Carbon dioxide source selection and supply planning for fracking operations in shale gas and oil wells

As a promising alternative approach for shale gas and oil withdrawal, fracking using CO2 instead of water has been proved to be not only technically feasible but also environmentally friendly. This paper aims at evaluating CO2 fracking from an economic perspective by considering the collection, supply, transportation, and storage of CO2. More specifically, a CO2 source selection and supply planning problem is defined and discussed from three aspects: CO2 collection and storage at sources, CO2 transportation, and CO2 storage and usage at well pads. Cost models for the three aspects are built, based on which, a mixed-integer nonlinear programming model is developed to determine the optimal set of sources, the corresponding supply and transportation plan, and the investment in associated facilities and equipment. A two-stage algorithm is proposed, which decomposes the original model into a large set of simple sub-problems and a mixed-integer linear problem. A case study for three emerging well pads in North Dakota is presented to illustrate the implementation of the mathematical model and algorithm, and a sensitivity analysis is conducted to analyze the influences of four key parameters over the cost of using CO2.