Research On Reservoir Fine Geological Modeling Of The East Third Section Of Cha-71 Fault Block In Chaheji Oilfield

At present,Chaheji oilfield has entered the stage of high water cut and high production rate.Controlled by factors such as fault development,reservoir heterogeneity,and poor oil layer connectivity,the remaining oil presents complex characteristics of overall dispersion and local concentration.The effect of water injection development becomes worse,and the contradictions between layers are prominent.In order to understand the distribution characteristics of remaining oil and improve the oil recovery rate,This article takes the eastern third member of the Cha71 fault block in the Chaheji Oilfield as an example,and comprehensively utilizes the basis of multi-scale data such as drilling,geology,and seismic to carry out fine reservoir geological modeling research.Based on sequence stratigraphy,the dissertation adopts the method of small-layer comparison of "cycle contrast,hierarchical control,well-seismic combination,and skeleton closure" to divide the East third Member of the study area into 4 oil groups and 38 small layers.Comprehensively using the petrological characteristics,sedimentary structural characteristics,fossil characteristics,and logging response characteristics of the study area to establish a sedimentary microfacies division indicator and logging facies identification system for the target interval in the research area.A total of four types of sedimentary microfacies were identified,including underwater distributary channel,underwater natural dike,underwater interdistributary bay and far sand dam.By clarifying the combination of the plane and section of the fault,combining the complexity of the fault occurrence,selecting an appropriate grid,and using the breakpoint data to correct the quality of the model,a high-precision 3D structural model of the study area is established.On this basis,the method of phased sequential indicating random simulation and phased sequential Gaussian(co-location)random simulation are used to establish the reservoir sand body model and attribute model.The model established by analysis shows that there is a good consistency between each small layer sand body model and the attribute model.At the same time,the accuracy of the model was verified by using facies-constrained and non-facies-constrained inspection,thinning well inspection,and probability distribution consistency inspection,which showed that the model constructed was consistent with the real geological conditions.Aiming at the high water cut stage in the late development stage of the research area,a geological model that conforms to the actual reservoir is established,and accurate structural maps of small layers and single sand layers are extracted to accurately delineate the oil-bearing area of small layers.Completing the numerical simulation with quantitative data such as development dynamics,it is predicted that the remaining oil in the study area mainly consists of unopened layer remaining oil,interwell remaining oil,structural control remaining oil and lithologic control remaining oil.