The Study On Percolation Model And Production Evaluation Of Volume Fractured Horizontal Well In Tight Oil Reservoirs

In recent years,with the great progress of fracturing technology and the increasing demand of energy market,the exploration and development of tight reservoirs have become a global hot spot.Due to the relatively poor physical properties of tight oil reservoirs,horizontal well drilling and large-scale volumetric fracturing should be used in these reservoirs to enhance well productivity.How to establish a seepage model for volume fractured horizontal well and evaluate the productivity in tight oil reservoirs have great theoretical significance.In this paper,the nonlinear seepage characteristics of non-Darcy flow and stress sensitivity in tight oil reservoirs are firstly analyzed.Secondly,in combination with the fracture propagation pattern,the seepage field are divided for characterization and the seepage model based on stimulated pattern of volume fractured horizontal well is presented.Perturbation method and Laplace transformation are employed to get the pressure solution under constant rate and the production solution under constant pressure.The Stehfest numerical inversion is applied to draw the dynamic typical characteristic curve,the model is verified by analytical and numerical methods and the effects of related influential parameters on well pressure response and well production performance are investigated.Finally,the main controlling factors for production of volume fractured horizontal well in tight oil reservoirs are determined by orthogonal design method and the optimization method for volume fracturing parameters are formed.The research results indicate that the effect of non-Darcy flow and stress sensitivity can't be neglected in transient pressure and production performance analysis of volume fractured horizontal well in tight oil reservoirs;fracture conductivity and its half-length determine the initial and final productivity of the well,the impact of fracture number on well productivity gradually reduces and the effect of SRV width gradually increases;compared with conventional fracturing,the lower the matrix permeability,the more pronounced the effect of volume fracturing stimulation.The research content of this paper gives some guiding significance for the feasibility demonstration of volumetric fracturing and optimal design of fracture parameters in tight oil reservoirs.