Productivity Prediction of Fracturing Horizontal Gas Well Considering Fluid-Solid Coupling Effect

Productivity prediction is an effective means to guide gas reservoir development. However, there lie major differences between prediction results and the actual situation as most productivity prediction models do not consider the influence that pressure change has on physical property while part models do consider physical parameter change but are hard to apply due to complex computation and difficulty in parameter choice. According to gas percolation mechanism and potential superposition principle, the productivity model of fracturing horizontal gas well considering the mutual interference among fractures was established. In accordance with related theories of rock mechanics and petroleum physics, the relations between physical parameters, such as permeability and porosity, and volume strain were established. Based on the variation of formation pressure during production process, the mathematical model for the fluid-solid coupling of the variations in seepage and physical parameters of fracturing horizontal gas well was built and the solving method was given. It can be found from computational analysis of living examples that with the proceeding of exploitation, formation pressure gradually declined while porosity and permeability were in linear decline. Compared with the prediction model without considering the variations in physical property parameters, the predicted production in the model considering the variations in physical property parameters got declined by almost 13%.