Alternative groundwater resources in North-central Texas for the development of the Barnett Shale gas play

Texas water resources are under pressure due to population growth expected in the coming decades, increasing industrial demands, and frequent periods of drought. With this increasing demand for limited water resources it is important to explore alternative water sources within the State. One of those resources that can be developed is the many small aquifers which have never been well-characterized but could be an alternative source of fresh and brackish water for agriculture, municipal, and industrial applications. The natural gas industry’s demand for water is growing in Texas as new drilling techniques such a hydraulic fracturing have opened new reserves previously considered economically non-viable. The development of smaller aquifers containing brackish water is a viable alternative to the gas industry’s current reliance on fresh (potable) groundwater resources. The aquifer sections containing brackish water need to be mapped and characterized so they can be developed as an alternative water resource by the gas industry. The Barnett Shale in North-central Texas is one of the first major gas plays in the United States to use the technique of hydraulic fracturing in field development. This technique requires large quantities of water to create the required hydraulic pressure down the gas well to fracture the normally low permeability shale. A typical horizontal well completion consumes approximately 3.0 to 3.5 million gallons (11,400 to 13,200 m3) of fresh water. Projections of future groundwater demand for the Barnett Shale gas play total 417,000 AF (5.1x108 m3), an annual average of 22,000 AF (2.7x107 m3) over the expected 2007-2025 development phase. This level of water demand has the gas industry and groundwater managers exploring alternative sources of water for future development of the Barnett Shale.
One alternative source of water for the expanding footprint of the Barnett Shale gas play are the smaller local Paleozoic aquifers on the western edge of the play. These small aquifers are underutilized and contain waters with higher levels of TDS. These levels are, however, acceptable to the drilling industry. In order to characterize theses aquifers, TWDB databases were utilized to analyze water chemistry and well productivity.