Direct percolation on an FIB-reconstructed image of the pore space of chalk is our virtual mercury porosimetry tool.  The blue line segments denote the invading fluid which is connected from the inlet to the outlet.  The red segments denote the invading fluid prior to breakthrough.  The different capillary pressures were obtained from the different parts of the same image.  The dashed black line is from a chalk core experiment.  Again, there are no adjustable parameters.