贵州对江南井田煤储层粘土矿物特征及敏感性评价

煤层具有双重孔隙结构,孔喉结构复杂,颗粒表面吸附着黏土矿物,容易受到外来流体的影响,发生膨胀、迁移、沉淀,导致渗透降低,影响生产效率,为实现对江南井田煤层气高效开发。通过对煤岩心进行扫描电镜、X衍射、储层敏感性实验,对研究区储层黏土矿物特征和敏感性类型、伤害程度及敏感性影响因素进行分析。煤岩心分析表明,储层黏土矿物主要由伊蒙混层和绿蒙混层2种矿物类型,M18、M73、M74、M78煤储层具有中等偏强速敏,M18、M74、M78煤储层具有弱水敏,M73煤储层具有中等偏弱水敏,M18、M73、M74、M78煤储层无盐敏,M18、M73、M74、M78煤储层具有弱酸敏,M18、M73、M74、M78煤储层具有中等偏强碱敏,M18、M73、M74、M78煤储层具有强应力敏感性,建议后续煤层气勘探开发中应重点防止速敏、碱敏和应力敏感性,降低储层伤害,提高开采效率。

Clay Mineral Characteristics and Sensitivity Evaluation of Coal Reservoirs in Duijiangnan Mine Field,Guizhou province

Coal seam has dual pore structure, complex pore throat structure, clay minerals adsorbed on the surface of particles, which are vulnerable to the influence of external fluids. It is easy to expand, migrate and precipitate, which leads to the decrease of permeability and affects production efficiency. In order to realize the efficient development of coalbed methane in Duijiangnan mine field, The characteristics of clay minerals and sensitivity types, damage degree and sensitivity factors in the study area were analyzed by scanning electron microscopy, X-ray diffraction and reservoir sensitivity experiments on coal cores. Coal core analysis showed that clay minerals in reservoirs are mainly composed of Yimeng mixed layer and Green mixed layer. The M18, M73, M74, M78 coal reservoirs have moderately strong velocity sensitivity, the M18, M74, M78 coal reservoirs have weak water sensitivity, the M73 coal reservoirs have moderate bias. Weak water sensitivity, the M18, M73, M74, M78 coal reservoirs don"t have salt sensitivity, the M18, M73, M74, M78 coal reservoirs have weak acid sensitivity, the M18, M73, M74, M78 coal reservoirs have moderately strong alkali sensitivity, the M18, M73, M74, M78 coal reservoirs have strong stress sensitivity. It is suggested that the following exploration and development of coalbed methane should focus on the prevention of velocity sensitivity, alkali sensitivity and stress sensitivity, reducing reservoir damage and improving production efficiency.