Study On The Optimization Of High-concentration Polymer Flooding Of The First-order Oil Reservoir At The Late Stage Of Polymer Flooding In Sabei Development Block

The first-order oil reservoir of north-two-east eastern block in Sabei development block has entered into the conventional polymer flooding stage since2003.The water cut increased continuously with the increment of the polymer injection area, the remaining reservoir which was suitable to the polymer flooding decreased every year. Compared with the conventional polymer flooding, the higher concentration polymer flooding has stronger shearing resistance, stronger viscoelastic behavior, larger resistance coefficient and residual resistance factor. It has been an effective way to further enhance the oil recovery.In the paper, the geologic feature, the sedimentary feature, the water out condition and the remainder oil pattern of the first-order oil reservoir in north-two-east eastern block were analyzed. Optimizing programs about the concentration, the molecular weight, the slug combinations and the converted time of the higher concentration polymer solution were established. Using the physical simulation experiments, the concentration, the molecular weight, the slug combinations and the converted time of the higher concentration polymer solution were optimized. According to the dynamic and static characteristics of north-two-east eastern block, the fine geological model was established by using the Petrel software, and the permeability, the porosity and the effective thickness were calculated by using the phased interpolation. Using the viscosity modifier formula, the viscosity- concentration curve of higher concentration polymer solution was corrected, the elasticity of higher concentration polymer solution could be considered. The programs about optimizing the injection velocity and the usage of the higher concentration polymer solution were also established. Using the corrected viscosity-concentration curve and the Eclipse numerical simulation software, the injection rate and the usage of the higher concentration polymer solution were optimized.The injection parameters of the higher concentration polymer solution of the first-order oil reservoir in north-two-east eastern block were optimized in this paper which can provide a theoretical basis for the rational development of the block. It has an important significance for improving the potential capacity and the development effect of the first-order oil reservoir in the north-two-east eastern block.