Abstract:

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.

Key words: authigenic illite, K-Ar dating, sample selection, separating and purifying, interpretation and application