Analysis on the Effective Characteristic of Different Displacement Ways of Tertiary Oil Recovery in the Class II Reservoir of Sazhong Development Zone

Abstract

The first industrial tertiary oil recovery of the class II reservoir in the Sazhong Development Zone was the polymer flooding carried out in Block X at the end of 2002, and achieved noticeable effect. As the class II reservoir blocks were exploited one after another, by combining different geological structures and reservoir characteristics with distribution characteristics of remaining oil, the displacement modes successively went through polymer flooding, strong alkali ASP flooding, weak alkali ASP flooding, and salt-resistant polymer flooding, etc. Considering there are big differences in the geological structure, reservoir characteristics and layer combination of different class II reservoir blocks in the Sazhong Development Zone, and the development effects of different displacement modes are different as well; therefore, it is necessary to learn from the phased results achieved in typical blocks and leading pilot, on this basis, further conduct in-depth comparative study of the characteristics of effective rule and the changes of injection-production parameters of the class II reservoir blocks that have carried out tertiary oil recovery under different displacement modes, provide technical support and selection basis for betting modes up and down of the class II reservoir in the future, and it is of great practical significance to the realization of quality and efficiency improvement and sustainable development of the oilfield.