Reservoir Characteristics And Evaluation Of Upper Jiufotang Formation In Naiman Depression

According to core observation and the data of cast thin section, scanning electron microscope, physical property and pore structure,the result shows the reservoir is fan delta front subfacies in Upper Jiufotang Formation of Naiman Depression. The lithology is mainly glutenite, conglomeratic sandstone, pebbled anisomerous sandstone. The main pore spaces are intergranular pores and intergranular dissolved pores. The physical property quality is poor. The reservoir belongs to middle-low porosity and low-ultra low permeability reservoir. For fast proximal deposit, it includes high nonresistance mineral and authigenic mineral is developed. At the same time quartz and feldspar overgrowth make porosity communication deteriorate further in epidiagenesis process. It leads to the coordination number of throat lowing,filtration ability pooring and intraformational heterogeneity increasing.Applying logging technology calibrated by core data, characteristic parameter―porosity, ermeability, shale content and oil saturation were scaled. Logging evaluation of reservoir was holded and Logging interpretation models with suitable local area are put forword. By the research of four-characteristic ralations,net pay thickness standard was established with combining producing test date. For wells in Naiman area, the effective thicknesses have been division and reservoir parameters have been interpreted.This text used relatively rich capillary pressure datas, after treatment by the J function, reservoir evaluation was classified. Reservoir was divided into three categories in Naiman area. The text summarized pore structure corresponding with three types of reservoir to identify the effective reservoir, divide the effective thickness. TypeⅠand TypeⅡare the effective reservoir. TypeⅢis dry layer or low productivity layer. Based on the reservoir classification,classification evaluation method of reservoir was applied in effective reservoir. Seven parameter including reservoir thickness, porosity, permeability are taken as evaluating parameters. Comprehensive classification evaluation has been applied to the evaluation of each reservoirs in Naiman area. The main oil layer and relationship between effective thickness of single well and the production was established. It realizes the quantitative evaluation of low permeability sandstone layers .