盐水离子组成对岩石表面润湿性的影响机理  

Effect mechanism of brine ion composition on rock surface wettability

作　　者：杨子浩[1] 尹太恒[1] 康帅 沈浩 董朝霞[1,2] 林梅钦 YANG Zihao;YIN Taiheng;KANG Shuai;SHEN Hao;DONG Zhaoxia;LIN Meiqin(Unconventional Petroleum Research Institute,China University of Petroleum(Beijing),Beijing 102249,China;School of Energy Resources,China University of Geosciences(Beijing),Beijing 100083,China)

机构地区：[1]中国石油大学(北京)非常规油气科学技术研究院,北京102249 [2]中国地质大学(北京)能源学院,北京100083

出　　处：《东北石油大学学报》2020年第2期113-118,I0008,共7页Journal of Northeast Petroleum University

基　　金：国家科技重大专项(2017ZX05009-004);中国石油大学(北京)科学基金项目(2462015YQ1104)。

摘　　要：采用宏观与微观实验结合的方法,研究低矿化度水中阳离子种类和浓度对岩石表面润湿性和原油采收率的影响;利用场发射扫描电镜,获得不同水驱阶段岩石表面的微观化学成分和形貌信息,探讨盐水-原油-岩石之间的界面行为。结果表明:低矿化度水引起的原油脱附是润湿性变化的根本原因;随离子强度的降低,原油与岩石表面的粘附功下降,岩石表面润湿性发生改变,原油从岩石表面脱附;Na^+比Ca^2+更能改善岩石表面润湿性,盐水进入小孔道的渗吸作用增强,扩大波及体积,可获得更高的原油采收率。The effect of cation kinds and salinity in low salinity water flooding on rock surface wettability and oil recovery were studied by the method of combining macroscopic and microscopic experiments.The field emission scanning electron microscopy(FESEM)analysis was utilized to get information of microchemical composition and morphology of the rock surface of different flooding stages.The interfacial behavior between brine-crude-rock was discussed.The experimental results show that the main reason for the change of wettability is the desorption of crude oil caused by low salinity water.As the ionic strength decreases,the adhesion work between crude oil and rock surface decreases,the wettability of the rock surface changes and the oil tends to desorb from the rock surface.Na^+can make the rock more hydrophilic than Ca^2+,and the effect of infiltration and absorption of salt water into the small channel is enhanced,and the swept volume is expanded,so as to obtain higher oil recovery.

关 键 词：低矿化度水驱 离子组成 润湿性 粘附功 自渗吸 

分 类 号：TE343[石油与天然气工程—油气田开发工程]