无机盐离子对石英表面油-水润湿性的影响  

Effects of inorganic salt ions on the oil-water wettability of quartz surfaces

作　　者：孙成珍[1] 刘美 白博峰[1] 伍家忠[2] 史永兵 Chengzhen Sun;Mei Liu;Bofeng Bai;Jiazhong Wu;Yongbing Shi(State Key Laboratory of Multiphase Flow in Power Engineering,Xi’an Jiaotong University,Xi’an 710049,China;State Key Laboratory of Enhanced Oil Recovery,Research Institute of Petroleum Exploration and Development of PetroChina,Beijing 100083,China;Xi’an Changqing Chemical Engineering Group Co.Ltd.,Xi’an 710021,China)

机构地区：[1]西安交通大学,动力工程多相流国家重点实验室,西安710049 [2]中国石油勘探开发研究院,提高石油采收率国家重点实验室,北京100083 [3]西安长庆化工集团有限公司,西安710021

出　　处：《科学通报》2020年第25期2775-2782,共8页Chinese Science Bulletin

基　　金：国家杰出青年科学基金(51425603);国家自然科学基金(51876169)资助。

摘　　要：油藏岩石表面油-水润湿性对原油的开采具有重要影响,润湿性向亲水转变被认为是低矿化度水驱技术的主要机制,但是低矿化度水注入后岩石表面发生润湿性转变的微观机理目前依然存在很多争议.本研究针对极性分子在岩石表面的极性吸附,研究水中无机盐离子对石英表面润湿性的影响及其作用机理.研究发现,相同浓度下,NaCl溶液和KCl溶液的接触角基本相同;在浓度较低时,CaCl2溶液使三相接触角降低的幅度比NaCl溶液更大,Na2SO4溶液比NaCl溶液效果更明显;在较高浓度下,Na2SO4溶液的接触角与NaCl溶液相似.当离子浓度大到一定程度时,不同溶液的接触角都趋于15°左右,离子使吸附的极性分子基本都脱附,导致石英表面润湿性向亲水转变.基于石英粉末的Zeta电位测量和石英片表面的原子力显微镜(atomic force microscopy,AFM)粗糙度分析,提出了两种机理解释:(1)癸烷中的十八胺在油水界面质子化带正电,与水中阴离子相互吸引,降低了油水界面张力;(2)水中的阳离子在带负电的石英表面吸附,使石英片表面负电性减弱,并置换了部分石英表面吸附的十八胺分子,使石英表面亲油性减弱.The oil-water wettability in reservoir rock plays an important role in the recovery of crude oil.However,the mechanism of wettability transition on reservoir rock surfaces after low salinity water injection is still controversial.In this paper,the influence of inorganic salt ions in water on the wettability of the rock surfaces with the adsorption of polar molecules and its mechanisms were studied.Amines commonly found in crude oil were selected to represent base polar components in oil,and a highly idealized experimental model was used to exclude the influence of various components and other effects in crude oil.By measuring the oil-water contact angle on the quartz surface,the influence of various salt ion concentration in water on the wettability of quartz in the presence of base polar molecule in oil was obtained,and the mechanism of wettability alteration was analyzed by Zeta potential and AFM measurement.The experiment result showed that,the cleaned surface of quartz was water-wet,when 0.1 mmol/L octadecylamine was added to decane,the contact angle rose to about 42°,that is,the surface of the quartz became more oil-wet.When salts with different kinds and concentrations were added to water,the water contact angles decreased sharply with the increase of the concentration of ions.The contact angles of NaCl solutions and KCl solutions were basically the same at the same concentrations.However,at low concentrations,the CaCl2 solutions reduced the contact angles more than the NaCl solutions.The contact angles of Na2SO4 solutions were smaller than those of NaCl solutions at low concentrations,while the contact angles of Na2SO4 solutions were similar to those of NaCl solutions at higher concentrations.When the ion concentrations reached a certain level,the contact angles of different solutions all tended to be about 15°,which indicated that the ions desorbed basically all of the adsorbed polar molecules,leading to the change of wettability of quartz surfaces to be water-wet.The clean quartz powder was highly elec

关 键 词：润湿性 接触角 极性分子 离子 多相流动 

分 类 号：TE357[石油与天然气工程—油气田开发工程]