The reason is the elastic and plastic deformation of the rock during the drop of pressure, and then the decline of the permeability and poritity which is partly reversible or completely reversible.

• 其中主要原因是在压力下降过程中储层发生弹塑性形变，储层的渗透率、孔隙度将会随压力的下降而发生部分不可逆或完全不可逆的变化。