Pursuit of Shale Gas May Contaminate Water, Says UT Study, But It's Not Due to Fracking
The University of Texas Energy Institute cast a skeptical eye on the likelihood that the actual act of fracking could result in groundwater contamination. Particularly in the Barnett Shale, where aquifers sit thousands of feet above the shale rock, head researcher Dr. Chip Groat reasoned that the danger of fracking fluid migrating thousands of feet upward through propagating fractures was far-fetched. (As opposed to a Pavillion, Wyoming, where horizontal fracks and aquifers are much closer together.)
But as the shale play moves out of the pasture and into densely populated areas, that doesn't mean, taken holistically, that the pursuit of shale gas doesn't pose risks to groundwater.
An even greater threat, says the completed UT study, comes from surface spills of the concentrated chemicals later diluted in fracking fluid. But regulatory bodies don't keep detailed enough records to gauge how serious they are, or how often they occur.
Much depends on proper well construction and integrity. Given the extremely high pressures at which fracking fluid is injected into shale formations -- up to 1,400 pounds per square inch -- the odds that a poorly constructed well will be compromised are good. Fracking fluid could conceivably penetrate the casing or cement and slip into aquifers.
Blowouts, or the uncontrolled release of natural gas and fracking fluids, are among the most common of well control problems. Blowout preventers keep them from reaching the surface. The side effect is that all that pressure has to go somewhere, and it could exploit weaknesses in the casing or cement. "For example, in the Barnett shale, the Railroad Commission of Texas determined that two of 12 blowouts were underground, but publicly available information is insufficient to evaluate the causes or consequences of the blowouts."
Blowouts, the study points out, appear under-reported. The truth is, instances where fracking fluid enters an aquifer through compromised casing and cement could be more prevalent than anyone knows.
The lighter setting a running faucet aflame is the iconic image of the anti-fracking movement. The study says the gas is likely naturally occurring and has been a problem for years. But water well owners complaining of cloudy, foul-smelling water shortly after nearby fracking operations begin may be onto something
"It appears that many of the water quality changes observed in water wells in a similar time frame as shale gas operations may be due to mobilization of constituents that were already present in the wells by energy (vibrations and pressure pulses) put into the ground during drilling and other operations rather than by hydraulic fracturing fluids or leakage from the well casing," the study says. "As the vibrations and pressure changes disturb the wells, accumulated particles of iron and manganese oxides, as well as other materials on the casing wall and well bottom, may become agitated into suspension causing changes in color (red, orange or gold), increasing turbidity, and release of odors.
"None of the water well claims involve hydraulic fracturing fluid additives, and none of these constituents has been found by chemical testing of water wells."
What the study observed about attitudes and public knowledge regarding fracking in Texas was just as interesting. Some 71 percent of those interviewed in 26 counties didn't know that the Railroad Commission doesn't regulate the setback distance between gas wells and homes. Another 42 percent overestimated the amount of scientific research surrounding fracking and its potential to contaminate water sources.
Sixty-seven percent placed a higher priority on the environment and health than energy production. Some 86 percent placed a higher priority on satisfying energy needs with fewer impacts to water and water consumption.
Get the This Week's Top Stories Newsletter