Reservoir EngineeringPVT and Rock-Fluid Properties
Compressibility Drive in Gas Reservoirs Formula
Compressibility Drive in Gas Reservoirs calculates compressibility index for pvt and rock-fluid properties workflows in reservoir engineering.
How engineers use this formula
Use this formula when the listed inputs (G, E_f, B_g, G_p) are known and the assumptions behind the cited pvt and rock-fluid properties relationship match the engineering case being checked.
Assumptions
- Input values are representative for the well, reservoir, fluid, or equipment case being evaluated.
- The declared units match the field-unit constants used in the formula.
- The cited formula applies to the selected petroleum engineering workflow.
Limitations
- The calculation does not replace a full engineering model or operating procedure.
- Accuracy depends on the source correlation, assumptions, input quality, and unit consistency.
Common mistakes
- Mixing unit systems without converting the inputs.
- Using default example values as field recommendations.
- Applying the formula outside the source assumptions.
Default example
Using the default inputs, CI equals 40 dimensionless.
GMSCF
10000
E_fbbl/MSCF
0.02
B_gbbl/MSCF
0.005
G_pMSCF
1000
Inputs
G
MSCFGas in Place
E_f
bbl/MSCFGas Compressibility Drive
B_g
bbl/MSCFGas Formation Volume Factor
G_p
MSCFGas Produced
Outputs
CI
dimensionless
Compressibility Index
G
MSCF
Gas in Place (rearranged)
E_f
bbl/MSCF
Gas Compressibility Drive (rearranged)
B_g
bbl/MSCF
Gas Formation Volume Factor (rearranged)
G_p
MSCF
Gas Produced (rearranged)
Source and review
reviewedAhmed, T., McKinney, P.D. Advanced Reservoir Engineering, Gulf Publishing House, Burlington, MA, 2015.
Source