Study On Logging Evaluation Method For Reef Flat Facies Reservoir In Zhanhua Area

Complex sedimentary types and well developed transition rocks are the significantcharacteristics of reef flat facies reservoir in Zhanhua. In this area, the lithology, physicalproperty, and oil-bearing property vary largely both on the horizontal and vertical direction.Together with the strong heterogeneity, diverse reservoir space, as well as complex structuremake the formation evaluation difficult by using conventional methods. On the basis ofanalysis and identification of sedimentary microface characterisitics, and well logging, test,core data, this thesis carried out reservoir parameters modeling, effective evaluation and fluidtype identification.data A set of logging evaluation methods are established, which isapplicable to reef flat facies reservoir in Zhanhua.Zhanhua Reef flat facies developed three microfacies including bioberm, limestone bermdam and sandy limestone berm dam."Four-property" analysis of sedimentary microfaceindicates that: bioberm, limestone berm dam and sandy limestone berm dam mainlydeveloped reef limestone (cloud) rock, limestone and sandy limestone respectively, and thesedimentary microfacies corresponds the lithology well Various physical property distribution,strong heterogeneity and fracture development are important controlling factors of reservoirvalidity. The fracture of bioberm and limestone berm dam were well developed, includingtight type, pore type and fracture-pore type; the fracture of sandy limestone berm damwererarely developed, mainly tight type and pore type; reef flat facies favorable reservoir facenot only depends on microfacies, but also lies on the reservoir space characteristics ofsedimentary microfacies.In view of the characteristic that reef flat facies reservoir developed both pore andfracture, total porosity and fracture calculation model were established by using dual-porositycrossplot, dual-lateral log numerical simulation, effectively ensuring the calculation accuracy. On the basis of petrophysics experiment data, reservoir rock-electro relationship wasresearched within sedimentary microface. Through the adaptability analysis of saturationmodel of different microfacies, saturation computation model was selected and modelparameters were determined, therefore realizing effective calculation of reservoir saturation.Based on the "four-property" analysis of sedimentary microface, effective classificationmethod of effective reservoir were established, Further, based on the characteristics of matrixporosity and fracture porosity and logging response, the effective reservoir were divided intothree types: type I, type II, type III, The reservior classification correclates well withthereservoir capacity level.Through selecting sensitive parameters, including acoustic travel time resistivitylogging et al, multi-parameter fusion method and P1/2judging method, were adopted toestablish fluid identification intersection chart on the basis of microfacies, and further theidentification criteria of oil-water layerswas determined, which improves the effectiveness offluid property identification for complex carbonate reservoirs.