A

=

pattern area , acres

Bo 
= 
oil formation volume factor , volume @ reservoir conditions divided by volume @ standard conditions, dimensionless 
Bw 
= 
water formation volume factor, volume @ reservoir conditions divided by volume @
standard conditions 
C 
= 
constant 
d 
= 
distance between adjacent rows of wells 
Ea 
= 
model areal sweep efficiency, area swept divided by total pattern area , fraction 
Ed 
= 
microscopic oil displacement efficiency , volume of oil displaced divided by total volume of oil , fraction 
Ev 
= 
volumetric sweep efficiency , fraction of total reservoir volume contacted by the injected fluid 
fo 
= 
fraction of total flowing stream composed of oil 
fw 
= 
fraction of total flowing stream composed of water 
h_{net} 
= 
formation thickness , ft 
i_{base} 
= 
injection rate of fluid having the same mobility as reservoir oil 
i_{w} 
= 
water injection rate , BPD 
k 
= 
absolute permeability , md 
k_{o} 
= 
effective permeability to oil , md 
k_{ro} 
= 
relative permeability to oil , fraction 
k_{rw} 

relative permeability to water, fraction 
k_{w} 
= 
effective permeability to water , md 
k_{w}k_{o} 
= 
water  oil permeability ratio, dimensionless 
Ln 
= 
natural logarithm , base

M 
= 
mobility ratio, mobility of the displacing fluid divided by the mobility of oil, dimensionless

N_{wf} 
= 
initial oil in place, bbl 
N_{p} 
= 
cumulative produced oil volume , bbl

DN_{p} 
= 
incremental oil produced , bbl 
p 
= 
pressure, psi

D
_{p}

= 
pressure difference, between the formation face injection pressure and the
pressure of the leading edge of the oil bank in the reservoir, psig 
p_{b} 
= 
bubble point or saturation pressure, psi 
p_{e} 
= 
pressure at external boundary, psi 
p_{i} 
= 
initial pressure, psi 
p_{iwf} 
= 
injection well bottom hole pressure , psi 
p_{o} 
= 
pressure in oil phase, atm 
p_{w} 
= 
pressure in water phase, atm or bottom hole pressure, psi 
p_{c} 
= 
capillary pressure, atm ( equal to po  pw ) 
q 
= 
production rate, BPD 
q_{o} 
= 
oil production rate, BOPD 
q_{w} 
= 
water production rate, BWPD 
Q_{i} 
= 
pore volumes of cumulative injected fluid 
r 
= 
radial distance, ft, water bank, prior to interference 
r_{e} 
= 
external boundary radius, ft, oil bank, prior to interference 
r_{w} 
= 
well radius , ft 
R_{s} 
= 
solution GOR, scf/bbl 
S_{g} 
= 
gas saturation , fraction of pore volume 
S_{g}* 
= 
gas saturation, in pilot flooding, equal to C * (S_{oi}S_{obt}) from fig E.7 
S_{gi} 
= 
initial gas saturation , fraction of pore volume 
S_{o} 
= 
oil saturation, fraction of pore volume 
S_{oi} 
= 
initial oil saturation , fraction of pore volume 
S_{or} 
= 
residual oil saturation, fraction of pore volume

S_{w} 
= 
water saturation, fraction of pore volume 
S_{w}

= 
average water saturation, fraction of pore volume 
S_{wi} 
= 
initial water saturation, fraction of pore volume 
S_{wc} 
= 
connate water saturation, fraction of pore volume 
dfw/dsw 
= 
slope of the fractional flow curve 
t 
= 
time , days 
V_{d} 
= 
displaceable volume , equal to the cumulative injected fluid as a fraction
of the product of the pattern pore volume and the displacement efficiency
of the flood

V_{p} 
= 
pore volume , bbl

W 
= 
water volume, bbl 
W_{i} 
= 
cumulative injected water volume, bbl 
DW_{i} 
= 
incremental injected water volume , bbl 
DW_{p}

= 
incremental produced water volume , bbl 
Wor 
= 
Water to oil ratio 
g 
= 
conductance ratio, ratio of injectivity of water at any pattern areal sweep to that of reservoir oil

l 
= 
mobility, ( k / m )

l_{g} 
= 
gas mobility , ( k_{g} /
m_{g}) 
l_{o} 
= 
oil mobility , ( k_{o} /
m_{o}) 
l_{w} 
= 
water mobility , ( k_{w} /
m_{w}) 
m 
= 
viscosity , cp 
m_{g} 
= 
gas
viscosity , cp 
m_{o} 
= 
oil viscosity , cp 
m_{w} 
= 
water viscosity ,
cp 
f 
= 
porosity , fraction 