我国煤层气资源丰富，发展煤层气储层地质学理论与技术有助于我国煤层气勘探开发的进一步突破。基于对文献调研与分析，阐述了煤层气储层地质与表征技术的研究内容及进展，分析了前缘发展方向。研究认为，煤层气储层地质学研究正在从宏观向微观、从定性向定量、从单学科到多学科协同发展，研究内容涉及煤储层成因类型、沉积环境、构造作用、应力特征、物性特征、几何形态、井网布置方式、储层改造及保护、井网调整及优化等产业全过程；煤层气运聚动力分为2类，一类是在气体浓度差作用下的扩散-渗流机制，另一类是压差或势差作用下的水动力-浮力机制；构造挤压应力主要通过骨架岩石的变形改变含水层与隔水层，并影响到流体渗流网络的疏导能力；沉积压实主要影响孔-裂隙空间及喉道，沉积物沉降速度过快容易形成异常高压带，不利于储层流体流动；流体在三维空间中所处的温度不同，温差效应常会引起流体发生瑞利和非瑞利对流驱动，一般浅部低温、密度较大的流体会向下运动，而深部高温、密度较小的流体会向上运动；渗透率研究经历了4个阶段，包括表观现象与经验推测定性分析、多种理化效应与细化各因素作用影响机制、数学模型与数值分析等多种模拟手段定量表征以及精细完善储层微米尺度传输介质渗透率动态变化。研究指出，未来需要精细研究深部构造煤和热改造煤储层纳米级孔隙气体的赋存状态与扩散运移机理，建立健全煤系非常规天然气合采技术制度，根据纳米孔隙超量吸附的聚散过程厘定不同温压条件下煤储层微纳米孔隙中气体凝聚与游离空间变化。

There are vast reserves of coalbed methane (CBM) resources in China, where the development of CBM reservoir geology theory and technology is helpful for the further breakthrough of CBM exploration and development. Based on the literature research and analysis, the research content and progress of CBM reservoir geology and characterization technology were described, and the development direction of the frontier was analyzed. The research results show that the coal reservoir geology research, whose contents include genetic types of coal reservoir, sedimentary environments, tectonism, stress feature, physical characteristics, geometrical morphology, well pattern arrangement, reservoir renovation-protection, and well pattern adjustment-optimization, is developing from macroscopic to microcosmic, qualitative to quantitative, and from single discipline to multi-discipline. CBM transport and accumulation dynamics are divided into diffusion-percolation mechanisms under the effect of gas concentration differences and hydrodynamic-buoyancy mechanisms under the effect of pressure or potential differences. Tectonic compressional stresses alter the aquifer and water barrier mainly through the deformation of the skeletal rock, which in turn affects the ability to evacuate the fluid seepage network. Sediment compaction mainly affects the pore-fracture space and throat, and too fast sediment settlement rate tends to form an anomalous high-pressure zone, which is not conducive to reservoir fluid flow. Due to the difference in temperature of fluid in three-dimensional space, the temperature difference effect often causes the fluid to be driven by Rayleigh and non-Rayleigh convection. Generally, the fluid with low temperature and high density in shallow part moves downward, while the fluid with high temperature and low density moves upward in deep part. The study of permeability has gone through four stages, including qualitative analysis based on apparent phenomena and empirical speculation, consideration of various physical and chemical effects and refinement of the influencing mechanism of various factors, quantitative characterization combined with mathematical models and numerical analysis, and fine improvement of the dynamic change of permeability for reservoir transmission medium in micro-scale. The study points out that we need careful research on the occurrence state and diffusion-migration mechanism of gas for nanoscale pore in deep structural and thermal coal reservoir, establishment and improvement in co-production technology system of unconventional coal-measure gas, confirming the changes of gas condensation and free space in the micro-and nano-pores of coal reservoirs under different temperature and pressure according to the polydispersity process of nano-pore excess adsorption.

0 引言

1 煤储层地质学概述

   1.1 研究意义

   1.2 储层理论应用

2 煤储层地质研究进展

   2.1 煤储层物性特征

   2.2 储层跨尺度非均质性

   2.3 煤储层流体地质

   2.4 储层动态评价

3 煤储层地质发展方向

   3.1 储层地质与工程更加紧密融合

   3.2 定性描述向定量评价转变

   3.3 实时动态和衍生性研究蓄势勃发

4 结论