油气储层自生伊利石K-Ar同位素年代学研究现状与展望

作为油气成藏史研究中的一项新内容,油气储层自生伊利石K-Ar同位素年代学研究受到了广泛重视并取得了一系列重要进展。充分发育的伊利石成岩作用及伊利石成岩作用与油气注入事件具有成因联系是应用该项技术的前提条件。对于具有埋藏较浅或尚未固结成岩,虽埋藏较深但含有蒙皂石和/或伊利石/蒙皂石无序间层矿物,高岭石、绿泥石含量较高以及虽然自生伊利石发育但与油气注入事件没有成因联系等特征的砂岩储层,可能并不适用。其次对年龄数据必须结合样品特征和各种地质资料进行综合分析,合理运用并允许所测得的年龄数据具有一定的偏差。开展模拟自然风化过程的冷冻-加热样品解离试验和X射线衍射、透射电镜伊利石成因类型鉴定及其定量分析技术是提高该项技术水平的主要发展方向。

K-Ar isotopic chronological study of authigenic illite in reservoirs

As a new component in the research of reservoiring history,K Ar isotopic chronological study of authigenic illite in hydrocarbon reservoirs has made remarkable improvement.Diagenesis of well developed illite and its genetic relation with hydrocarbon infilling events are the prerequisites of application of this technology.Sandstone reservoirs that may not be suitable for using this technology include the shallowly buried or unconsolidated reservoirs,deeply buried reservoirs with smectite and/or random layer illite/smectite,reservoirs with relatively high content of kaolinite and chlorite,and reservoirs with well developed authigenic illite but having no genetic relation with hydrocarbon infilling events.Comprehensive analysis of age data should be performed in combination with sample features and various geologic data.The measured age data should be reasonably used and certain bias should be allowed.For improving the technique,the following researches and tests should be strengthened:repetitive freezing and thawing experiment to model natural weathering process;XRD and TEM illite genetic type identifications and quantitative analysis technique.