Gas Expansion Factor from Formation Volume Factor Calculator
Enter the declared reservoir engineering inputs below to solve E_g. Variable definitions, units, the default calculation, and the available source trail are included on this page.
What is available in this record
This record provides the functioning calculator, formula, declared variables and units, a reproducible default result, and the available citation metadata. A separately written engineering interpretation has not yet been published for this calculation.
Formula, variables, and default calculation
Reproducible default result
With the default values shown below, the calculation returns E_g = 208.058824 SCF/ft³. Defaults demonstrate the implementation; they are not recommended field values.
3000
0.85
600
Input definitions
P
psiaReservoir Pressure
z
dimensionlessGas Compressibility Factor
T
°RReservoir Temperature
Output definitions
E_g
Gas Expansion Factor
P
Reservoir Pressure
z
Gas Compressibility Factor
T
Reservoir Temperature
Source and record status
Source metadata identifies the relationship implemented by the calculator. Check the cited edition, unit basis, and scope against the engineering case before operational use.
Ahmed, T. 2007. Equations of State and PVT Analysis, Natural Gas Properties, Equations 3-52 through 3-54.
Open source reference