Study raises new concern about earthquakes and fracking fluids

Study raises new concern about earthquakes and fracking fluids

By Sharon Begley

NEW YORK (Reuters) – Powerful earthquakes thousands of miles away can trigger swarms of minor quakes near wastewater-injection wells like those used in oil and gas recovery, scientists reported on Thursday, sometimes followed months later by quakes big enough to destroy buildings.

The discovery, published in the journal Science by one of the world’s leading seismology labs, threatens to make hydraulic fracturing, or “fracking,” which involves injecting fluid deep underground, even more controversial.

It comes as the U.S. Environmental Protection Agency conducts a study of the effects of fracking, particularly the disposal of wastewater, which could form the basis of new regulations on oil and gas drilling.

Geologists have known for 50 years that injecting fluid underground can increase pressure on seismic faults and make them more likely to slip. The result is an “induced” quake.

A recent surge in U.S. oil and gas production – much of it using vast amounts of water to crack open rocks and release natural gas, as in fracking, or to bring up oil and gas from standard wells – has been linked to an increase in small to moderate induced earthquakes in Oklahoma, Arkansas, Ohio, Texas and Colorado.

Now seismologists at Columbia University say they have identified three quakes – in Oklahoma, Colorado and Texas – that were triggered at injection-well sites by major earthquakes a long distance away.

“The fluids (in wastewater injection wells) are driving the faults to their tipping point,” said Nicholas van der Elst of Columbia’s Lamont-Doherty Earth Observatory in Palisades, New York, who led the study. It was funded by the National Science Foundation and the U.S. Geological Survey.

Fracking opponents’ main concern is that it will release toxic chemicals into water supplies, said John Armstrong, a spokesman for New Yorkers Against Fracking, an advocacy group.

But “when you tell people the process is linked to earthquakes, the reaction is, ‘what? They’re doing something that can cause earthquakes?’ This really should be a stark warning,” he said.

Fracking proponents reacted cautiously to the study.

“More fact-based research … aimed at further reducing the very rare occurrence of seismicity associated with underground injection wells is welcomed, and will certainly help enable more responsible natural gas development,” said Kathryn Klaber, chief executive of the Marcellus Shale Coalition.

‘DYNAMIC TRIGGERING’

Quakes with a magnitude of 2 or lower, which can hardly be felt, are routinely produced in fracking, said geologist William Ellsworth of the U.S. Geological Survey, an expert on human-induced earthquakes who was not involved in the study.

The largest fracking-induced earthquake “was magnitude 3.6, which is too small to pose a serious risk,” he wrote in Science.

But van der Elst and colleagues found evidence that injection wells can set the stage for more dangerous quakes. Because pressure from wastewater wells stresses nearby faults, if seismic waves speeding across Earth’s surface hit the fault it can rupture and, months later, produce an earthquake stronger than magnitude 5.

What seems to happen is that wastewater injection leaves local faults “critically loaded,” or on the verge of rupture. Even weak seismic waves from faraway quakes are therefore enough to set off a swarm of small quakes in a process called “dynamic triggering.”

 

File photo of anti-fracking rally at the state legislature …

 
Anti-fracking protestors demonstrate at the state legislature in Albany, New York in this January 24 …

“I have observed remote triggering in Oklahoma,” said seismologist Austin Holland of the Oklahoma Geological Survey, who was not involved in the study. “This has occurred in areas where no injections are going on, but it is more likely to occur in injection areas.”

Once these triggered quakes stop, the danger is not necessarily over. The swarm of quakes, said Heather Savage of Lamont-Doherty and a co-author of the study, “could indicate that faults are becoming critically stressed and might soon host a larger earthquake.”

For instance, seismic waves from an 8.8 quake in Maule, Chile, in February 2010 rippled across the planet and triggered a 4.1 quake in Prague, Oklahoma – site of the Wilzetta oil field – some 16 hours later.

That was followed by months of smaller tremors in Oklahoma, and then the largest quake yet associated with wastewater injection, a 5.7 temblor in Prague on November 6, 2011.

That quake destroyed 14 homes, buckled a highway and injured two people.

The Prague quake is “not only one of the largest earthquakes to be associated with wastewater disposal, but also one of the largest linked to a remote triggering event,” said van der Elst.

The Chile quake also caused a swarm of small temblors in Trinidad, Colorado, near wells where wastewater used to extract methane from coal beds had been injected.

