Simulation-optimization model for water management in hydraulic fracturing operations

Hernandez, E. A.; Uddameri, V.

Simulation-optimization model for water management in hydraulic fracturing operations | Modèle de simulation et d’optimisation de la gestion de l’eau dans les opérations de fracturation hydraulique Modelo de simulación y optimización para la gestión del agua en operaciones de fracturación hidráulica 水力压裂过程中水管理模拟-最优化模型 Modelo simulação-otimização para gestão da água em operações de fraturamento hidráulico

2015

Hernandez, E. A. | Uddameri, V.

A combined simulation-optimization model was developed to minimize the freshwater footprint at multi-well hydraulic fracturing sites. The model seeks to reduce freshwater use by blending it with brackish groundwater and recovered water. Time-varying water quality and quantity mass balance expressions and drawdown calculations using the Theis solution along with the superposition principle were embedded into the optimization model and solved using genetic algorithms. The model was parameterized for representative conditions in the Permian Basin oil and gas play region with the Dockum Formation serving as the brackish water source (Texas, USA). The results indicate that freshwater use can be reduced by 25–30 % by blending. Recovered water accounted for 2–3 % of the total blend or 10–15 % of total water recovered on-site. The concentration requirements of sulfate and magnesium limited blending. The evaporation in the frac pit constrained the amount blended during summer, while well yield of the brackish (Dockum) aquifer constrained the blending during winter. The Edwards-Trinity aquifer provided the best quality water compared to the Ogallala and Pecos Valley aquifers. However, the aquifer has low diffusivity causing the drawdown impacts to be felt over large areas. Speciation calculations carried out using PHREEQC indicated that precipitation of barium and strontium minerals is unlikely in the blended water. Conversely, the potential for precipitation of iron minerals is high. The developed simulation-optimization modeling framework is flexible and easily adapted for water management at other fracturing sites.

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