Reservoir Characters And Intercalation Assessment Of The Lower2^nd And The Upper3^rd Members Of Shahejie Formation Of Ming1Block, Wenmingzhai Oilfield

Wenmingzhai Oilfield, is a typically complicated fault-block oilfield, whose recoverypercent has reached to30.49%through the twenty years of waterflooding development, withextremetly scattered remaining oil and high interlayer and plane producing degree. However,insufficient consideration has been paid to in-layer potential tapping, causing a comparatively highcapacity. Hence, unraveling in-layer heterogeneity of the study area will provide basis forpredicting remaining oil and hence adjust injection strategy accordingly. Besides, as fewresearches have been launched on diagenesis of Ming1Block, Wenmingzhai Oilfield, analyses ondiagenesis are hereby given to explain the formation of interbed and to reveal diagenetic controlon reservoir. This thesis is focused on the Lower2ndand the Upper3rdmembers of ShahejieFormation of Ming1Block, Wenmingzhai Oilfield. Comprehensively using assay data, such asconventional thin section and physical property, utilizing cast thin section as well as SEM(Scanning Electron Microscope), interpretating logging of more than230wells, systemeticresearches were carried out to reveal reservoir plane, interlayer and in-layer heterogeneities.Interbed recognition was emphasized and describe its vertical and plane distribution.Understanding and results about this research on the Lower2ndand the Upper3rdmembersof Shahejie Formation of Ming1Block are listed as follows：(1) It is indicated from the thin section that sandstones of the Lower2ndand the Upper3rdmembers of Shahejie Formation of Ming1Block are occupied by lithic arkose, followed byFeldspatic litharenite and arkose taking up only a small amount. The textual maturity andcompositional maturity of the Lower2ndmember are higher than those of the Upper3rdmember.Both of the two members have medium-high porosity and permeability.(2) Carbonate cement, feldspar, siliceous cement and clay mineral are widely spreadthroughout the study area. Carbonate cement include calcite, dolomite, and ferroan calcite andankerite, clay mineral includes illite, chlorite, I/S mixed layer and so on. Kaolinite is seldom seen in the study area. The sandstones have been undergoing mesogene period A. Intergranular pore isthe prime pore type. Intragranular pore and moldic pore become less. extra hole could be hardlyobserved(3) Data were pre-interpretated, including standardization of238loggings and corerelocation. Analysis of four characters of reservoir helped establish reservoir parameter models aswell as standard of net pay thickness.(4) Reservoir in-layer heterogeneity, interlayer heterogeneity and plane heterogeneity isstrong. A set of logging, including microelectrode (ML1&ML2), GR, SP, AC as well as welldiameter difference (d), which is applicable to the study area, is chosen to recognize interbedswithin rythmic layers. It is found that there are three types of interbed say, muddy interbed, limeinterbed and low-physical-property interbed, with the first one to be the dominant type. Theformation of interbed is explained from sedimentory and diagenetic aspects. Interbed in the studyarea is divided mainly into2types according to its scale and thickness. Interlayer heterogeneityand the distribution of porosity, permeability and net pay are closely related to sedementary facies.