杨华+张文正+彭平安+刘飞+罗丽荣新

摘要：含油盆地同一类型原油的精细划分与油源对比是有机地球化学研究的重要课题。大量样品的GCMS分析资料显示，与鄂尔多斯盆地中生界延长组湖相烃源岩的17α（H）C30重排藿烷（C*30）相对丰度的变化特征相耦合，原油的C*30相对丰度也表现出了较为明显的差异性与规律性，并且C*30相对丰度的变化与重排甾烷、C29Ts 、Ts等具有良好的关联性。因而，以C*30相对丰度为主要依据，进行C*30/C29降藿烷值C*30/C30藿烷值、C29Ts/C29降藿烷值C*30/C30藿烷值等图解分析，可将中生界湖相油型油细分为异常高的C*30相对丰度、较高—高的C*30相对丰度和低C*30相对丰度等3类。在此基础上，开展油岩的甾烷、萜烷生物标志物的分布特征及相关参数、单体烃碳同位素组成等的对比，进一步结合烃源岩的发育特征、成藏组合特征等进行综合分析。结果表明：长7优质烃源岩（油页岩）是盆地中生界的主力烃源岩，长7、长9黑色泥岩是次要烃源岩，长6、长8暗色泥岩对油源的贡献有限。中生界油源供给呈“一源主导、多源参与”的特征。这一认识对于盆地中生界资源评价与进一步勘探具有指导意义。

关键词：有机地球化学；17α（H）重排藿烷；生物标志物；单体烃碳同位素；油源对比；烃源岩；鄂尔多斯盆地

中图分类号：P618.13；TE122.1+14文献标志码：A

Oil Detailed Classification and Oilsource Correlation of Mesozoic Lacustrine Oil in Ordos Basin

YANG Hua1，2， ZHANG Wenzheng1，3，4， PENG Pingan4， LIU Fei3， LUO Lirong3

（1. National Engineering Laboratory for Exploration and Development of Lowpermeability Oil and Gas Fields，

Xian 710018， Shaanxi， China； 2. Changqing Oilfield Company， PetroChina， Xian 710018， Shaanxi， China；

3. Research Institute of Petroleum Exploration and Development， Changqing Oilfield Company，

PetroChina， Xian 710021， Shaanxi， China； 4. Guangzhou Institute of Geochemistry，

Chinese Academy of Sciences， Guangzhou 510640， Guangdong， China）

Abstract： The oil detailed classification and oilsource correlation are important topics for organic geochemistry in petroliferous basins. Analysis with GCMS reveals that the relative abundances of 17α（H）C30 diahopanes （C*30） are various both in Mesozoic Yanchang Formation lacustrine source rocks and oils of Ordos Basin. Correspondingly， the contents of rearranged sterane， C29Ts and Ts are also different. Therefore， according to the abundance of C*30， such as the diagrams of C*30/C29 norhopane valueC*30/C30 hopane value and C29Ts/C29 norhopane valueC*30/C30hopane value， the Mesozoic lacustrine oil can be divided into three genetic types including exceptional richness of C*30， relative richness of C*30 and lower C*30 contents. By studying the distribution of sterane and terpane biomarkers in oilsource rock with relevant parameters， and carbon isotopic compositions of monomer hydrocarbon， based on source rock distribution and reservoir forming combination， it has been proved that Chang7 highquality sources are the main oil source rocks in Mesozoic reservoirs of Ordos Basin， and the black mudstones of Chang7 and Chang9 are the secondary source rocks， while the contribution of dark mudstone of Chang6 and Chang8 is limited. In conclusion， the Mesozoic oil supply is characterized by “one source is dominating， multiply sources are participated”. This study is significant in Mesozoic resource assessment and further exploration of Ordos Basin.

Key words： organic geochemitry； 17α（H）diahopanes； biomarker； carbon isotope of monomer hydrocarbon； oilsource correlation； source rock； Ordos Basin

0引言

鄂尔多斯盆地是中国典型的大型低渗透陆相油气盆地，中生界低渗透储层（特别是延长组低渗透、致密性碎屑岩储层）含油普遍，油气资源十分丰富[1]。长期的石油勘探揭示，盆地中生界含油层组多，从中侏罗统直罗组一直到上三叠统延长组底部的长10油层组均已发现工业油流（藏），含油层段在纵向上的最大跨度约1 000 m。……