Eideard

Fracking without water! Shale gas production in arid regions

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Carbon Dioxide pipeline

Hydraulic fracturing, or fracking, uses large amounts of water injected into wells under high pressure to help free natural gas and oil from shale deposits…Yet some of the world’s largest sources of shale gas are found in deserts, making the technique seem impractical.

It’s possible to fracture gas-rich rock formations without using any water at all. Indeed, gas and oil companies have been using carbon dioxide this way for decades, albeit on a limited basis. But if this approach is going to be used on a large scale, it will require a major investment in infrastructure for getting carbon dioxide to fracking sites. And in some cases a price on carbon emissions may be the only way to make the economics work.

In the United States, the abundant natural gas made available by fracking has spurred a huge shift to this fuel from coal, reducing greenhouse-gas emissions from power plants…But shale gas is also plentiful in places such as China, which is estimated to have 50 percent more of this resource than the United States.

Right now carbon dioxide fracking is used in places, like Wyoming, that already have carbon dioxide pipelines. Economics alone could justify building more in some places, says Robert Dilmore, a research engineer at the U.S. National Energy Technology Laboratory.

In other cases building pipelines might require a push from governments. A price on carbon, for example, could create a big supply of cheap carbon dioxide by giving utilities incentive to capture it from power plants’ smokestacks. This might make sense in China, where the best shale gas deposits are in arid areas…One of the largest shale gas resources in the world is the Tarim Basin in northeast China, located beneath the Taklamakan Desert—one of the largest sandy deserts in the world, with nearly 300,000 square kilometers of shifting dunes. Piping in water would strain already tight supplies. But these days, as China quickly adds to its stock of coal-fired power plants, the country has plenty of carbon dioxide—it’s just not capturing and using it.

Fracking with carbon dioxide has a number of potential advantages. Not only would it eliminate the need for millions of gallons of water per well, it would also eliminate the large amounts of wastewater produced in the process…

Water-free fracking could also solve other problems. In conventional fracking, half the water pumped into a well flows back to the surface, but the other half stays in the rock formation. The water that’s left behind can block the path of the natural gas, slowing down production and possibly decreasing the total amount a well can produce over its lifetime, Dilmore says…

When carbon dioxide is used instead of water, most of it comes back out of the well (where it can be captured and used again). This in turn allows natural gas to flow out more freely…

After the well is done producing, it can be sealed up, storing the carbon dioxide permanently underground. That would help reduce greenhouse-gas levels in the atmosphere…

The obvious conclusion is that since we’re talking about a quid pro quo that removes carbon from the air – uses it to free up natural gas [instead of scarce water] – and finishes off the task with sequestered carbon it would be worth making this the primary technology. But, not until we get to it, working out costs, etc..

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Written by Ed Campbell

March 24, 2013 at 10:30 am

2 Responses

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  1. I had only heard this method mentioned in an off hand way previously. Thanks for the info., something I will look into.

    earthstonestation

    March 24, 2013 at 12:41 pm

  2. Can’t see this sequesting enough carbon to make an atmospheric difference, but the elimination of water usage is good news.

    Mark

    March 25, 2013 at 4:27 am


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