Page 146 - Petrophysics
P. 146
PERMEABILIW-POROSITY RELATIONSHIPS 119
TABLE 3.3
2D PIA PORE SHAPE FACTORS
0 1
0 1.27
1.65
0 3.75
0 5.84
practical relation between the 2D pore shape factor fps and the 3D pore
shape factor Kps. For an ideal spherical pore fps = 1 and Kps = 6.
The nuclear magnetic resonance or NMR method appears to be
currently the most accurate technique for estimating the specific surface
area. In this case, the specific surface areas SVgr and spv are obtained
from:
(3.37)
(3.38)
where:
ANMR = NMR surface area of dry material, m2/g
pm = grain-matrix density, g/cm3
svgr = specific surface area per unit grain volume, m2/cm3
Values of spv and svgr obtained from NMR are generally higher than
values obtained by PIA or the gas adsorption technique. Several studies
have found that the specific surface area, measured with any of these
