Experimental evaluation of flow friction resistance of CO2 foam fracturing fluid and numerical simulation of fracture extension

Abstract The main area of shale gas exploratory development is in the Sichuan basin. It requires a huge water source for shale gas hydraulic fracturing, but the well sites are mainly located in the hills, which limits the industrialization of shale gas development. The CO2 foaming fluid can meet the requirements of the fracturing fluid in fracking and relieve pressure on water resources. The friction calculation of the CO2 foaming hydro-fracturing fluid in the conduit flow is key to the reliability of the overall fracture engineering, which affects the formation stimulation effect. The friction properties of CO₂ foaming hydro-fracturing fluids were investigated by conducting flow experiments in HTHP conditions, and the influence of pressure, temperature, foam mass, and flow rate on the friction properties was obtained. Mathematical models of frictional drag coefficients have been developed to predict the frictional force of CO2 foaming gel hydro-fracturing fluids in turbulent flows, which can be useful in evaluating the rating of CO2 foaming hydro-fracturing designs at well sites.