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Subscript symbols in alphabetical order

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Letter Subscript Reserve SPE Subscript Subscript Definition
Greek and Numerical
ε E strain
η diffusivity
θ angle, angular, or angular coordinate
λ M mobility
ρ density
Φ f,ε porosity
Φ f,ε porosity data, derived from tool-description subscripts: see individual entries such as "amplitude log," "neutron log," etc.
0 (zero) zr formation 100% saturated with water (used in R0 only)
1 p,pri primary
1,2,3, etc. location subscripts; usage is secondary to that for representing times or time periods
1,2,3, etc. numerical subscripts (intended primarily to represent times or time periods; available secondarily as location subscripts or for other purposes)
1,2,3, etc. times or time periods
½ half
2 s,sec secondary
conditions for infinite dimensions
a A abandonment
a A,α acoustic
a active, activity, or acting
a altered
a Ap apparent (general)
a A atmosphere, atmospheric
aF air/fuel
an AN annulus apparent (from log readings: use tool description subscripts)
anh anhydrite
ani anisotropic
ar after royalty
at after taxes
A a amplitude log
A areal
b B band or oil band
b bank or bank region
b r,β base
b bubble
b s,bp bubblepoint (saturation)
b B,t bulk (usually with volume, Vb)
b B burned or burning
bE burned in experimental tube run (usually with volume, VbE)
bh w, BH bottomhole
bp bubblepoint or saturation (usually with volume, Vbp)
Br before royalty
Bt B before taxes
B turbulence (used with F only, FB)
BT bt breakthrough
c C capillary (usually with capillary pressure, Pc)
c cg casing or casinghead
c chemical
c C compressional wave
c C constant
c C contact (usually with contact angle, θc)
c conversion (usually with conversion factor in Newton’s laws of motion, gc)
c C core
c cr critical
c ec electrochemical
cap capture
cb CB cement bond log
cf casing, flowing (usually with pressure)
cl cla clay
cn cln clean
cor corrected
cp compaction
cs casing, static (usually with pressure)
C calc calculated
C c caliper log
C c coil
C components(s)
C convective
CB cb bond log, cement
CD cd compensated density log
CL cl chlorine log
CN cn compensated neutron log
CO carbon monoxide
CO2 carbon dioxide
C1 methane
C2 ethane
d decay
d δ delay
d δ depleted region, depletion
d dewpoint
d differential separation
d dip (usually with angle, αd)
d D dispersed
d s,D displaced
d drainage (usually with drainage radius, rd)
dh DH downhole
dol dolomite
dy dty dirty (clayey, shaly)
D d density log
D dimensionless quantity
D s,σ displacing or displacement (efficiency)
DI di dual induction log
DLL dll (script ll) dual laterolog
DM dm diplog, dipmeter
DR dr directional survey
DT dt differential temperature log
Db displacement from burned portion of in-situ combustion pattern (usually with efficiency, EDb)
Dm dimensionless quantity at condition m
Du displacement from unburned portion of in-situ combustion pattern (usually with efficiency, EDu)
e o boundary conditions, external
e i cumulative influx (encroachment)
e E earth
e effective (or equivalent)
e E electric, electrical
e E entry
e o external or outer boundary conditions
el eℓ (script el) electron
eq EV equivalent
ext extrapolated
E e electrode
E EM empirical
E est estimated
E EX experimental
Eg experimental value per mole of produced gas (usually with fuel consumption, mEg)
EL el,ES electrolog, electrical log, electrical survey
EP ep electromagnetic pipe inspection log
f F finger or fingering
f F flash separation
f fl fluid
f fm formation (rock)
f R fraction or fractional
f F fracture, fractured, or fracturing
f F front, front region, or interface
d future
f fm rock (formation)
F F fill-up
F f free (usually with gas or gas/oil ration quantities)
F fuel (usually with fuel properties, such as ρF)
Ff free fluid
Fi free value, initial (usually with gas, GFi)
FP cumulative produced free value (usually with gas GFp)
G G gas
ga gas at atmospheric conditions
gb gas at bubblepoint conditions
gD gas, dimensionless
gr grain
gyp gypsum
G geometrical
ls lst limestone
L (script l) lateral, lineal
L (script l) lateral (resistivity log)
L (script l) liquid or liquid phase
Lp cumulative produced liquid (usually with condensate, GLp)
LL ℓℓ (script ll) laterolog (add further tool configuration subscripts as needed)
LLD ℓℓ (script ll) deep laterolog
LLS ℓℓs (script ll) shallow laterolog
LOG log log
Lp liquid produced, cumulative (usually with condensate, GLp)
LP ℓp (script l) light phase
M mass of fuel (usually with fuel concentration, Cm)
M mud
ma grain (matrix, solids)
