Water Resources Management for Shale Energy Development

Abstract:

The increase in the exploration and extraction of hydrocarbons, especially natural gas, from shale formations has been facilitated by advents in horizontal drilling and hydraulic fracturing technologies. Shale energy resources are very promising as an abundant energy source, though environmental challenges exist with their development, including potential adverse impacts to water quality. The well drilling and construction process itself has the potential to impact groundwater quality, however if proper protocols are followed and well integrity is established then impacts such as methane migration or drilling fluids releases can be minimized. Once a shale well has been drilled and hydraulically fractured, approximately 10-50% of the volume of injected fluids (flowback fluids) may flow out of the well initially with continued generation of fluids (produced fluids) throughout the well’s productive life. Produced fluid TDS concentrations often exceed 200,000 mg/L, with elevated levels of strontium (Sr), bromide (Br), sodium (Na), calcium (Ca), barium (Ba), chloride (Cl), radionuclides originating from the shale formation as well as fracturing additives. Storing, managing and properly disposisng of these fluids is critical to ensure water resources are not impacted by unintended releases. The most recent data in Pennsylvania suggests an estimated 85% of the produced fluids were being recycled for hydraulic fracturing operations, while many other states reuse less than 50% of these fluids and rely moreso on underground injection wells for disposal. Over the last few years there has been a shift to reuse more produced fluids during well fracturing operations in shale plays around the U.S., which has a combination of economic, regulatory, environmental, and technological drivers. The reuse of water is cost-competitive with sourcing of fresh water and disposal of flowback, especially when considering the costs of advanced treatment to or disposal well injection and lessens the use of fresh water and disposal needs thus is a major innovation for the industry. Proper water resource managment techniques from the begining of drilling through production are critical to ensure the energy necessary for society is produced while also protecting the environment.