Page 203 - Formulas and Calculations for Petroleum Engineering
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196 Formulas and calculations for petroleum engineering
3.45 Pressure buildup equation (Horner equation)
Input(s)
P i : Initial Reservoir Pressure (psi)
Q o : Stabilized Well Flow Rate before Shut-in (bbl/d)
m o : Oil Viscosity (cP)
B o : Oil Formation Volume Factor (rb/stb)
k: Permeability (mD)
h: Height (ft)
t p : Flowing Time before Shut-in (day)
Dt: Shut-in Time (day)
Output(s)
P ws : Pressure (psi)
Formula(s)
t + Dt
o
o
162:6 Q B m o p
P ¼ P log
i
ws
k h Dt
Reference: Ahmed, T., McKinney, P.D. 2005. Advanced Reservoir Engineering, Gulf Publishing of Elsevier, Chapter: 1,
Page: 54.
3.46 Radius of investigation
Input(s)
k: Permeability (mD)
t: Time (h)
ø: Porosity (fraction)
m: Viscosity (cP)
c t : Total Compressibility (1/psi)
Output(s)
r i : Radius of Investigation at the end of Injection Time (ft)
Formula(s)
!
0:5
k t
r ¼ 0:0359
i
ø m c
t
Reference: Ahmed, T., McKinney, P.D. 2005. Advanced Reservoir Engineering, Gulf Publishing of Elsevier, Chapter: 1,
Page: 134.
3.47 Radius of investigation (flow time)
Input(s)
t: Flow time (h)
k: Permeability (mD)