Nanotechnology and pollution
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January 1, 2012 Nanotechnology helps stop pollution in shale gas drilling
Nanotechnology, that is, the technology and science of controlling materials that range in dimension between 1 and 100 nanometers, has been in the spotlight lately as an area providing emerging solutions to the issues of water pollution in the Marcellus and worldwide shale developments.
Nanoglass cleans frac water and greens drilling and fracturing fluids. Nanoglass_unit 2 bbl/min nanoglass pilot plant for produced water - Photo courtesy of ABS Materials
Waste water, especially drilling fluid waste and produced water, is often contaminated with so-called dissolved hydrocarbons. This organic matter is difficult and expensive to remove. The most common way to treat hydrocarbon pollution, such as oil and BETX (Benzene, Ethylbenzene, Toluene and Xylenes), is with an activated carbon filter that absorbs the pollutant as the water passes through it. Now there is an effective and cost-effective way to remove these contaminants--nanoglass. The substance is hydrophobic--that is, it hates water--but loves to scavange organic compounds. In fact, it swells to 6 times its normal size. Nanoglass only absorbs pollutants and not water.
Assuming proper handling of drilling and completion fluids, and little or no leakage of waste water at the well site, then water from drilling operations tends to be disposed of by trucking or piping it to a water treatment plant.
At a public waste water facility, the waste gets added in with other effluent. Alternatively, it can be recycled at a private facility for later reuse in drilling. Also, it can be stored in tanks or storage ponds. In the latter case of storage, water either evaporates when exposed to the sun, or else can be trucked to an injection well where it gets pumped deep underground. Due to the geography of the Marcellus shale, injection wells are not possible in many areas of Pennsylvania. The nearest injection wells are in the neighboring state of Ohio. It must be trucked there at no small expense. Thus, a technology that can absorb water-borne organic pollutants means more water can be recycled and reused at more reasonable cost, and less of it needs to be disposed of at public waste water plants or injected underground.
Nanoglass is normally used for coating and sealing paint, glass, and ceramics, as well as for electronics applications. Quite by accident, a college student and her chemistry professor discovered that nanoglass has the property of absorbing organic compounds from water. This substance is a nano-structured silicate material that swells like a sponge when it comes in contact with dissolved hydrocarbons in water. The process is mechanical, like a sponge, and not the result of chemical reaction. It can slurp up hydrocarbons and other organics, chlorinated solvents, oils, and contaminants from water. Best of all, the nanoglass can be thermally regenerated so it can be reused up to 100 times. The pollutants become harmless gases and salts.
The nanoglass primarily works on uncharged molecules. Water has a polar charge. That explains why it is not absorbed by the nanoglass particles. It does swell in anything ranging from alcohols, such as methanol, to hydrocarbons.
Nano-fluids lead to so-called green fracturing fluid
Houston, Texas-based Flowtek Industries, Inc. is an oil services company that has recently introduced a nanofluid micro-emulsifier. A nanofluid, as Flowtek uses the term, is a fluid that contains complex nano-fluids (microemulsifiers). Nanofluids contain nanometer-sized particles, called nanoparticles. These are considered to be environmentally friendly, and are picking up industry interest. Flowtek states that these fluids also enhance production and improve reservoir integrity. They have also been getting positive results with slickwater fracs. The company has been testing its fluids in the Barnett Shale and Green River Basin and claims good results in both.
Nanotechnology-based drilling fluids
Nanotechnology-based drilling fluids are a newly patented, largely untested, technique for utilizing silica nanoparticles five to 40 nanometers in diameter, that are virtually the same size as the pores in the shales being drilled. These particles plug up the pores and make them impervious to water, thereby reducing water invasion. Water-based drilling fluids may cause the shale to expand and/or contract. This can lead to an unstable wellbore. Usually the work-around for this problem is to use oil-based drilling fluids. However, oil-based drilling fluids may lead to environmental issues. Nanotechnology may ultimately enhance the usefulness of the less environmentally-problematic water-based drilling fluids.
Patents for drilling fluid nanoparticles were developed by Professor Mukul Sharma in the Department of Petroleum and Geosystems Engineering at the University of Texas. During the Fall of 2009 these patents were licensed by M-I SWACO--the world's largest supplier of drilling fluids.
Resources:
Boston Museum of Science, Sci-Tech Today, "Super-absorbent Nanoglass Cleans Pollutants" (video), January 28, 2010 broadcast posted to youtube.com, Accessed January 1, 2012.
Braswell, Gentry, "Expanding Organic Nanoglass Cleans Flowback/Produced Water", JPT Online, Society of Petroleum Engineers, November 29, 2011, Accessed January 1, 2012.
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