Study On Enhanced Oil Recovery In Sa Ertu Oil Layer Of Xingbei Oilfield

According to unified standards of Daqing oilfield, the geological reservoir of Xing Bei oilfield is divided into two categories. One is PuⅠ2～3 belonging to the first class oil layer and its geologic reserve accounts for 35.5%. The others belong to the third class oil layer. At present, the third class oil layer is flooded by water in every layer, containing 90.0% water. Besides, it is difficult to explore and oil recovery of water flooding is very limited.Aiming at deposition characteristics of Xing Bei oilfield (Sa Ertu layer), the property of deposit characteristics, reservoir condition, distribution of reserves, reservoir litho logy, porosity, crude oil properties, development status, and distribution of the remaining oil is analyzed. By experiment of physics simulation, the molecular weight, injection rate and injection volume of polyacrylamide in polymer flooding of Sa Bei oilfield is decided, 2500×10~4, 1.0m/d and 0.8PV, respectively. The effect of Injection way on flooding is studied. The injection sequence of different molecular weight, 3500×10~4→2500×10~4→1600×10~4, is decided. Oil recovery of water flooding is enhanced more than 10%. The flooding effect of ASP is studied in third class oil layer. The surfactant concentration of weak alkali ASP ranges from 0.0166% to 0.4% to reach ultra-low interfacial tension by laboratory evaluation of weak alkali ASP. The concentration of Sodium carbonate ranges from 0.4% to 1.2%. Weak alkali ASP system prepared by petroleum sulfonates also has ultra-low interfacial tension after many adsorptions. The oil recovery of the third class oil layer in Xing Bei oilfield is enhanced by 15% by ASP system (30mPa.s). The application has good prospects.