A New Boom in Natural Gas Threatens Drinking Water

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.

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.

This frac-water mixture is blasted at high pressure into shale deposits up to 10,000 feet deep, fracturing them. The sand lodges in the cracks, propping them open and providing a path for the gas to exit after external pressure is released. Besides using vast amounts of groundwater, scientists and environmentalists worry that toxic frac water 30 percent or more remains underground and may years later pollute freshwater aquifers.

Millions of gallons of frac water come back to the surface. It could be treated, but in Texas it is most often reinjected into the ground. Millions more gallons of produced water flow out later during gas production. This flow, too, is often tainted with radioactivity and poisons from the shale. Often stored in pits, that waste can leak or overflow while awaiting reinjection.

Simply put: "Each of these wells uses millions of gallons of fresh water, and all of it is going to be contaminated," Ms. Carluccio says.

"Industry spokesmen say such fears are overblown. 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.

Targets for this new kind of drilling

One huge target is the Marcellus shale basin that spans large parts of New York, Pennsylvania, Ohio, and West Virginia. States are eager to get to get new revenues and so are many landowners lining up to sign leases.