As Eagle Ford Shale continues to grow, so does the debate over the process that has made the economic boom possible – the high-pressure pumping of water and chemicals into subterranean geologic formations, known as hydraulic fracturing or “fracking.”
To understand why this process is used, it is necessary to understand the geology of the Eagle Ford Shale. It is an oil-bearing shale formation made up of sedimentary rock that includes organic-rich material from the Late Cretaceous period, which contains “tight” oil. Tight oil is light crude oil similar to what is normally drilled for in traditional oil fields. The shale is, in other words, porous rock containing oil.
Extracting shale oil is not simply tunneling a well to an oil deposit, as in a conventional oil field, though the initial steps are similar. A drilling rig is built to bore a cement-encased well down 4,000 to 14,000 feet beneath the surface. Similarities end there, as the next step is to set off explosive charges to induce cracks in the shale formation. Hydraulic fracturing fluid, a proprietary mixture of water, sand and other chemicals, is then inserted under pressure to the shale formation to force oil and natural gas to escape up the well to the surface.
The major controversy surrounding fracking is the use of toxic chemicals in the hydraulic fracturing fluid: chemicals that could seep into the water table and potentially affect the drinking water of residents in the surrounding areas.
According to FracFocus, the national hydraulic fracturing chemical registry, drilling companies build multiple steel or cement casings, or shells, around their wells to ensure that natural gas, oil and other chemicals do not seep into the surrounding earth. These protections are typically heavy near the surface, and lessen as the well reaches the shale formations deep underground.
FracFocus also states that over 99.5 percent of fracturing fluid is made up of water and sand. The remaining percentage consists of gelling agents, pH adjusting agents, iron controllers, corrosion inhibitors, biocides, disinfectants, acids and friction reducers. FracFocus claims that the insignificant amount of “other” chemicals, particularly toxic chemicals, negates any threat to the water table or to the surrounding areas.
The documentation for a sample oil well in Dimmit County, a south Texas county in the heart of the Eagle Ford drilling area, states that a fracturing fluid mix contains 0.55568 percent hydrochloric acid. When accounting for how much chemical is used, amounts reach almost 22,000 gallons. In this way, even negligible percentages of chemicals can be major factors when this much liquid is involved.
The flux on the subject can be captured by the controversy surrounding a recent study on the effects of fracking. The report, by the Energy Institute at the University of Texas at Austin, states that contamination as a result of the fracking process is not inherent to the fracking process itself. Rather, when water is contaminated, it is caused by errors that occurred in other parts of the drilling process, and the fracking process itself is considered safe.
However, according to Farzad Mashhood at the Austin-American Statesman, the study is now undergoing an independent audit. The lead author of the fracking study, UT Austin professor of geological sciences Charles Groat, did not disclose that he was on the payroll of an oil and gas exploration company, which constitutes a conflict of interest, tarnishing the results of the study. Because of this, the controversy over the safety of fracking drags on.