Published On: Fri, Apr 24th, 2015

New Studies Link Earthquakes With Oil, Gas Drilling

New scientific findings released Tuesday linked earthquakes to the practice of injecting wastewater from oil and gas operations deep underground, adding to a growing consensus among researchers that energy development is probably causing seismic activity in Oklahoma, Texas and other parts of the U.S.

The Oklahoma Geological Survey released a statement Tuesday saying that it now “considers it very likely” that most of the hundreds of earthquakes in the state’s center in recent years were “triggered by the injection of produced water in disposal wells.” Produced water is salty fluid that naturally flows up wells along with oil and gas.

Meanwhile in Texas, a team of college and federal researchers headed by scientists at Southern Methodist University released a new study concluding that a string of earthquakes that began in 2013 northwest of Fort Worth was also likely caused by wastewater injection.

Oklahoma Gov. Mary Fallin, a Republican, called the findings by state geologists significant and said the state was working to toughen regulations in response to an increase in quakes. “State agencies are already taking action to address this issue and protect homeowners,” she said in a statement.

Oklahoma last year experienced 585 earthquakes of 3.0 or greater magnitude—big enough to be felt indoors—according to the state,more than in the previous 30 years combined.

The energy industry has called for more research into the issue before conclusively linking wells to specific seismic events. Several industry representatives said Tuesday that the research by experts in Oklahoma and Texas constituted a step forward, but more study was needed.

Kim Hatfield, the president of Crawley Petroleum Corp. and chairman of the Oklahoma Independent Petroleum Association’s regulatory committee, noted that oil and gas companies have been injecting fluids in central Oklahoma for many years.

“It worked out smashingly right up to the point where it didn’t,” Mr. Hatfield said. “Something changed and we need to figure out why that is.”

The team behind the Texas study, which also included researchers from the U.S. Geological Survey and the University of Texas, also linked the quakes, centered on the town of Azle, Texas, to the extraction of produced water from nearby natural gas wells. It published its findings in the journal Nature Communications.

“This is new, the possible role that extraction or removal of water could play,” said Heather DeShon, an SMU seismologist.

Geologists concluded decades ago that injecting fluid into a geologic fault can lubricate slabs of rock, causing them to slip and triggering earthquakes. But concerns over man-made quakes have intensified in recent years. Every year, companies have to dispose of billions of barrels of briny, toxic water that comes out of wells along with oil and gas, as well as a smaller amount of fluid called flowback left over from hydraulic fracturing.

The practice of disposal wells isn’t new, and not limited to the oil and gas industry, but has proliferated in recent years with the U.S. energy boom. That in turn has led a number of states to begin enacting tougher regulations amid a spike in seismic activity in oil- and gas-producing states.

A team of researchers led by a Cornell University professor last year tied a central Oklahoma quake swarm to nearby disposal wells. Homeowners who suffered damage and injuries following a particularly severe earthquake near Prague, Okla., in 2011 have filed lawsuits against two energy companies, raising concerns in the industry that it could be forced to pay for damages if found liable for quakes.