Page 59 - Fundamentals of Reservoir Engineering
P. 59
NOMENCLATURE
ENGLISH G wellbore liquid gradient (McKinley after-flow
analysis, ch. 7)
A area G a apparent gas in place in a water drive gas
B Darcy coefficient in stabilized gas well reservoir (ch. 1)
inflow equations (ch. 8) G p cumulative gas production
B g gas formation volume factor h formation thickness
B o oil formation volume factor h p thickness of the perforated interval
B w water formation volume factor H total height of the capillary transition zone
c isothermal compressibility J Bessel function (ch. 7)
c e effective compressibility (applied to pore J Productivity index
volume) k absolute permeability (chs. 4,9,10)
c f pore compressibility k effective permeability (chs. 5,6,7,8)
c t total compressibility (applied to pore k r relative permeability obtained by normal-
volume) izing the effective permeability curves by
dividing by the absolute permeability
c total aquifer compressibility (c w+c f)
C arbitrary constant of integration r k thickness averaged relative permeability
C coefficient in gas well back-pressure k′ r end point relative permeability
equation (ch. 8) k iteration counter
C pressure buildup correction factor (Russell K r relative permeability obtained by
afterflow analysis ch. 7) normalizing the effective permeability
C A Dietz shape factor curves by dividing by the end point
permeability to oil (ch. 4)
D non-Darcy flow constant appearing in rate
dependent skin (ch. 8) I length
D vertical depth L length
e exponential m ratio of the initial hydrocarbon pore volume
ei exponential integral function of the gascap to that of the oil (material
balance equation)
E gas expansion factor m slope of the early, linear section of pressure
E f,w term in the material balance equation analysis plot of pressure (pseudo pressure)
accounting for the expansion of the vs. f(time), for pressure buildup, fall-off or
connate water and reduction in pore multi-rate flow test
volume m(p) real gas pseudo pressure
E g term in the material balance equation m′(p) pseudo pressure for two phases (gas-oil)
accounting for the expansion of the flow
gascap gas
E o term in the material balance equation M end point mobility ratio
accounting for the expansion of the oil M molecular weight
and its originally dissolved gas M s shock front mobility ratio
f fraction n reciprocal of the slope of the gas well back
f fractional flow of any fluid in the reservoir pressure equation (ch. 8)
f function; e.g. f(p) - function of the n total number of moles
pressure N stock tank oil initially in place (STOIIP)
F cumulative relative gas volume in PVT N p cumulative oil production
differential liberation experiment (ch. 2)
N pd dimensionless cumulative oil production (in
F non-Darcy coefficient in gas flow equation pore volumes)
(ch. 8)
N pD dimensionless cumulative oil production (in
F production term in the material balance moveable oil volumes)
equation (chs. 3,9) p pressure
F wellbore parameter in McKinley afterflow average pressure in aquifer (ch. 9)
analysis (ch. 7) p a
p b bubble point pressure
g acceleration due to gravity
g function; e.g.- g(p) function of pressure p c critical pressure
G gas initially in place – GIIP p d dynamic grid block pressure
p D dimensionless pressure
G gravity number (ch. 10)
p e pressure at the external boundary
p i initial pressure
