Numerical simulation of fractured horizontal well considering threshold pressure gradient, non-Darcy flow, and stress sensitivity

Conventional numerical simulators cannot accurately predict the production of fractured horizontal wells in tight sandstone gas reservoirs due to the threshold pressure gradient (TPG) and stress sensitivity. Additionally, non-Darcy flow in hydraulic fractures further complicates the prediction. Therefore, a numerical simulation model was developed to accurately predict the production of fractured horizontal wells that considers the TPG, non-Darcy flow, and stress sensitivity using the embedded discrete fracture model. The model was solved using the automatic differentiation framework of MATLAB Reservoir Simulation Toolbox. The numerical simulation demonstrated that the Darcy flow model provided an optimistic prediction of the productivity of fractured gas wells in tight reservoirs. The TPG, non-Darcy flow, and stress-sensitive phenomena reduced the productivity of gas wells to varying degrees and severely affected the production of gas wells. The TPG effect, non-Darcy effect, and stress sensitivity phenomenon reduced the gas well production by 1.66%, 12.9%, and 42.42%, respectively, compared with that of the Darcy flow. In contrast to the conventional Darcy flow model, the model established in this study can accurately predict the production of gas wells in production history matching.

Automated summary

A numerical simulation model is developed to accurately predict the production of fractured horizontal wells in tight sandstone gas reservoirs, considering the threshold pressure gradient, non-Darcy flow, and stress sensitivity.