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现代地质 ›› 2022, Vol. 36 ›› Issue (02): 742-754.DOI: 10.19657/j.geoscience.1000-8527.2022.199

• 油气勘探 • 上一篇    

鄂尔多斯盆地甘泉地区延长组长8段原油地球化学特征及来源

朱必清1,2(), 陈世加1,2(), 白艳军3, 雷俊杰2,3, 尹相东1,2   

  1. 1. 油气藏地质及开发工程国家重点实验室,西南石油大学,四川 成都 610500
    2. 西南石油大学 地球科学与技术学院,四川 成都 610500
    3. 延长油田股份有限公司,陕西 西安 710000
  • 收稿日期:2021-11-05 修回日期:2021-12-07 出版日期:2022-04-10 发布日期:2022-06-01
  • 通讯作者: 陈世加
  • 作者简介:陈世加,男,博士,教授、博士生导师,1964年出生,有机地球化学专业,主要从事油气成藏地球化学、非常规油气地质方面的研究和教学工作。Email:chensj1964@swpu.edu.cn
    朱必清,男,硕士研究生,1997年出生,石油地质学专业,主要从事油气成藏地球化学研究。Email:1304480374@qq.com
  • 基金资助:
    国家自然科学基金项目(41872165);国家自然科学基金项目(42002176);中国石油-西南石油大学创新联合体科技合作项目(2020CX030000);中国石油-西南石油大学创新联合体科技合作项目(2020CX050000)

Geochemical Characteristics and Source of Crude Oil in Chang 8 Member of Yanchang Formation, Ganquan Area, Ordos Basin

ZHU Biqing1,2(), CHEN Shijia1,2(), BAI Yanjun3, LEI Junjie2,3, YIN Xiangdong1,2   

  1. 1. State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation, Chengdu, Sichuan 610500, China
    2. School of Geosciences and Technology, Southwest Petroleum University, Chengdu, Sichuan 610500, China
    3. Yanchang OilField Co., Ltd., Xi’an, Shaanxi 710000, China
  • Received:2021-11-05 Revised:2021-12-07 Online:2022-04-10 Published:2022-06-01
  • Contact: CHEN Shijia

摘要:

通过系统采集鄂尔多斯盆地东南部甘泉地区原油、砂岩和烃源岩样品,分析了延长组长8段原油地球化学特征,明确了原油成因和来源。研究表明:长8段原油为正常原油,具有低黏度、低初馏点、低凝点和低含硫量的特征;生物来源为混合型输入,形成于弱氧化-弱还原环境,是生油高峰阶段的产物。根据C30重排藿烷和二环倍半萜类分布特征可将原油分为Ⅰ类和Ⅱ类原油,Ⅰ类原油主要分布于长81段,Ⅱ类原油主要分布于长82段。长9段和长8段烃源岩具低C24TeT/C26TT、高-异常高C30重排藿烷含量、低8β(H)升补身烷和8β(H)补身烷含量的特征,长7段烃源岩与之相反。油源对比结果表明,Ⅰ类原油为长7烃源岩贡献,Ⅱ类原油为长8和长9段烃源岩贡献。甘泉地区主要发育长82油藏,其西部原油为长8和长9烃源岩贡献,而东部原油主要为长9烃源岩贡献,长7烃源岩次之。研究认识到长8和长9烃源岩的烃类贡献可能是促使长82段较长81段富集的重要因素,对下步勘探有指导意义。

关键词: 鄂尔多斯盆地, 甘泉地区, 长8段原油, 原油地球化学特征, 油源对比

Abstract:

Through systematic collection of crude oil, sandstone and source rock samples from Ganquan in the southeastern Ordos Basin, the geochemical characteristics of Chang 8 crude oil in Yanchang Formation were characterized, and the origin and source of the crude oil clarified. We show that Chang 8 crude oil is the normal crude oil featured by low viscosity, initial boiling point, pour point and sulfur content. The Chang 8 crude oil have mixed organic matter sources, which were formed in a weakly reducing environment during the peak oil generation stage. According to the distribution characteristics of C30DiaH and dicyclic sesquiterpenes, the crude oils can be divided into type I and II: Type I crude oil is mainly distributed in Chang 81 reservoir, and type II crude oil is distributed in Chang 82 reservoir. The Chang 9 and Chang 8 source rocks are featured by low C24TeT/C26TT, abnormally high C30DiaH, high 8β(H)-homodrimane and 8β(H)-drimane, while Chang 7 source rock show the opposite features. Oil-source correlation shows that type I crude oil was sourced from Chang 7 source rock, whilst type II crude oil was sourced from Chang 8 and Chang 9 source rocks. The crude oils in Ganquan are mainly enriched in Chang 82 member, and Chang 82 reservoir in western Ganquan was contributed by Chang 8 and Chang 9 source rocks, while Chang 82 reservoir in eastern Ganquan was mainly contributed by Chang 9 (and minor Chang 7) source rocks. We recognize that the hydrocarbon contribution of the Chang 8 and Chang 9 source rocks may have been key to the crude oil enrichment in the Chang 82 member, which has guiding significance for future exploration.

Key words: Ordos Basin, Ganquan area, Chang 8 crude oil, geochemical characteristics of crude oil, oil source correlation

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