Apparatus and method for measuring relative permeability and capillary pressure of porous rock

Method for measuring two-phase, steady-state relative permeability of a porous rock at reservoir conditions, comprising the steps of:

• a) injecting a first fluid into a core sample of a porous rock to effect a first fluid saturation throughout said porous rock,
• b) scanning said saturated core sample with X-rays and measuring the attenuation of said X-rays as they pass through said core sample to determine fluid saturation,
• c) desaturating said core sample to effect a first irreducible first fluid saturation condition by injecting a second fluid into said core sample that is immiscible with said first fluid and displacing said first fluid from said core sample through a first member that is permeable to said first fluid and impermeable to said second fluid,
• d) repeatedly scanning said core sample with X-rays during step c) and measuring the attenuation of said X-rays as they pass through said core sample to determine fluid saturation,
• e) injecting a plurality of increasing ratios of said first fluid to said second fluid into said core sample and displacing said first and second fluids from said core sample through a second member that is permeable to both said said first and second fluids to effect a plurality of differing steady-state conditions,
• f) repeatedly scanning said core sample with X-rays during each of the steady-state conditions in step e) and measuring the attenuation of said X-rays as they pass through said core sample to determine fluid saturation,
• g) terminating steps e) and f) at 100% first fluid injection into said core sample,
• h) injecting a plurality of decreasing ratios of said first fluid to said second fluid into said core sample to displace said first and second fluids through said second member to effect a plurality of differing steady-state conditions until a second irreducible first fluid saturation condition is reached,
• i) repeatedly scanning said core sample with X-rays during each of the steady-state conditions in step h) and measuring the attenuation of said X-rays as they pass through said core sample to determine fluid saturation,
• j) measuring pressure gradient along said core sample during steps b) through i), and
• k) determining two-phase, steady-state relative permeability of said first and second fluids in said core sample from said saturation and pressure measurements taken from said core sample during steps b) through i).