Few notions have sparked more hope among environmentalists than the possibility of replacing toxic chemicals used in drilling with what are being called “green” or non-toxic drilling fluids.
A review of scientific documents and interviews with drilling companies and the chemists who supply them shows that the transition is more than theoretical. It’s starting to happen.
EnCana, a Canadian company that operates on both sides of the border, recently said it stopped using 2-Butoxyethanol, a solvent that has caused reproductive problems in animals. BJ Services, one of the largest fracturing service providers in the world, has discontinued the use of fluorocarbons, a family of compounds that are persistent environmental pollutants.
Neither company would say what it is using to replace these chemicals. But a presentation made by Denver-based Antero Resources and obtained by ProPublica says that plant-based oils are occasionally replacing mineral oil and that soy can replace some toxic polymers. David Holcomb, director of research for the Texas-based drilling chemistry company Frac Tech, offered more specifics: He uses orange citrus to replace some solvents, and palm oil in place of a common slicking agent that has been prohibited in Europe but is still allowed in the United States.
The “single biggest move” the industry has made to reduce the toxicity of its fluids, according to David Dunlap, chief operating officer for BJ Services, is phasing out diesel fuel, a solvent that contains the potent carcinogen benzene.
Diesel was once a common solvent used in hydraulic fracturing, the process where water, sand and chemical additives are pumped underground at high pressure to break apart rock and release gas. In some fracturing jobs – like those in the Marcellus Shale in Pennsylvania and New York – more than 40,000 gallons of fracturing chemicals can be used at a single well.
Today, many companies have replaced diesel with mineral oil, a less toxic hydrocarbon solvent, in most of their fracturing solutions. The shift began in 2003, after the EPA pressed the nation’s dominant fracturing companies to voluntarily eliminate diesel from some of their fluids.
“It sounds like a simple thing, but it’s the largest single volume other than water that is used in a frack job,” said Dunlap, whose company is being acquired by Baker Hughes, the international drilling company. BJ no longer uses diesel in its fracturing fluids, Dunlap said, though it may still be used in other applications.
Despite these improvements, it is still difficult to say how safe the drilling and fracturing fluids are for people, and for the environment. The EPA says “green” chemistry should not be dangerously toxic and should not build up in plants or organisms. But because there are no laws that dictate what chemicals can be used for drilling on U.S. soil — and because most companies still keep the exact makeup of their fluids a secret from state and federal regulators — the definition of “green” remains subjective. “Green” is often shades of gray.
New York’s Department of Environmental Conservation raised the “green” issue in its new environmental review for drilling in the Marcellus Shale. The report said that while non-toxic fracturing fluids would be preferable, “it may not be feasible to require the use of ‘green’ chemicals because presently there is no metric or chemicals approvals process in place in the U.S.”
Actually, such standards do exist, but only for the fracturing fluids used in offshore drilling. Both European law and the regulations of the U.S. Minerals and Management Services dictate that chemicals used in the North Sea and the Gulf of Mexico must be safe enough that they won’t kill fish and other organisms if they are dumped overboard.
“You can always do it,” said BJ Services’ Dunlap, whose company has been a leader in innovating sustainable materials. But, Dunlap said, the chemistry costs more, and is justifiable to his shareholders only because the regulations for offshore drilling left no choice.
“There are places around the world where the type of adherence is not required,” he said, “and where the cost of using those chemicals is something operators are not required to pay for.”