Optimization Of Polymer Flooding Scheme In X 13 District Based On Pore Structure

Since Daqing Oilfield to carry out polymer flooding,through the refinement of the layer system,reducing distance of the well spacing,fine tracking,personalized adjustment,the recovery of the central well from 7.01 to 14.95 percentage points.To achieve a class of oil required to improve the recovery rate should reach the level and have a series of better development efficiency.In the summary of its dynamic changes and adjustment methods found that it has different development results of polymer flooding in those wells which have similar reservoir development.Whether the pore structure has an effect on the polymer flooding scheme and the effect of the stimulation treatment has not been carried out.So,we need study on optimization of polymer flooding based on pore structure in this paper.Firstly,the pore structure is classified according to the pore structure parameters and analyse the distribution of pore structure.Find the correlation between microporous structure and permeability.Combining the historical data of the block,determine the initial injection scheme.At the same tame,the injection parameters were determined by the method of polymer slug injection,and the determination of the suction range and thefluid entry profile.Through the establishment of the relationship between the suction range ratio and the amplitude of pressure rise,the best time to adjust the solution is found.The effects of various pore structures on the effectiveness of stimulation treatment were analyzed by taking the suction range and thefluid entry profile.Finally,in the process of polymer flooding,the polymer flooding scheme is determined,which is "high molecular weight and low injection rate in the early stage,low molecular weight and high injection rate in later period".The best time to reduce the concentration of polymer solution and increase the injection rate is the inflection point when the thickness of liquid is narrower.Based on the analysis of the effectiveness of stimulation treatment on the pore structure,one or two types of pore structure thickness ratio of more than 60%,the fracturing in low water cut stage.one or two types of pore structure thickness ratio of less than 60%,the fracturing in water cut descend or recovery period.Adjust the profile object to select one or two types of pore structure of the well of single layer breakthrough.For the one or two kind of well developed pore structure and the single layer breakthrough well,layering adjust the profile object should be adopted,avoiding the profile control liquid entering the non profile purpose layer.