两淮煤田不同变质作用机制下煤储层精细物理化学结构定量表征及其地质意义

The Carboniferous-Permian coal-bearing strata of LiangHuai Coalfield located in the southern of north China was formed in the Paleozoic Era, which was experienced multiphase reformation effect of tectonic movement and igneous intrusion, producing various coal types under the different metamorphosed mechanism. In recent years, it is deemed that LiangHuai Coalfield is acted as one of the important district of coalbed methane exploration and development research in China, which has experienced a series of physical exploration engineering and scientific research work. However, the actual value is not very ideal. The reason is that because of determining the location of drilling hole and objective coal seam, only considering these necessary conditions such as the high content of coalbed methane and the thickness of coal seam, the sufficient condition, namely physicochemistry fine structure of coal reservoir, was ignored. The object of this study is derived from different metamorphosed degree of coal reservoir selected from LiangHuai Coalfield. On the basis of the evolution of regional geological structure, numerous coal samples of different rank will be directionally collected. By the application of high precision testing instruments, the fine physical and chemical structure of coal will be quantitatively determined. The object of this work: (1) indicating the characteristics of time-space distribution of different metamorphosed coal; (2) clarifying the physical and chemical properties of coal reservoir from LiangHuai coalfield; (3) establishing the digital information of quantitative characterization of fine physical and chemical structure of coal reservoir from LiangHuai coalfield. On the basis of above these observation, this project is of important significance in developing quantitative characterization techniques of different ranked coal reservoir, and in better understanding the reservoir and enrichment theory of district coalbed methane.

华北南部两淮煤田古生代形成的石炭二叠系含煤地层历经多期地质构造运动和岩浆侵入的改造作用，在不同变质作用机制下形成了多种多样的煤质类型。近几年来，两淮煤田煤层气勘探实物和科研工作相继开展，然而未取得理想成果。究其原因是仅考虑了煤层含气量高、煤层厚度大等必要条件，特别忽视了煤储层物理化学精细结构发育的充分条件。本项目选择两淮煤田不同变质作用机制下煤储层为研究对象，根据两淮煤田区域地质构造演化史，定向采集不同变质作用类型煤岩样品，利用高精度精密测试仪器开展了煤精细物理化学结构定量表征技术研究。本项目的开展立在：（1）阐明两淮煤田不同变质类型煤时间-空间分布特征；（2）厘清两淮煤田煤储层物化特性；（3）建立两淮煤田煤储层精细物理化学结构定量表征数字化信息源。基于此，本项目研究成果对发展不同变质作用机制下煤储层精细物化结构定量表征技术及完善区域煤层气成藏理论具有重要的科学意义。

华北南部两淮煤田石炭二叠纪煤系地层经历多期地质构造运动，不仅提高了煤岩变质程度，在变质变形作用下改变了煤岩结构，导致煤储层物理—化学结构系统复杂化。近些年来，随着两淮煤田煤层气资源勘探开发战略的实施，煤储层精细结构定量表征理论技术引起了国内外学者的广泛关注。项目围绕煤层气资源勘查和煤与瓦斯突出等重大科技攻关问题，系统开展两淮煤田不同变质作用机制下煤储层精细结构定量表征题研究。项目分别在淮北煤田和淮南煤田定向采集正常埋藏变质煤、岩浆接触变质煤和动力变质煤样品。运用X射线衍射（XRD）、傅里叶转换红外光谱（FTIR）、激光共焦显微拉曼光谱（Raman）和13C核磁共振（13C NMR）高精度光谱技术，定量表征煤储层精细化学结构；运用原子力显微镜（AFM）和透射电镜（TEM）纳米级分辨率显微技术，定量表征煤储层精细物理结构。在此基础上，阐明煤岩变质变形作用程度与其精细物理—化学结构之间的耦合关系。