Study on the Limit and Time of Separated Layer Injection of Polymer Flooding in Second-class Oil Layers

Abstract

Separated Layer Injection is widely used as an effective means of development in oilfields and the limit and time of Separated Layer Injection has a great influence on the development effect. According to the achievement of the fine reservoir description of research area, theory model is established. According to the oil displacement plan and development status of Second-class Oil Layers, the polymer flooding parameters are designed. Theory models with different permeability differential are designed, with the range of 1-6. Each model is simulated in different injection mode and separated injection timing. From the variation of water cut, remaining oil distribution and increment value of recovery rate, simulation results show that separated layer injection of polymer flooding should be applied when permeability differential reached 2. The best time of separated layer injection is related to the intensity of injection of high permeability reservoirs and low permeability reservoir. When the high permeability and low permeability oil layers have the same injection strength, Separated layer injection should be applied earlier. In the process of polymer flooding, water injection rate should not be excessively restricted on control layer injection, and it should be ensured in order to maximize the use of thick layer potential.