Reservoir EngineeringFluid Flow in Porous Media
Low-Pressure Gas Radial Flow Rate Formula
Low-Pressure Gas Radial Flow Rate calculates gas flow rate for fluid flow in porous media workflows in reservoir engineering.
How engineers use this formula
Use this formula when the listed inputs (k, h, p_R, p_wf, T, mu_g, z, r_e, r_w, s) are known and the assumptions behind the cited fluid flow in porous media 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, q_g equals 15,398,735.37929 scf/day.
kmD
50
hft
40
p_Rpsia
1200
p_wfpsia
800
T°R
620
mu_gcP
0.018
zdimensionless
0.9
r_eft
1000
r_wft
0.328
sdimensionless
0
Inputs
k
mDPermeability
h
ftNet Pay Thickness
p_R
psiaAverage Reservoir Pressure
p_wf
psiaFlowing Bottom-Hole Pressure
T
°RReservoir Temperature
mu_g
cPGas Viscosity
z
dimensionlessGas Compressibility Factor
r_e
ftDrainage Radius
r_w
ftWellbore Radius
s
dimensionlessSkin Factor
Outputs
q_g
scf/day
Gas Flow Rate
Source and review
reviewedAAPG Wiki. Fluid flow fundamentals, low-pressure gas reservoir IPR equation.
Source