Page 188 - Formulas and Calculations for Petroleum Engineering

Well test analysis formulas and calculations Chapter 3 181

Output(s)

P Ds : Dimensionless Pressure (dimensionless)

Formula(s)

kh P P ws
i
P ¼
Ds
sc
0:4568v qBm
Reference: Ramey Jr, H. J. (1981). Reservoir Engineering Assessment of Geothermal Systems. Department of Petroleum
Engineering, Stanford University, Page: (5.7).
3.13 Dimensionless buildup pressure for steam or gas flow

Input(s)
k: Effective Permeability of Flowing Phase (D)
h: Net Formation Thickness (m)
P i : Initial Reservoir Pressure (psi)
P ws : Shut in Pressure (psi)
M: Molecular Weight (g/g mol)
q: Production Rate (tons/h (1000 kg/h))
Z: Real Gas Law Deviation Factor (Ratio)
m: Viscosity of Flowing Fluid (cP)
T: Absolute Formation Temperature (°K)

Output(s)
P Ds : Dimensionless Pressure (dimensionless)

Formula(s)

2 2
Mkh P P ws
i
P ¼
Ds
0:01291qmZT
Reference: Ramey Jr, H. J. (1981). Reservoir Engineering Assessment of Geothermal Systems. Department of Petroleum
Engineering, Stanford University, Page: (5.7).

3.14 Dimensionless buildup time

Input(s)
k: Effective Permeability of Flowing Phase (D)
t: Time (h)
∅: Porosity (Per cent)
m: Viscosity of Flowing Fluid (cP)
2 1
c t : Total System Effective Isothermal Compressibility (kg/cm )
r w : Well Radius (m)

Output(s)

t D : Dimensionless time (dimensionless)