Production EngineeringWell Performance
Flow Efficiency with Skin Pressure Drop Formula
Flow Efficiency with Skin Pressure Drop calculates flow efficiency for well performance workflows in production engineering.
How engineers use this formula
Use this formula when the listed inputs (p, p_wf, q, B, mu, s, k, h) are known and the assumptions behind the cited well performance 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, E equals 0.66112 fraction.
ppsi
3000
p_wfpsi
2500
qSTB/day
500
BRB/STB
1.2
mucP
2
sdimensionless
5
kmD
100
hft
50
Inputs
p
psiReservoir Pressure
p_wf
psiFlowing Bottom-Hole Pressure
q
STB/dayOil Flow Rate
B
RB/STBOil Formation Volume Factor
mu
cPOil Viscosity
s
dimensionlessSkin Factor
k
mDFormation Permeability
h
ftReservoir Thickness
Outputs
E
fraction
Flow Efficiency
Source and review
reviewedLee, Rollins and Spivey. Pressure Transient Testing, Page 43.
SourceRelated formulas and calculators
Effective Wellbore Radius of a Well in Presence of Uniform Flux Fractures
Well Performance
Effective Wellbore Radius of a Horizontal Well – Method 1 (Anisotropic Reservoirs)
Well Performance
Effective Wellbore Radius of a Horizontal Well – van der Vlis et al. Method
Well Performance