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Fracking Wells Linked To Earth Quakes In The Dallas-Fort Worth Region

August 28th, 2012

According to an article published by StateImpact, a local reporting project of NPR, hydraulic fracking disposal wells may be causing earthquakes in the Dallas-Fort Worth area. Pursuant to a new study conducted by the University of Texas, seismologists believe that wells used to dispose of hydraulic fracking waste water may be responsible for the recent rise of earthquakes in the area. Further, the UT study discovered that there have been more than eight times as many earthquakes in the area than previously thought.

Industry sources say hydraulic fracking is a procedure in which a mixture of chemicals, sand and water is injected into the earth’s crust creating small fissures which release trapped oil and gas. According to StateImpact, the recent natural gas boom in the Dallas-Fort Worth area has coincided with an increase in the number of wells needed to dispose of the water used in the drilling process. Sources say that once the waste water comes back up the well, it has to be disposed of, so drillers inject it into deep wells underground, as deep as 13,000 feet below the surface in the Barnett Shale.

The article features a new study by Dr. Cliff Frohlich, senior research scientist at the University’s Institute for Geophysics. The study is premised upon the fact that some of those disposal wells around Dallas-Fort Worth are also on fault lines. In order to explain his findings, Dr. Frohlich compares the wells to an air hockey table. According to the Dr. Frolich, if the air is turned off the puck will not move, but when you pump in the air the puck moves easily. With disposal wells sending fracking waste water deep underground, liquid and pressure are migrating into a stuck fault. The fault wants to move but it cannot. However, when oil and gas companies introduce fluids in the fault it slips. According to StateImpact, over 6 million gallons of fracking waste water a month was pumped into each of the wells near the epicenters examined in the study.

The article points out that the Texas Railroad Commission (TRC) is the governing body which regulates the hydraulic fracking of wells, but the organization did not respond to StateImpact’s requests for an interview. However, in a recent article in Forth Worth Weekly, the TRC claimed that it had no science or data at the time linking the minor seismic events to oilfield activities. Yet, the StateImpact article articulates that the first study linking the small earth quakes to hydraulic fracking was released in early 2010, and another came out earlier this year. Accordingly, the University of Texas study is now the third study linking disposal wells and earthquakes in the Barnett Shale. Reportedly, this area had seen no seismic activity before the disposal wells began operating.

According the article, most of the earthquakes in the Barnett Shale occur in groups. In the new study, Frohlich found eight groups of quakes, all within two miles of disposal wells. Before this new report, there had been only two groups of earthquakes in the area linked to disposal wells in the area. Further, those disposal wells are injecting at very high rates. According to the study, all the wells nearest to the earthquake groups reported maximum monthly injection rates exceeding 150,000 barrels (equivalent to 6.3 million gallons) of water per month since October 2006. The study suggests that oil and gas companies should inject less water into the wells in order to prevent the earthquakes.

Although there are high injection counties which did not suffer seismic activity, the study suggests it might be that an injection can only trigger an earthquake if injected fluids reach and relieve friction on a nearby fault that is already ready to slip. According to the article, most of these earthquakes are small, registering below 3.0 on the Richter scale. Further, the study only looked at earthquakes between November 2009 and September 2011. However, according to StateImpact, over the past few months, there have been ten earthquakes registered in the area, one of them as high as 3.5 on the Richter scale.

The article articulates the fear of many environmentalists that the earthquakes could impact pipelines around the Dallas-Fort Worth metro area. Industry representatives have suggested that although pipeline operators typically consider a multitude of factors when constructing a pipeline, the usually do not plan for earth quakes in the Barnett shale region. The study does note that the rewards of drilling the wells still seem to outweigh the risks, as a 3.5 magnitude earth quake will typically only cause damage to a very tiny area. Frohlich was quoted as saying, “just because a thunderstorm could drop a tree on your house, does not mean that we cannot have trees.”

It’s also important to note that there a tens of thousands of injection and disposal wells in Texas, yet only a few dozen of them are suspected of inducing quakes. It’s also true that disposal and injection wells have been known to induce seismic activity since the 1960s. What’s happening now is that with the rise of fracking, there is a need for more disposal wells. And in areas where fracking waste water is disposed of near population areas, it’s going to be noticed more.

The study will be published this week in the Proceedings of the National Academies of Sciences. Frohlich also plans to look at disposal wells and seismic activity in other drilling areas, like the Eagle Ford Shale in South Texas and the Bakken Shale in North Dakota. He also hopes to collaborate with the industry to evaluate faults near injection wells.

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