Double Action of Cr~(3+) Gel on Modifying Profile and Removing CaCO_3 in ASP Flooding

摘要

To decrease fluid emulsification and system scale caused by NaOH/surfac-tant/polymer flooding, a pilot test of Na_2CO_3/surfactant/polymer flooding was devel-oped in Daqing Oilfield. The results show that the two problems mentioned above were controlled, but scale in the injecting system is becoming a new technical problem and the scale aggravates reservoir heterogeneity. By analyzing the scaling mecha-nism and the properties of the profile control agent, the study presents technique of Cr~(3+) polymer gel for improving the fluid sucking profile of an injection well in Na_2CO_3/surfactant/polymer flooding. The optional formula, property evaluation, and compatibility condition between Na_2CO_3/surfactant/polymer flooding and polymer gel were studied, and a pilot test was used to judge the availability of Cr~(3+) polymer gel in 2-1-P56 well of Daqing Oilfield. The study shows that polymer gel functions include scavenging and blanking off high permeability zone. The scale of the instrument of injection, pipes, and well wall is thoroughly explained. The fluid entry in the high-permeability layer decreased from 100 to 64.9%, and fluid entry in the low-permeability layer increased from 0 to 35.1%. The profile control of the injection well was effectively improved.