Page 34 - Formulas and Calculations for Petroleum Engineering

Reservoir engineering formulas and calculations Chapter 1 27

Formula(s)

G
app
G ¼
R

Reference: Ahmed, T., McKinney, P.D. 2005. Advanced Reservoir Engineering, Gulf Publishing of Elsevier, Chapter: 3,
Page: 216.

1.59 High-pressure region gas flow rate
Input(s)

k: Permeability (mD)
h: Thickness (ft)
P r : Average Reservoir Pressure (psi)
P wf : Bottom-hole Flowing Pressure (psi)
m gavg : Average Gas Viscosity (cP)
B gavg : Average Gas Formation Volume Factor (bbl/SCF)
r e : Drainage Radius (ft)
r w : Wellbore Radius (ft)
S: Skin (dimensionless)

Output(s)
Q g : Gas Flow Rate (MSCF/d)

Formula(s)

6
7:08 10 k h P P
r wf
Q ¼
g
r
B ln e 0:75 + S
r w
m gavg gavg
Reference: Ahmed, T., McKinney, P.D. 2005. Advanced Reservoir Engineering, Gulf Publishing of Elsevier, Chapter: 3,
Page: 189.
1.60 Horizontal well breakthrough time—With gas cap or bottom water
Input(s)

r o : Oil Density (g/cc)
r q : Gas Density (g/cc)
t bt : Breakthrough Time (days)
ø: Porosity (fraction)
h: Oil Column Thickness (ft)
m o : Oil Viscosity (cP)
q o : Flow Rate (cP)
B o : Oil Formation Volume Factor (rb/STB)
k h : Vertical Permeability (mD)
k v : Horizontal Permeability (mD)

Output(s)
t dbt : Breakthrough Time if breakthrough time is given (days)
q d : Dimensionless Flow Rate (dimensionless)