Study On Physical Properties Of Tight Reservoirs And Productivity Prediction Of Fractured Horizontal Wells

Tight oil is a kind of unconventional oil and gas resources.The pore structure of tight reservoir is complex and the pore size reaches sub-micron-nanometer level.The fluid percolation process in reservoir is complex.The law of fluid percolation is very different from that of conventional sandstone reservoir.The existing basic theory of percolation can not accurately characterize and describe it.According to the reservoir characteristics of tight reservoir,based on the laboratory experimental study of the petrological characteristics,pore throat characteristics and basic percolation characteristics of tight reservoir,the percolation law of multi-stage fracturing based on horizontal wells is studied,the productivity prediction model of multi-stage fracturing horizontal wells is established and the influencing factors of productivity are analyzed.In this paper,the basic properties of tight reservoir are obtained by mineral analysis,scanning electron microscopy and high pressure mercury pressure experiments,and the pressure sensitivity effect,threshold pressure gradient and dynamic capillary force effect of Chang 7 reservoir are found.A two-hole and two-permeability oil-water two-phase percolation model considering the threshold pressure gradient of oil-water phase,stress sensitivity of reservoir,dynamic capillary force effect and failure of fracture conductivity is established and productivity is calculated.Finally,combined with field data,the factors affecting productivity are analyzed by software simulation method,and the optimum values of fracture parameters are given in order to provide some guidance for the effective development of the tight reservoir.