Treating and recycling flowback from a hydraulically fractured gas shale reservoir is vital to the development of several shale plays. The use and disposal of water in emerging shale plays is expensive and a significant public and political concern. A breakthrough in water treatment combines an advanced oxidation process (AOP) using ozone and ultrasonic transducers to oxidize heavy metals, soluble and insoluble organics. When combined with reverse osmosis (RO) in a mobile unit, this process allows for significant volumes of flowback to be returned to the environment as fresh, clean water, thereby significantly reducing truck traffic. The hydraulic fracturing process in the Woodford Shale requires 50,000 to 110,000 barrels of water per well. By treating flowback on location with the AOP/RO process, 75% of the volume treated will become clean water with total dissolved solid levels less than 500 ppm. 25% will be clean, concentrated brine water which can be used in subsequent hydraulic fracturing operations. Newfield Exploration executed a pilot 4Q08 during which flowback was processed on location with an AOP/RO unit. Sample analysis from this pilot will be provided to state and federal agencies as a validation of the technology. The mobile unit processed 100 barrels per hour using 220 kW power generation to provide a fresh water stream and brine stream from flowback. The proper application of the AOP/RO process could reduce the fluid disposal carbon footprint by 50 tons of CO2 per well and transform a large portion of industry water use from consumptive to non-consumptive—as much as 25,000 bbl per well. The AOP/RO process could untangle complex operating environments, reduce operating expense and help the environment.

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