The capillary bundle model is one of the most common physical models for the porous media. The most classic physical model is the straight capillary bundle model with same diameter. But the bendability of the porous media is neglected in this physical model. Therefore

based on the tight sandstone

combined with the mercury data

and by the introduction of the correction factor-tortuosity

we put forward a new approach to establish the capillary bundle model. This approach considers the bendability of the capillary bundle model and can accurately calculate the radius of capillary

capillary porosity and permeability

capillary volume of different radius and permeability contribution of capillary bundle model with different radius. This new approach has great significance for the study of the reservoir fluid imbibition of specific pressure and quantitatively characterizing the water invasion reservoir damage.