Study On Numerical Simulation Method Of Stimulated Reservoir Volume Horizontal Wells In Fractal Tight Gas Reservoirs

At present,many stimulated reservoir volume models are based on Euclidean geometry.However,the network of reservoirs is crisscrossed and it's heterogeneity is very strong after fracturing.The accuracy of traditional models for such reservoirs is low.Consideration of the fractal and anomalous diffusion theory,using the fractional differential,Matlab program and well test analysis,this paper builds a fractal dense gas reservoir fracturing horizontal wells composite three linear flow model,and research the pressure dynamic features of fracturing horizontal well in dense gas reservoir.This has a guiding significance for the development of tight gas reservoir.Firstly,the stimulated reservoir volume area of three linear flow model is rebuild to two-dimensional pressure drop.Establish the diffusion model of composite three linear normal flow.Get the pressure distribution over time.Draw the double logarithmic curve of pressure and pressure derivative,comparison with the analytic solutions to verify the accuracy.Comparing the fractal composite three linear flow model with three linear conventional flow model,this paper found that the composite model can better match the occurrence time of channeling stage..Then,based on the conventional diffusion model,anomalous diffusion equation is established by using the fractional derivative.Matrix equations are obtained with series by the definition of Caputo differential,and obtain results.Comparing with the normal diffusion curve,this paper found that the numerical of pseudo pressure and pseudo pressure derivative in anomalous diffusion model is high,and response time delay.Finally,based on the anomalous diffusion model of fractured horizontal wells in fractal tight gas reservoirs,the double logarithmic curve is calculated and plotted by input parameters,and the characteristics and intrinsic causes of each flow stage are analyzed.The fractal dimension,the anomalous diffusion index,the artificial crack length and the distance are changed,and the sensitivity analysis of the parameters is carried out.It is found that changing the fractal dimension of bedrock affects channeling and all the later stage,which is later than the fractal dimension of fracture.