LOG CURVE and PARAMETER MNEMONICS
The log curve names and parameter names used in the equations on this website have been chosen to be easily recognized and to be "computer-ready". The names do not reflect any particular service company's nomenclature.

Three simple rules were used: input parameters and input log curves are always UPPER case; output curves or output result values are MIXed case. There are no subscripts or superscripts, and Greek symbols are spelled ponetically

As for all rules, there are exceptions, especially for output result values where commonly used abbreviations are well established, such as OOIP for original oil in place. Output curves from one calculation step are often input curves for a succeeding calculation, but the inout curve does not become upper case, because it is still an output curve from the prior step.

For example:
  DENS or PHID or RESD are input log curves
  DENSMA or CPERM are an input analysis parameters
  DENSma or PHIe are output log curves and could be inputs to another calculation
  Reserves or OOIP are output result values

Computer software needs to distinguish between a log curve and a parameter value. Each software package does this in different ways. For example, the distinction is declared in some packages, or a special symbol may be used to define a loog cure, such as [ ] after the curve name.

See Also:
Log Curve Alias Table     Abbreviations for Seismic Petrophysics

THE LIST
A = tortuosity exponent (fractional)

Alith = calculated neutron density lithology factor (fractional)

ALITH1 = neutron density lithology factor for 1st mineral (fractional)

ALITH2 = neutron density lithology factor for 2nd mineral (fractional)

ALITH3 = neutron density lithology factor for 3rd mineral (fractional)

API = oil gravity (API units)

AREA = area of reservoir (acres)

 

Bg = gas formation volume factor (fractional)

BHT = bottom hole temperature (degrees F or degrees C)

BHTDEP = depth at which BHT was measured (ft or m)

Bo = oil formation volume factor

BVW = bulk volume of free water (fractional)

BVWm = bulk volume of moveable water (fractional)

BVI = bulk volume of irreducible water (fractional)

BVWir = bulk volume of irreducible water (fractional)

BVH = bulk volume of hydrocarbon (fractional)

BVHm = bulk volume of moveable hydrocarbon (fractional)

BVHr = bulk volume of residual hydrocarbon (fractional)

BVWsh = bulk volume of water bound to 100 % shale (fractional)

 

C = intermediate term in Simandoux equation

CAL = caliper log reading, borehole diameter (mm or inches)

CBW = clay bound water (fractional)

Ccl = water salinity (ppm Cl)

CPERM = permeability constant (fractional)

 

D = intermediate term in Simandoux equation

DTC = sonic log reading (usec/ft or usec/m)

DTCc = sonic log reading corrected for shale (usec/ft or usec/m)

DTCMA = sonic log reading in 100% matrix rock (usec/ft or usec/m)

DTCSH = sonic log reading in 100% shale (usec/ft or usec/m)

DTCW = sonic log reading in 100% water (usec/ft or usec/m)

DTC1 = sonic log reading in 1st mineral (usec/ft or usec/m)

DTC2 = sonic log reading in 2nd mineral (usec/ft or usec/m)

DTC3 = sonic log reading in 3rd mineral (usec/ft or usec/m)

DENS = density log reading (gm/cc or Kg/m3)

DENSc = density log reading corrected for shale (gm/cc or Kg/m3)

DENShy = calculated hydrocarbon density (gm/cc or Kg/m3)

DENSMA = density log reading in 100% matrix rock (gm/cc or Kg/m3)

DENSma = calculated matrix density (gm/cc or Kg/m3)

DENSSH = density log reading in 100% shale (gm/cc or Kg/m3)

DENSW = density log reading in 100% water (gm/cc or Kg/m3)

DENS1 = density log reading in 1st mineral (gm/cc or Kg/m3)

DENS2 = density log reading in 2nd mineral (gm/cc or Kg/m3)

DENS3 = density log reading in 3rd mineral (gm/cc or Kg/m3)

DEPTH = formation depth (ft or m)

DPERM = porosity exponent for permeability calculation (fractional)

DTC = compressional travel time (usec/ft or usec/m)

DTMA_C = matrix rock compressional travel time (usec/ft or usec/m)

DTMA_S = m atrix rock shear travel time (usec/ft or usec/m)

DTS = shear travel time (usec/ft or usec/m)

 

E = intermediate term in Simandoux equation

EPERM = irreducible saturation exponent (fractional)

 

F = formation factor (unitless)

FFI = free fluid index (fractional)

FT = formation temperature (degrees Fahrenheit or Celcius)

