The Research Of Cycle Alternate Polymer Waterflooding In Sazhong Development Area

Since 1996 the polymer waterflooding in Sazhong development area genera oil layer put into industrial application, has experienced from points, high marks to the ultra-high and from normal concentration to high concentration of research promotion process, the enhanced oil recovery increased. But look from the oil used in the process of the polymer injection condition, longitudinal permeability differences on single well layer and relatively poor reservoir properties, they use situation is not ideal. In recent years, research unit of alternating injection were studied, it is concluded that the alternating injection can improve the oil recovery efficiency, but also can save polymer dry powder consumption. According to the goals of oil displacement “520”of Daqing Oilfield Limited Company and "four most" requirements, selecting the no.2 injection plant in Sazhong development area as tracts, developing alternating injection experiment of different molecular weight and concentration, exploring the new way of further enhanced oil recovery and save dry powder.Based on the description of reservoir of tracts, systematic analysis of genera reservoir characteristics, reservoir distribution, reserves are now well pattern of use condition and remaining oil potential. Through the cycle of different molecular weight polymer polymer injection alternately, combined with such as fracturing, separate injection, profile control measures, improve the degree of thin poor reservoir filling ability and use, efficient use of polymer, reduces the cost of polymer, to further improve the block development effect. The enhanced oil recovery has been improved to 12%, saving the cost of chemicals by 21.7%.The test results can be applied to the blocks of polymer flooding industrialization of the major reservoir which well spacing is125 m, Under the premise that does not affect the final recovery efficiency, cut down the cost of polymer, reduce cost, reflect the maximization of economic benefit, it has guidance for the research and application of main layer of close spacing and the second type reservoir alternating injection.