石油学报 ›› 2020, Vol. 41 ›› Issue (9): 1060-1072.DOI: 10.7623/syxb202009003

• 地质勘探 • 上一篇    下一篇

从原油地球化学特征看致密油聚集机制——以柴达木盆地西部扎哈泉油藏为例

何媛媛1, 张斌1, 桂丽黎1, 张国卿2, 袁莉2   

  1. 1. 中国石油勘探开发研究院 北京 100083;
    2. 中国石油青海油田公司勘探开发研究院 甘肃敦煌 736202
  • 收稿日期:2019-05-12 修回日期:2020-03-17 出版日期:2020-09-25 发布日期:2020-09-29
  • 通讯作者: 何媛媛,女,1983年1月生,2005年获中国石油大学(北京)学士学位,2013年获荷兰代尔夫特理工大学石油工程专业博士学位,现为中国石油勘探开发研究院石油地质实验研究中心工程师,主要从事地球化学方面的研究。
  • 作者简介:何媛媛,女,1983年1月生,2005年获中国石油大学(北京)学士学位,2013年获荷兰代尔夫特理工大学石油工程专业博士学位,现为中国石油勘探开发研究院石油地质实验研究中心工程师,主要从事地球化学方面的研究。Email:yyhe@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(2016E-0101)资助。

Insight into the accumulation mechanism of tight oil from the geochemical characteristics of crude oil: a case study of the Zahaquan oil reservoir in the western Q aidam Basin

He Yuanyuan1, Zhang Bin1, Gui Lili1, Zhang Guoqing2, Yuan Li2   

  1. 1. PetroChina Research Institution of Petroleum Exploration and Development, Beijing 100083, China;
    2. Research Institution of Petroleum Exploration and Development, PetroChina Qinghai Oilfield Company, Gansu Dunhuang 736202, China
  • Received:2019-05-12 Revised:2020-03-17 Online:2020-09-25 Published:2020-09-29

摘要:

以柴达木盆地西部扎哈泉地区致密油勘探区为研究对象,选取下干柴沟组上段和上干柴沟组原油和烃源岩样品进行实验分析,对不同层段原油和烃源岩中生物标志化合物特征的对应关系进行了精细对比,探讨了致密油的生成和运移过程,并对存在另一套与下干柴沟组上段和上干柴沟组不同的潜力烃源岩进行了推断。扎哈泉地区共发现4类原油:第1类主要为来自上干柴沟组的自生自储型原油;第2类主要为分布在上干柴沟组Ⅳ砂组和Ⅵ砂组中的原油,在扎2井和扎3井形成工业油流,其来源为下干柴沟组上段和上干柴沟组烃源岩的混合;第3类主要为赋存在上干柴沟组Ⅲ砂组中的原油,其中,上干柴沟组Ⅲ砂组是现阶段开发原油的主力产层之一,其原油主要来源于下干柴沟组上段烃源岩,属于深层油源充注;第4类主要为分布在下干柴沟上段的原油,根据生物标志化合物特征推断其来源于深层下干柴沟组下段。扎哈泉地区的原油与其所在层位烃源岩的地球化学特征不完全一致,推断油源断层所形成的开放输导通道能够将深层烃源岩生成的油气向上运移至新近系。扎哈泉地区致密油的聚集、运移方向并不只局限于自生自储,如果存在开放性的断层或裂缝作为油气运移通道,致密油藏完全可能为远源成藏。远源供烃也可能形成规模性的油藏。

关键词: 生物标志化合物, 致密油, 油源对比, 柴达木盆地, 扎哈泉地区

Abstract:

Taking the tight oil exploration zone in the Zahaquan area of the western Qaidam Basin as the research object, this paper selects the crude oil and source rock samples from the Upper Member of Xiaganchaigou Formation and the Shangganchaigou Formation for experimental analysis. A fine comparison was performed on the biomarker correlation between crude oils and source rocks in various intervals. The formation and migration process of tight oil was discussed. The existence of another set of source rocks with different hydrocarbon potential as compared with those from the Upper Member of Xiaganchaigou Formation and the Shangganchaigou Formation was deduced. A total of 4 types of oil have been discovered in the Zhahaquan area. The first type is mainly self-generation and self-accumulation crude oil from the Shangganchaigou Formation. The second type mainly consists of the crude oil in the sand group Ⅳ and Ⅵ of Shangganchaigou Formation, which forms commercial oil output in Well Zha-2 and Well Zha-3, and its source rocks is the mixture of the Upper Member of Xiaganchaigou Formation and the Shangganchaigou Formation. The third type is mainly the crude oil occurring in the sand group Ⅲ of Shangganchaigou Formation, which is one of the main production layers for oil development at the present stage, and its source rock is the Upper Member of Xiaganchaigou Formation and undergoes deep oil charging process. The fourth type mainly consists of the crude oil in the Upper Member of Xiaganchaigou Formation, whose source rock is inferred to the Lower Member of Xiaganchaigou Formation according to biomarker characteristics. The geochemical characteristics of crude oil in the Zhahaquan area are not completely consistent with those of the source rocks at the same horizon. It is inferred that the hydrocarbon generated from deep source rocks might migrate upward to the Neogene through the open transporting pathway formed by faults. The accumulation model of tight oil in the Zhahaquan area is not limited by self-generation and self- accumulation. If there are open faults or fractures as the hydrocarbon migration channels, the tight oil reservoirs are quite possible to form reservoirs far from sources. Large-scale reservoirs can be also formed by hydrocarbon supply far from source rocks.

Key words: biomarker, tight oil, oil-source correlation, Qaidam Basin, Zhahaquan area

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