Page 201 - Formulas and Calculations for Petroleum Engineering

194 Formulas and calculations for petroleum engineering

Formula(s)

!
w ø h c m r w tp + Dt
2
m
m
m
l ¼
1:781 k t Dt
1 o f p 1
or
!
1 ø h c m r w tp + Dt
2
m
m
m
l ¼
1:781 k t Dt
1 o f p 2
Reference: Ahmed, T., McKinney, P.D. 2005. Advanced Reservoir Engineering, Gulf Publishing of Elsevier, Chapter: 1,
Page: 84.
3.42 Minimum shut-in time to reach pseudo-steady state for tight gas
reservoirs being hydraulically fractured
Input(s)
m g : Gas Viscosity (cP)
ø: Porosity (fraction)
c t : Total Compressibility (1/psi)
x f : Fracture Half Length (ft)
k: Permeability (mD)

Output(s)
t pss : Time (h)

Formula(s)

474 ø m c x 2
g t f
t ¼
pss
k
Reference: Ahmed, T., McKinney, P.D. 2005. Advanced Reservoir Engineering, Gulf Publishing of Elsevier, Chapter: 3,
Page: 23.

3.43 Permeability and reservoir pressure from buildup tests

Input(s)
t p : Time till which drawdown was done (h)
dt a : Time of shut in 1 from given values or trendline (h)
dt b : Time of shut in 2 from given values or trendline (h)
pws a : Well flowing Pressure at shut in point 2 from given values or trendline (psi)
pws b : Well flowing Pressure at shut in point 1 from given values or trendline (psi)
h: Thickness of Reservoir (ft)
m: Viscosity of Oil (cP)
p hr : Pressure at t ¼ 1 h (psi)
p wf : Pressure flowing well (psi)
Ø: Porosity (fraction)