Quantitative Comparison of Three Shale Gas Extraction Schemes via Coupled Hydromechanical Simulation

This study employs COMSOL Multiphysics to build a hydromechanical (HM) coupling model for shale gas production based on classic poroelasticity and Darcy’s law. Considering effective stress variation during depletion, a stress-dependent permeability model is incorporated into the dual-porosity framework. Numerical simulations evaluate three extraction methods—single-well, dual-well, and single-well with hydraulic fracturing—on pressure in the fracture system, permeability evolution, and gas production. The results show consistent fracture permeability decline with extraction, more pronounced in early stages. Single-well hydraulic fracturing accelerates pressure reduction to 6.7 × 105 Pa after one year, equivalent to five years of conventional production. The dual-well model exhibits negligible boundary effects but notable inter-well interference on permeability. These findings provide a preliminary reference for well spacing analysis and fracturing design in shale gas development.