Page 24 - Formulas and Calculations for Petroleum Engineering

Reservoir engineering formulas and calculations Chapter 1 17

Formula(s)
h
L ¼
cos aðÞ
h
r
L h i L
w
r ¼ 0:454 * sin 360
w
4 h
Reference: Joshi, S. D. 1991, Horizontal Well Technology. Tulsa, Oklahoma: PennWell Publishing Company. Chapter: 3,
Page: 96.
1.34 Estimation of average reservoir pressure—MDH method

Input(s)
p ws : Shut-In Pressure (psi)
p DMDH : MDH Pressure (dimensionless)
m: Semi-log Straight Line of the MDH Plot (psi/cycle)

Output(s)

P r : Average Reservoir Pressure (psi)

Formula(s)
p DMDH
P ¼ p +m
r ws
1:1513
Reference: Ahmed, T., McKinney, P.D. 2005. Advanced Reservoir Engineering, Gulf Publishing of Elsevier, Chapter: 1,
Page: 59.

1.35 Formation temperature for a given gradient

Input(s)
T s : Temperature Near Surface (degree °F)
D: Total Depth (ft)
g G : Geothermal Gradient (degree °F/100 ft)

Output(s)
T f : Formation Temperature (degree °F)

Formula(s)

D
T ¼ T + g
f s G
100
Reference: Bassiouni, Z., 1994, Theory, Measurement, and Interpretation of Well Logs. SPE Textbook Series Vol. 4.
Chapter 4, Page: 75.
1.36 Fraction of the total solution gas retained in the reservoir as free gas

Input(s)

N: Oil in Place (STB)
R p : Produced Gas-Oil Ratio (SCF/STB)
N p : Cumulative Oil Production (STB)
R si : Initial Gas Solubility (SCF/STB)
R s : Gas Solubility (SCF/STB)