Numerical Simulation Research On The Performance Of Fracturing Horizontal Well In Shale Gas Reservoir

With the progress of production technology,unconventional gas reservoir development has gradually increased.The development and utilization of unconventional gas reservoir has become the focus of global attention.The geological conditions of shale gas reservoirs are poor,and the seepage mechanism after fracturing is complex.After fracturing,the production of shale gas wells decreases rapidly and the duration of low production period is longer.lt is of great significance to study the seepage characteristics of shale gas reservoirs after fracturing and improve the productivity of shale gas wells to ensure energy security in China.This paper establishes the productivity model of shale gas well on the basis of combining the micro-seepage characteristics of shale gas reservoir after fracturing and studies the influence of reservoir parameters and fracturing construction parameters on production performance.The following research contents are mainly completed:(1)The lithological characteristics,physical properties,storage state and seepage mechanism of shale gas reservoir are studied and summarized in detail.(2)Considering the flow characteristics of Knudsen diffusion,slippage effect and gas adsorption and desorption effect,the mathematical model of apparent permeability of shale gas reservoir is deduced and established by introducing contribution coefficient based on the principle of flow state equation.(3)Based on the mathematical model of apparent permeability,the terms of shale gas adsorption and desorption are introduced to establish the continuous equations of matrix system and fracture network system respectively.Considering the micro-seepage of shale gas in matrix and the high-speed non-Darcy seepage in artificial fracture,the mathematical model of horizontal well productivity in shale gas reservoir is established.Finite difference method and Visual Basic 6.0 software programming language are used for calculation.(4)The field data is used to validate the calculation results.On this basis,the effects of factors such as the half-length of fracture,fracture conductivity,fracture number,stress sensitivity,Langmuir volume,Langmuir pressure on production are studied,and suggestions for optimizing fracturing design parameters are put forward.