Study On The Distribution Of Remaining Oil In The Lower Section Of Guantao Formation Of The 29 Block In Taiping Oil Field

At present,most of the main oilfields in China have entered the stage of high or super high water cut and production decline.The recovery rate is relatively low,while a considerable amount of remaining oil is distributed scatteredly in water-flooding reservoirs with different scales and different forms.The main problems existing in block 29 of Taiping Oilfield are:low recovery,low productivity of single well,low utilization of total reserves and high degree of water cut,showing"three low and one high"characteristics.In order to effectively tap the remaining oil,enhance oil recovery,and maintain the stable production of the block,this paper studies the distribution law of remaining oil in the area.The results provide a geological basis for tapping the potential of remaining oil and enhancing recovery in block 29.The distribution of remaining oil is studied on the basis of four kinds of data,which are geology,logging data,laboratory data and production dynamic data.By using the method of"cycle correlation",subdivision and contrast study are carried out in the lower section of the Guantao formation in the study area.Then,the sedimentary microfacies and reservoir heterogeneity are studied,especially the development of interlayers and the distribution of porosity and permeability.Based on three-dimensional geological modeling technology,sand body and interlayer model,sedimentary microfacies model,facies-controlled reservoir parameter model and net-to-gross ratio model.Further more,reservoir numerical simulations are conducted on the study area to analyze the remaining oil distribution characteristics controlled by sedimentary rhythm,structural relief,interlayers,and injection-production well pattern.The remaining oil distribution law is summarized.The following conclusions are got:the distribution of remaining oil is controlled by the sand body rhythm,and the remaining oil is concentrated in the middle and upper part of the sand body.The activity of edge and bottom water leaded to the flooding of the reservoir and the remaining oil is concentrated in the middle and upper part of the small layer.The structural relief controls the distribution of the remaining oil,and the remaining oil concentrates on the high part of the local structure.The original geological reserves affect the remaining oil distribution,and the remaining oil is concentrated in small layers and single sand bodies with high original geological reserves.The remaining oil enriches in the sandstone area where the injection well pattern is difficult to control.The remaining oil is concentrated where the well network is difficult to control.The remaining oil is mainly distributed in the Ng_x1^2-3,Ng_x1^2-4,Ng_x2⁰,and Ng_x2¹ layers.