油气成藏年代学研究进展

Advances in geochronology of hydrocarbon accumulation

总结了国内外主要油气成藏定年技术和方法,并对其优、缺点做出了评述,认为油气成藏年龄确定已由过去的地质间接确定方法为主,发展到今天多种放射性同位素直接测年的新阶段;其中,在配备电子倍增器和UV激光纯化系统的高灵敏度质谱仪上,开展流体包裹体与自生钾长石Ar-Ar定年相结合的方法,实现了微区、微量和多期次油气充注精确定年,对叠合盆地油气成藏动力学建模和次生油气藏勘探均具有重要意义。同时指出,油气成藏年代学研究不仅需要多学科的交叉、渗透,而且需要发展更加具有代表性的成岩矿物定年和多种定年结果相互验证,为正确揭示不同盆地油气成藏年龄提供可靠依据。

Through summarizing the dating techniques and methods commonly employed in geochronology of hydrocarbon accumulation and evaluating their advantages and disadvantages, it is suggested that the indirect dating of hydrocarbon accumulation through geological methods be replaced by direct determination of hydrocarbon charging ages through radioactive isotope approaches. By using highly sensitive mass spectrometer equipped with electron multiplier and UV laser probe system, an integrated method of fluid inclusion with Ar/Ar dating of authigenic K-feldspar overgrowth has been successfully applied in precise dating of multiple-phase hydrocarbon charging of small amount in small areas, bearing significance for the kinetic modeling of hydrocarbon migration and accumulation and the exploration of secondary reservoirs in superimposed basins. It is also worthy of note that the geochronology study of hydrocarbon accumulation needs not only the intersection and interpenetration of multiple disciplines, but also the development of more representative diagenetic mineral dating methods that could be validated by the results of many other dating techniques, thus providing reliable bases for hydrocarbon accumulation dating in different sedimentary basins.