Pressure Behavior Of The Multiple Fractured Horizontal Well Considering Fracturing Fluid Incompletely Flowback

The fracturing fluid in the stimulated area of the multiple fractured horizontal well in the low-permeability reservoirs can’t completely flowback,that is,some fracturing fluid remain in the reservoir and have impact on the reservoir.However,the current well test interpretation model does not take the factors that the fracturing fluid incomplete flowback into account,which leads to erroneous results in well test interpretation.In this paper,the trilinear-flow and five-region composite physical models considering the fracturing fluid retention zone are established.The trilinear-flow and fiveregion well test models are also established.And more,the inner region porosity coefficient and the permeability coefficient and the fracture region permeability coefficient are added to the model.The Laplace transform is used to obtain the analytical solution of the bottom pressure in the Laplace space.The solution in real space is based on numerical inversion method.The typical plot of the trilinear-flow is divided into five stages: wellbore storage,transitional period,bilinear flow,stratigraphic linear flow,pseudo-steady flow,and the five-region flow curve is one more stages than the trilinearflow curve.Sensitivity analysis of the fracturing region coefficient,width of the fluid retention zone and reservoir boundary of the trilinear-flow and five-region models are conducted.The analysis shows that the fracturing region coefficient will affect the level of pressure curve,and the size of fracturing zone will affect the flow stage of the curveThe establishment of this model has a certain value.Through the analysis of Curve shape can determine the effect of fracture treatment and diagnose the impact of fracture treatment on the formation.We can also analyze the boundary conditions of reservoir.For more,it is of practical significance to evaluate the fracture treatment of horizontal wells.