Method for determining physical properties of a porous sample using capillary pressure measurement

A method for determining pore-dependent properties of a porous sample, including the steps of:

• (a) performing nonwetting fluid intrusion measurements on the sample to generate capillary pressure data indicative of volume of intruded fluid versus applied pressure;
• (b) determining from the capillary pressure data the threshold capillary pressure, p.sub.c, and the associated characteristic length, l.sub.c =(-4).gamma.(cos.sub..theta.)/p.sub.c, where .gamma. is the nonwetting fluid surface tension and .theta. is the contact angle;
• and
• (c) determining, from the capillary pressure data, the pore diameter, l.sub.max.sup..sigma., at which the product of capillary diameter and the intruded fluid volume is a maximum, and the fraction S.sub.max.sup..sigma., of connected pore space filled with nonwetting fluid at the applied pressure corresponding to l.sub.max.sup..sigma. ;
• (d) determining the ratio, .sigma./.sigma..sub.0, from the expression .sigma./.sigma..sub.0 =(l.sup..sigma. max/l.sub.c)(.PHI.)(S.sub.max.sup..sigma.), where .PHI. is the porosity of the sample, .sigma. is the electrical conductivity of the sample when saturated with liquid, and .sigma..sub.o is the electrical conductivity of the liquid.

A method for determining pore-dependent properties of a porous sample, including the steps of:

• (a) performing mercury intrusion measurements on the sample to generate capillary pressure data indicative of volume of intruded mercury versus applied pressure;
• (b) determining from the capillary pressure data the threshold capillary pressure, p.sub.c, and the associated characteristic length l.sub.c =(-4).gamma.(cos.sub..theta.)/p.sub.c, where .gamma. is the surface tension of mercury and .theta. is the contact angle;
• (c) determining from the capillary pressure data the parameter l.sub.max.sup.k, where l.sub.max.sup.k is equal to the pore diameter at which the product of the cube of pore diameter and the volume of intruded mercury is a maximum, and the parameter S.sub.max.sup.k, where S.sub.max.sup.k is the fraction of connected pore space filled with mercury at the applied pressure corresponding to l.sub.max.sup.k ;
• and
• (d) determining from the capillary pressure data the parameter l.sub.max.sup..sigma., where l.sub.max.sup..sigma. is equal to the pore diameter at which the product of pore diameter and the volume of intruded mercury is a maximum, and the parameter S.sub.max.sup..sigma., where S.sub.max.sup..sigma. is the fraction of connected pore space filled with mercury at the applied pressure corresponding to l.sub.max.sup..sigma..