石油学报 ›› 2013, Vol. 34 ›› Issue (4): 712-719.DOI: 10.7623/syxb201304011

• 地质勘探 • 上一篇    下一篇

基于卸压煤层气开发的构造煤储层孔渗特征与类型划分——以淮南矿区为例

吴国代1,2,3, 桑树勋4, 程军1,2,3, 柳天均1,2,3, 黄华州4, 任波4   

  1. 1. 重庆地质矿产研究院 国土资源部页岩气资源与勘查技术重点实验室 重庆 400042;
    2. 重庆地质矿产研究院 重庆市页岩气资源与勘查工程技术研究中心 重庆 400042;
    3. 油气资源与探测国家重点实验室重庆页岩气研究中心 重庆 400042;
    4. 中国矿业大学资源与地球科学学院 江苏 徐州 221116
  • 收稿日期:2013-01-16 修回日期:2013-04-08 出版日期:2013-07-25 发布日期:2013-07-04
  • 通讯作者: 吴国代
  • 作者简介:吴国代,男, 1982年10月生, 2007年获中国矿业大学学士学位,2010年获中国矿业大学硕士学位,现为重庆地质矿产研究院工程师,主要从事非常规油气、地球化学方面研究工作。Email:miahwu@qq.com
  • 基金资助:

    国家高技术研究发展计划(863)项目(2007AA06Z220)和教育部重大科学技术项目(307014)资助。

Poroperm characteristics and classification of tectonic coal beds for pressure-relieved methane exploitation:a case study on Huainan mining area

WU Guodai1,2,3, SANG Shuxun4, CHENG Jun1,2,3, LIU Tianjun1,2,3, HUANG Huazhou4, REN Bo4   

  1. 1. Key Laboratory for Shale Gas Resource & Exploration, Ministry of Land & Resources, Chongqing Institute of Geology & Mineral Resources, Chongqing 400042, China;
    2. Chongqing Engineering Research Center for Shale Gas Resource & Exploration, Chongqing Institute of Geology & Mineral Resources, Chongqing 400042, China;
    3. Chongqing Shale Gas Research Center, State Key Laboratory of Petroleum Resource & Prospecting, Chongqing 400042, China;
    4. School of Resource & Earth Science, China University of Mining and Technology, Xuzhou 221116, China
  • Received:2013-01-16 Revised:2013-04-08 Online:2013-07-25 Published:2013-07-04

摘要:

在淮南矿区卸压煤层气地面开发取得积极进展的背景下,应用扫描电镜和汞注入法对淮南矿区构造煤样进行孔裂隙测试,结合井下煤层透气性和试井渗透率测试数据,探讨了构造煤储层孔渗特征。对比分析了卸压煤层气开采现场测试渗透率变化差异,揭示了构造煤卸压开采条件下影响煤层渗透率变化的影响因素及煤体结构差异对煤储层改造的控制作用,提出了构造煤储层类型划分方案。研究表明:随着构造变形的增强,煤中外生孔裂隙规模增大,孔容、中值孔径、孔隙度等参数增大,煤储层渗流孔含量与构造变形呈正相关,但地层条件下构造煤储层的渗流性受储层压力、煤体结构、地下水等因素控制。构造煤储层特性决定了当前原位煤层气开发技术的不可行性;而卸压煤层气开采有效解决了构造煤储层渗透率低、压力传递困难以及压裂改造效果差等技术难题,卸压开采对煤储层的改造导致的"卸压增透增流"效应主要受煤体结构控制。煤体变形越强,改造效果越好,基于不同煤体结构构造煤储层中渗流孔的含量与改造效果的一致性,认为糜棱煤是卸压煤层气开发的优质储层,碎粒煤是较优质储层,碎裂煤和鳞片状煤是一般储层,原生结构煤是不利储层。

关键词: 构造煤储层, 卸压煤层气开采, 煤体结构, 渗流孔, 渗透率

Abstract:

Against the background of progresses made in the ground exploitation of pressure-relieved methane in the Huainan mining area, we tested poricidal fracture systems of tectonic coals from this mining area by SEM and mercury injection, and discussed poroperm characteristics of tectonic coal beds based on well-testing data of penetrability and permeability of borehole coal seams. A comparative analysis of differences in permeability variations measured in practical exploitation of pressure-relieved methane was performed and it revealed influencing factors of permeability variations of tectonic coals under conditions of pressure-relieved exploitation and control effects of the coal texture difference on coal bed reworking, by doing so, a classification method of tectonic coal beds was introduced. The result indicates that with increasing structural deformation, the scale of exogenously poricidal fractures in coals increases, and correspondingly other parameters including pore volume, median aperture and porosity increase as well. The seepage pore content of coal beds is positively correlated with structural deformation, while seepage properties of real tectonic coal beds are controlled by pressure, coal texture, underground water, etc. Characteristics of tectonic coal beds make development techniques of in-situ CBM infeasible, while some problems encountered in CBM development, such as low permeability, difficulty in pressure transmission and poor effects of fracturing of coal beds, can be solved with techniques of pressure-relieved methane exploitation, The effect of "increasing permeability and fluidity by pressure relief" caused by reworking of coal beds in pressure-relieved methane exploitation is controlled mainly by coal textures,i.e. the stronger the coal deformation, the better the reworking effect. Based on the consistency of the seepage pore content of different coal textures in coal beds with the reworking effect, a mylonitic coal is considered to be a high-quality coal bed for pressure-relieved methane exploitation, a granulated coal comes next, fractured /scaly coals are ecumenic, while a coal with original texture is a poor coal bed for pressure-relieved methane exploitation.

Key words: tectonic coal bed, pressure-relieved CBM exploitation, coal texture, seepage pore, permeability

中图分类号: