Fractured Tight Reservoir Of Chang 3 In Weibei Experimental Study On Seepage Law And Productivity Of Single-Phase Fluid

With the rapid development of the economy,in order to meet the growing demand for oil and gas resources in China,tight oil and gas resources have become one of the focuses of China's exploration and development.The WB Chang 3 reservoir in the Ordos Basin is a typical shallow tight reservoir with poor reservoir properties,low productivity,and the development of natural bedding microfractures.The seepage shows typical nonlinearities that are greatly affected by the starting pressure gradient and stress sensitivity.Characteristics,as an important seepage channel for tight reservoirs,natural fractures gradually close with the pressure drop of the formation,making the reservoir physical properties worse.Therefore,it is urgent to carry out research on the mechanism of matrix and fracture seepage in this fractured tight reservoir to guide the development of actual reservoirs.Based on the existing research on tight reservoirs,this paper studies the seepage characteristics of the core and fracture cores of the WB Chang 3 reservoir and the experimental study of the fracture conductivity of the fractures in the actual development of the reservoir.the study.Based on the experimental test results,the steady-state productivity model of fracturing horizontal wells in accordance with WB Chang 3 reservoir characteristics was established.Based on the geological conditions of WB Chang 3 reservoir,a reservoir numerical simulation mechanism model was established.To conduct unsteady capacity research on fractured horizontal wells.The paper has achieved the following results:(1)Through the WB Chang 3 reservoir sensitivity experiment,it is determined that the critical flow rate of the experimental fluid is 0.25 mL/min?0.5 mL/min and the critical salinity is between 35000-40000mg/L;In the experimental study of seepage,the relationship between the pressure gradient and the fluidity and the regression equation were obtained.The experimental study on rock stress sensitivity was carried out to determine the relationship between the porosity and permeability of the matrix and the fracture and the effective stress.The matrix stress sensitivity coefficient and crack stress sensitivity coefficient are 0.01?0.1 MPa-1 and 0.1?0.2MPa-1,respectively.(2)Based on the experimental research,the fractal dimension is introduced to describe the degree of fracture development,and the steady-state productivity of multi-stage fracturing horizontal wells considering crack development degree,starting pressure gradient,matrix stress sensitivity coefficient and fracture stress sensitivity coefficient is established.The model is used to analyze the influence degree of each factor on the horizontal well productivity,and the influence degree of each factor is sorted and analyzed.(3)Through the experimental study on the conductivity of the WB Chang 3 reservoir pressure crack,it is determined that the proppant used in the actual fracturing construction is the ceramsite with higher sand concentration.(4)With reference to the geological data of the WB Chang 3 reservoir,a reservoir numerical simulation mechanism model consistent with the actual situation of the WB Chang 3 reservoir was established and tested for feasibility.On this basis,the six main factors affecting the steady-state capacity and production of horizontal wells are analyzed.Based on the horizontal well engineering parameters,the optimization design analysis of the influence parameters of horizontal well productivity is carried out to develop horizontal wells in WB Chang 3 reservoir.The way provides technical support.