Posted: 06 Nov 2011 03:00 AM PST
Little-noticed drilling technique uses propane gel, not water, to release natural gas. Higher cost, lack of data and industry habit stand in the way.
By Anthony Brino, InsideClimate News and Brian Nearing, Albany Times-Union
ALBANY, N.Y.—In the debate over hydraulic fracturing for natural gas, two facts are beyond dispute: Huge amounts of water are used to break up gas-bearing rock deep underground and huge amounts of polluted water are returned to the surface after the process is complete.
Tainted with chemicals, salts and even mild radioactivity, such water, when mishandled, has damaged the environment and threatened drinking water, helping fuel a heated debate in New York and other states over whether gas drilling is worth its risk to clean drinking water, rivers and streams.
Now, an emerging technology developed in Canada and just making its way to the U.S. does away with the need for water. Instead, it relies on a thick gel made from propane, a widely-available gas used by anyone who has fired up a backyard barbecue grill.
Called liquefied propane gas (LPG) fracturing, or simply "gas fracking," the waterless method was developed by a small energy company, GasFrac, based in Calgary, Alberta.
Still awaiting a patent in the U.S., the technique has been used about 1,000 times since 2008, mainly in gas wells in the Canadian provinces of Alberta, British Columbia and New Brunswick and a smaller handful of test wells in states that include Texas, Pennsylvania, Colorado, Oklahoma and New Mexico, said GasFrac Chief Technology Officer Robert Lestz.
Like water, propane gel is pumped into deep shale formations a mile or more underground, creating immense pressure that cracks rocks to free trapped natural gas bubbles. Like water, the gel also carries small particles of sand or man-made material—known as proppant—that are forced into cracks to hold them open so the gas can flow out.
Unlike water, the gel does a kind of disappearing act underground. It reverts to vapor due to pressure and heat, then returns to the surface—along with the natural gas—for collection, possible reuse and ultimate resale.
And also unlike water, propane does not carry back to the surface drilling chemicals, ancient seabed salts and underground radioactivity.
"We leave the nasties in the ground, where they belong," said Lestz.
Monday, November 7, 2011
Waterless Fracking Method
Check out this interesting article on a new method for fracking that does not require water.