When the particulate is less than pore throat,it can be distorted after absorbing water and successfully pass the pore throat under the driving of injecting water.

• 小于孔喉的颗粒,由于粘弹性较好,吸水膨胀后,颗粒可发生形变,表现出"变形虫"特征,在注入水的驱动下,可以顺利通过孔喉;