Page 376 - Petrophysics

344 PETROPHYSICS: RESERVOIR ROCK PROPERTIES

TABLE 5.1C
CALCULATION OF THE INLET SATURATION, Si, USING THE HASSER-BRUNNER METHOD.
{Si = S(AVE) + Pc(HY) x (DsAvEIDP~)) and
{DSAVEIDP, = - (1 + c X SAVE)~~/(B - A X c)}

dS/dP P x dS/dP Si
1 .om 2.258 -0.036 -0.081 0.964
0.950 2.682 -0.034 -0.090 0.916
0.900 3.167 -0.031 -0.099 0.869
0.850 3.731 -0.029 -0.108 0.821
0.800 4.391 -0.027 -0.1 17 0.773
0.750 5.177 -0.024 -0.126 0.726
0.700 6.127 -0.022 -0.135 0.678
0.650 7.300 -0.020 -0.145 0.630
0.600 8.782 -0.017 -0.154 0.583
0.550 10.716 -0.01 5 -0.163 0.535
0.500 13.345 -0.013 -0.172 0.487
0.450 17.127 -0.01 1 -0.181 0.439
0.400 23.033 -0.008 -0.190 0.392
0.350 33.549 -0.006 -0.199 0.344
0.300 57.532 -0.004 -0.208 0.296
0.278 82.400 -0.003 -0.212 0.275

Substituting Equation 5.55 into Equation 5.54 yields:

(5.56)

for one pore volume, i.e. Vp = 1,

(5.57)

Assuming that cos 6 in Equation 5.1 1 is equal to 1.0, and substituting
Pc x r for 20 into Equation 5.56, the equation used for interpretation of
the pore throat size distribution from the capillary pressure is obtained:

(5.58)

The maximum pore throat size for the sample occurs at S, = 1.0
where rmax = 20/Pc-, and the minimum pore size that will conduct fluid
occurs at an irreducible water saturation (Si,) where rmi, = 20/Pcmm.