论文部分内容阅读
页岩压裂改造过程中渗透率变化和压裂缝扩展的机理对页岩气开发压裂工程设计具有重要意义,通过页岩岩心首次加载-卸载-二次加载流-固耦合物理模拟实验和二次加载实验后岩心微米CT成像分析,揭示出两个重要现象:(1)首次加载-卸载-二次加载过程,有助于提高岩心的渗透率;(2)在二次加载过程中,岩心渗透率随轴压增加出现增加或降低不同的现象,分别对应压裂缝的有序化和方向性扩展或无序化和局部糜棱化扩展.实验获得的认识对页岩储层压裂改造有两条启示:(1)泵入-停泵-再泵入循环压裂有助于改善页岩气储层的渗透率;(2)对天然裂缝发育的页岩储层,压裂规模的针对性设计十分关键.
The mechanism of permeability change and fracture propagation during shale fracturing is of great significance to the design of shale gas fracturing engineering. Based on shale core first-load-unload-secondary-load fluid-solid coupling physics simulation experiment and two After the secondary loading experiment, the core micron CT imaging analysis reveals two important phenomena: (1) the first loading-unloading-secondary loading process helps to improve the core permeability; (2) During the secondary loading, the core Permeability increases or decreases with the increase of axial pressure, which is corresponding to the order of fracturing seam orientation and directional expansion or disorder and local mylonized expansion respectively. Two implications: (1) pump-in-pump-re-pump cycle fracturing can help to improve the permeability of shale gas reservoirs; (2) for shale reservoirs with natural fractures and fracturing scale Sexual design is crucial.