An integrated model for fracture propagation and production performance of thermal enhanced shale gas recovery

Thermal enhanced recovery (TER) is a promising approach to improving the production efficiency of shale gas reservoirs. TER involves complex physical behaviors including fracture propagation, matrix deformation, gas flow, and heat transfer. Traditional numerical models are generally simplified as the regular bi-wing cracks at each production well which cannot account for the underlying correlation between the fracture network and multi-physics phenomenon. In this work, an integrated framework to evaluate the hydraulic stimulation and production performance of thermal enhanced shale gas recovery is proposed. The reliability of the integrated fracturing model which is based on cohesive zone method (CZM) and multi-physics coupling gas production model is well verified with the analytical results and field data, respectively. On this basis, the production performance of shale gas reservoirs under different heating temperatures (380-780 K), well patterns, and reservoir conditions (e.g., adsorption parameters, thermal parameters, and fracturing parameters) are investigated, demonstrating that the heating excitation could effectively enhance the cumulative gas production and improve the recovery cycle of shale reservoir. By the overall consideration of gas production and heating efficiency with various engineering factors, the optimal strategies for the thermal enhanced recovery of shale gas reservoirs are further discussed.