The fractal dimension (FD) of sedimentary rocks has become an important petrophysical parameter. The importance is partly because capillary presure (Pc) -and other transport coefficients-scale as power laws of fluid saturation. The scaling exponents are often related to the supporting media's FD. -Water Pc, in particular, is known to scale as a power law of water saturation, in imbibition at low saturation of the wetting phase, and the scaling exponent is related to the FD of the pore-rock surface. Here we show results of mercury intrusion tests, in drainage at high capillary presure, which clearly show power law dependence between intrusion volume and Pc. We relate the scaling exponent to the pore bulk FD. We also report results of two dimensional image analysis which indicate that, in fact, both pore bulk and pore-rock interfaces are fractal.