Multiobjective Optimization Model for Minimizing Cost and Environmental Impact in Shale Gas Water and Wastewater Management

Unconventional resource extraction from shale plays involves complex operations for water and wastewater management. These water management operations are expensive for companies and emit significant quantities of criteria air pollutants and greenhouse gases that impact human health and the environment (HHE). We present a multiobjective mixed integer linear programming (MILP) framework for assessing the trade-offs between financial cost and HHE costs for shale gas water acquisition, transport, storage, and treatment under realistic scheduling, operational, and regulatory constraints. We formulate objective functions to identify water management strategies that minimize financial cost, minimize HHE cost, and minimize combined financial and HHE costs. The model was applied to a 14 wellpad case study that is representative of shale gas extraction in the Marcellus Play. We observe significant variation in the financial and HHE costs under different objective functions and regulatory scenarios.