Page 232 - Formulas and Calculations for Petroleum Engineering

Production engineering formulas and calculations Chapter 4 225

4.48 Lifetime of a hydraulically fractured well

Input(s)
m: Slope of the Production Decline Curve (bbl/day)
Q a : Production Rate just before the Abandonment of the Well (bbl/d)
Q 0 : Initial Production Rate following the Hydraulic Fracturing Operation (bbl/d)

Output(s)
t: Lifetime of a Hydraulically Fractured Well (days)

Formula(s)

Q a 1
t ¼ ln
Q 0 m jj
Reference: Saydam, T., (1967). Principles of Hydraulic Fracturing, ARI Publishing Co., Page: 86.

4.49 Mass of rock dissolved per unit mass of acid (acidizing)

Input(s)
M wm : Molecular Weight of Mineral (Rock) (g/mol)
M wa : Molecular Weight of Acid (g/mol)
A: Stoichiometric Coefficient of Mineral (Rock) (Number of Molecules)
B: Stoichiometric Coefficient of Acid (Number of Molecules)

Output(s)
β: Acid Dissolving Power (g/g)

Formula(s)

M wm A
β ¼
M B
wa
Reference: Williams, B. B., Gidley, J. L., & Schechter, R. S. (1979). Acidizing Fundamentals. Henry L. Doherty Memorial
Fund of AIME, Society of Petroleum Engineers of AIME, Page: 13.

4.50 Mass transfer in acid solutions by Fick’s law (acidizing)

Input(s)
2
D A : Diffusion Coefficient of Component A (cm /s)
4
∂c a /∂Y: Concentration Gradient (mol/cm )

Output(s)
2
U a,y : Diffusion Flux of a Component A in Y direction (mol/cm s)