In the USA, nearly 150 billion gallons of water were used in fracturing operations in 2017 and the demand is expected to double by 2019. Nearly half of the wells fractured are in regions with high or extremely high water stress. Typically 20-50 percent of the fluids are produced back and require disposal. Recycling of produced water can be both an economic, and socially responsible, approach to reduce the demand on fresh water.
The salinity of produced water varies from nearly fresh water to very salty with total dissolved solids (TDS) as high as 250,000 mg/l. There is a perception that it is only feasible to use produced water for hydraulic fracturing operations if the salinity is moderate, for example, TDS < 80,000 mg/l.
Following an extensive literature search, laboratory testing was conducted to evaluate which, if any, fracturing fluid systems could be used with high salinity produced waters typical of the Bakken Play. Produced water systems, both slick water and cross-linked gels, were developed using multiple chemical approaches: CMHPG-Zirconate, Guar-Borate, STFR (salt tolerant friction reducer) and HVFR (high viscosity friction reducer) systems. This presentations demonstrates that “bad produced waters” can be considered candidates for recycling in hydraulic fracturing operations.
Primary Author / Conference Presenter:
Mary Van Domelen
Edmond, Oklahoma USA