CO₂ Fracturing in Shale Reservoirs

Abstract

An analysis of the fracture geometry resulting from fracturing with carbon dioxide base fluids (CBF), such as pure, gelled, foamy and binary mixture of CO2 (95% mol) with N2 (5% mol) and H2 (5% mol) compared to hydraulic fracturing with water-based fluid (WBF), such as slickwater, is performed using specialized software (EFRAC). The impure components used for modeling are based on the main components in anthropogenic CO2 streams. Factors such as: fracture height and length, fracture width, the fracture volume, and the filtered volume (leaked off), temperature and density of the fracture fluid, are analyzed. Finally, a sensitivity analysis of parameters such as the Poisson ratio, Young modulus, pumping rate, reservoir net-pay and reservoir temperature are performed to study the optimization of fracture geometry. The results show that CBF and binary mixture of CO2 fracturing produce results similar to WBF fracturing in terms of fracture geometry. This encourages the study of CO2 fracturing using mixtures from CO2 capture plants containing high levels of CO2 with low levels of gas impurities to substitute the water in conventional fracturing treatment.