Page 147 - Petrophysics 2E
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120 PETROPHYSICS: RESERVOIR ROCK PROPERTIES
100
75
50
25
50 psl caplllaty pressure data
0 I I I I
0 50 100 150 200 250 300 350 4W 450 500
Specific Sulface Area, m*/cm3
Figure 3.19. Irreducible water saturation as a function of suvace area (spv) in
sandstone formation f28J
three methods, is related to the irreducible water saturation or simply
water saturation by a relationship of the general form:
spv = aeb& (3.39)
where a and b are constants of correlation. Zemanek investigated
low-resistivity sandstone reservoirs and found surface areas measured
with the NMR technique were quantitatively consistent with the
irreducible water saturations from the capillary pressure curve data [28].
Figures 3.19 and 3.20 demonstrate a good correlation between spv and
S, and hi, yielding, respectively:
sPv = 66.493e0.0339% (3.41)
where S, and !&, are expressed in percent and spv in m2/cm3. The
values of spv used in Figures 3.19 and 3.20 were obtained from
Equation 3.38.
FLOW UNIT CHARACTERIZATION FACTORS
(a) Reservoir quality index (RQI). Amaefule et al. also introduced
the concept of reservoir quality index (RQI), &/+)'I2, considering
the pore-throat, pore and grain distribution, and other macroscopic
