石油学报 ›› 2018, Vol. 39 ›› Issue (5): 491-503.DOI: 10.7623/syxb201805001

• 地质勘探 •    下一篇

酒西坳陷原油地球化学特征与成熟度分类

陈建平1,2,3, 魏军4, 倪云燕1,2,3, 陈建军4, 邓春萍1,2,3, 田多文4, 胡健1,2,3, 黄振凯1,2,3, 张蒂嘉1,2,3, 韩永科1   

  1. 1. 中国石油勘探开发研究院 北京 100083;
    2. 提高石油采收率国家重点实验室 北京 100083;
    3. 中国石油天然气集团公司油气地球化学重点实验室 北京 100083;
    4. 中国石油玉门油田公司 甘肃酒泉 735000
  • 收稿日期:2017-09-14 修回日期:2018-04-05 出版日期:2018-05-25 发布日期:2018-06-06
  • 通讯作者: 陈建平,男,1962年10月生,1983年获山东矿业学院学士学位,2003年获中国矿业大学(北京)博士学位,现为中国石油勘探开发研究院教授级高级工程师,主要从事油气地球化学研究工作。Email:chenjp@petrochina.com.cn
  • 作者简介:陈建平,男,1962年10月生,1983年获山东矿业学院学士学位,2003年获中国矿业大学(北京)博士学位,现为中国石油勘探开发研究院教授级高级工程师,主要从事油气地球化学研究工作。Email:chenjp@petrochina.com.cn
  • 基金资助:

    中国石油天然气股份有限公司科技重大专项课题(2013E-3301)资助。

Geochemical features and maturity classification of crude oil in the Jiuxi depression, Jiuquan Basin

Chen Jianping1,2,3, Wei Jun4, Ni Yunyan1,2,3, Chen Jianjun4, Deng Chunping1,2,3, Tian Duowen4, Hu Jian1,2,3, Huang Zhenkai1,2,3, Zhang Dijia1,2,3, Han Yongke1   

  1. 1. PetroChina Research Institute of Petroleum Exploration and Development, Beijing 100083, China;
    2. State Key Laboratory of Enhanced Oil Recovery, Beijing 100083, China;
    3. CNPC Key Laboratory of Petroleum Geochemistry, Beijing 100083, China;
    4. PetroChina Yumen Oilfield Company, Ganshu Jiuquan 735000, China
  • Received:2017-09-14 Revised:2018-04-05 Online:2018-05-25 Published:2018-06-06

摘要:

酒西坳陷属于典型的勘探程度非常高的含油气坳陷,目前已发现的原油主要分布于青西凹陷和鸭儿峡—老君庙—石油沟构造带。这些原油绝大多数为正常密度和黏度的中—高蜡原油,只有少量为中—高蜡稠油,具有典型湖相原油的地球化学特征,全油碳同位素δ13C值为-32 ‰~-30 ‰,生物标志物组成总体相似,但分布特征存在一定差异,可以分为3类不同类型或成熟度原油。第1类为低成熟原油,甾烷以规则甾烷为主,没有重排甾烷;规则甾烷以ααα-20R甾烷为主,C27、C28、C29甾烷呈不对称V型分布,C29甾烷20S/(20S+20R)和ββ/(αα+ββ)值一般小于0.4;萜烷以五环萜烷为主,Ts、C29Ts和C30重排藿烷低,伽马蜡烷较高。第2类为中等成熟原油,Pr/Ph值一般小于1.0;甾烷也是以规则甾烷为主,没有重排甾烷,但ααα-20S和αββ甾烷明显高于第1类原油,C29甾烷20S/(20S+20R)和ββ/(αα+ββ)值一般为0.40~0.55,C27、C28、C29 ααα-20R甾烷呈不对称V型分布,C27/C29比值一般大于0.6;萜烷分布特征与第1类原油类似,Ts/Tm一般小于0.5;甾烷/萜烷比值基本大于1.0。第3类为高成熟原油,Pr/Ph值一般大于1.0;甾烷以规则甾烷为主,但重排甾烷明显且含量变化大,αββ甾烷明显高于ααα甾烷,C29甾烷20S/(20S+20R)和ββ/(αα+ββ)值分别大于0.5和0.6,C29甾烷含量明显高于C27甾烷,C27/C29比值一般小于0.6;萜烷分布特征与前两类原油相似,但Ts、C29Ts和C30重排藿烷相对较高,Ts/Tm一般大于0.5,伽马蜡烷含量变化较大;甾烷/萜烷比值基本上小于1.0。

关键词: 酒西坳陷, 原油, 碳同位素, 生物标志物, 分类

Abstract:

Jiuxi depression in Jiuquan Basin is a typical well-explored petroliferous depression, where the crude oil that have been found is mainly distributed in Qingxi sag and the tectonic belt of Yaerxia-Laojunmiao-Shiyougou. The vast majority of crude oil is medium-high waxy crude oil with normal density and viscosity, while only a small amount is medium-high waxy heavy oil, and all is characterized by the geochemical characteristics of typical lacustrine crude oil with the whole-oil carbon isotope δ13C ratio of -32 ‰——30 ‰, overall similar biomarker compositions and distribution characteristics. However, there are some differences, based on which this study has classified three types of crude oil with different categories or maturities. The first type is low-maturity crude oil, of which the steranes are dominated by regular steranes and no diasterane exists. Regular steranes mainly consist of ααα-20R steranes, and C27, C28 and C29 steranes show asymmetric V-type distribution; the 20S/(20S+20R)and ββ/(αα+ββ) ratios of C29 sterane are generally less than 0.4. Terpanes are mainly composed of pentacyclic terpanes with low contents of Ts, C29Ts and C30 diahopane and high content of gammacerane. The second type is generally characterized by medium maturity, of which Pr/Ph value is generally less than 1.0. The steranes are also dominated by regular steranes; no diasterane is found. But ααα-20S and αββ steranes are significantly higher as compared with the first type of crude oil, and the 20S/(20S+20R)and ββ/(αα+ββ) ratios of C29 steranes generally range from 0.40 to 0.55. The ααα-20R C27, C28 and C29 steranes show an asymmetric V-type distribution, and the C27/C29 ratio is generally greater than 0.6; terpanes present the similar distribution with the first type of crude oil; the Ts/Tm ratio is generally less than 0.5. The sterane/terpane ratio is essentially above 1.0. The third type is generally high-maturity crude oil, of which the Pr/Ph value is generally greater than 1.0. The steranes are dominated by regular steranes, but apparently contain diasteranes with great changes in content. The αββ steranes are significantly higher than ααα steranes, and the 20S/(20S+20R)and ββ/(αα+ββ) ratios of C29 steranes are greater than 0.5 and 0.6 respectively. The C29 sterane content is significantly higher than the C27 sterane, while the C27/C29 ratio is generally less than 0.6. This type of crude oil has similar distribution of terpanes with the former two types, the Ts, C29Ts and C30 diahopanes have higher contents, and the Ts/Tm is generally greater than 0.5; the content of gammacerane changes greatly; the sterane/terpane ratio is basically below 1.0.

Key words: Jiuxi depression, crude oil, carbon isotope, biomarker, classification

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