What chemicals are used in the fracking process and why are they used at all?

What chemicals are used in the fracking process and why are they used at all?

This question seems to come up a lot during the debate about fracking, its safety and its effects on the environment. Public-advocacy groups and others have cried foul over the oil and gas industry’s reluctance, in some instances, to release what chemicals they use during the process and the disclosure laws that allow them to protect certain ingredients as trade secrets.

But often overlooked are the lengths that some companies have gone to make their processes more transparent. Listings of chemicals, or additives, as the industry calls them, are available on several state regulatory sites and on material data safety sheets at drilling locations.

It has now become universal knowledge, especially in states where shale-gas development is prevalent, that hydraulic fracturing, or fracking, is a process that uses water, chemicals and sand to force out the oil and gas trapped in the small pores of impermeable shale rock deep underground.

But the process is more complex than that, and the techniques, technology and completion fluids used to achieve this end vary from company to company, making it hard to say what sort of cocktail each company specifically uses when they frack a well.

For the most part, though, fracking solutions have three main ingredients: water, sand and additives. The solution consists of more than 90 percent water, and the chemicals that are added are weakened and diluted by the abundance of water used in the mix.

Test samples from spills of fracking fluid have turned up carcinogenic substances, such as toulene and benzene, while common components used in the mixture, such as ethlyene glycol — which prevents scale buildup in the pipe and acts as an anti-freezing agent — are considered lethal at high exposures.

It’s important to note, though, that many of the chemicals used to frack wells are commonly found in water-treatment systems, plastics and household cleaners. At the same time, other industries, such as those in construction, use chemicals that are considered near-safe during the building process.

For instance, mechanical contractors often use low-toxicity propylene glycol in the heating systems of larger commercial buildings that act as an anti-freezing agent.

Equally as important is the construction of the well itself. Although drilling takes place thousands of feet blow the surface and the well head, the drilling hole, or well bore, is isolated with millions of pounds of steel casings and concrete. Any leftover drilling solution remains trapped thousands of feet below the surface or it gets collected in a closed-loop system for disposal.

After the well is constructed, operators force a mixture of sand, chemicals and water down the well bore at incredible pressures that crack the shale rock. The sand holds those fissures open and allows the oil and gas to flow to the surface. The chemicals are used to clean the well bore, prevent scale formation and bacterial growth that can generate a hazardous gas. Hydrochloric acid helps dissolve cement and minerals and initiate fractures. Polyacrylamide reduces friction between the fluid and the pipe and glutaraldehyde eliminates bacteria in the water used, which can produce corrosive properties.

A list of other chemicals used in the process can be found at http://fracfocus.org/chemical-use/what-chemicals-are-used, while a more comprehensive listing of each chemical and its properties can be found at www.epa.gov/chemfact/.

Questions about shale development or the fracking

process can be sent to news@shalesheet.com.

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