Optimizing the Water-Energy Relationship in Hydraulic Fracturing by Utilizing CO2 and Water as Fracturing Agents

Economic and population growth is the main cause of the continuous sharp increase in energy demand. As a result, new energy sources like renewable energy and unconventional gas have attracted a lot of attention. Recent advancements in hydraulic and horizontal fracture have made shale gas a significant worldwide energy source. The extraction of shale gas from the rock requires a significant volume of water, which is utilized as a fracturing fluid in this process. However, the issues surrounding the use and disposal of water raise grave worries about potential negative effects and have also made complex water management measures necessary. This chapter offers an alternate approach to lowering freshwater usage by using CO2 captured from power plants as a fracturing fluid. To account for system uncertainty, this project implemented a mathematical programming approach to create networks of water and CO2 that are related to shale gas hydraulic fracture operations (water availability, CO2 generation, and flowback water based on a horizon time). The presented formulation demonstrates strategic planning that reduces the total annual cost (TAC) while considering the need for water, the production and capture of CO2, the equipment’s capacity for treatment technologies, transportation costs, storage units, and disposal. To demonstrate how the presented approach can be applied, an example problem is provided. The model shows that when the fracking fluid’s CO2 content rises, the TAC rises but the amount of freshwater needed falls. Additionally, since using water is less expensive than using CO2, freshwater availability is the primary factor affecting the TAC.