On August 22, 2011, a magnitude 5.3 quake hit Trinidad, damaging dozens of buildings.

The 9.1 earthquake in Japan in March 2011, which caused a devastating tsunami, triggered a swarm of small quakes in Snyder, Texas – site of the Cogdell oil field. That autumn, Snyder experienced a 4.5 quake.

The presence of injection wells does not mean an area is doomed to have a swarm of earthquakes as a result of seismic activity half a world away, and a swarm of induced quakes does not necessarily portend a big one.

Guy, Arkansas; Jones, Oklahoma; and Youngstown, Ohio, have all experienced moderate induced quakes due to fluid injection from oil or gas drilling. But none has had a quake triggered by a distant temblor.

Long-distance triggering is most likely where wastewater wells have been operating for decades and where there is little history of earthquake activity, the researchers write.

“The important thing now is to establish how common this is,” said Oklahoma’s Holland, referring to remotely triggered quakes. “We don’t have a good answer to that question yet.”

Before the advent of injection wells, triggered earthquakes were a purely natural phenomenon. A 7.3 quake in California’s Mojave Desert in 1992 set off a series of tiny quakes north of Yellowstone National Park in Wyoming, for instance.

Now, according to the Science paper, triggered quakes can occur where human activity has weakened faults.

Current federal and state regulations for wastewater disposal wells focus on protecting drinking water sources from contamination, not on earthquake hazards.

(Reporting by Sharon Begley; Additional reporting by Edward McAllister; Editing by Michele Gershberg and Xavier Briand)

Advertisements

Fracking Wastewater Disposal Seen Linked to Earthquakes

Fracking Wastewater Disposal Seen Linked to Earthquakes

Disposing of wastewater from hydraulic fracturing may make fault zones more prone to earthquakes, according to researchers from Columbia University and the University of Oklahoma.

The researchers found a “profound” increase in the number of earthquakes at three sites where wastewater from fracking was injected into the ground, said Nicholas van der Elst, a scientist at Columbia’s Lamont-Doherty Earth Observatory in Palisades, New York, and lead author of an article published today in the journal Science.

Oil and natural gas producers typically dispose of water and other fluids from fracking by injecting it into the ground. The report found that as subsurface rocks become saturated, fault lines in the area may become less stable, van der Elst said.

“This study helps show the link between the pumping and the earthquakes,” van der Elst said in an interview.

The report found that significant seismic activity elsewhere on the planet, sometimes even on other continents, may “induce” quakes in injection zones hours or days later.

“Seismic waves from the distant earthquake can squeeze the rock like a sponge,” he said. The researchers studied injection sites in Oklahoma, Texas and Colorado, and recorded “hundreds” of earthquakes in a year “where you might have expected a dozen.”

Injecting Wastewater

Disposing of wastewater and other fluids by permanently injecting them into the ground may have a greater impact on fault lines than fracking, which typically involves pumping the liquids into the earth and then extracting them, according to the study.

More than half of the earthquakes in the U.S. in the past decade with magnitudes of 4.5 or more “occurred in regions of potential injection-induced seismicity,” according to the report.

“While the earthquakes are natural, relieving natural stresses, you’re making them happen in your lifetime rather than somebody else’s lifetime,” van der Elst said. “They can’t just be dismissed.”

To contact the reporter on this story: Justin Doom in New York at jdoom1@bloomberg.net

To contact the editor responsible for this story: Reed Landberg at landberg@bloomberg.net

A Gamble on Shale Job Growth Fails to Pay Off for Governor Corbett, as Fracking Worries Grow Nationwide

A Gamble on Shale Job Growth Fails to Pay Off for Governor Corbett, as Fracking Worries Grow Nationwide (via Desmogblog)

Last Friday in Philadelphia, a small crowd gathered outside the Franklin Institute, protest signs in hand. Only a few days before, word went out that Governor Tom Corbett, one of the nation’s least popular governors, would be in Philadelphia, a city…

Continue reading

Terra Slicing Technology

Terra Slicing Technology (TST) is a patented oil and gas completion technology that increases production of under-performing oil and gas assets by excavation, cutting through damaged zones, increasing permeability, creating non-existent vertical permeability, avoiding damage caused by perforation, increases the drainage area, and is safer than a frac. TST can be used in almost any situation with high risk wells and is the only tool that can work in less than 5% porosity/permeability.