Optimal design of supply chain network with carbon dioxide injection for enhanced shale gas recovery

To optimize the configuration of a supply chain network for shale gas production (SGSCN), we develop a novel optimization model that considers ‘enhanced gas recovery by carbon dioxide (CO₂) injection’ (EGR-CO₂) technology, which simultaneously achieves decrease in net CO₂ emissions. Then, the developed framework is used to identify the optimal SGSCN configuration in a mixed-integer linear programming problem that maximizes the overall profit of shale gas production. The optimal framework of the proposed SGSCN model is compared to the case (Case 1) when the improvement technology for the shale gas production rate like EGR-CO₂ is not used, to demonstrate its superiority over existing approaches. The simulation results that consider application on the Marcellus shale play indicate that the overall profit of SGSCN that uses EGR-CO₂ technology and purchases the CO₂ on the market (Case 2) achieves 2.56% higher profit than the SGSCN without an injection strategy (Case 1) and 10.00% higher profit than the SGSCN that uses CO₂ that is recovered from the flue gases generated during combustion of shale gas to produce electricity (Case 3). The profitability of Case 3 is reduced by the cost of constructing and operating a CO₂-capture facility. For Case 3 to achieve the same profitability as Case 2, the CO₂ purchase must be more expensive than 5 US$ per MCF CO₂ (0.18 US$ per m³).