石油学报 ›› 2019, Vol. 40 ›› Issue (7): 786-797.DOI: 10.7623/syxb201907003

• 地质勘探 • 上一篇    下一篇

低煤阶煤层气成藏模式和勘探方向

皇甫玉慧1, 康永尚1,2, 邓泽3, 李贵中3, 毛得雷4,5, 刘洪林3, 赵群3, 孙天竹1   

  1. 1. 中国石油大学(北京)地球科学学院 北京 102249;
    2. 油气资源与探测国家重点实验室 北京 102249;
    3. 中国石油勘探开发研究院 北京 100083;
    4. 煤层气开发利用国家工程研究中心 北京 100095;
    5. 中联煤层气国家工程研究中心有限责任公司 北京 100095
  • 收稿日期:2018-10-16 修回日期:2019-03-03 出版日期:2019-07-25 发布日期:2019-07-28
  • 通讯作者: 康永尚,男,1964年11月生,1984年获中国矿业学院学士学位,1991年获法国洛林理工学院博士学位,现为中国石油大学(北京)教授,主要从事非常规油气勘探开发及油气储量及价值评估研究工作。Email:kangysh@sina.com
  • 作者简介:皇甫玉慧,女,1991年5月生,2017年获中国石油大学(北京)学士学位,现为中国石油大学(北京)硕士研究生,主要从事煤层气开发地质研究。Email:2956986046@qq.com
  • 基金资助:

    国家科技重大专项(2016ZX05041-001,2016ZX05044-005)资助。

Low coal rank coalbed methane accumulation model and exploration direction

Huangfu Yuhui1, Kang Yongshang1,2, Deng Ze3, Li Guizhong3, Mao Delei4,5, Liu Honglin3, Zhao Qun3, Sun Tianzhu1   

  1. 1. College of Geosciences, China University of Petroleum, Beijing 102249, China;
    2. State Key Laboratory of Petroleum Resources and Prospecting, Beijing 102249, China;
    3. PetroChina Research Institute of Petroleum Exploration and Development, Beijing 100083, China;
    4. National Engineering Research Center of Coalbed Methane Development & Utilization, Beijing 100095, China;
    5. National Engineering Research Center of China United Coalbed Methane, Beijing 100095, China
  • Received:2018-10-16 Revised:2019-03-03 Online:2019-07-25 Published:2019-07-28

摘要:

中国低煤阶煤层气资源丰富,但勘探和认识程度较低,煤层气成藏的主控因素和富集规律认识不足。在分析国内外不同盆地、不同区块低煤阶煤层气含气量随埋深变化趋势差异的基础上,从现今和古水文地质条件两个方面,探讨了中国低煤阶煤层气成藏的前提条件,分析了成煤环境对含气量的影响。研究结果表明:①低阶煤(Ro<0.65%)主要分布于埋深<1 200 m的中-新生界煤系地层中,低煤阶煤层气主要是次生生物成因气;②低煤阶煤层气含气量随埋深总体呈现先增加后降低的趋势,普遍存在"最佳深度"这一特征,现今淡水入渗或古淡水入渗水文地质条件是次生生物气生成的前提条件;③除淡水入渗水文地质条件控制低煤阶煤层气的生成与富集外,煤岩组分、煤层厚度、煤岩顶底岩性以及煤岩物性等储层特征对含气量也有重要影响;④低煤阶煤层气存在盆缘斜坡带新近成藏和小型断陷古成藏两类成藏模式,指示了低煤阶煤层气勘探的两个方向。

关键词: 煤层气, 低煤阶, 次生生物气, 水文地质, 成藏模式, 勘探方向

Abstract:

Low coal rank coalbed methane resources are rich in China, but are less known and explored; there is still insufficient understanding of the main controlling factors and enrichment laws of coalbed methane accumulation. Based on analyzing the variation trends in the gas content of low coal rank coalbed methane changing with depths in different basins and blocks worldwide, this paper explores the premise of low coal rank coalbed methane accumulation in terms of the present and ancient hydrogeological conditions, and also analyzes the impact of coal-forming environment on gas content. Research indicates:(1) Low rank coals (Ro<0.65%) are mainly distributed in the Mesozoic and Cenozoic coal measures strata with buried depth<1200 m, and low rank coalbed methane is mainly dominated by secondary biogenic gas. (2) The gas content of low rank coal tend to increase firstly and then decrease with the buried depth, generally showing an optimal depth. The present hydrogeological conditions of fresh water infiltration or paleo-fresh water infiltration are the preconditions for secondary biogas generation. (3) In addition to the formation and enrichment of low coal rank coalbed methane controlled by hydrogeological conditions for freshwater infiltration, the reservoir characteristics such as coal-rock component, coal seam thickness, coal-rock top lithology and coal-rock physical properties also have an important influence on gas content. (4) Low coal rank coalbed methane presents two accumulation modes, i.e., the Neogene hydrocarbon accumulation in marginal slope zone of the basin and the paleo-accumulation in small fault depressions, indicating two directions of low coal rank coalbed methane exploration.

Key words: coalbed methane, low coal rank, secondary biogenic gas, hydrogeology, accumulation model, exploration direction

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