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Water Supply for Eagle Ford Seen as Sufficient

There's enough water in the Carrizo Wilcox Aquifer in South Texas to support Eagle Ford Shale oil and gas drilling and hydraulic fracturing as well as other uses, such as irrigation, according to the Eagle Ford Task Force. This is in spite of a drought that has gripped most of Texas, according to experts.

The task force advises the Railroad Commission of Texas (RRC) on matters related to the booming oil and gas play. The group met late last year in San Antonio to consider data on water usage from the aquifer with an eye to determining whether sufficient supplies were available.

"I am pleased to announce, after exhaustive research, our task force has found water sourcing in South Texas is currently not an issue," said Railroad Commissioner David Porter, founder of the task force. "We will continue to study best practices for water management in the region to help mitigate any future issues."

Data presented to the task force indicated that drilling and completions in the Eagle Ford Shale account for about 6% of the water demand in South Texas, while irrigation accounts for 64% and municipal uses account for 17%. According to the Texas Water Development Board, irrigation accounted for 60% and municipal 27% of the water used statewide in 2009, while mining accounted for just 1%.

The energy industry has reduced the amount of water it uses to hydraulically fracture wells, according to the RRC. Currently, industry is reporting an average use of approximately 11 acre-feet of water used to complete each well, down from the approximately 15 acre-feet previously used. One acre-foot is about 326,000 gallons.

Industry experts informed the task force that approximately 2,600 to 2,800 new wells are expected to be completed annually in the Eagle Ford at peak demand, which translates into about 30,000 acre-feet of water per year during the heaviest point of development. In 2008 the Carrizo Wilcox Aquifer contained 540,000 acre-feet of available water.

"...[T]here is still concern that this pumping may have localized impacts on water levels in the aquifer and on aquifer discharges to streams and springs," said the Sierra Club's Teresa Carrillo, a task force member. "We are hopeful that through this task force process our concerns will be addressed. Texas is on a world stage and we can make this a model for all the nation and the rest of the world to follow."

Some task force members said their companies are looking into using brackish water for hydraulic fracturing instead of fresh water, freeing up more resources in the Carrizo Wilcox Aquifer. "EOG is always looking for ways to conserve natural resources and we are taking significant steps to minimize water usage," said task force member Steve Ellis, senior division counsel for EOG Resources, Inc. "In addition, we are expanding the use of brackish water in our completion operations to reduce the demand for fresh water."

Water usage in the region is monitored in several ways. For one, local groundwater conservation districts measure water levels monthly to determine whether levels are increasing or decreasing. Historically, during periods of drought, like the one South Texas has been experiencing, water levels will decline until normal rain patterns return. At which time, water levels tend to return to pre-drought levels.

"We have seen water levels drop this past year due to the drought, which has caused everyone to pump more groundwater," said task force member Mike Mahoney, general manager of the Evergreen Underground Water Conservation District. "However, we do not see groundwater pumping for oil and gas drilling and completions as a significant contribution to the decline in water levels when compared to overall pumping."

During the height of the drought last year, Mahoney told NGI's Shale Daily curtailment of water takes from the Carrizo Wilcox by oil and gas producers were not expected. "In general [oil and gas companies] want to be good neighbors; they're willing to work with us. This is in a developing stage. What I'm seeing is they want to come to the table; they want to sit down and they want to try to find solutions and work with us..." he said at the time (see Shale Daily, Aug. 11, 2011).

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