Unconventional Oil and Gas Production: Waste Management and the Water Cycle

Abstract Approximately 81% of the nation's energy demands are supported by hydrocarbons, largely in part to the relatively recent exploration of oil and gas from unconventional shale energy reserves. The extraction of shale energy requires technological ingenuity, such as hydraulic fracturing and horizontal drilling, and significant freshwater resources to successfully recover the previously sequestered hydrocarbons from low porosity formations. As unconventional oil and gas development continues to expand to meet the growing energy demands, it becomes increasingly more important to understand the potential environmental implications and to practice proper environmental stewardship. For example, concerns over water usage and the related consequences have dramatically increased due to the demand for water used in hydraulic fracturing, the increased volumes of wastewater being produced, and the need to dispose of or reuse the wastewater without compromising the surface and subsurface environments. As such, this chapter will cover the life cycle of water in oil and gas development (conventional and unconventional), including water use and waste production in the drilling, stimulation, and production phases; the current waste management strategies and challenges within the various treatment modalities; and the widespread implications of the varying forms of waste management.