EVOLUTION OF THE SHALE ENERGY PRODUCED WATER RECYCLING REVOLUTION

Development of the Marcellus and Utica/Point Pleasant Shales is occurring at a rapid pace, especially in Pennsylvania where more than 7,300 wells have been drilled through 2013, with over 4,200 producing wells, each of which has been hydraulically fractured. The volume of fluid used to hydraulically fracture a horizontal shale well is typically 4 to 5 million gallons, which is necessary to open fractures in the low permeability shale. Once the hydraulic fracturing process has been completed, approximately 5-10% of the injected fluids, may flow out of the well initially as it cleans up over the course of several days or weeks prior to being put into production. Each well will continue to generate brine (often referred to as produced fluids) during the well’s active life at a rate of 5 to 10 barrels per million cubic feet of gas produced. These produced fluids typically has elevated concentrations of total dissolved solids (TDS) which may include salts, metals, volatile organic compounds, radionuclides, and residual fracturing fluid additives. Produced fluids must be properly contained and treated due to the high levels of TDS, that would be considered toxic to fresh water species or could adversely impacts soil and/or water quality if released to the environment. Shale gas formation like the Marcellus shale are very promising as an abundant domestic energy source, but their development faces environmental challenges including proper water resources management. A variety of approaches and technologies have been implemented over the last five years to increasingly recycle the produced fluids for subsequent fracturing operations. This presentation will review how shale energy produced water management practices have evolved over the last several years, what technologies are being utilized for produced water treatment, and consider future needs and challenges that the industry may face.