waste water disposal — Eagle Ford Shale News

The U.S. Geological Survey (USGS) confirmed a 3.2 magnitude earthquake on Wednesday, two miles southeast of Charlotte, TX in Atascosa County, which is almost entirely in the liquids-rich or oil window of the Eagle Ford Shale. Last week, 13 active rigs were running in the area. According to the USGS, there is evidence that some central and eastern North American earthquakes have been triggered or caused by human activities that have altered the stress conditions in earth's crust. The cause of this most recent quake is unknown; however, in the Eagle Ford Shale and other areas for oil & gas development in Texas, a link has been made between waste water disposal/injection wells and seismic activity.

Injection wells are necessary to the fracking process, a method by which a well is completed using treated water under extreme pressure. When a well is fracked, it produces flowback or produced water that must be disposed of properly in waste water disposal/injection wells deep underground. Recently, EagleFordShale.com posted a story about new waste water disposal rules that could be put into practice soon in Texas, following a rash of low magnitude earthquakes across the state.

“There are two primary ways in which the oil and gas industry commonly “ads” energy (pressure) into the ground. That is through hydraulic fracturing and water injection. The industry “subtracts” energy from the ground by producing hydrocarbons and the associated water that generally comes with it. These two forces are constantly opposing and offsetting each other. On a localized basis, at any given point in time, it is possible that the net result of these two forces is great enough (in either direction) to cause small and local trimmers. No doubt many of these are of such short duration and so small that they are never even noticed. Then there are some that make it to the observable and measurable threshold. Local and hyperlocal geology will generally determine the susceptibility of a particular area to these trimmers.”

— EagleFordShale.com Founder, Kenny DuBose

New waste water disposal rules could soon impact oil and gas development in Texas.

After a rash of low-magnitude earthquakes linked to injection/waste water disposal wells across the state, new rules could soon be on the table soon for industry to dispose of its drilling waste water. According to The Houston Chronicle, the proposed rules would require companies to submit more information about the seismic history of the drill site and the underground pressure the water will cause. The rules also give the Railroad Commission (RRC) more power to modify permits and requests.

Since the drilling boom began in the Eagle Ford Shale, scientists have recorded a steady up-tick in earthquakes in South Texas. Most scientific findings link injection wells, and not fracking to the earthquakes; however, injection wells are necessary to the fracking process. Fracking of just one Eagle Ford well uses approximately 4.2 million gallons of water, and the flowback or produced water needs to be disposed of in an injection well. In addition to Eagle Ford quakes, the more highly publicized North Texas' quakes, stemming from development of the Barnett Shale, have also been linked to injection wells.

Law makers in Austin on a seismic activity subcommittee heard testimony on new waste water disposal rules at the end of August. According to the Chronicle, the subcommittee will report their findings to the House Committee on Energy Resources. The committee will take comment on the proposed rules through Sept. 29th.