高岭石和伊利石表面润湿性的分子动力学研究  

Molecular Dynamics Simulation of the Wettability of Kaolinite And Illite

作　　者：薛荣[1] 邓倩[1] 陆现彩[1] 张立虎[1] 张迎春[1] 

机构地区：[1]南京大学地球科学与工程学院,南京210023

出　　处：《高校地质学报》2015年第4期594-602,共9页Geological Journal of China Universities

基　　金：大学生创新训练计划项目和国家973课题(2012CB214803)资助

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泥质烃源岩的油气初次运移、土壤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,分别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:伊利石表面总是表现出亲水性,而高岭石的两种表面具有不同的润湿性,羟基面更加亲水;Na Cl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。Clay minerals are widely distributed in soils and sedimentary rocks. The surface wettability of clay mineral is closely relatedto primary petroleum migration in argillaceous source rocks, and mobility of organic pollutant in soils. Aiming at investigating theinfluences of surface wettability of clay minerals on the primary migration of hydrocarbon, this study constructs slit pores with walls ofkaolinite and illite basal surface. The spatial distribution of water and organic matters in the pore systems has been revealed usingmolecular dynamics simulations. The difference in wettability of clay mineral in pure water and in saline water has been disclosed.Different behaviors of hydrocarbon, alcohol, and benzene have also been revealed. It is indicated that the basal surface of illite alwayspresents hydrophilic as well siloxane surface of kaolinite is hydrophobic and hydroxyl surface hydrophilic. The presence of Na Cl altershydrophobic siloxane surface into totally hydrophilic. In addition, the organic matter with polar groups tends to be adsorbed ontohydrophilic clay surface although these molecules aggregate together in the pore water, which leads to their different distribution.

关 键 词：润湿性 分子动力学 粘土矿物 狭缝型孔隙 

分 类 号：P618.13[天文地球—矿床学]