Does fracking cause earthquakes? Studies show link to oil and gas waste water wells

Adrian Hedden
Carlsbad Current-Argus

Injecting waste water from fracking operations became the top solution to the problem as the practice led to a historic boom in production throughout the Permian Basin.

Fracking, or hydraulic fracturing, is a popular method of oil and gas extraction that involves pumping a combination of water, sand and chemicals underground to break up shale formations and pull out oil and natural gas.

Saltwater disposal (SWD) facilities were built throughout the region to send the water, often drawn up during the drilling process from the same shale where crude oil and natural gas was extracted from, back into the formation from whence it came.

While the practice caused little seismic activity in the Permian’s geology and the industry touted it as a procedure safe from contaminating drinking water supplies, in other oil and gas regions, earthquakes were reported in increasing numbers.

Mathias Sayer, NGL Energy Partners’ vice president for legal, said it could happen here.

That’s why NGL is planning to construct “multiple” water recycling facilities in the area, to begin the revolution away from disposal wells.

Sayer said if even a couple earthquakes in the Permian were linked to waste water injection, operators would face more stringent regulations and higher costs.

“No one could conclusively say seismicity wasn’t going to be a problem in the Permian,” he said. “We’re talking potentially billions of barrels per year. There are very few entities that are treating water and discharging.”

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He said SWDs are the “easy answer right now,” but new solutions will be needed in the future to not only conserve water and the space beneath the surface, but to prevent seismic events that Sayers said were not ruled out by the research community.

A history of concern

In the 1960s, scientists linked a waste water injection well in the Rocky Mountain Arsenal National Wildlife Refuge to seismicity in the area.

A 1966 report from the Stanford University School of Earth, Energy and Environmental Sciences detailed how the disposal well drilled in the Denver area within years caused hundreds of earthquakes.

The well was drilled in 1961 northeast of Denver, with fluid injection beginning in March of 1962.

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Between April 1962 and September 1965, 710 earthquakes were reported in the Denver area, with the “majority” having epicenters within a five-mile radius of the Arsenal well, the report said. 

The only earthquake felt in the region before the well went into operations was in November 1882, according to the report.

 “The volume of fluid and pressure of fluid injection appear to be directly related to the frequency of earthquakes,” the 1966 report said.

“Evidence also suggests that rock movement is due to the increase of fluid pressure within the fractured reservoir and that open fractures may exist at depths greater than previously considered possible.”

Another study published in 2017 and the University of Colorado Boulder looked at a rash of earthquakes in the Raton Basin in southern Colorado and northern New Mexico, where 1,800 earthquakes were reported in the areas between 2008 and 2010. 

That study linked most of those quakes to waste water injection. 

“We have shown for the first time a plausible causative mechanism for these earthquakes,” said Jenny Nakai, lead study author at the university's Department of Geological Sciences.

“The spatial patterns of seismicity we observed are reflected in the distribution of wastewater injection and our modeled pore pressure change.”

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A 2013 study published by the Journal Geology and the Earth Institute at Columbia University said waste water injection led to a string of “unusual” earthquakes in central Oklahoma.

It pointed to a magnitude 5.7 earthquake near Prague, Oklahoma, in November 2011, possibly the biggest ever linked to injection felt as far away is Milwaukee, Wisconsin, while smaller earthquakes were continually recorded in the area.

“The water linked to the Prague quakes was a byproduct of oil extraction at one set of oil wells and was pumped into another set of depleted oil wells targeted for waste storage,” read the study.

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Despite the incidents, waste water injection continued in Oklahoma in the following years.

A safe process?

The U.S. Geological Survey (USGS) reported that fracking was not directly causing most of the induced earthquakes, which spiked throughout the country since 2009, when the average grew from 25 to 362 per year between 1973 to 2009.

In 2015, about 1,010 such earthquakes were reported nationwide, but the average decreased to 690 in 2016 and 364 in 2017, records show.

Waste water disposal was likely a greater cause of the quakes, according to a report from the USGS, with only 1 to 2 percent linked directly to the implantation of fracking.

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Still, the USGS reported that most injection wells do not cause earthquakes.

Factors such as the rate of injection, the presence of geological faults and pathways for fluid to reach these faults must also be considered, said the report, in addition to the presence of the SWD wells themselves.

“Most injection wells are not associated with felt earthquakes,” the report said. “A combination of many factors is necessary for injection to induce felt earthquakes.”

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And much of the waste water was not associated with fracking at all, said the report, as less than 10 percent of the water injected into disposal wells contained fracking fluid.

“In many locations, waste water has little or nothing to do with hydraulic fracturing,” the report said. “Most of the waste water in Oklahoma is saltwater that comes up along with oil during the extraction process.”

Ryan Flynn.

So as the water midstream sector of the oil and gas industry evolves to include more water recycling and reuse technology — an alternative to injection — Ryan Flynn, executive director of the New Mexico Oil and Gas Association, said disposal will continue to be a mainstay of the industry.

“I think that disposal wells, so long as they’re located in a safe place which we have the tech to ensure that we’re locating disposal wells in areas that will avoid any type of seismic activity,” he said. “I think using disposal wells makes sense from an environmental perspective. We’re reinjecting that water.

“It’s a waste product when we’re done using it, so (we're) putting it in the safest place to put it, which is right back into the same formation from which we have extracted it.”

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He said the safety of the wells lies in the practices of operators to select the proper locations for injection, to avoid problems.

“Some of the challenges associated with disposal that we’ve seen in other jurisdictions have really been based on people not using best practices in terms of where they’re locating their disposal wells,” Flynn said.

“We clearly have the technology to ensure that we’re locating any type of disposal away from any faults or areas that would have the potential to induce any sort of seismic activity. We can continue to dispose water in these deep injection wells safely.

“It’s a sound environmental practice when done correctly.”

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Flynn said the idea of recycle and reuse, rather than use and dispose, could present an opportunity for the industry to provide water supplies to other industries such as agriculture in the future while addressing New Mexico’s unique struggles with water scarcity.

“We’ll continue to see disposal for the near term. That’s the big opportunity though, is that rather than put this water, we can treat it to meet different standards,” he said.

“There’s this potential new source of water that can be used in other applications beyond the oil and gas industry.”

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Adrian Hedden can be reached at 575-628-5516, achedden@currentargus.com or @AdrianHedden on Twitter.

This story has been supported by the Solutions Journalism Network, a nonprofit organization dedicated to rigorous and compelling reporting about responses to social problems. www.solutionsjournalism.org.