Study On The Distribution Of Residual Oil In C78 Block Of Liaohe Oilfield

The fault block area of C78 is a thin oil area of waterflood development in C oil production plant of liaohe oilfield.In the process of development,there are three high levels,the reservoir interpretation is inconsistent with the production state,and the production capacity distribution is inconsistent with the structural understanding.Based on the existing problems in the block,this paper studies the distribution of the remaining oil in the S32 segment of the main layer to improve the production status of the block.The distribution characteristics of remaining oil in the block were explored from four entry points,and combined with the computer numerical simulation technology,the distribution rules of remaining oil in the third sand section of block C78 were studied under the condition of small error between the numerical simulation and the actual reservoir dynamic data,and the remaining oil accumulation area in the block was found.The results are as follows: 1)C78block sand three times for the fan delta front subfacies depositional environment,the development of underwater distributary channel microfacies,river mouth bar microfacies,distributary channel microfacies,frontal sheet sand microfacies,lake mud microfacies five sedimentary microfacies,including S33 period,when the west and east strong fault activities,wellblock in deep lake environment,S32,during the period of west and east fault relatively inactive,but provenance supply changes,repeated oscillation and the migration of the channel,the direction of the river channel and branch also has changed to a certain extent,S31 periods tectonic movement from stable deposition to the overall rise strongly,appear overlap sedimentary phenomenon,wellblock chronically exposed to the environment,Oxidation is strong.The reservoir of S3 in block C78 is mostly fine sandstone,which belongs to mesoporous and medium-permeable reservoirs with strong heterogeneity.On the plane,the sand body is deposited in the main channel area with a thick strip tiled.Longitudinally,because the ancient channel flows through here repeatedly,the riverbed is constantly changing,so the reservoirs are superimposed and interbedded.(3)the oil layer of block C78 is mainly affected by structural and lithologic factors.It is a structural and lithologic reservoir.The oil layer in the S31 oil group is only developed at the bottom near the denudation surface.The S32 II oil formation is affected by the fault,and the oil layer is developed at the structural height along the fault.(4)through the combination of dynamic data and reservoir numerical simulation,the distribution of remaining oil in block C78 is mainly affected by deposition,reservoir and boundary water,and the potential of remaining oil on the plane is concentratedin the fault area near the structural high point,the blank zone between Wells and the low permeability layer with serious interference between layers.And longitudinal,has a high potential for S32-Ⅰ 2,2 sandstone S32-Ⅱ group,relative to other horizon using this sandstone group is poor,so can be used as the development of the next step of remaining oil potential area.