Reservoir EngineeringPressure Transient Analysis
Time to Pseudosteady State in Circular Reservoir Formula
Time to Pseudosteady State in Circular Reservoir calculates time to pseudosteady state for pressure transient analysis workflows in reservoir engineering.
How engineers use this formula
Use this formula when the listed inputs (phi, mu, c_t, r_e, k) 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, t_pss equals 51.84 h.
phifraction
0.18
mucP
1.2
c_t1/psi
0.00001
r_eft
1000
kmD
50
Inputs
phi
fractionPorosity
mu
cPFluid Viscosity
c_t
1/psiTotal Compressibility
r_e
ftReservoir Drainage Radius
k
mDPermeability
Outputs
t_pss
h
Time to Pseudosteady State
phi
fraction
Porosity
mu
cP
Fluid Viscosity
c_t
1/psi
Total Compressibility
r_e
ft
Reservoir Drainage Radius
k
mD
Permeability
Source and review
reviewedMatthews, C. S. and Russell, D. G. Pressure Buildup and Flow Tests in Wells, Page 13.
Source