Page 240 - Formulas and Calculations for Petroleum Engineering

Production engineering formulas and calculations Chapter 4 233

Output(s)

2
σ z : Principal Stress in z-axis (kp/cm )

Formula(s)

γ h
σ ¼
z
10
Reference: Saydam, T., (1967). Principles of Hydraulic Fracturing, ARI Publishing Co., Page: 5.

4.67 Productivity index (for generating composite IPR curve)

Input(s)

q: Tested Flow Rate (STB/D)
P b : Bubble Point Pressure (psi)
P w : Wellbore Pressure (psi)
P: Reservoir Pressure (psi)

Output(s)
J i : Productivity Index (STB/D/psi)

Formula(s)

q
J ¼
i 2 !
P b P w P w
ð P P Þ + 1 0:2 0:8
b
1:8 P P
Reference: Boyun, G., William, C., & Ali Ghalambor, G. (2007). Petroleum Production Engineering: A Computer-Assisted
Approach, Page: 3/38.

4.68 Productivity ratio
Input(s)

J: Productivity Index of a well in any condition (fraction)
J sw : Productivity index of a standard well (fraction)

Output(s)

PR: Productivity Ratio (fraction)