Another spill into our region's drinking water sources. And more lame coverage and fact-checking of science-based claims.
"Bentonite is a form of impure clay that easily absorbs water and is used to facilitate gas and oil well drilling." Absorb water, is that all the drilling industry uses it for?
Here's the article.
Thursday, November 17, 2011
The Associated Press
JOHNSONBURG, Pa. -- A company has halted Marcellus drilling in one northwestern Pennsylvania town after a kind of clay used to expedite the process spilled into a local reservoir.
Hunt Marcellus Operating Co. tells the Bradford Era that it stopped drilling in Johnsonburg after some bentonite gel was released into Silver Creek and made its way into a drinking water reservoir controlled by the Johnsonburg Municipal Authority. Bentonite is a form of impure clay that easily absorbs water and is used to facilitate gas and oil well drilling.
It wasn't immediately clear how much of the substance got into the reservoir. But water authority chairman Eric Poague says the substance is not expected to affect the safety of the water -- though it could make it cloudy -- because bentonite is a "non-toxic substance that comes from the earth."
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Sure Bentonite clay is "a non-toxic substance that comes from the earth" -- it is also known as "Haliburton Gel." But how is bentonite being used by the gas drilling industry?
Bentonite clay is a super absorbant powder/clay substance used in multiple ways -- in drilling mud slurries, to soak up chemical/hydrocarbon spills. Some say that highly concentrated flowback water and drill cuttings are being treated with bentonite clays which turn this drilling waste into a semi-solid slurry 'frackwater goo' that can then processed as part of the solid waste stream and sent to landfills.
According to the Oil and Gas Accountability Project, “drilling fluids or muds are made up of a base fluid (water, diesel or mineral oil, or a synthetic compound); weighting agents (most frequently barite is used); bentonite clay to help remove cuttings from the well and to form a filter cake on the walls of the hole; chrome lignosulfonates and lignites to keep the mud in a fluid state; and various additives that serve specific functions, such as biocides, diesel lubricants and chromate corrosion inhibitors….Drilling muds that circulate through the well and return to the surface may contain dissolved and suspended contaminants including cadmium, arsenic, and metals such as mercury, copper and lead; hydrocarbons; hydrogen sulfide and natural gas, as well as drilling mud additives, many of which contain potentially harmful chemicals (e.g., chromate, barite).” (http://www.earthworksaction.org/pubs/OGAPMarcellusShaleReport-6-12-08.pdf)
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A little more digging into the incident (see comment below) brings up the industry phrase "Inadvertent Returns" that occur during the HDD drilling of natural gas pipelines which go under streams, wetlands and other kinds of enviromentally sensitive areas where the "cut and cover" trench option is not doable. Seems like they were drilling to place a pipeline under Silver Creek, and these kind of blowout incidents of bentonite clay based slurries are not uncommon. The acticle for the really curious.
Inadvertent Slurry Returns during Horizontal Directional Drilling: Understanding the Frequency and Causes.
