Abstract: The velocity of the oil film scaling off the solid was used to estimate the surfactant to scale off the oil from the solid．The oil film shrank in the OP or Na₂CO₃ solution was researched．It shows that the oil shrank fastest in the OP－10 solution
and the shrink velocity is close in the OP－8 and OP－30.The oil shrank slowest in OP－40solution．In the Na₂CO₃ solution the area of oil do not change ，but the thickness of the oil changed．It indicates that the OP molecule adsorbs on the water －solid surface and reduces the water －solid interfacial tension．The balance in the contact point is broken and the oil film shrinks．In
the Na₂CO₃ solution，although the oil －water interfacial tension is changed，the solid－water interfacial tension is not changed so that the oil film area do not shrink．The Na₂CO₃ reacts with the petroleum acid and the surface－active substance distribute asymmetrically，so that it causes the interfacial tension gradient and non－uniform thickness．

Key words: Surfactant , Enhance oil recovery , Interfacial tension , Oil film shrink velocity , Alcali

摘要： 为了评价表面活性剂剥离固体表面油膜的能力，提出了采用油膜剥离速率作为评价驱油剂的一项指标，分别研究了油膜在OP类表面活性剂以及Na₂CO₃溶液中的收缩规律。结果表明油膜在OP- 10溶液中收缩的最快，在OP-8和OP-30中的收缩速率相近，在OP-40中的油膜收缩速率最慢；在Na₂CO₃溶液中只有油膜的厚度发生变化，而油膜的面积并没有变化。通过分析杨氏方程可知，表面活性剂(OP)吸附在水-固界面上降低了水-固界面张力 ,油膜在水平力的作用下收缩；Na₂CO₃只改变油-水界面张力，没有降低固-液界面张力，所以油膜没有收缩，而Na₂CO₃与原油中的酸性物质反应，生成的表面活性物质在油膜表面分布不均匀造成了局部的界面张力梯度，从而出现厚薄不均的现象。

关键词: 表面活性剂 , 提高采收率 , 界面张力 , 油膜收缩速率 , 碱