Page 508 - Enhanced Oil Recovery in Shale and Tight Reservoirs

472 Nomenclature

V w1 normalized water volume imbibed into the dry plug 1, L 3
V wsi water spontaneous imbibition volume, L 3
2
W work, mL /t 2
W dry weight of a dry core, m, g
W end weight of the core plug at the end of each flood, m, g
W exp weight of a core after removing the core from the vessel, m, g
W i weight of a core with water and oil at the end of cycle i, m, g
WI o wettability index of oil
WI w wettability index of water
3
W omin minimum oil content to maintain in situ combustion defined in Eq. 13.16, m/L ,
kg/m 3
W rDwDo weight of a core saturated with water and oil initially, m, g
W sat weight of an oil saturated core, m, g
x atomic H/C ratio of the fuel, or mole fraction, m/m
c W mole fraction of oil in the aqueous phase, m/m, fraction
o
c O mole fraction of oil in the oleic phase, m/m, fraction
o
c O mole fraction of water in the oleic phase, m/m, fraction
w
c W mole fraction of water in the aqueous phase, m/m, fraction
w
c O mole fraction of surfactant in the oleic phase, m/m, fraction
s
c W mole fraction of surfactant in the aqueous phase, m/m, fraction
s
x sw surfactant mole fraction in the aqueous surfactant solution, m/m, fraction
y gas mole fraction in oil, m/m, fraction (Chapter 2)
y w mole fraction of water in the gas mixture, fraction
Greek symbols
a surface deposition rate coefficient, 1/t, 1/day
b CO/CO 2 ratio in the exhaust gases (Chapter 13), or entrainment rate coefficient,
1/L, 1/ft (Chapter 3), or stress sensitivity index or permeability-stress exponent
(Chapters 2 and 12)
g plugging deposition rate coefficient, 1/L, 1/ft (Chapter 3), or interpolation
parameter for k r and p c at different wettabilities (Chapter 9)
g g gyromagnetic ration
g i rate coefficient for instantaneous plugging deposition, 1/L, 1/ft
d dimensionless parameter defined in Eq. 13.14
d c dimensionless parameter for the critical condition defined in Eq. 13.15
d o,SI fraction of oil volume by spontaneous imbibition in the total oil imbibition
volume in Eq. 9.61
d w,SI fraction of water volume by spontaneous imbibition in the total water imbibition
volume in Eq. 9.60
D operator that refers to a discrete change
2
2
DH heat value of crude from a DSC test, mL /t ,J

DT f front temperature minus a room temperature from a combustion tube test, T, K
q contact angle, degree
q osi oil wetting angle during spontaneous imbibition
q wsi water wetting angle during spontaneous imbibition
3
l thermal conductivity of the system, mL/t T, W/(m∙K)