四川盆地东南缘南华系大塘坡组烃源岩特征及其油气勘探意义

发布时间：2018-06-22 12:37

本文选题：四川盆地 + 南华纪　；参考：《天然气工业》2017年06期

【摘要】：随着四川盆地的油气勘探不断向深层—超深层领域拓展,以及在盆地中部地区(川中)稳定继承性古隆起区域的中上元古界—下古生界储量超1×1012 m~3大气田的发现,该盆地深部古老层系烃源岩发育环境、烃源岩有机质生源构成及其成烃特征等备受关注。为此,基于前人的研究成果,开展了四川盆地东南缘南华系大塘坡组野外露头剖面观察和烃源岩样品的有机地球化学、有机岩石学分析测试。结果表明:(1)四川盆地东南缘在南华纪古城期和南沱期2个冰期之间发育拉张背景下的大塘坡组黑色页岩优质烃源岩,其厚度介于16~180 m,矿物组成以黏土矿物和碎屑石英为主;(2)大塘坡组页岩为高丰度过成熟腐泥型优质烃源岩,其低姥植比(0.32~0.83)、低伽马蜡烷丰度、高丰度三环萜烷以及相对高含量的C_(27)、C_(29)甾烷等特征,反映了低盐度强还原环境下藻类和细菌微生物为其主要生源构成。结论认为:(1)川中地区南华纪裂谷内可能发育大塘坡组烃源岩,加里东期之前的古隆起、古斜坡区域是源于大塘坡组烃源岩的古油藏或分散液态烃的有利聚集场所;(2)该盆地内部稳定区域有可能发现源于大塘坡组烃源岩的古油藏或分散有机质裂解气的规模聚集区。
[Abstract]:Along with the exploration of oil and gas in Sichuan basin expanding to deep and super deep field, and the discovery of gas fields in the Middle and Upper Proterozoic and Lower Paleozoic in the stable inherited paleouplift area in the middle part of the basin (central Sichuan), the reserves of the Middle and Upper Proterozoic have exceeded 1 脳 1012 mm3 gas fields. The development environment of the source rocks of the ancient strata in the deep part of the basin, the organic composition of the source rocks and the characteristics of hydrocarbon generation have attracted much attention. Based on the previous research results, the outcrop profile of Datangpo formation of Nanhua series in the southeastern margin of Sichuan Basin was observed and the organic geochemistry and organic petrology of source rock samples were analyzed. The results are as follows: (1) the black shale source rocks of the Datangpo formation developed between the two glacial periods in the Nanhua Jiangucheng and Nantuo periods in the southeastern margin of the Sichuan Basin. The mineral composition is mainly clay and clastic quartz. (2) the shale of Datangpo formation is a Gao Feng mature saprotic high quality source rock with low base-to-plant ratio (0.32 ~ 0.83) and low abundance of gamma-alkane. The characteristics of high abundance tricyclic terpene and relatively high content of C _ (27) C _ (29) sterane reflect that algae and bacteria are the main biogenic components in the environment of low salinity and strong reduction. The conclusions are as follows: (1) the source rocks of Datangpo formation and the paleouplift before Caledonian may be developed in the South China rift in central Sichuan. The paleo-slope region is the paleoreservoir derived from the source rock of the Datangpo formation or the favorable accumulation place for dispersed liquid hydrocarbon. (2) it is possible to find the paleoreservoir derived from the source rock of the Datangpo formation or the scale accumulation area of dispersed organic cracking gas in the stable region of the basin.
【作者单位】：中国石油勘探开发研究院;中国石油天然气集团公司天然气成藏与开发重点实验室;中国石油西南油气田公司;中国科学院大学渗流流体力学研究所;
【基金】：国家科技重大专项(编号:2016ZX05007-003) 中国石油天然气股份有限公司科技项目(编号:2016B-0602)
【分类号】：P618.13

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