The Produced Water Conundrum Grows Across Unconventionals

Abstract

Shale players have a love-hate relationship with water. It’s an essential ally going into downhole to help proliferate fractures in the subsurface and free up stuck hydrocarbons. It’s a parasite coming out - a briny byproduct that can easily outpace oil production from any given well. Likewise, operators must deal with water management on dual fronts. The first is sourcing the water to be used in the fracturing of the well. Second is finding the right solution for the flowback and formation water coming out of the well. Early on, the answer for the former was freshwater sources. However, once the strain set in from general scarcity, drought, environmental concerns or the like, industry started looking hard at the recycle and reuse of produced water - a solution where the problem becomes the answer. Water recycling rates vary widely between unconventional basins. For the domestic oil industry, data provider IHS Markit forecast in an April 2020 report the vast majority of wastewater leaving an oil field in 2022 will still not be recycled. It will instead be injected into disposal wells, which is currently the most common practice for produced water management. This option is costly and risky, especially for wells that are located some distance from the nearest disposal well. It has also come under increased scrutiny because of the potential effects of disposal well use on the surrounding area’s seismic activity. “Going back to the beginning of unconventional resource production, the focus was understandably on the water needed for drilling and completions,” Paola Perez-Pena, a principal researcher at IHS Markit, commented in an analysis. “Now that there is a considerable, established production, operators are realizing the extent to which produced water is not only a sizable matter, but an ongoing and essentially, perpetual one.” Produced water is a mix of the water pumped down the well to assist with fracturing plus residual drilling fluid and formation water. On average, with every barrel of oil produced in the US, more than 4 bbl of wastewater is produced, though that number varies from basin to basin. “With water, what you find is producers consider a number of different piping configurations, storage, and disposal well options, as well as reuse opportunities,” said John Walsh, principal technologist for Worley Advisian and author of the book, Produced Water. “There’s no one single strategy or approach that’s going to solve the water problem. There is no silver bullet.” According to an industry brief by Raymond James in July 2019, pre-pandemic US oilfield water production was already a whopping 50 million BWPD. For scale, this amount of water could cover more than 8,000 football fields with a foot of water, every day. The investment bank estimated just under half of the total produced water came from horizontal basins, despite making up close to 80% of onshore crude production. The report forecast that the total volume of produced water from major oil basins in the US could grow to more than 60 million BWPD by 2030 (Fig. 1).