摘要:
塔里木盆地深层烃源岩主要是指埋深大于4000 m的寒武—奥陶系海相碳酸盐岩和三叠—侏罗系陆相泥岩、碳质泥岩和煤。研究表明,塔里木盆地深层烃源岩可溶有机组分的碳同位素组成具有母质继承效应,寒武—奥陶系海相腐泥型烃源岩可溶有机组分的碳同位素组成一般小于-28‰,而三叠—侏罗系陆相腐殖型烃源岩可溶有机组分的碳同位素组成一般大于-28‰。对于高演化的寒武—奥陶系海相深层烃源岩而言,在热力作用下,其可溶有机组分的碳同位素组成普遍发生强烈逆转,并出现饱和烃>芳烃>非烃>沥青质的完全反序分布现象,显示出深层环境下高演化烃源岩可溶有机组分的碳同位素组成特征。
Abstract:
In Tarim Basin, the deep source rocks, with depth deeper than four thousand meters, include the Cambrian and Ordovician marine carbonate rocks, the Triassic and Jurassic terrestrial mudstones, carbargillites and coals. The results show the carbon isotope inherited effect of parent materials for the soluble organic components of deep source rocks in Tarim Basin. For the soluble organic components of the sapropelic type of the Cambrian and Ordovician source rocks, its carbon isotopic compositions are ordinarily lighter than -28‰. On the contrary, for the soluble organic components of the humic type of the Triassic and Jurassic terrestrial source rocks, its carbon isotopic compositions are usually heavier than -28‰. Because of the effects of heating on the soluble organic components of the Cambrian and Ordovician marine deep source rocks, its carbon isotopic compositions have apparently reversed distribution. Especially, there are totally reversed distribution in some samples, that is the distribution of δ13C values of the group components are as follows: saturated hydrocarbons﹥aromatics﹥non-hydrocarbons﹥asphaltenes. It is a characteristic of carbon isotopic composition for the higher evolution source rocks in deep environments.