应用TEM／EDAX研究粘土矿物的结构和成份特征

Study on Microtextural and Compositional Characteristics of Clay Minerals During the Late Diagenetic Stage Using TEM/EDAX Technique

利用ＴＥＭ／ＥＤＡＸ技术对粘土矿物作超显微结构观察和微区成分测定；表明蒙脱石、伊利石、高岭石和绿泥石在（００１）方向的晶面间距为１．３ｎｍ，１ｎｍ，０．７ｎｍ和１．４ｎｍ，月有明显的晶格像转化．其主要转化类型有：蒙脱石→伊利石、高岭石→绿泥石、伊利石→绿泥石和伊利石→高岭石在转化过程中产生的ＣＯ２、Ｈ＋和Ｈ２Ｏ会降低孔隙水ｐＨ，促进烃类运移和储层中次生孔隙形成．

Supermicroscopic observation and chemical composition in spot location using TEM/EDAX technique show that authigenic clay minerals like smectite, illite, kaolinite and chlorite display characteristic lattice layer spacing 1. 3, 1,0.7 and 1. 4nm respectively, parallel to (001), and also display distinct transition of lattice image of minerals. The major mineral trangitions are smectite→illite, kaolinite→chlorite, illite→chlorite and illite→kaolinite.The previous mineral transitions may release certain amount of CO2, H+ and H2O resulting in the decrease of pH in porewater, and, therefore, promote hydrocarbon migration in source rocks and secondary porosity generation in sandstone reservoirs.