FT1 = formation temperature (degrees Fahrenheit)

 

GOR = gas oil ratio (cf/bbl or m3/m3)

GPERM = constant in Coates permeability equation

GR = gamma ray log reading (API units)

GR0 = gamma ray log reading in 100% clean zone (API units)

GR100 = gamma ray log reading in 100% shale (API units)

GRAD = temperature gradient (degrees F/ft or degrees C/m)

 

HPV = HydH = hydrocarbon volume per unit area (ft or m)

HPERM = constant in permeability equation

I = formation resistivity index (unitless)

JPERM = exponent in permeability equation

 

KBUCKL = Buckles number, porosity times water saturation product  (fractional)

KCP = sonic log compaction factor (fractional)

KD = gas correction factor for density porosity (fractional)

Kh = flow capacity or permeability-thickness product (md-ft or md-m)

Klith = calculated sonic density lithology factor (fractional)

KLITH1 = sonic density lithology factor for 1st mineral (fractional)

KLITH2 = sonic density lithology factor for 2nd mineral (fractional)

KLITH3 = sonic density lithology factor for 3rd mineral (fractional)

KN = gas correction factor for neutron porosity (fractional)

KPERM = permeability constant (fractional)

KS = gas correction factor for sonic porosity (fractional)

KSP = temperature factor for SP calculation (degrees F)

Krg = relative permeability to gas (fractional)

Kro = relative permeability to oil (fractional)

Krw = relative permeability to water (fractional)

KRwg = water to gas permeability ratio (fractional)

KRwo = water to oil permeability ratio (fractional)

 

Lh = any log reading in 100% hydrocarbon

Li = any log reading in 100% of the ith component of matrix rock

LOG = any log reading

Lsh = any log reading in 100% shale

Lw = any log reading in 100% water

 

M = cementation exponent (fractional)

Min1,2,3 = relative volume of mineral 1, mineral 2, mineral 3, etc (fractional)

Mlith = calculated sonic density lithology factor (fractional)

MLITH1 = sonic density lithology factor for 1st mineral (fractional)

MLITH2 = sonic density lithology factor for 2nd mineral (fractional)

MLITH3 = sonic density lithology factor for 3rd mineral (fractional)

 

N = saturation exponent (fractional)

NetH = net pay thickness (ft or m)

Nlith = calculated neutron density lithology factor (fractional)

NLITH1 = neutron density lithology factor for 1st mineral (fractional)

NLITH2 = neutron density lithology factor for 2nd mineral (fractional)

NLITH3 = neutron density lithology factor for 3rd mineral (fractional)

 

PE = effective photoelectric cross section (barns/cm3)

Perm = calculated permeability (millidarcies)

Permd = calculated permeability from Dumanoir method (md)

Permp = calculated permeability from porosity method (md)

Permw = calculated permeability from Wyllie method (md)

PEsh = photoelectric log reading in 100% shale (barns/electron)

PE1 = photoelectric log reading in 100% of 1st matrix component (barns/electron)

PE2 = photoelectric log reading in 100% of 2nd matrix component (barns/electron)

PF = formation pressure (psi or KPa)

PHIavg = average porosity (fractional)

PHIbvw = effective porosity from BVW method (fractional)

PHID = density log reading (fractional)

PHIdc = porosity from density log corrected for shale (fractional)

PHIDDC = density dry clay point (fractional)

PHIDm = density log reading corrected for matrix offset (fractional)

PHIDSH = density log reading in 100% shale (fractional)

PHIe = effective porosity (fractional)

PHIept = total porosity from electromagnetic log (fractional)

PhiH = pore volume per unit area (ft or m)

PHIMAX = maximum expected porosity in clean rock (fractional)

PHImx = effective porosity from PHIMAX method (fractional)

PHIN = neutron porosity log reading (fractional)

PHInc = neutron porosity corrected for shale (fractional)

PHINDC = neutron log dry clay point (fractional)

PHINm = neutron log reading corrected for matrix offset (fractional)

PHINMA = neutron log reading in 100% matrix rock (fractional)

PHInml = nuclear magnetic log reading (fractional)

PHINSH = neutron log reading in 100% shale (fractional)

PHINW = neutron log reading in 100% water (fractional)

PHIrt = porosity calculated from deep resistivity log (fractional)

PHIs = total porosity from sonic log (fractional)

PHIsc = porosity from sonic log corrected for shale (fractional)

PHIsec = secondary (vuggy) porosity from sonic log (fractional)

