Pseudo-Skin Factor Due to Partial Penetration - Papatzacos Correlation Formula
Pseudo-Skin Factor Due to Partial Penetration - Papatzacos Correlation calculates partial-penetration pseudo-skin factor for well performance workflows in production engineering.
How engineers use this formula
Use this formula when the listed inputs (h_p, h, h_1, k_h, k_v, r_w) 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, s_p equals 4.185235 dimensionless.
40
100
20
100
25
0.33
Inputs
h_p
ftPerforated Interval
h
ftTotal Pay Thickness
h_1
ftDistance from Reservoir Top to Top of Open Interval
k_h
mDHorizontal Permeability
k_v
mDVertical Permeability
r_w
ftWellbore Radius
Outputs
s_p
Partial-Penetration Pseudo-Skin Factor
b
Penetration Ratio
A_p
Papatzacos Anisotropy Constant A
B_p
Papatzacos Location Constant B
h_d
Dimensionless Payzone Thickness
Source and review
reviewedHorizontal Well Technology, Joshi, S.D. (1991)
Joshi, S.D. Horizontal Well Technology, Page 498.