Effect and Analysis on Cr3+ Gel Improving Profile Control in Alkalescent lkaline/Surfactant/Polymer (ASP) Flooding

摘要

The produced fluid emulsification and producing system scale have always been one of the most difficult problems in NaOH/surfactant/polymer flooding. 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 emulsification and producing system scale have 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 and compatibility condition between Na2CO3/surfactant/polymer flooding and polymer gel are studied, and pilot test has been used to judge its availability in 2-1-P56 well of Daqing oilfield. 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. The fluid entry in high permeability layer is decreased from 100% to 64.9%, and fluid entry in low permeability layer is increased from 0% to 35.1%. The profile control of injection well is effectively improved.