The Arkansas Oil and Gas Commission has banned fracking disposal wells for unconventional gas drilling wastes due to earthquakes. The Commission voted unanimously to ban them, and the decision requires the immediate closure of one disposal well and prohibits the construction of new wells within a 1,150 square mile radius.
Arkansas residents insisted that there was a correlation between the increase in earthquake activity in the state and wastewater disposal wells. Imagine being on your way out one afternoon, opening your garage door, and experiencing an earthquake that you knew was being caused by gas drills. After monitoring hundreds of earthquakes, investigators have begun to conform the connection between unconventional gas-related drilling and the quakes. The Oil and Gas Commission discovered that four disposal wells were located on a fault line responsible for dozens of earthquakes.
As reported by the Associated Press, “after two of the four [disposal wells] stopped operating in March, there was a sharp decline in the number of earthquakes. In the 18 days before the shutdown, there were 85 quakes with a magnitude 2.5 or greater, but there were only 20 in the 18 days following the shutdown, according to the state Geological Survey.” The local press had reported “a shocking surge” in quake activity prior to the wells being shut down. The number of earthquakes recorded in Arkansas for 2010 — more than 600 — nearly equals all of Arkansas’ quakes for the past 100 years.
The Arkansas Oil and Gas Commission has not banned unconventional gas drilling in the area, only the use of disposal wells. As natural gas supply in traditional locations dwindles, the industry is searching and drilling for unconventional sources. Earthquakes pose an enormous threat to the integrity of unconventional gas and disposal wells, potentially damaging cement casings, the sole barrier protecting underground aquifers from contamination.
Jack Century of J.R. Century Petroleum Consultants Ltd., said “When we start perturbing the system by changing fluid pressure, we have the potential for activating faults.” And “once local seismicity starts, it can’t be turned off.” Changing fluid pressure uses huge amounts of water mixed with sand and dozens of toxic chemicals, all of which is injected under extreme pressure to shatter the underground rock reservoir and release gas.
Freshwater contamination and damage to aquifers are major concerns, and now communities must worry that this practice can trigger earthquakes. Not only does the practice utilize millions of gallons of freshwater taken from lakes, rivers, or municipal water supplies, the toxic chemicals mixed in endanger groundwater aquifers and threaten to pollute nearby water-wells. The toxic flow back of wastewater from fracking (as much as 3 million gallons per well) is usually re-injected into deep disposal wells.
While much of the concern about this type of drilling is due to its impact on water supplies, other impacts include air pollution, wastewater disposal, industrialization of farm land, increased carbon dioxide emissions, and destruction of wildlife habitat from multi-pad drilling sites. Earthquakes are just the latest side effect that has been added to this long list of issues with the practice. In 2009, the Wall Street Journal (June 12) called earthquakes “the natural gas industry’s big fracking problem.” Looks like that may be true.