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现代地质 ›› 2018, Vol. 32 ›› Issue (05): 963-974.DOI: 10.19657/j.geoscience.1000-8527.2018.05.09

• 煤田地质 • 上一篇    下一篇

煤岩孔隙度主控地质因素及其对煤层气开发的影响

刘娜1(), 康永尚1,2(), 李喆1, 王金1, 孙良忠1, 姜杉钰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
  • 收稿日期:2018-01-19 修回日期:2018-09-02 出版日期:2018-10-10 发布日期:2018-11-04
  • 通讯作者: 康永尚,男,教授,1964年出生,油气田开发地质专业,主要从事非常规油气勘探开发地质工程以及海外油气项目储量和价值评估的教学和研究工作。Email:kangysh@sina.com
  • 作者简介:刘 娜,女,硕士研究生,1992年出生,油气田开发地质专业,主要从事非常规油气勘探开发地质工程研究工作。Email:m18811367739@163.com
  • 基金资助:
    国家科技重大专项(2016ZX05044);国家科技重大专项(2017ZX05035)

Geological Controlling Factors of Coal Pore System and Its Significance in CBM Development

LIU Na1(), KANG Yongshang1,2(), LI Zhe1, WANG Jin1, SUN Liangzhong1, JIANG Shanyu1   

  1. 1. College of Geosciences, China University of Petroleum, Beijing 102249, China
    2. State Key Laboratory of Petroleum Resources and Prospecting, Beijing 102249, China
  • Received:2018-01-19 Revised:2018-09-02 Online:2018-10-10 Published:2018-11-04

摘要:

为系统分析煤岩孔隙度主控地质因素及对其煤层气开发的影响,统计分析了全国37个主要煤层气区块/矿区的压汞孔隙度等数据。利用相关趋势分析方法分煤级着重探讨煤级、煤体结构、镜质组、灰分等因素对煤岩孔隙度以及煤层气开发的影响。结果表明:Ro,max是储层物性评价的重要参数,低煤级区煤岩孔隙度对Ro,max的变化最为敏感,且孔隙度平均值随成熟度升高呈现出高-低-高-低的变化。低煤级区同一煤层气区块/矿区内部,孔隙度变化区间大于高煤级区同一煤层气区块/矿区内部孔隙度的变化区间。中低煤级区,复杂的煤体结构对煤储层物性具有破坏作用;高煤级区,复杂的煤体结构对物性有一定的改善作用。镜质组含量与孔隙度呈负相关关系,灰分产率与孔隙度无明显相关性,且在低煤级区镜质组含量和灰分产率与孔隙度均具有明显的负相关性,是孔隙度评价的重要参数;而在中高煤级区,二者对孔隙度的影响可以忽略。煤岩大中孔比例和储层平均渗透率随平均孔隙度的增高而增高,孔隙度大小尤其是孔隙度随煤级的变化规律对不同煤级区煤层气开发潜力评价具有重要指导意义。

关键词: 孔隙度, 煤级, 煤体结构, 镜质组含量, 灰分产率, 大中孔比例, 渗透率

Abstract:

To systematically analyze the key geological controlling factors of coal pore system and the significance for coalbed methane development, we present new statistical data for the mining area of 37 major CBM blocks/mercury, and use the trend analysis method to clarify the coal rank, coal body structure vitrinite and ash effect coal porosity, and the significance of porosity research for coalbed methane development. Our results suggest that Ro,max is an important parameter for reservoir property evaluation, and that coal porosity in low rank area is most sensitive to Ro,max. Besides, the average porosity shows successive peaks and troughs with increasing coal maturity. The range of porosity in the same coalbed methane block/mining area of low rank is wider than that of high rank. Complex coal body structure has a destructive effect on the coal reservoir properties, whereas the high coal rank region and complex coal structures are beneficial to the properties; Vitrinite content is negatively correlated with porosity, and no obvious correlation is found between ash content and porosity. In the low coal rank region, vitrinite and ash content have obvious negative correlation with porosity, whereas the effect on the porosity is negligible in the high coal rank region. The proportion of meso/macro-pores and average permeability increase with increasing average porosity and porosity size. In particular, the changes of porosity with the coal rank in different areas have important guiding significance for the coalbed methane development.

Key words: porosity, coal rank, coal body structure, vitrinite content, ash content, proportion of meso-and macropore, permeability

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