Multiphysical modeling of supercritical CO2 foam flow and heat transfer in rough fractures considering filtration loss

Supercritical CO 2 (SC-CO 2 ) foam is widely applied in reservoir fracturing and stimulation operations. SC-CO 2 foam fracturing technique can not only enhance oil and gas recovery but also facilitate geological CO 2 storage. However, the flow of SC-CO 2 foam in fractures and the heat transfer between the foam and matrix are not yet fully understood. To further investigate the flow and heat transfer of SC-CO 2 foam within rough fractures, this study develops a coupled flow and heat transfer model considering fluid filtration loss and variations in CO 2 thermal properties. This model is then used to numerically simulate the effects of fracture roughness, foam quality, injection velocity, and filtration loss pressure difference between SC-CO 2 foam and reservoir pressure on SC-CO 2 foam flow and heat transfer behaviors. The results indicate that SC-CO 2 foam exchanges heat continuously with the surrounding rock during foam flowing, leading to a rise in the foam temperature and a decrease in matrix temperature. The heat transfer coefficient and the thermal stress region increase with fracture roughness increases. As SC-CO 2 foam quality increases, its heat transfer coefficient decreases, suggesting that higher foam quality can inhibit the heat exchange. The heat transfer coefficient was reduced by about 40% when the foam mass was increased from 20% to 80%. The faster injection velocity of the foam and the greater filtration pressure difference can improve the heat transfer efficiency between the foam and the matrix. The findings of this study may help inform the selection and evaluation of CO 2 foam fracturing parameters.