石油学报 ›› 2020, Vol. 41 ›› Issue (10): 1174-1187,1218.DOI: 10.7623/syxb202010002

• 地质勘探 • 上一篇    下一篇

东海盆地西湖凹陷古近系煤的生烃动力学

刘金水1, 李树霞2, 秦兰芝1, 易琦2, 陈晓东1, 康世龙2, 沈文超2, 邵龙义2   

  1. 1. 中海石油(中国)有限公司上海分公司 上海 200030;
    2. 中国矿业大学(北京)地球科学与测绘工程学院 北京 100083
  • 收稿日期:2019-07-08 修回日期:2020-06-13 出版日期:2020-10-25 发布日期:2020-11-05
  • 通讯作者: 邵龙义,男,1966年2月生,1983年获焦作矿业学院学士学位,1989年获中国矿业大学(北京)博士学位,现为中国矿业大学(北京)教授、博士生导师,主要从事沉积学与煤田地质学方面的科研与教学工作。Email:ShaoL@cumtb.edu.cn
  • 作者简介:刘金水,男,1966年9月生,1988年获中国地质大学(武汉)学士学位,2005年获同济大学硕士学位,现为中海石油(中国)有限公司上海分公司教授级高级工程师,主要从事综合地质研究。Email:liujinshui@126.com
  • 基金资助:

    国家科技重大专项(2016ZX05027-001)资助。

Hydrocarbon generation kinetics of Paleogene coal in Xihu sag, East China Sea Basin

Liu Jinshui1, Li Shuxia2, Qin Lanzhi1, Yi Qi2, Chen Xiaodong1, Kang Shilong2, Shen Wenchao2, Shao Longyi2   

  1. 1. Shanghai Branch, CNOOC China Limited, Shanghai 200030, China;
    2. School of Geoscience and Surveying Engineering, China University of Mining and Technology, Beijing 100083, China
  • Received:2019-07-08 Revised:2020-06-13 Online:2020-10-25 Published:2020-11-05

摘要:

通过高温高压封闭体系条件下的热模拟实验和生烃动力学模拟分析,获得了西湖凹陷古近系平湖组和花港组煤生成气态烃的产率及其动力学参数。结合古地温演化史和热演化史恢复了西湖凹陷西部斜坡带、西次凹及中央构造带的古近系平湖组和花港组煤的生烃演化历史,并基于预测的镜质体反射率(Ro)建立了研究区煤的生气演化模式。研究结果表明,西湖凹陷煤所生成的天然气以甲烷(C1)为主,重烃气(C2—C5)较少,C1和总气态烃(C1—C5)的产率增长速率在煤的高成熟阶段(1.10%≤Ro<2.20%)最大,在成熟阶段(0.50%≤Ro<1.10%)次之,在过成熟阶段(Ro≥2.20%)最小,且含碳原子个数不同的重烃气(C2、C3、C4和C5)的主裂解期不同。在西湖凹陷煤的生烃演化过程中,西部斜坡带平湖组和花港组中的煤所生成的气态烃最少,生烃条件最差;而西次凹、中央构造带平湖组和花港组中煤所生成的气态烃较多,是比较有利的生烃区。花港组中煤生成气态烃的产率远小于平湖组,且至今尚未达到生烃高峰。

关键词: 西湖凹陷, 煤, 生烃动力学, 生烃史, 生气演化模式

Abstract:

Through thermal simulation experiments and simulation analysis of hydrocarbon generation kinetics under the closed system with high temperature and high pressure, this paper obtains the yields and kinetic parameters of gaseous hydrocarbons generated by coal from the Paleogene Pinghu Formation and Huagang Formation in Xihu sag. Further in combination with the evolution history of paleo-temperature and thermal evolution, the paper restores the hydrocarbon generation and evolution history of coal from the Paleogene Pinghu Formation and Huagang Formation in the western slope belt, the western sub-sag and the central structural belt of Xihu sag, and establishes the gas generation and evolution model of coal in the study area based on the predicted vitrinite reflectance value (Ro). The research results show that gas produced by coal in Xihu sag is domininated by methane (C1), with less heavy hydrocarbon gas (C2-C5). The rate of rise in the yield of C1 and the total yield of gaseous hydrocarbons (C1-C5) is the largest in the high mature stage of coal (1.10% ≤ Ro<2.20%), followed by the mature stage (0.50% ≤ Ro<1.10%), and the smallest in the over-mature stage (Ro ≥ 2.20%). Moreover, the heavy hydrocarbon gas with different numbers of carbon atom (C2, C3, C4 and C5) have different main cracking periods. During the hydrocarbon generation and evolution of coal in Xihu sag, coal in Pinghu Formation and Huagang Formation in the western slope belt produced the least gaseous hydrocarbons and had the worst hydrocarbon generation conditions; while Pinghu Formation and Huagang Formation in the western sub-sag and central structural belt produces more gaseous hydrocarbons and are favorable source areas. The yield of gaseous hydrocarbon from coal in Huagang Formation is much lower than that in Pinghu Formation, and it has not yet reached the hydrocarbon generation peak.

Key words: Xihu sag, coal, hydrocarbon generation kinetics, hydrocarbon generation history, gas generation and evolution model

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