【摘要】 采用水力压裂进行页岩开发时，页岩吸水能力较强，水与矿物之间的物理化学作用导致孔隙结构的变化。以龙马溪组露头页岩岩心为研究对象，采用平衡水分法、氮气吸附实验和扫描电镜观察，获取不同含水饱和度前后的孔径吸附曲线及原位孔隙结构图片。利用图像处理软件、SPSS软件分析无机微观孔隙的结构参数，分析结构参数在不同含水饱和度前后的均值、峰度、中位数变化趋势，以及矿物颗粒间特征长度变化。结果表明：水侵入页岩初期速度较快，后期侵入速度逐渐变慢，微观孔隙的结构参数与含水饱和度非线性相关；水对页岩微观孔隙结构存在两类相反的作用机制，新裂缝或孔隙的产生源于黏土矿物较强的脱水皱缩效应。水基压裂液中的水对微观孔隙结构的作用较为复杂，颗粒运移、矿物颗粒排列扭转对储层物性及地层结构稳定性产生负面影响。更多还原

【Abstract】 Hydraulic fracturing is essential method for shale gas development,due to strong hydrophilicity of shale,the chemical and physical reaction between water and minerals can directly cause changes of pore structure.By utilizing Longmaxi outcrop,acquire SEM pictures or pore size distribution curves before and after processing degree through equilibrium moisture test,nitrogen adsorption test and SEM observation.Parameter changes of average value,kurtosis,median and characteristic length between mineral particles before and after different processing degree by adopting Image-Pro Plus and SPSS to analyse inorganic pore parameters.The results show that:water invasion speed is initially larger then gets smaller,the relationship between micro pore structure parameter and saturation is nonlinear;two opposite mechanisms of water influence on shale are the compressing force of clay expansion and enlarging function of water flush and substrate clay expansion,new fracture or pore is caused by shrinkage of clay mineral.Water influence on micro pore structure is complicated,moving particles and twisted arrangement of mineral particles can reduce the geological structure stability and rock percolation.更多还原