The ternary combination of polymer gel, microsphere and surfactant for conformance control and oil displacement to improve oil recovery in strong heterogeneous reservoir

The reservoir heterogeneity of Suizhong 36-1 oilfield is very obvious, the average permeability reaches 2000mD. Long-term water injection development leads to serious water channeling in high permeability layers, resulting in ineffective circulation of injected water and reduction of oil recovery. It is urgent to form an effective EOR method. In this paper, the oil displacement effect of different combination slugs including polymer gel, polymer microsphere and surfactant is evaluated by means of conformance control and chemical flooding. Three-layer heterogeneous 3-D plate model is used for oil displacement experiment. The experimental results show that the combination slug sequentially composed of polymer gel, polymer microspheres and surfactant have the best oil displacement effect with the oil recovery increment by 21.2% after the first water flooding. In addition, using the best slug combination for two rounds flooding, the recovery factor increased by 28.2% compared with the first water flooding. This paper provides some new insights for enhanced oil recovery in strong heterogeneity reservoir.