Productivity Prediction Of Fractured Reservoir

Tight reservoir rock particles tend to be small,strong compaction and high clay content,so the reservoir with small pore space and low permeability usually has no natural productivity or very low productivity.We often need to drill horizontal wells and fracturing.For this type of reservoir,fractures are not only the space for the oil and gas,but also an important flow channel of fluid,and have big influence on the productivity.Therefore,evaluating the fractures effectively and forecasting productivity have big significance on the exploration and development of the tight oil.In this paper,for the special circumstances of the fractures,we analyze the response characteristics of conventional logging data,FMI images and mud-logging data.Based on the logging attribute analysis,we extract the corresponding attribute parameters of fractures,and calculate the fracture development comprehensive index.And the degree of fracture development is divided into three levels: well development,general development and not development.We systematic analyze the relationship of the fracture development,organic carbon TOC content,rock brittleness index and productivity,and the reservoir is divided into three categories.Considering the effect of hydraulic fractures on the productivity,we have deprived the solutions for infinite formation and finite boundary formation,and have deprived the skin factor at any point along the horizontal well.And we use formation testing,oil-bearing occurrence,mercury injection experiments and core nuclear magnetic measurement to determine reservoir lower limit.Using flow unit method and macro porous method to determine the air permeability,and based on the experimental analysis of overburden pressure,we determine the overburden permeability,effectively improving the accuracy of permeability.For the size of the porosity.Oil saturation is calculated from the perspective of electrical and nonelectrical.And we calculate the fracture parameters for KGD and PKN model.Finally,based on the thickness,porosity,oil saturation and rock brittleness index,we build productivity index,and quantitative evaluate the productivity of reservoir.And analytical formulas are used to calculate the productivity for horizontal wells of infinite formation and finite boundary formation.The results show that compared with productivity index method,analytical formulas method is closer to the real situation of the formation,and the productivity are more accurate,showing the feasibility of the method...