构造煤甲烷吸附/解吸特征及与其微晶结构耦合机理

Suffered multiple episodes and different kinds of the tectonic movements, the coal reservoir of Late Paleozoic coal basins in North China had a strong transformation and became various types of tectonically deformed coal. Methane adsorption / desorption properties of tectonic coal is controlled by its crystalline structure, at the same time, the process of coal methane adsorption also have effect on the crystallite structure. This study selects the tectonically deformed coal (compared with normal coals) of Huainan-Huaibei coal field area as the research samples. We will systematically analyze the evolutional characteristics of crystallite structure of tectonically deformed coals by using modern testing techniques and experiment methods like High-Resolution Transmission Electron Microscope (HRTEM), Atomic Force Microscope (AFM), X ray diffraction (XRD), Nuclear Magnetic Resonance (NMR) and Laser Raman spectroscopy to reveal the deformation-metamorphic mechanism of coal microcrystalline structure. Through the methane isothermal adsorption experiment of tectonically deformed coals at the different temperature and pressure conditions, the methane adsorption/desorption kinetics process and its controlled mechanism needs to be further in-depth study. We will also go deep into study of the impact of the desorption process on the coal macromolecular structure. On this basis, this project aims to reveal the evolution of tectonically deformed coal macromolecular structure, adsorption/desorption kinetics of the process, and their coupling mechanism. It also has a great significance to for further investigate coalbed methane desorption law of the strong tectonically deformed coal reservoirs and coal and gas outburst mechanism in the developed areas of tectonically deformed coals.

我国华北晚古生代煤盆地历经多期次、不同性质构造作用后，煤储层结构发生了强烈改造，形成了各种类型构造煤。构造煤的甲烷吸附/解吸性能受其微晶结构的控制，同时煤吸附甲烷的过程对微晶结构也有影响。本项目选取两淮煤田不同类型的构造煤为研究对象（含原生结构煤进行对比），采用高分辨透射电镜、原子力显微镜、X射线衍射、核磁共振和激光拉曼光谱等方法对构造煤和原生结构煤的微晶结构进行详细研究，旨在揭示煤微晶结构演化的变质变形机制。通过不同温度条件下构造煤甲烷等温吸附实验研究，剖析不同温度和压力条件下构造煤甲烷吸附/解吸特征及受控机制。研究甲烷吸附/解吸前后煤体微晶结构的变化特征，深入探讨吸附/解吸过程对煤大分子结构的影响。在此基础上，揭示构造煤甲烷吸附/解吸过程与其微晶结构演化的耦合关系及作用机理。本项目的研究，对于进一步探寻强变形煤储层煤层气解吸规律及构造煤发育区煤与瓦斯突出机理具有重要意义

构造煤大分子结构、纳米级孔隙结构、吸附/解吸特征及其受控机制是煤层气地质研究的重点内容。构造煤甲烷吸附解吸特征与其大分甲烷吸附/解吸性能受其微晶结构的控制，同时煤吸附甲烷的过程对微晶结构也有影响。本研究采用高分辨原子力显微镜分析技术对不同类型构造煤的表面超微结构特征（大分子聚集体和纳米级孔隙）进行了定量表征，揭示了变质作用、变形作用对煤大分子聚集体和纳米级栅格间孔隙表面形态影响。采用小角X射线散射和低温液氮吸附实验对煤中纳米级孔隙进行了定量研究，揭示了构造变形已经影响到煤中纳米级孔隙结构，揭示了煤中开放孔隙、封闭孔隙及总孔隙的孔体积和比表面积分布特征及其演化规律，深入探讨了煤中开放孔隙和封闭孔隙结构演化的变质、变形机理。采用高分辨透射电镜、X射线衍射和激光拉曼光谱等方法对构造煤和原生结构煤的微晶结构和纳米级孔隙结构进行了精细定量表征，揭示了煤微晶结构和纳米级孔隙结构演化的变质变形机制。联合甲烷高压等温吸附实验和煤微晶结构参数的定量表征，研究了甲烷吸附/解吸前后煤体微晶结构的变化特征，揭示了吸附/解吸过程对煤大分子结构的影响。通过煤中裂隙精细定量研究，揭示了煤中裂隙的非均质特征以及与渗透性的关系。.本项目的研究，对于进一步探寻强变形煤储层煤层气解吸规律及构造煤发育区煤与瓦斯突出机理以及煤层气含量精确预测具有重要意义。项目研究过程中已发表SCI论文14篇(其中2篇ESI高被引论文)，目前SCI他引97次，组建了“煤层气储层物性及其地质控制”河南省高校科技创新团队。