Production EngineeringInflow Performance

Damaged to Undamaged Productivity Ratio - Acidizing Formula

\frac{J_s}{J_o}=\frac{F_k\ln(r_e/r_w)}{\ln(r_s/r_w)+F_k\ln(r_e/r_s)}

Damaged to Undamaged Productivity Ratio - Acidizing calculates damaged or stimulated to undamaged productivity ratio for inflow performance workflows in production engineering.

Calculate

How engineers use this formula

Use this formula when the listed inputs (F_k, r_e, r_w, r_s) are known and the assumptions behind the cited inflow 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, J_ratio equals 0.527658 dimensionless.

F_kdimensionless

0.2

r_ein

12000

r_win

r_sin

Inputs

F_k

dimensionless

Permeability Ratio

r_e

Drainage Radius

r_w

Wellbore Radius

r_s

Damaged or Stimulated Zone Radius

Outputs

J_ratio

dimensionless

Damaged or Stimulated to Undamaged Productivity Ratio

F_k

dimensionless

Permeability Ratio

Source and review

reviewed

Williams, B.B., Gidley, J.L. and Schechter, R.S. 1979. Acidizing Fundamentals. Henry L. Doherty Memorial Fund of AIME, Society of Petroleum Engineers of AIME, Page 6.

Source