Key Issues in the Application of Supercritical Carbon Dioxide Fracturing in Unconventional Gas Well

Abstract

Abstract Supercritical carbon dioxide is a promising approach to enhance oil recovery in a greener way compared to conventional fracturing technology. SC-CO2 fracturing has advantages of the complicated fracture network, low formation pollution, and methane replacement on account of its good performance of permeability, anhydrous fracturing fluid, less chemical additives, and solubility. Technical features and research state of SC-CO2 fracturing were discussed in this paper. Key issues in the application of SC-CO2 fracturing was summarized in the following aspects: Flow laws of SC-CO2 in the wellbore and fracture need to be lucubrated to provide a basis for fracturing design; Interactions between formation rock and SC-CO2 need to be studied to find the Fracture propagation laws; The proppant-carrying laws need to be explained clearly to form better support effect of the fracture; Effective CO2 tackifier and ultra-light proppant need to be found to improve the proppant-carrying capacity; SC-CO2 source and fracturing devices should be further considered to reduce the cost, increase the efficiency ensure production safety of SC-CO2 fracturing.