Evolving water management practices in shale oil & gas development

Advances in horizontal drilling coupled with hydraulic fracturing have unlocked trillions of cubic feet (billions of cubic meters) of natural gas and billions of barrels (millions of cubic meters) of petroleum in shale plays across the United States. There are over 72,000 unconventional well sites in the United States, with anywhere from 2 to 13 million gallons (7500-49,000 cubic meters) of water used per unconventional well. While unconventional wells produce approximately 35% less waste water per unit of gas than conventional wells, the sheer number of wells and amount of oil and gas being produced means that water use has increased by as much as 500% in some areas. Such large water demands give rise to questions about water management, including acquisition, transportation, storage, treatment, and disposal. While these issues vary by play, some key concerns include competition for drinking water sources, impacts of fresh and wastewater transportation, the extent of wastewater recycling, contamination, and the effects of various treatment and disposal methods on communities and watersheds. These concerns have not been fully resolved, yet there is a noticeable, and largely quantifiable, evolution of management practices toward operating more sustainably and with smaller regional impacts. Here we explore water management issues as they arise throughout the unconventional drilling process, particularly focusing on how practices have changed since the beginning of the shale boom and how these issues vary by play. (C) 2015 Elsevier Ltd. All rights reserved.