黔北坳陷小草坝古油藏储层沥青成因及演化

发布时间：2018-01-12 11:19

本文关键词：黔北坳陷小草坝古油藏储层沥青成因及演化　出处：《石油实验地质》2017年01期 　论文类型：期刊论文

【摘要】：黔北坳陷小草坝泥盆系古油藏储层沥青充填于生物碎屑白云岩的溶蚀孔洞、晶间孔及裂缝中,储层沥青为固态,沥青等效镜质体反射率在4.08%~4.14%之间,在有机溶剂中基本不溶解。沥青正构烷烃轻重比较高,一般介于1.5~9.0之间,前峰优势显著;多数沥青样品的萜烷中三环萜丰度相对于霍烷具有明显优势,这些样品甾烷中C_(21)孕甾烷和C_(22)升孕甾烷丰度相对于C_(27)-C_(29)甾烷同样具有明显优势。沥青及沥青包裹体不发荧光,红外光谱中无脂族基团和含氧基团吸收峰。沥青的物理、光学性质及地球化学特征表明其经历了高温热演化,为热裂解成因。沥青的甾萜烷参数和碳同位素组成与筇竹寺组、龙马溪组烃源岩区别明显,而沥青碳同位素与上古生界烃源岩有很好的可比性,表明沥青的油源来自上古生界烃源岩。成藏史恢复表明,古油藏于三叠纪中晚期形成,白垩纪早期深埋裂解形成固体沥青,燕山-喜马拉雅期抬升暴露至地表。
[Abstract]:The asphalt of the Devonian paleoreservoir in Xiaocaoba depression of Qianbei depression is filled in the dissolution hole of bioclastic dolomite, intergranular pore and fracture, and the reservoir asphalt is solid. The equivalent vitrinite reflectance of asphalt is between 4.08% and 4.14%, which is basically insoluble in organic solvent. The trichloroterpene abundance in the terpenes of most bitumen samples is superior to that of the octadecane. In these samples, CST21) pregnenosterane and CST22) have the same obvious advantage over CSP 27C / C ~ (29) sterane. The bitumen and its inclusions do not emit fluorescence. Absorption peaks of aliphatic and oxygen-containing groups in IR spectra. The physical, optical and geochemical characteristics of asphalts indicate that they have undergone high temperature thermal evolution. The steroterpene parameters and carbon isotopic compositions of asphalt are obviously different from those of Qiongzhusi formation and Longmaxi formation, while the carbon isotopes of bitumen are comparable with those of upper Paleozoic source rocks. It is shown that the oil source of asphalt comes from the source rock of Upper Paleozoic. The recovery of accumulation history indicates that the paleo-reservoir was formed in the middle and late Triassic, the deep burying and cracking formed solid asphalt in the early Cretaceous, and the Yanshan-Himalayan uplift was exposed to the surface.
【作者单位】：中国石油杭州地质研究院;长江大学;
【基金】：中国石油天然气股份有限公司科技项目(2012B-0504)资助
【分类号】：P618.13
【正文快照】： 在中国南方海相层系中发现众多古油藏,这些古油藏主要分布于江南—雪峰山隆起、黔中隆起周缘、秦岭—大别造山带前缘,从震旦系到中上三叠统所有海相层系均有发育,以震旦系—下古生界较多。其中,规模较大、研究较多的有麻江、瓮安、凯里、泰山、岩孔、大厂等古油藏[1-5]。这些

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