利用表面电势表征砂岩储层岩石表面润湿性

利用Stern双电层模型研究岩石表面荷电机制,考察岩石表面电势与表面基团的对应关系,从微观岩石表面基团的电性变化出发,分析归纳岩石表面电势与砂岩储层岩石表面润湿性间的关系。结果表明:岩石表面上分布有各类带电或中性基团,这些表面基团与液体分子之间存在相互作用力,包括范德华力、库伦力和氢键,油藏润湿性是这些分子间作用力的性质、大小和综合作用的宏观表现;岩石表面电势的正负和绝对值反映了岩石表面化学基团的电性和密度,可用于表征评价岩石表面润湿性。

Characterization of sandstone surface wettability by surface potential

The mechanism of rock surface charge formation was investigated by Stern electric double layer model. The relationship between the surface potential and the surface groups on rock surface was studied. On the basis of the micro-level charge change of rock surface groups, the relationship between the rock surface potential and the wettability of sandstone surface was analyzed. The results show that there are various groups with or without charges on the rock surface. The intermolecular forces between these surface groups and liquid molecules are van der Waals forces, Coulomb forces, and hydrogen bonds. And the wettability of sandstone surface is the macroscopic behavior of these intermolecular forces. The surface potential on rock surface indicates the charge and number of surface groups on rock surface, which can be used for evaluating the sandstone surface wettability.