Pseudosteady-State Flowing Pressure for Non-Circular Reservoir Formula
Pseudosteady-State Flowing Pressure for Non-Circular Reservoir calculates well flowing pressure for pressure transient analysis workflows in reservoir engineering.
How engineers use this formula
Use this formula when the listed inputs (p_i, k, h, B, mu, C_A, r_w, Q, c_t, phi, t, A) are known and the assumptions behind the cited pressure transient analysis relationship match the engineering case being checked.
Assumptions
- Input values are representative for the well, reservoir, fluid, or equipment case being evaluated.
- The declared units match the field-unit constants used in the formula.
- The cited formula applies to the selected petroleum engineering workflow.
Limitations
- The calculation does not replace a full engineering model or operating procedure.
- Accuracy depends on the source correlation, assumptions, input quality, and unit consistency.
Common mistakes
- Mixing unit systems without converting the inputs.
- Using default example values as field recommendations.
- Applying the formula outside the source assumptions.
Default example
Using the default inputs, P_wf equals 3,837.143375 psi.
4000
100
50
1.2
1
31.6
0.25
500
0.00001
0.2
100
4356000
Inputs
p_i
psiInitial Reservoir Pressure
k
mDPermeability
h
ftFormation Thickness
B
bbl/STBFormation Volume Factor
mu
cPViscosity
C_A
dimensionlessReservoir Shape Factor
r_w
ftWellbore Radius
Q
STB/dayFlow Rate
c_t
1/psiTotal Compressibility
phi
fractionPorosity
t
hFlowing Time
A
ft^2Drainage Area
Outputs
P_wf
Well Flowing Pressure
p_i
Initial Reservoir Pressure
Q
Flow Rate
B
Formation Volume Factor
h
Formation Thickness
Source and review
reviewedAdvanced Reservoir Engineering, Ahmed, T., McKinney, P. D. (2005)
Ahmed, T. and McKinney, P. D. 2005. Advanced Reservoir Engineering, Gulf Publishing of Elsevier, Chapter 1, Page 33.
Source