Many geophysical processes can be modelled as interconnected networks. The small-world network model has recently attracted much attention in physics and applied sciences. In this paper, we modify and apply the small-world network theory to model geophysical processes such as diffusion and transport in disordered porous rocks. We develop an analytical approach as well as numerical simulations to characterize the properties of small-world networks in geophysics using system saturation time and fractal dimensions. ¿ 2001 American Geophysical Union