Classification Method And Potential Evaluation Of High Water-Consuming Zone

In order to solve the problem of high water-consumption zone in the late period of high water cut in shengli oilfield,this paper establishes the identification and classificatio n method of high water-consumption zone by using of numerical simulation method and statistical data.This paper also defines the effective measures of different types of high water-consumption zone,forms the potential evaluation technology of high water-consumption zone,and thus provides the basis for improving the effect of water flooding.Firstly,Based on the accumulation characteristics of shengli oilfield,and the change of the late for determining oil-water relative permeability curve,a conceptual model is established for 162.Using statistical method,each index is determined through the analysis of three indicators including the ratio of water absorption intensity,the ratio of water consumption and the ratio of water saturation,and the division standard of high-water consumption zone was established.By using Levenberg-Marquardt method,four factors including reservoir water content,permeability grade difference,subsurface oil viscosity and injector-production strength were taken into account comprehensively,and the high water-consuming zone formula in the block without mathematical model data was obtained.Secondly,analytic hierarchy process(AHP)is used to construct judgment matrix,and the weight of evaluation index of actual development unit is calculated by square root method.According to the regulation measures of separate zone water injection,the optimal segmentation method was selected to calculate the diameter of all attributes in the scheme,and finally the total diameter of the combination was obtained.Considering that the shengli oilfield is in the late stage of extremely high water cut and the water cut rate has reached more than 95%,the residual oil method is selected for injection allocation,and the typical well group of unit 1-3 in shengli district is analyzed with an example.Based on the concept of balanced displacement in reservoir engineering and the objective function of NPV and the constraint condition of the maximum and minimum liquid amount in each well,the optimized mathematical model of injection-production is established by combining genetic algorithm with mathematical modeling software.The results show that the control effect of separate zone water injection is better than the optimization of water injection and production in the typical well group of unit 1-3,shengli district.Finally,the response surface methodology method(RSM)and the central combined design method(CCD)were used to obtain a large number of experimental data.Based on response surface analysis,the main control factors for the regulation potential of high water-consumption zones were screened out.According to the main control factors,a numerical simulation model was designed to predict the development status and regulation effect of high water-consumption zones.The statistical regression method is used to establish the model of regulating potential of high water-consumption zone and the chart of regulating potential of high water consumption zone.