摘要
我国原油主要产自中、新生代陆相地层,除高成熟原油和生物降解原油外,几乎都以“高蜡低硫”为特征(含蜡量一般大于15%,南阳凹陷和大民屯凹陷部分油田可达50%左右),因而显著不同于典型海相原油(含蜡量一般小于3%)。Hedberg(1968),Tissot 和 Welte(1978),Corbett(1955),Thomas(1982),Abelson(1963)以及 Lijmbach(1975)等人曾从不同角度对高蜡原油进行过研究,认为高蜡原油的生成与非正常海相条件下陆源母质的聚集有关。但是,对高蜡原油及其生油岩的地球化学特征,迄今还没有人系统地进行过研究,特别是高蜡原油生油岩的熟化机制,还基本上没有进行过研究。
Abstract
Geochemistry of superhigh-wax crude oils and soluble organic matters in source rocks of Nanyang and Damintun downwarps are studied.The content of wax and saturated hydrocarbon in oii is about 50%,80% respectively.From this,we could see that terrestrial lipoid has a great contribution to the wax-bearing petroleum,and the origin of the later might be related to the parent matters rich in phyto-wax.The similarity in distribution of normalalkanes from pyrolytic kerogen,from extraction of source rocks as well as from crude oil has proved that the super high-wax crude oil of Nanyang depressionare resulted from the sapropelic source rocks near the threshold depth of mature stage.Both Nanyang and Damintun downwarps were fault-confined lakes in Tertiary developed nearby with coniferous trees.This kind of forest had certainly con-tributed a great deal of materials rich in phytogenic-wax which give rise to the foundation for formation of superhigh-wax crude oil in these basins.The meta-akaline hydrological environment was favourable to the accumulation of terrestrial lipoid and phytogenic-wax in such a downwarp like Nanyang.
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