Optimization of water management in shale gas production process

We propose an optimization model for the design and operation of the water management system in shale gas production process. The objective is to maximize the profit per unit freshwater consumption. This model is formulated as a mixed-integer linear fractional programming (MILFP) problem, which takes into account both the economic performance and water-use efficiency associated with the shale gas production. We also present tailored optimization algorithms for efficiently solving the MILFP problem, which results from the water management optimization model. We apply the proposed optimization model to a long-term spatially explicit case study. The optimal results show that the net profit for shale gas production per unit freshwater consumption after water treatment is $1,756 per thousand barrels of freshwater. The results also indicate that an efficient water management strategy should be a combination of different water management options, including centralized wastewater treatment, underground disposal, and onsite treatment.