Distribution And Controlling Factor Of Remaining Oil In Multilayer Fault Block Reservoir

Multilayer fault block reservoir has the characteristics of complex structure,fault development,numerous oil-bearing layers and so on.Recovery between layers makes large difference,It is difficult to understand the accumulation of residual oil,limiting the use of reservoir.The paper uses the data of regional geological,seismic,drilling,logging,core analysis and testing,oil field dynamics and other information.The ?stratigraphic–thickness? and other contrast methods were used to do the detailed stratigraphic division.The covariant body and the ant body,which are extracted by the seismic data,are used to identify the low-grade faults,and the characteristics are determined.The study shows that the structure and microstructure is complex but inherited.Microstructure highs are developed along the rise of the fault plate.Groove and peak are alternated at the waist.Beveled microstructures are developed at the east and the west area.The sedimentary facies study shows that the research area belongs to the delta plain surfaces,developed branch river,natural embankment,flood plain microfacies.The overall direction is North-East and the source is from northeastern.Structure model,sedimentary facies model and reservoir parameter model controlled by variance function is constructed using the modeling software and the results of geological description.Finally,The geologic model with complex structure,low-grade fault and multilayer fault block reservoir is obtained.Model validation shows that it has high accuracy and credibility.The production data of the whole area and single well are fitted using the numerical simulation software.The simulation results are basically the same as the actual production data,and the fitting degree is high.Quantitative simulation of the remaining oil saturation distributions shows that remaining oil controlled by construction;physical properties and development reached 90.8 million tons in total.Recovery reached 38.5%.Remaining oil distribution patterns are summarized.In fault controlling pattern,remaining oil is concentrated at the angle of fault and the high part of the structure whether it is curved opening fault,fan-shaped opening fault,or closed fault.In microstructure controlling pattern,minor peak and small broken nose microstructure tends to enrich remaining oil due to all directions push oil up.Minor low tends to gather water because all directions push oil down.In development controlling pattern,remaining oil is trapped between wells and place without wells.In physical controlling pattern,remaining oil is enriched in poorly permeable layer and strong heterogeneity layer.A set of research methods for studying the remaining oil of the multilayer fault block reservoir with low-grade fault is developed through the paper.