Study On Comprehensive Evaluation Method Of Profile Control And Displacement Effect In Extra High Water Cut Stage Of Sandstone Reservoir

After the sandstone oil field enters the ultra-high water cut stage,the effect of profile control is getting worse and worse.The use of profile control and flooding can better realize the increase of oil and precipitation,the increase of oil recovery and the decrease of decline rate.Because of the different percolation mechanism and performance between profile control and profile control,it is necessary to study an evaluation method for the effect of profile control and displacement in sandstone oilfield.Based on the basic principle of seepage mechanics,the multi-source data in the field is analyzed systematically,and the evaluation indexes are preliminarily selected according to the screening principle.The grey correlation analysis method is used to study the correlation between each index and the effect of profile control and flooding,select the evaluation indexes that have significant influence,and establish an evaluation index system.The distribution range and evaluation standard of each index are determined by field statistics,and the evaluation system of profile control and flooding effect is improved.Apply analytic hierarchy process to determine the weight of each index.The fuzzy comprehensive evaluation principle is used to carry out multi-index comprehensive evaluation on the effect of profile control and flooding.Twelve sandstone reservoirs were selected for the evaluation index of the effect of profile control and flooding in the ultra-high water cut period,and comprehensive evaluation was conducted from three aspects: oil well,water well and well group.Among them,the evaluation indexes of oil wells include oil increase during the effective period of the measure,evaluation coefficient of decline rate,evaluation coefficient of water cut,and precipitation during the effective period of the measure;Water well evaluation indexes include starting pressure evaluation coefficient,permeability evaluation coefficient,fluidity ratio evaluation coefficient,and pressure index evaluation coefficient;The evaluation indexes of the well group include the effective period of the measure,the evaluation coefficient of the water absorption profile,the evaluation coefficient of the water injection utilization rate,and the breakthrough time of the tracer.According to the survey results of the oil production process in Shengli Oilfield,the production data of 481 wells corresponding to profile control and flooding were counted,and the distribution range and evaluation criteria of the evaluation indicators were obtained.The fuzzy comprehensive evaluation method is used to evaluate the effect of profile control and drive in extra high water cut stage.The results of field application show that the method has high accuracy and effectiveness.On this basis,taking Matlab 2017 b as the platform,through the object-oriented programming of Matlab,the evaluation software for the effect of profile control and flooding in the extra high water cut stage of sandstone oilfield is compiled.