Multiscale flow simulation of shale oil considering hydro-thermal process

The multiscale pores within organic matter, inorganic matter, natural fracture and hydraulic fracture make the fluid flow in shale reservoir quite complex. Meanwhile, multiple flow mechanism including convection, boundary slip and oil adsorption is closely related to temperature. In this paper, we propose a fully coupled hydro-thermal model, in which the fluid flow in shale matrix and natural fracture is handled by triple continuum model, and transport in hydraulic fracture is described using discrete fracture model (DFM). This model incorporates multiscale characteristics of shale matrix with multiple flow mechanism and is solved by COMSOL Multiphysics. Subsequently, we investigate the effect of thermal process on recovery of shale oil and the results show that 31.16% additional shale oil can be produced with temperature rising 60 K, indicating this method is profitable. Besides, the adsorption oil is more sensitive to temperature than free oil and contributes more than 75% of total shale oil production. Moreover, the sensitivity analysis is also conducted to investigate the effectiveness of formation factors and fractal parameters.