Shale Gas Production - Modelling With Non-linear Flow Mechanisms

Abstract

Unconventional shale gas reservoirs are well known as a low permeable reservoirs so production study from such reservoirs is very complex. In recent years, by introducing new techniques such as of massive fracture and horizontal drilling for extraction of gas from shale formations, production has resulted in oversaturated market and strong decline in oil price. Because of the complexity of shale gas reservoirs, conventional simulator studies are not accepted and this project includes the study of mechanism used for shale gas production simulation. The modelling of diffusion, gas desorption and non-Darcy flow were done for a model that considers a porous cube containing a sphere inside where sphere represents matter where gas is adsorbed. By pressure decline, adsorbed gas fills the pore media and then goes toward the well through the fracture. All cells considered in the model are put together where well, fracture and reservoir are connected. Due to the low matrix permeability, gas velocity is significantly higher in comparison with the conventional reservoir, and as a result of that many non-linear mechanism, such as non-Darcy flow, adsorption, Klinkenberg effect, geomechanics shall be taken into consideration for successful reservoir characterization study. Mathematical modelling of non-linear mechanism was done, and based on the numerical model, FSGP simulator, that is developed by Dhruvit Berawala 2015., is updated for a non-linear mechanisms. Also effects of viscosity and density variation with pressure are taken into account. As a results of introducing non-linear mechanism in reservoir characterization study, smoother results are gotten when production moves from one block to another due to the inertial effect.