The Characterization Of Heterogeneity Of Chang 8 Tight Sandstone Reservoir In H3 Area Of Ji Yuan Oilfield

Using the core,well logging,Cast sheet data and Scanning electron microscopy,based on the stratigraphic division andcorrelation,and sedimentary microfacies,this paper focuses on the H8 area of Jiyuan Oilfield Chang 8 oil groupmacro and micro heterogeneity.Researches showed that the delta front subfacies develope duringsedimentary period of Chang 8,including underwater diversion channel,underwaternatural levee,branch Bay.The study find that reservoir rock types of Chang 8 inJiyuan area is mainly lithic feldspathic sandstone and feldspathic sandstone,with high maturity structure and low composition maturity.The reservoir ofresearch area experiences compaction,cementation,dissolution,metasomatism and rupture and so on,totally in the middle diagenetic A stage and partly in the B stage.The reservoir space is mainly composed of intergranular pores and dissolution holes.The main value of reservoir porosity is distributed in the range of 10% ~ 12%.The main value of permeability is distributed in(0.4 ~ 0.8)× 10-3?m2,and the reservoir type is low pore-Ultra low porosity and low permeability-ultra low permeability reservoirs.The heterogeneity of reservoirs in the research areais elucidated from macroscopic and microscopic heterogeneity,and the macroscopic heterogeneity of the reservoir is quantitatively represented by fuzzy clustering analysis.It is concluded that the macroscopic heterogeneity of the study area is the Class1 and 2 are mainly distributed in the middle of the underwater distributary channel.The Class3 and 4 are mainly distributed in the underwater diversion channel flank.Finally,the main factors influencing the reservoir heterogeneity in the study area are sedimentary microfacies,diagenesis and tectonism.