Study: Only 0.1 Percent of North Texas Injection Wells Potentially Involved in Earthquakes

Natural Gas Drilling
AP Photo/Ralph Wilson

Underground wastewater injection wells used in hydraulic fracturing, or “fracking,” have virtually no role whatsoever in the earthquakes in the North Texas area during the past few years. This information comes from a study, conducted by a group affiliated with the petroleum industry, but used publicly available data on seismic activity in the region and a long list of independent peer-reviewed scientific research to reach this conclusion.

The study was performed by Energy In Depth (EID), a research and education program of the Independent Petroleum Association of America and was released on Wednesday. A release from Energy in Depth provided to Breitbart Texas stated that the claims from anti-fracking activist groups “have been explicitly refuted by the scientists who have studied North Texas seismicity the closest.”

After reviewing all records of earthquakes in the region, which injection wells had been connected to seismicity in peer-reviewed literature, and comparing that against all the wells in the area, the study found that only 0.1 percent of all the wells in the Barnett Shale have been identified as having any connection whatsoever to earthquakes. Moreover, a number of the wells in that 0.1 percent were connected only spatially, with no connection shown between the wells’ operation and the earthquake other than proximity.

Specifically, the study found that out of the 14,000 injection wells in the Barnett Shale region, which stretches across twenty-five counties, there were only 20 such wells (0.1 percent) that were identified by peer-reviewed studies and local on-site scientists as “having a spatial relationship to felt seismic events,” or earthquakes that were strong enough to be detected by humans.

In other words, according to EID’s analysis, over 99 percent of Barnett Shale injection wells have no connection with any felt seismic events. Naturally occurring fault lines were also present in the area. “[G]iven the complicated fault  system and wide dispersion of injection wells in North Texas, any naturally occurring earthquake may have injection wells nearby – and such wells will immediately be subject to guilt by association,” says the study.

The study also cited a number of other independent experts who over the years had come to the same conclusion that injection wells and other activities associated with fracking did not pose a significant risk of causing earthquakes. The repeated findings were that there may be some potential that fracking could trigger an earthquake, but the risk was miniscule, especially compared to the scale of overall fracking operations across the country, and any seismic activity that had occurred — and had any connection to fracking — was minor.

Back in 2012, then-Interior Department Secretary David Hayes posted a release on the Department of Interior’s website stating that the work of the U.S. Geological Survey (USGS) showed “no evidence” connecting fracking to an increased rate of earthquakes. Furthermore, Hayes noted that, “[a]lthough we cannot eliminate the possibility, there have been no conclusive examples linking wastewater injection activity to triggering of large, major earthquakes even when located near a known fault.”

The National Research Council acknowledged that while “[i]njection for disposal of wastewater derived from energy technologies into the subsurface does pose some risk for induced seismicity…very few events have been documented
over the past several decades relative to the large number of disposal wells in operation.”

Bill Ellsworth, with the USGS, stated in 2012 that in the rare cases where there was believed to be a connection between injection wells and seismic activity, “in many of these cases, it’s been fixed by either shutting down the offending well or reducing the volume that’s being produced. So there are really straight-forward fixes to the problem when earthquakes begin to occur.” Ellsworth has also emphasized that “very few of the more than 30,000 wells designed for this purpose appear to cause earthquakes.”

Another USGS study stated that “the actual hydraulic fracturing process is only very rarely the direct cause of felt earthquakes,” because “[w]hile hydraulic fracturing works by making thousands of extremely small ‘microearthquakes,’ they are, with just a few exceptions, too small to be felt; none have been large enough to cause structural damage.”

One easy-to-visualize example was from Stanford University Geophysicist Mark Zoback, who compared the “small microseismic events” that occur during fracking operations to a gallon of milk falling off the kitchen counter.

Cliff Frohlich, a geophysicist at the University of Texas at Austin, has said that his department’s research had been unable to find any “strong signal” between fracking and earthquakes, despite the “considerable amount of hydraulic fracturing activity in the Eagle Ford.” Frohlich characterized the issue as “a phenomenon that we need to understand, but it’s not appropriate to say it’s vastly dangerous.”

EID’s study also described in detail the multiple layers of regulation that apply to injection wells, including oversight by both the Environmental Protection Agency (EPA) and state agencies, plus the years of study conducted by these agencies.
An EPA report released last month concluded that “very few” of the tens of thousands of wells in the United States had produced any notable seismic activity.” This was reflected in two separate peer reviewed studies at the DFW airport, one of which found that “seismicity was still ongoing at DFW Airport for at least two years after injection activities had stopped, highlighting further the possibility that naturally occurring stress changes in the subsurface could be driving the seismic events.”

The EID study describes some of the claims made by opponents to fracking, noting that many of them are using their “own interpretations of the scientists’ findings” to support their calls for restrictions or bans on fracking. “But scientists – some of whom have authored the most extensive research on North Texas seismicity – disagree with the activists’ claims,” says the study. Earthquake researchers at Southern Methodist University posted a statement directly criticizing anti-fracking activists’ use of the word “frackquake,” stating that it was not accurate to describe North Texas’ earthquakes in that way.

“Wastewater injection is an activity that has been occurring for many decades, and contrary to what anti-fracking activists have claimed, it has compiled an impressive safety record.” Steve Everly, EID’s Team Lead, told Breitbart Texas. “Nonetheless, local concerns about earthquakes are real, and they should be addressed with facts and science. As this report suggests, geology is not uniform, so one-size-fits-all approaches — including fringe activists’ calls to ban disposal entirely — may not be appropriate.”

The EID study concludes by pointing out that people in areas experiencing seismic activity have valid concerns, but that the evidence was indicating that injection wells were connected to an extremely small number of earthquakes, and urges policymakers to “avoid overreaching measures that may do more harm than good.”

Addressing concerns about seismicity must begin by identifying all of the variables where the earthquakes occurred. If individual injection sites are suspected of inducing seismic events, then the proper way to address that situation is by focusing on conditions at that individual site…

Broad regulatory measures premised on the assumption that every injection well poses the same risk may not effectively address the specific conditions that contributed to a particular seismic event. Effective risk management requires addressing problems where they occur, not expending resources to fix problems where they do not exist. For example, a ban on injection activities after a naturally-occurring seismic event may not be an appropriate response, since underground injection was not the culprit. Additionally, policies that restrict or even prohibit wastewater injection over a broad region will also restrict economic activity, threatening jobs and other opportunities for growth – and potentially in places where such a policy may be unnecessary.

REPORT – North Texas Injection and Earthquakes

Follow Sarah Rumpf on Twitter @rumpfshaker.