I know at least one of my readers who will love this post, as it lends creedence to her contention that the energy companies are the biggest threat to the planet's water. In this case...well, who knows?
Yesterday's Christian Science Monitor featured Mark Clayton's story on the rising natural gas production in the USA, due primarily to the extraction of gas from low-permeability shale formations. Shales, sometimes more descriptively called mudstones, are what we hydrogeologists and reservoir engineers call "tight" rocks - fluids cannot flow through them very easily, as opposed to a rock like a sandstone or cavernous limestone.
Clayton's story begins:
After decades of declining US natural-gas production, an advanced drilling system so powerful it fractures rock with high-pressure fluid is opening up vast shale-gas deposits.
Instead of falling, US gas production is rising, with up to 118 years’ worth of “unconventional” natural gas reserves in 21 huge shale basins, an industry study in July reported. Such reserves could make the nation more energy self-sufficient and provide more of a cleaner “bridge fuel” to help meet carbon-reduction goals urged by environmentalists.
Shale gas reserves have a powerful economic lure. Companies, states, and landowners could all reap a windfall in the tens of billions. Some also predict lower heating costs for residential gas users as production increases.
Now, scores of natural gas companies are fanning out from Fort Worth, Texas, where hydraulic fracturing of shale has been done for at least five years, to lease shale lands in 19 states, including Pennsylvania and New York.
So if these tight shales have lots of gas, it is difficult to get the gas out. Reservoir engineers have developed hydraulic fracturing, or "hydro-fracking", to extract the gas. Water is injected into the shale at very high pressure. Sand or some other natural/man-made material ("proppant") is included in the water. The high pressure water fractures the rock, and the proppant serves to prop the fractures "open" after the injection stops. The gas can then flow more easily to the well.
Hydro-fracking is also used for oil, geothermal, and regular water wells to improve yields. Sometimes fluids other than water are used and chemicals are oftenadded to the fracturing fluid. The problem? Large amounts of water are required, and the injected fluids could contaminate water in aquifers or ultimately, surface water bodies.
Clayton's story continues:
But some warn that by expanding “hydraulic fracturing” of shale, America strikes a Faustian bargain: It gains new energy reserves, but it consumes and quite possibly pollutes critical water resources.
“People need to understand that these are not your old-fashioned gas wells,” says Tracy Carluccio, special projects director for Delaware Riverkeeper, a watchdog group worried about a surge in new gas drilling from New York to Pennsylvania and from Ohio to West Virginia. “This technology produces tremendous amounts of polluted water and uses dangerous chemicals in every single well that’s developed.”
Traditional gas wells bore straight into porous stone, using a few thousand gallons of water during drilling. But dense shale has gas locked inside.
Hydraulic fracturing, or “fracking,” and horizontal drilling unlock it.
Each hydraulically fractured horizontal well can require from 2 million to 7 million gallons of fresh water mixed with sand and thousands of gallons of industrial chemicals to make the water penetrate more easily.
An industry viewpoint:
“The wells we drill … are insulated with concrete,” says Chip Minty, a spokesman for Devon Energy, an Oklahoma City-based gas company that pioneered hydraulic fracturing in the Barnett shale formation beneath Fort Worth, Texas. “The purpose is to protect any kind of aquifer or ground water layer. Those processes are controlled by regulatory agencies, and that keeps us safe from any kind of aquifer pollution.”
A pioneer in “best practices,” Devon has also developed a way to purify and reuse frac water. But those techniques are costly and not widely used at present. Whether such practices will be required elsewhere is an open question.
The wells themselves may not leak, but how about the water that gets injected into the shale formation? Where will that go?
The story suggests that New York City's Catskills watershed drinking-water supply, which provides about 90% of the city's 8 million+ customers , could be at risk. The water is so good that it does not require filtration.
And to top it off, we don't really know what is in the injected fluid. Consider this:
Today, chemicals used in fracturing are considered by the companies to be trade secrets. The Energy Policy Act of 2005 exempts companies from being forced by the Clean Water Act, Safe Drinking Water Act, and other federal laws to reveal what chemicals are in their fracturing fluids.
But some say that it’s critical to know what’s being injected deep underground.
“We’re very concerned about this toxic drilling and hydraulic fracturing,” says Gwen Lachelt, director of the Oil and Gas Accountability Project in Durango, Colo. “We need to know what’s in what they’re putting into the ground.”
You had better believe we need to know; that's a no-brainer, folks!
"I think God's will has to be done in unifying people and companies to get that gas line built, so pray for that." -- Gov. Sarah Palin (R-AK), 8 June 2008, Wasilla Assembly of God Church
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