Page 192 - Formulas and Calculations for Petroleum Engineering

Well test analysis formulas and calculations Chapter 3 185

Output(s)

P d : Dimensionless Pressure (dimensionless)

Formula(s)

P P
i
P ¼
d
P P wf
i
Reference: Lee, J., Rollins, J. B., & Spivey, J. P. (2003). Pressure Transient Testing (Vol. 9). Richardson, Texas: Society of
Petroleum Engineers, Page: 9.

3.22 Dimensionless pressure (radial-flow/constant rate production)

Input(s)
p i : Initial Reservoir Pressure (psi)
p: Reservoir Thickness (psi)
k: Permeability (mD)
h: Reservoir Thickness (ft)
q: Formation Volume Factor (STB/day)
B: Volume Factor (RB/STB)
m: Oil Viscosity (cP)

Output(s)

P d : Dimensionless Pressure (dimensionless)

Formula(s)

k h
P ¼ p pð i Þ
d
141:2 q B m
Reference: Lee, J., Rollins, J. B., & Spivey, J. P. (2003). Pressure Transient Testing (Vol. 9). Richardson, Texas: Society of
Petroleum Engineers, Page: 8.

3.23 Dimensionless pressure drop across a skin at the well face
Input(s)

k: Effective Permeability of Flowing Phase (D)
h: Net Formation Thickness (m)
P i : Initial Reservoir Pressure (psi)
P 1hr : Pressure at 1 hour on semi-log straight line or its extension (psi)
P ws : Shut in Pressure (psi)
P wf : Bottomhole Pressure at a flowing well (psi)
v sc : Specific Volume at Standard Conditions (cc/g)
3
q: Production Rate (m /h)
B: Formation Volume Factor (Reservoir Volume/Standard Volume)
m: Viscosity of Flowing Fluid (cP)
2 1
c t : Total System Effective Isothermal Compressibility (kg/cm )
r w : Well Radius (m)
2
m: Slope of Semi-Log Graph (kg/cm )/ Log cycle for Liquid
∅: Porosity (Per cent)