关键词: 超低界面张力驱油体系, 表面活性剂, 润湿性, 低渗透率油藏, 临界渗透率, 岩心驱替试验, 驱油效率

Abstract: An oil-displacement system of surfactant with ultra-low interfacial tension of 10^-3mN/m without alkaline and ploymer was prepared.This system is favorable for different wettability of rock.The test results identified that oil recovery increased gradually with the increment of permeability under different wettability of rock.When permeability got to a certain value,oil recovery sharply increased.Then oil recovery slowly increased or unchanged with the increment of permeability.The corresponding permeability is named as the critical permeability.The minimum pore throat radium and permeability for improving the activity of remaining oil drop decreased obviously with the increase of water wettability of rock.This means that the oil-displacement system with ultra-low interfacial tension is useful to enhance oil recover in low or ultra-low permeability reservoir.

Key words: oil-displacement system with ultra-low interfacial tension, surfactant, wettability, low-permeability reservoir, critical permeability, core flooding test, oil-displacement efficiency