鄂尔多斯盆地陕北地区延长组长8暗色泥岩特征及其成藏意义

发布时间：2018-03-22 04:31

本文选题：陕北地区　切入点：延长组　出处：《西北大学学报(自然科学版)》2017年06期 　论文类型：期刊论文

【摘要】：鄂尔多斯盆地陕北地区延长组长8中部发育一套暗色泥岩,明确该套暗色泥岩的地球化学特征及生烃潜力,对该区延长组下组合的油气勘探具有重要意义。利用岩心刻度测井圈定长8暗色泥岩的分布范围,通过地球化学测试分析其沉积环境、生烃潜力及成藏意义。研究结果表明,长8暗色泥岩厚度2~10 m,分布广泛,主要形成于相对局限的汇水区,属弱还原陆相淡水环境。暗色泥岩的有机质丰度、生烃转化率较高,生烃母质以I,II1型为主,有机质热演化程度处于成熟生油阶段,总体评价为好烃源岩。研究区长8暗色泥岩具有C_(30)藿烷、C_(30)重排藿烷、重排甾烷丰度高,γ蜡烷丰度低,ααα20R构型C27,C28,C29规则甾烷呈"L"型分布等典型特征,与长7,长9的烃源岩特征差异明显。该套烃源岩的发现,为陕北地区延长组下组合岩性油藏的勘探提供了新思路。
[Abstract]:A set of dark mudstone is developed in the middle of Yanchang No. 8 in northern Shaanxi area, Ordos Basin. The geochemical characteristics and hydrocarbon generation potential of this set of dark mudstones are determined. It is of great significance for oil and gas exploration in the lower assemblage of Yanchang formation in this area. The distribution range of Chang 8 dark mudstone is delineated by core calibration logging, and its sedimentary environment, hydrocarbon generation potential and reservoir formation significance are analyzed by geochemical tests. Chang8 dark mudstone, with a thickness of 2 ~ 10 m, is widely distributed and is mainly formed in a relatively limited catchment area, belonging to a weakly reduced continental fresh water environment. The dark mudstone is rich in organic matter and high in hydrocarbon generation conversion. The thermal evolution of organic matter is at the stage of mature oil generation, and the overall evaluation is good source rock. The rearrangement sterane abundance is high, the 纬 -paraffin abundance is low, and the 伪伪伪 20R configuration C _ (27) C _ (28) C _ (29) regular sterane is a "L" type distribution, which is obviously different from that of Chang 7 and Chang 9 source rocks. It provides a new idea for the exploration of the lithologic reservoirs of the Lower Yanchang formation in northern Shaanxi.
【作者单位】：低渗透油气田勘探开发国家工程实验室;中国石油长庆油田分公司勘探开发研究院;中国石油集团测井有限公司油气评价中心;
【基金】：国家科技重大专项基金资助项目(2011ZX05044;2011ZX05001)
【分类号】：P618.13

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