Numerical investigation of the in situ oil shale pyrolysis process by superheated steam considering the anisotropy of the thermal, hydraulic and mechanical characteristics of oil shale

The in situ pyrolysis process of oil shale by superheated steam is a complex process that is affected by the thermal-hydraulic-mechanical coupled process. Meanwhile, oil shale’s physical properties show strong anisotropy in the thermal, hydraulic and mechanical characteristics due to the mineral arrangements and sedimentary structures. To accurately simulate the in situ oil shale pyrolysis process, the anisotropic thermal, hydraulic, and mechanical characteristics at different temperatures were first determined through laboratory experiments. Then, a thermal-hydraulic-mechanical coupled model that considers the anisotropic thermal-hydraulic-mechanical characteristics was established to simulate the in situ pyrolysis process of oil shale by superheated steam. The distributions of the pore pressure, temperature, stress, deformation, permeability and production during the in situ pyrolysis process were analyzed. The main results are as follows: (1) the temperature field distributions in oil shale reservoirs ...