A major issue in shale plays is the use of underground supplies of fresh water to fracture-stimulate the well. Horizontal shale wells are fracture-treated with fresh water to which various chemicals are added, and huge volumes of fresh water are needed. A 5,000-foot lateral horizontal well will use up to seven million gallons of fresh water. Depending on the availability of underground water at the lease, the operator's use of that resource could have a substantial adverse impact on the landowner's subsurface water supply.
The impact of fracing in the Barnett Shale was a subject of study by the Texas Water Development Board in 2007. The TWDB concluded that 89% of the water supply for the region of the Barnett Shale field was supplied by surface water sources, and that groundwater used for Barnett Shale development accounted for only 3 percent of all groundwater used in the study area. In East Texas, underground water is more plentiful and using it to frac wells may not place a strain on aquifers. But the Eagle Ford Shale is generally in a more arid part of the state where surface water supplies are more scarce and underground water is a more precious resource. Where the mineral owner also owns the surface estate, attention needs to be paid to the impact of mineral development on underground water supplies.
Companies have developed recycling methods to re-use frac water, which have been tested on an experimental basis. Devon has reported that it has been able to recycle a small percentage of the frac water used in its Barnett Shale wells and in the last three years has recycled nearly 4 million gallons. One obstacle is cost. It was reported that it costs about 40 percent more to recycle the water than to dispose of it by underground injection. Devon has said that its cost of recycling water in Barnett Shale wells is $4.43 per barrel, vs. $2 to $2.50 per barrel for typical water disposal into an injection well. Devon said that less than 5% of Devon's revenue goes toward the cost of handling flow-back water. For a good article on recycling frac water, go to this link.