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FieldTwin Design comes with a set of pre-defined unit settings namely Metric, Field, and SI units.

Field units are primarily used by petroleum engineers, and Metric and SI are the same and are used internationally across the industry.

Metadata Unit Conversion

FieldTwin Design support on the fly conversion of numerical metadata values if you change the Unit type in the UI. As an example you can change the unit for the Outer Diameter shown below:


So to change this from inches to e.g. centimeters you select centimeters from the units drop down list as shown here:


This will the present the following dialog box to confirm the unit conversion:


Please Note!

Be aware that our unit conversion system may not be able to support all conversions!

After a succesful conversion the result will show in the metadata value reflecting the new unit selection.


Units for projects

You select which one to use for your project in Default Unit System under Project Settings.

Unit Categories

The following predefined units are available in the system:

Category Unit Type Unit Suffix
General Surface Power Density W/m2, mW/m2, kW/m2
General Frequency Hz, Hertz
General Force N, kN, Kg m/s2, lbf, g cm/s2
General Moment Nm, kNm, Kg m2/ s2, lbf – ft, g cm2/ s2
General Permeability um2, md
General Velocity mm/s, cm/s, m/s, km/s, in/s, ft/s, mi/s, mm/min, cm/min, m/min, km/min, in/min, ft/min, mi/min, mm/hr, cm/hr, m/hr, km/hr, in/hr, ft/hr, Mph, Knot
General Angle deg, rad, grad
General Density lb/gal, lb/ft3, g/cm3, kg/m3
General Dry Unit Weight N/m^3, kN/m^3
General Electrical V, kV, A, Hz
General Power W, kW, MW, hp, Btu/d, Btu/h, Btu/s, kcal/h, kcal/s
General Energy J, kJ, MJ, GJ, Wh, kWh, MWh, GWh
General Specific Heat Capacity kJ/(kg.K), Btu/(lbm.F), J/(g.K), J/(kg.K)
General Coefficient of thermal expansion 1/K, 1/C
General Thermal Conductivity W/m-K, Btu/(h.F.ft)
General U Value J/(s.C.m2), Btu/(h.F.ft2), kcal/(h.C.m2), W/m2/K, W/m2/C
General Viscosity kg/(m.s), cP, lbm/(ft.s)
General Volume ft3, cm3, bbl, gal, m3, L, mL, Mbbl
General Standard Volume MSm3, Sm3, scf, mscf, mmscf, MMSm3, mmstb
General Weight g, kg, te, Te, Short tons, lb
General Linear weight kg/m, Te/m, lb/ft, N/m, kN/m
General Area mm2, m2, in2, ft2, acre
General Time Seconds, Minutes, Hours, Days, Months, Years
General Stiffness lb/in, N/m, kN/m
Flowrate Gas Flowrate mmsm3/d, mmscf/d, MSCF/d, scf/d, scf/h, sm3/d, sm3/h, sm3/min, sm3/s, 1000sm3/d
Flowrate Liquid Flowrate STB/d, STB/h, STB/min, scf/min, sm3/d, sm3/h, sm3/min, sm3/s, m3/h, MSm3/d, litres/h, litres/m
Flowrate Barrels Per Day bpd, kbopd, kbpd, kbwpd
Flowrate Mass Flowrate lb/s, lb/h, lb/d, kg/s, kg/h, kg/d
Ratio Concentration ppm, mg/kg, mg/L
Ratio Gas Liquid Ratio SCF/STB, SCF/bbl, sm3/sm3, sm3/m3, %GVF
Ratio Gas Oil Ratio SCF/STB, SCF/bbl, sm3/sm3, sm3/m3, STB/MMscf​
Ratio Proportions %, fraction, decimal
Productivity Index Gas PI MMsm3/(d.bar2), mmscf/(d.psi2), mmscf/(d.kPa2), Msm3/(d.kPa2), sm3/(s.Pa2)
Productivity Index Liquid PI STB/(d.psi), STB/(d.kPa), sm3/(, sm3/(d.kPa), sm3/(d.MPa), sm3/(s.Pa)
Length Long Length m, km, ft, mi
Length Short Length mm, cm, m, km, in, ft, mi, 1/64in
Pressure Pressure bara, psia, psig, barg, atma, atmg, kPa a, kPa g, MPa a, MPa g, kgf/cm 2 a, kgf/cm 2 g, Pa a, Pa g
Pressure Pressure Differential bar, psi, atm, kPa, Pa, MPa, kgf/cm2
Temperature Temperature K, C, F
Unitless Unitless -
undefined undefined -

Request new unit types

There might be a need for you to include a new set of units for e.g. your metadata definitions or because of requirements for custom integrations etc. If so, we suggest that you contact, and explain your requirements and the use case so it can be considered for inclusion in a maintenance release. Note! Please include a sample unit description example as outlined below.

Unit Description Example

A Unit definition can :

  • Have a category
  • Have multiple units
  • Must have default for each unit system we support ( Metric, Field, SI ).

As an example:

<NumericalType Name="Gas Liquid Ratio" Category="Ratio" InternalUnit="STD_m3/m3" IsDefault="True">
    <Unit A="0.178108" B="1" C="0">SCF/STB</Unit>
  <Unit A="0.178108" B="1" C="0">SCF/bbl</Unit>
    <Unit A="" B="" C="">sm3/sm3</Unit>
    <Unit A="1" B="1" C="0">sm3/m3</Unit>
<NumericalType Name="Gas Oil Ratio" Category="Ratio" InternalUnit="STD_m3/m3" IsDefault="True">
    <Unit A="0.178108" B="1" C="0">SCF/STB</Unit>
  <Unit A="0.178108" B="1" C="0">SCF/bbl</Unit>
    <Unit A="" B="" C="">sm3/sm3</Unit>
    <Unit A="1" B="1" C="0">sm3/m3</Unit>   


"Gas Liquid Ratio": 
  "Metric": "sm3/sm3",
  "Field": "SCF/STB",
  "SI": "sm3/sm3"
"Gas Oil Ratio": 
  "Metric": "sm3/sm3",
  "Field": "SCF/STB",
  "SI": "sm3/sm3"

A, B, C values are not uses for now, but can be useful to define different constants of an equation to translate from one "InternalUnit" to the Unit defined.