PHISSH = sonic porosity of 100% shale (fractional)

PHIt = total porosity from any log (fractional)

PHItrue = true porosity from core analysis or density neutron crossplot (fractional)

PHIuse = useful porosity (fractional)

PHIwtr = total porosity in a water zone, used to find RW@FT from R0 (fractional)

PHIx = intermediate result in density neutron porosity calculation

PHIxdn = porosity from density neutron crossplot (fractional)

PS = standard surface pressure (psi or KPa)

Pv = Pore Volume (ft or m)


Qg = calculated gas productivity (mcf/day)

Qo = calculated oil productivity (bbl/day)

 

R0 = resistivity of rock filled with water (ohm-m)

RESD = deep resistivity log reading (ohm-m)

R0 = resistivity of rock filled with water (ohm-m)

RESD = deep resistivity log reading (ohm-m)

RESM = medium resistivity reading (ohm-m)

RESS = shallow resistivity log reading (ohm-m)

RF = recover factor (fractional)

Rgas = recoverable reserves of gas (mcf or m3)

RMFE = equivalent mud filtrate resistivity (ohm-m)

RMF@FT = mud filtrate resistivity (ohm-m)

RMF@TRMF = mud filtrate resistivity at measured temperature (ohm-m)

Ro = computed resistivity of rock filled with water (ohm-m)

Roil = recoverable reserves of oil (bbl or m3)

RSH = resistivity of shale (ohm-m)

RSP = RWE / RMFE in SP calculation (fractional)

RW@FT = water resistivity at formation temperatures (ohm-m)

RW@TRW = water resistivity at measured temperature (ohm-m)

RWa = apparent water resistivity (ohm-m)

RWai = apparent water resistivity of ith layer (ohm-m)

RWSH = water resistivity of water bound to shale (ohm-m)

 

Smo = moved oil water saturation from any method (fractional)

SP = spontaneous potential log reading in zone of interest (mv)

SP0 = spontaneous potential log reading in 100% clean zone (mv)

SP100 = spontaneous potential log reading in 100% shale (mv)

Sro = residual oil water saturation from any method (fractional)

SUFT = surface temperature (degrees Fahrenheit or Celcius)

Sw = calculated water saturation from any method (fractional)

SWa = water saturation from Archie method (fractional)

SWavg = average water saturation (fractional)

SWd = water saturation from Dual Water method (fractional)

Swpt = invaded zone saturation from EPT method (fractional)

SWir = irreducible water saturation (fractional)

SWp = water saturation from porosity saturation product (fractional)

SWs = water saturation from Simandoux method (fractional)

SWt = total water saturation (fractional)

Sxo = water saturation in the invaded zone from any method (fractional)

 

TARwt% = tar weight (percent)

THICK = zone or layer thickness (ft or m)
TRW = temperature at which RW was measured (deg F or deg C)

 

Uma = computed matrix photoelectric absorption cross section  (barns/cm3)

UMA1 = photoelectric absorption cross section of 1st mineral (barns/cm3)

UMA2 = photoelectric absorption cross section of 2nd mineral (barns/cm3)

UMA3 = photoelectric absorption cross section of 3rd mineral (barns/cm3)

USH = photoelectric absorption cross section in 100% shale (barns/cm3)

 

Vcl = bulk volume of clay (fractional)

VISd = viscosity of dead oil (cp)

VISg = viscosity of gas (cp)

VISo = viscosity of live oil (cp)

VISw = viscosity of water (cp)

Vi = bulk volume of ith component of matrix rock (fractional)

Vrock = bulk volume of rock matrix (fractional)

Vsh = shale volume from any method (fractional)

Vshc = shale volume corrected for non-linear effects (fractional)

Vshg = shale volume from gamma ray log (fractional)

Vshmin = shale volume from minimum method (fractional)

Vshs = shale volume from spontaneous potential log (fractional)

Vshx = shale volume from density neutron crossplot method (fractional)

Vsilt = volume of silt (fractional)

 

WCg = water cut for gas well (fractional)

WCo = water cut for oil well (fractional)

WGr = water gas ratio (fractional)

WOr = water oil ratio (fractional)

WS = water salinity input constant (ppm NaCl)

WTrock = rock weight (tonnes/m2)

WTsh = shale weight (tonnes/m2)

WTsnd = sand weight (tonnes/m2)

WToil = oil weight (tonnes/m2)

WTwtr = water weight (tonnes/m2)
Woil = oil mass (fractional)

 

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