Page 26 - Formulas and Calculations for Petroleum Engineering

Reservoir engineering formulas and calculations Chapter 1 19

1.39 Gas adsorbed in coal bed methane reservoirs

Input(s)
A: Area (acres)
h: Height (ft)
r b : Density (g/cc)
V: Adsorption Gas (SCF/ton)

Output(s)

G a : Gas Adsorbed (SCF)

Formula(s)
G ¼ 1359:7 A h r V
a b

Reference: Ahmed, T. & McKinney, P.D. Advanced Reservoir Engineering, Gulf Publishing House, Burlington, MA, 2015.

1.40 Gas bubble radius
Input(s)

A: Drainage Area (acres)
h: Thickness (ft)
s B : Bulk (g/cc)
G c : Gas Content (SCF/ton)

Output(s)
G: Gas-in-Place (SCF)

Formula(s)
G ¼ 1359:7 A h s G
B c
Reference: Ahmed, T., McKinney, P.D. 2005. Advanced Reservoir Engineering, Gulf Publishing of Elsevier, Chapter: 3,
Page: 227.

1.41 Gas cap ratio
Input(s)

G: Initial Gas Cap Volume (SCF)
B gi : Initial Gas Formation Volume Factor (bbl/SCF)
N: Initial Oil in Place (STB)
B oi : Initial Oil Formation Volume Factor (bbl/STB)

Output(s)
m: Gas Cap Ratio (dimensionless)

Formula(s)
G B
gi
m ¼
N B
oi
Reference: Ahmed,T., McKinney,P. Advanced Reservoir Engineering, Gulf Publishing House, Burlington, MA, 2015,
Chapter: 4, Page: 317.