| 鄂尔多斯盆地西南部长8段砂岩沥青地球化学特征及其来源分析 |
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| 引用本文： | 王自翔,王永莉,孙则朋,朱深圳,汪亘,徐亮,孙丽娜.鄂尔多斯盆地西南部长8段砂岩沥青地球化学特征及其来源分析[J].海相油气地质,2017,22(2). |
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| 作者姓名： | 王自翔 王永莉 孙则朋 朱深圳 汪亘 徐亮 孙丽娜 |
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| 作者单位： | 1. 中国石油化工股份有限公司江汉油田分公司;2. 中国科学院地质与地球物理研究所兰州油气资源研究中心/中国科学院油气资源研究重点实验室;3. 中国科学院地质与地球物理研究所兰州油气资源研究中心/中国科学院油气资源研究重点实验室;中国科学院大学;4. 长江大学湖北省非常规油气协同创新研究中心 |
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| 摘 要： | 系统采集了鄂尔多斯盆地西南部地区延长组8段沥青砂岩,对砂岩沥青的地球化学特征进行了研究,探讨了沥青的母质特征、形成环境和成熟度。研究结果表明:(1)长8段砂岩沥青中高碳数的正构烷烃优势明显,规则甾烷中C_(29)含量相对较高,萜烷系列中四环萜烷含量较高,C_(24)四环萜烷/(C_(24)四环萜烷+C_(26)三环萜烷)的值为0.26~0.52,C_(23)三环萜烷/(C_(23)三环萜烷+C_(30)藿烷)的值分布范围为0.06~0.41,这些都指示研究区长8段砂岩沥青母质来源为混合型,并且陆源有机质贡献较大;(2)砂岩沥青中Pr/Ph为0.67~1.07,同时,沥青中检测出低丰度的β胡萝卜烷,说明沥青形成环境为弱氧化—弱还原环境,较低丰度的伽马蜡烷与C_(30)+藿烷指示沥青的母质形成于淡水或微咸水湖泊环境;(3)长8段砂岩沥青的C31藿烷22S/(22S+22R)、C_(29)甾烷20S/(20S+20R)、C_(29)甾烷ββ/(αα+ββ)和C_(29)重排甾烷20S/(20S+20R)均接近或已经达到平衡值,反映沥青为成熟沥青。将研究结果与已报道潜在烃源岩的生物标志化合物特征进行对比,显示出研究区长8段砂岩沥青主要来源于延长组7段烃源岩,表明长7段烃源岩是研究区最主要的烃源岩之一。
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| 关 键 词： | 鄂尔多斯盆地 延长组8段 沥青 烃源岩 生物标志化合物 油源对比 |
Geochemical Characteristics and Oil-source Correlation of Bitumen in Sandstone of Chang-8 Member in Southwestern Ordos Basin |
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| Wang Zixiang,Wang Yongli,Sun Zepeng,Zhu Shenzhen,Wang Gen,Xu Liang,Sun Li&#;na.Geochemical Characteristics and Oil-source Correlation of Bitumen in Sandstone of Chang-8 Member in Southwestern Ordos Basin[J].Marine Origin Petroleum Geology,2017,22(2). |
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| Authors: | Wang Zixiang Wang Yongli Sun Zepeng Zhu Shenzhen Wang Gen Xu Liang Sun Li&#;na |
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| Institution: | Wang Zixiang,Wang Yongli,Sun Zepeng,Zhu Shenzhen,Wang Gen,Xu Liang,Sun Li'na |
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| Abstract: | 21 bituminous sandstone samples of Chang-8 member in southwestern Orders Basin were collected, and the biomarkers of bitumen were detected by means of GC-MS. The compositional and distributional characteristics of biomarker compounds of bitumen samples were studied and the origin of bitumen is discussed. The result shows that:(1) The relative content of tetracyclic terpane to hopanes and C29 regular steranes to C27 are high, C24 tetracyclic terpane/(C24 tetracyclic terpane+C26 tricyclic terpane) ranges from 0.26 to 0.52,C23 tricyclic terpane/(C23 tricyclic terpane+C30 hopanes) ranges from 0.06 to 0.41, these data indicate that their organic parent materials are mixed ones and the higher land plants make a great contribution to the oil generation. (2) The low-content ofβ-carotane, gammacerane and C30+hopanes,and that the ratio of Pr/Ph is 0.67~1.07,indicate that the oil was formed under the weak oxidizing to weak reducing freshwater or brackish-water lacustrine environment. (3) Several ratios, including C31 hopanes 22S/(22S+22R),C29 sterane 20S/(20S+20R),C29 sterane ββ(/αα+ββ) and C29 diasterane 20S/(20S+20R), completely or almost completely reached such equilibrium value that it indicates the studied bitumens are mature. The results of oil-source rock correlation show that the geochemical characteristics of bitumen in sandstone of Chang-8 Member from southwest area of Ordos Basin are similar to those of the upper Triassic Chang-7 subsection, so it is proposed that the bitumen originated mainly from the Chang-7 source rock. |
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| Keywords: | Bitumen Source rock Biomarkers Oil-source correlation Ordos Basin |
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