A Laboratory Feasibility Study of Surfactant-Polymer Combinational Flooding in Low Permeability Reservoirs

Focused on the characteristics of bad water flooding effects and low recovery ratio in low permeability reservoirs, laboratory experiments for the adaptability evaluation of surfactant-polymer combinational flooding in low permeability reservoirs were carried out. Experimental results indicated that surfactant, which is the combined system of xinjiang petroleum sulfonate and cocamidopropyl hydroxysultaine, could enhance oil displacement efficiency by 20% and decrease the injection pressure. Meanwhile, polymer FP3640 only enhances oil displacement efficiency by 10%. Oil displacement experiments in heterogeneous low permeability cores, the results clearly showed that surfactant-polymer combinational flooding had better performance than surfactant flooding only. In addition, the injection strategy that the surfactant slug is injected into after the first polymer is the best way and enhances the recovery ratio by 17.74%. Therefore, the technology of surfactant-polymer combinational flooding can be adopted in the development of low permeability reservoirs.