred by U.S. efforts for energy independence.Modern hydraulic fracturing, or fracking, is one particularlycontroversial technique.

Fracking - which involves the injection of water, sand andchemicals under high pressure into bedrock to increase the flowof oil or gas - has been the culprit in some small earthquakesaround the country. But it is not suspected as the cause of thebigger and more frequent quakes that have occurred recently,according to the Interior Department.

Disposal of the wastewater generated by fracking and byother types of oil and gas production is the "focal point" forresearch into what scientists call "induced" earthquakes.

The increase in earthquakes might be due in part to newdrilling and well-completion technologies that enable theextraction of oil and gas from previously unproductiveformations, according to William Ellsworth, a scientist with theU.S. Geological Survey's Earthquake Science Center.

In a report published in July, Ellsworth linked wastewaterdisposal to a 2011 Youngstown, Ohio, quake, and a series ofearthquakes from October 2008 to May 2009 near Dallas, Texas.

Ellsworth also tied wastewater injection to arecord-breaking 5.6-magnitude quake in Oklahoma in November,2011, a tremor that damaged more than a dozen homes and severalbusinesses.

The oil industry is not disputing the possibility of links,said Steve Everley, a spokesman for Energy In Depth, a websiterun by the Independent Petroleum Association of America. Butonly a handful of injection wells are actually associated withseismic events large enough to be felt, he said. Still, he said,the industry is paying attention to the new scientific findings.

"Sound research and good data can help inform the industryand improve its operations to further reduce risk," he said.

DO-IT-YOURSELF EARTHQUAKE

Holland's research primarily focuses on analyzing howseismic activity around the state correlates with injectionvolumes and the numerous fault zones underlying the region. Buthe is also drawing up a proposal that would create a smallearthquake in the south-central part of the state.

That region was rattled by dozens of earthquakes inSeptember, including one that registered 3.4 on the Richterscale, and the quakes began within two weeks of the startup of anew wastewater injection well there. Data showed that as thevolume of pressurized wastewater injections grew, so did theseismic activity.

The well operator closed the well after regulators limitedits volumes in response to the quakes, but Holland is seekingpermission from regulators and the well operator to reopen thewell and inject ever-greater amounts of wastewater whilemonitoring the seismic reaction. He hopes the work can helpidentify safe levels of injection and strategies to reduce risksfor further earthquakes.

Regulators and the oil and gas industry say they welcome theresearch.

"Those people that live in areas that have been seismicallyactive ... they are very concerned," said Matt Skinner, aspokesman for the Oklahoma Corporations Commission, whichoversees the state's 11,000 injection wells.

Tom Dunlap, owner of the injection well Holland wants to useas the test site, said he welcomes Holland's proposal as a wayto limit further earthquake risk.

"What our work does ... and how that plays into seismicstuff ... we don't know," Dunlap said.

(Reporting By Carey Gillam in Norman, Oklahoma; Editing byDavid Greising, Peter Henderson and Douglas Royalty)

Rates

View Comments