Research on S/P combinational flooding technology and its application in Fault Block Hainan 3

Polymer microsphere/surfactant flooding technology was investigated based on the specific characteristics of oil reservoir in Fault Block Hainan 3, Liaohe Oilfield.By means of indoor physical simulation experiments, the effects of polymer microsphere concentration, surfactant concentration and slug size on polymer microsphere/surfactant flooding were analyzed and their basic parameters were optimized.It is indicated that the optimal mass fraction of surfactant complex in polymer microsphere/surfactant flooding used in Fault Block Hainan 3 is 0.007 5% betaine 17+0.01% surfactant 6501, and that of polymer microsphere is 0.30%.The polymer microsphere/surfactant flooding effect is more affected by the slug size.With the increasing of slug size, the increasing amplitude of recovery ratio declines gradually after the recovery ratio reaches 26.12%.The optimal size of injection slug is 0.35 PV.After this technology was applied in Fault Block Hainan 3 during 2015, interim cumulative oil incremental was over 10 000 t.It is indicated that polymer microsphere/surfactant flooding technology is extensively promising to apply in middle and low permeability oil reservoirs in the late stage of water flooding development.