流动电势和电渗压力的连续测量实验研究及低矿化度下Onsager互易性的验证  

Verification of Onsager reciprocity in low salinity with successive measurements of streaming potential and electroosmotic pressure

作　　者：尹诚刚[1] 胡恒山[1] 王军[1] YIN ChengGang;HU HengShan;WANG Jun(Department of Astronautics and Mechanics,Harbin Institute of Technology,Harbin 150001,China)

机构地区：[1]哈尔滨工业大学航天学院

出　　处：《地球物理学报》2019年第7期2774-2783,共10页Chinese Journal of Geophysics

基　　金：国家自然科学基金项目(11734017和41674121)资助

摘　　要：连续测量岩心的流动电势效应和电渗效应,可以获得岩心的动电渗透率,并验证Onsager互易性.通常这两个实验的岩心夹持器需要使用不同的堵头,而更换堵头会导致岩心内流体的参数和边界条件发生变化.本文设计了新的岩心夹持器和激励压力源,避免了在测量过程中更换堵头,提高了两个实验的一致性.本文测量了蒸馏水、以及0.01、0.02、0.05、0.1、0.2、0.4和0.6mol/L氯化钠溶液饱和的10块岩心的流动电势效应和电渗效应,获得了动电渗透率,并验证了低矿化度下的Onsager互易性.结果表明,Onsager互易性在低矿化度下是成立的;对于高矿化度,电渗效应能够取代流动电势效应用于反演渗透率.Electrokinetic effects,which include the streaming potential and electroosmotic effects,refer to the coupling of fluid flow and electric current due to electric double layer phenomenon at the solid-liquid interface in a fluid-saturated porous medium. Successive measurements of streaming potential and electroosmotic pressure can be used to pick up electrokinetic permeability and verify Onsager reciprocity theorem. In previous studies,core-holders for streaming potential and electroosmotic experiments required different plugs. However,replacing the plugs can result in inconsistent core parameters between the two experiments. In this work,a new core-holder is designed to avoid the replacement of the plugs during the measurement process,ensuring the consistency of the measurement environments between two experiments. We also design a new pressure source,which separates the pressure source and core-holder on two different working platforms,thus suppressing the interference of pressure source noise. Based on the newly designed equipment,10 sandstone cores saturated with 8 solutions (distilled water,and 0.01,0.02,0.05,0.1,0.2,0.4,and 0.6 mol/L sodium chloride solution) are measured. The results show that Onsager reciprocity holds at low salinity. For the case of high salinity,the electroosmotic effect can replace the streaming potential effect in inversion for permeability.

关 键 词：动电耦合效应 流动电势 电渗压力 渗透率 Onsager互易性 

分 类 号：P631[天文地球—地质矿产勘探]