高岭石和伊利石表面润湿性的分子动力学研究.pdf

2015年12月,第21卷,第4期,594-602页
高校地质学报
Decembel2015,Vol.21,No.4,pp.594-602
Geological Journal of China Universities
DO:10.16108 l.Issn1006-7493.2015210
高岭石和伊利石表面润湿性的分子动力学研究
荣,邓倩,陆现彩,张立虎,张迎春
南京大学地球科学与工程学院,南京210023
摘要:粘土矿物广泛分布于地表土壤和沉积地层中,粘土矿物的表面润湿性与混质烃源岩的油气初次运移、土壞中污染物
的赋存形式和活动性等重要过程密切相关。本文着眼于探究泥质烃源岩中粘土矿物表面润湿性对初次排烃的影响,分別构
建了由高岭石和伊利石基面构成的狭缝型孔隙,采用分子动力学方法研究孔隙体系中有机分子癸烷和水的分布情况,分析
了纯水和低盐度孔隙流体条件下表面润湿性的差别以及烷烃、醇、苯等不同有机物在矿物表面分布的不同趋势。研究表
明:伊利石表面总是表現出亲水性,面高岭石的两种表面具有不同的润湿性、羟基面更加亲水:NaCl会使粘土的硅氧面由
部分亲水向完全亲水转变;另外、有机质的类型不同,极性有机分子在倾向于吸附在粘土表面的同时,还受其他有机分子
聚集的影响而呈现不同的分布。
关键词:润湿性:分子动力学:;粘土矿物:狭缝型孔隙
中图分类号:P619.23
文献标识码:A
文章编号:1006-7493(2015)04-0594-09
Molecular Dynamics Simulation of the Wettability
of Kaolinite And nlite
XUE Rong, DENG Qian, LU Xiancai, ZHANG Lihu, ZHANG Yingchun
School of Earth Seienees and Engineering, Nanjing University, Nanjing 210023, China
Abstract Clay minerals are widely istibutel in soils and seimentary rocks. The suface wettability of clay mineral is cosely related
to primary petroleum migration in argillaceous souree rocks, and mobility of organic pollutant in soils, Aiming at investigating the
influences of surface wettability of clay minerals on the primary migration of hydrocarbon, this study constructs slit pores with walls of
kaolinite and illite basal surface. The spatial istribution of water and organic matters in the pore systems has been revealed using
moleeular dynamies simulations, The difference in wettability of clay mineral in pure water and in saline water has been disclose
Different behaviors of hydrocarbon, alcohol and benzene have also been revealed. It is indicated that the basal surface of illite always
presents hydrophilic as well siloxane surface of kaolinite is hydrophobic and hydroxyl surface hydrophilic. The presence of Nacl alters
hydrophobic siloxane suace into to ally hydrophilic In addition the organic matter with polar groups tends to be adsorbed onto
hydrophilic clay surfaee although these molecules aggregate Together in the pore water, which leads to their different distribution
Key words: wellability; molecular dynamics simulation; clay mineral; slit pore
Corresponding author: LU Xiancai, Professor; E-mail: xcljun(@nju, eu. n
粘土矿物是地表系统中最为常见的矿物类型怀,2001;陆现彩等,2003)。在油气初次运移过
之一,因其比表面积大、表面能高而在多种地质程中,油气分子脱离烃源岩矿物或干酪根表面进
过程中发挥着重要作用(王晓蓉等,1997;鲁安入孔隙体系,从而进入油气成藏系统的输运体
收稿日期:2015-05-20;修回日期:2015-10-15
基金项目:大学生创新训练计划项目和国家973课题(2012CB214803)资助
作者简介:醉荣,女,193年生,本科生,地球化学专业;E- mail: xuerong nju@126.eorm
通讯作者:陆現彩,男,1972年生,教授,研究方向:地质微生物学和计算矿物学;E- mail: xc jun(enju.ecu.cn