Page 15 - Geology and Geochemistry of Oil and Gas

xiv NOMENCLATURE

seismic velocity
V s
v specific volume
variation of anisotropy
v l
variation of resistivity
v R
altitude of comparison surface with equal normalized pressure
z o
a level of significance (confidence level)
SP reduction factor
a SP
b modulus of elasticity
b c irreversible compaction factor (compressibility factor)
g density
g o oil density
g w water density
Z cl relative clay content in rock
Z p pore-pressure gradient
Z pore-pressure gradient in shales
sh
Z r formation-pressure gradient in reservoir rocks
l anisotropy coefficient
m dynamic viscosity
n kinematic viscosity
s stress; tension
s standard deviation, or mean square error
s R standard deviation of resistivity
s r standard deviation of correlation coefficient
t electrical tortuosity of pore channels
t w thickness of pore-water film
f porosity
f 0 ‘‘residual’’ porosity
f eff effective porosity
f sh shale porosity
w sh relative content of argillaceous (shale) beds
o frequency or probability
So cumulative frequency or cumulative probability
S macroscopic cross-section of thermal neutron capture (absorption)