Technology Study On Improving ASP Flooding To Enhance Oil Recovery

The producing system and porous media scale have always been one of the most difficult problems in NaOH/surfactant/polymer flooding, which will not only increase the flow resistance, reducing fluid absorption, but also impacting on the production dynamic of oil wells, hence the effect of increasing oil can enhance. In order to decrease those influences on production, the pilot test of Na2CO3/surfactant/polymer flooding is developed in Daqing Oilfield. The results show fluid producing system scale has been controlled, but the injecting system scale aggravating reservoir heterogeneity is becoming a new technical problem. By analyzing scaling mechanism and the property of profile control agent, the author presents technique clue of Cr³⁺polymer gel of improving fluid entry profile of injection well in Na2CO3/surfactant/polymer flooding. The optional formula, property evaluation, gelling mechanism and compatibility condition between Na2CO3/surfactant/polymer flooding and polymer gel and the mechanism of removing scale are studied, and pilot test has been used to judge its availability in 2-1-P56 well of Daqing oilfield. By the data analysis, scaling in non-heterogeneous reservoir is conducive to improving the well fluid production profile. Scale exist positive and negative impact on profile absorption of water wells. The results shows polymer gel has double functions on scavenge and blanking off high permeability zone. The scale of the instrument of injection, pipes and well wall is thoroughly cleared up. Pilot test results show that Cr³⁺ polymer gel can remove the scale of injection system and formation, reduce injection pressure, improve profile absorption, and expand swept volume. Ultimately, increasing oil recovery is increased.