Tolerable Trade-offs
There are many detractors of hydraulic fracturing, just as there are many detractors for coal mining, hydroelectric dams, and nuclear power plants. There is no such thing as a perfectly benign source of energy, and there’s no way the world can maintain a functional civilization without plenty of ready fuel and the energy it produces, so the search for an acceptable compromise continues.
In the United States, most conventional oil fields have already been tapped, so their productive years are numbered. The economy has faced disruptions before due to its vulnerability to geopolitical conflicts and global market variations, so government and industry leaders have chosen to develop new technologies in horizontal drilling and hydraulic fracturing, and other well stimulation techniques. These new capabilities permit petroleum companies to access enormous oil and gas reserves that are still untapped because they have been too difficult to exploit until recently.
In an earlier article, we discussed the process of hydraulic fracturing and there are elements of the drilling process and potential physical disruptions that trigger environmental concerns. However, for fracking, one of the biggest concerns centers around the composition of fracking fluid. Let’s take a look at some of the key points.
A Strange Brew
Fracking fluid is a fairly benign looking liquid that’s composed of 3 primary components: water, sand or other type of proppant, and a concoction of perhaps hundreds of different chemicals intended to simplify and ease the extraction process. There are concerns about the excessive use of each of these individual components, but the chemical component of fracking fluid is an exceptionally hot button.
The chemical component of fracking fluid is actually a very small volume when considered in proportion to the whole. In fact, industry leaders are happy to point out that typically only 0.5 to 2.0% of fracking fluid is made up of chemicals, with the rest being sand and water. Those numbers can be misleading, though. When a single well frack can consume four million gallons of fluid, that could represent between 80 and 330 tons of chemicals. That’s a harder number to swallow when a precise and reliable list of those chemicals is protected as a trade secret.
The chemical component of fracking fluid performs many important engineering functions in the success of fracking, but while some chemicals are easily recognizable and relatively benign, others are clearly toxic and could pose significant risks to people and the environment if there were accidental exposure.
Functions of Chemicals in Fracking Fluids:
- Acids are used to dissolve rock in the borehole and remove obstructions to the flow of oil and gas.
(Hydrochloric acid, muriatic acid) - Breakers reduce the viscosity of fracking fluid, so it flows easily through tiny fractures and delivers proppants where they’re needed.
(Peroxydisulfates) - Bactericides and Biocides are used to prohibit the growth of microorganisms that produce undesirable and polluting gases or that could block fractured channels. (Glutaraldehyde; 2-Bromo-2-nitro-1,2-propanediol)
- Buffers are used to adjust the pH of the fluid to enhance the effectiveness of other chemicals.
(Sodium or potassium carbonate; acetic acid) - Clay Stabilizers prevent swelling of clay within the shale, which can close fractures and pores.
(Salts, such as potassium chloride) - Corrosion Inhibitors reduce damage from rust and corrosion on steel components in and around the well.
(Methanol, ammonium bisulfate) - Crosslinkers help increase fluid viscosity so that fracturing liquid is able to carry more proppant into cracks
(Potassium hydroxide, borate salts) - Friction Reducers allow fluids to be injected at optimal pressure and rates by minimizing friction.
(Sodium acrylate-acrylamide copolymer; polyacrylamide (PAM); petroleum distillates) - Gelling Agents increase viscosity of the fracking fluid so that the liquid can support more proppant as it flows into the fractures.
(Guar gum; petroleum distillate) - Iron Controls prevent the formation of precipitates which could plug passages.
(Ammonium chloride; ethylene glycol; polyacrylate) - Solvents may be used to prevent the formation or breakage of emulsions, or to regulate the contact between liquid and surfaces.
(Aromatic hydrocarbons) - Surfactants reduce surface tension, making fluids easier to recover.
(Methanol; isopropanol; ethoxylated alcohol)
Industry professionals often point to the use of typical food ingredients such as guar gum, salts, and acetic acid (the primary ingredient in vinegar) that are present in fracking fluid to demonstrate that it’s harmless, but even salt in high enough concentrations is toxic. Petroleum distillates (gelling agents, friction reducers), hydrochloric acid (acids), and methanol (surfactants, corrosion inhibitors) can all be toxic in high enough concentrations.
Some chemicals used in fracking are toxic in such low amounts that even minute quantities can contaminate a huge volume of water. For example, benzene, which is a human carcinogen often found in petroleum distillates, is so deadly that less than 1 ounce will render a million gallons of water toxic. Other chemicals, such as Volatile Organic Compounds (VOCs), readily evaporate, causing breathing problems, damage to the central nervous system, and sometimes cancer.
Even more troubling is that until recently, fracking companies were either not required or actively protected from having to disclose a complete list of the chemicals used in their fluid. This meant that if an accident or leak happened, emergency services, medical professionals, and environmental scientists did not have a complete picture of what they were dealing with. Similarly, water treatment plants that were attempting to process wastewater from fracking operations didn’t know what contaminants they should test for to determine if the treated water was safe enough to release.
The good news is that industry compliance with both legislated and voluntary disclosure of fracking chemicals has improved significantly over the last decade, but this well-established reputation for opacity regarding widespread public health concerns doesn’t help efforts to bolster public support for fracking.