ma matrix [solids except (nonstructural) clay or shale]
max maximum
mc mudcake
Mf mud filtrate
min minimum
M z,m mixture
M molal (usually with volume, VM)
M m Mth period or interval
M z,m slurry ("mixture")
ML mℓ (script l) contact log, microlog, minilog
MLL mℓℓ (script ll) microlaterolog
n net
n normal
n r,R normalized (fractional or relative)
ne noneffective
nw NW nonwetting
N n neutron
N n neutron log
N n normal (resistivity) log (add numerical spacing to subscript N; e.g., N16)
N2 nitrogen
NA na neutron activation log
NE ne neutron log, epithermal
NF nf neutron log, fast
NL nℓ (script l) neutron lifetime log, TDT
NM nm nuclear magnetism log
NT nt neutron log, thermal
o N oil (except when used with resistivity)
ob oil at bubblepoint conditions (usually with formation volume factor, Bob)
ob oil from burned volume (usually with displacement ratio, δob)
oD oil, dimensionless
og oil in gas cap (usually with saturation, Sog)
ou oil from unburned volume (usually with displacement ratio, δou)
O2 oxygen
p particle (usually with diameter, dp)
p P pore (usually with volume, Vp)
P present
p P produced
p produced, cumulative
p P production period (usually with time, tp)
p pseudo
pressure, mean or average
pc pseudocritical
pD pore value, dimensionless (usually with volume, VpD)
pD pseudodimensionless
pE produced in experiment
pj produced component j (usually with moles, npj)
po payout
pr pseudoreduced
pSP pseudo-SP
pv present value
P pattern (usually with pattern efficiency, Ep)
P phase or phases
P p proximity log
r R radius, radial, or radial distance
r reduced
r b,ρ reference
r R relative
r R residual
R rate
R ratio
R recovery (usually with recovery efficiency, ER)
R r reservoir
R resistivity
R r,ρ resistivity log
Rb reservoir rock, burned
Ru reservoir rock, unburned
Re Reynolds (used with Reynolds number only, NRe)
s d damage or damaged (includes "skin" conditions)
s formation, surrounding
s gas/oil ratio, solution
s S,σ segregation (usually with segregation rate, qs)
s τ shear
s τ shear wave
s S skin (stimulation or damage)
s σ slip or slippage
s σ solid (usually with volume or density)
s solution (usually with gas/oil ratios)
s spacing
s specific (usually with J and I)
s S stabilization (usually with time)
s S steam or steam zone
s S stimulation (includes "skin" conditions)
s σ surface
s surrounding formation
s S,σ swept or swept region
s σ system
sb solution at bubblepoint conditions (usually with gas/oil ratio, Rsb)
sc scattered, scattering
sc σ standard conditions
sd sa sand
sE solids in experiment
sh sha shale
si solution, initial (usually with gas/oil ratio, Rsi)
sl slt silt
sp separator conditions
sp single payment
ss sst sandstone
st stock-tank conditions
st s structural
sw solution in water (usually with gas solubility in water, Rsw)
S SW sidewall
S s,σ storage or storage capacity
saturation, mean or average
SN sn neutron log, sidewall
SP sp self potential
SSP spontaneous self potential
SV sv sonic, velocity, or acoustic log
SWN swn sidewall neutron log
t T gross (total)
t T total
t Τ treatment or treating
t tr true (electrical logging) (opposed to apparent)
t tg tubing or tubinghead
tD time, dimensionless
tf tubing flowing (usually with pressure)
ti total initial in place in reservoir
ts tubing, static (usually with pressure)
T h,θ temperature
T t,h temperature log
T t tool, sonde
T t transmissibility
TV tv televiewer log, borehole
u unburned
u U unit
u U unswept or unswept region
u U upper
ul a ultimate
v V vaporization, vapor, or vapor phase
v V velocity
V v vertical
V v volume or volumetric
Vb volumetric or burned portion of in-situ combustion pattern (usually with efficiency, EVb)
VD vd microseismogram log, signature log, variable density log
w W water
w well conditions
w W wetting
wa wellbore, apparent (usually with wellbore radius, rwa)
wb water from burned volume (usually with displacement ratio, δwb)
wD water, dimensionless
wf bottomhole, flowing (usually with pressure or time)
wf f well, flowing conditions (usually with time)
wF water/fuel
wg water in gas cap (usually with saturation, Swg)
wg wet gas (usually with composition or content,Cwg)
wgp wet gas produced
wh th wellhead
wo water/oil (usually with instantaneous producing water/oil ratio, Fwo)
wop water/oil, produced (cumulative) (usually with cumulative water/oil ratio, Fwop)
ws static bottomhole (usually with pressure or time)
ws s well, static, or shut-in conditions (usually with time)
W w weight
xo flushed zone
Y Young’s modulus, refers to
z conductive liquids in invaded zone
z zone, conductive invaded