Horner Pressure Buildup Equation Formula
Horner Pressure Buildup Equation calculates shut-in bottomhole pressure on horner straight line for pressure transient analysis workflows in reservoir engineering.
How engineers use this formula
Use this formula when the listed inputs (P_i, Q_o, B_o, mu_o, k, h, t_p, delta_t) 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_ws equals 3,418.721384 psi.
3500
500
1.2
2
50
50
240
24
Inputs
P_i
psiInitial or extrapolated reservoir pressure
Q_o
STB/dayStabilized oil rate before shut-in
B_o
RB/STBOil formation volume factor
mu_o
cPOil viscosity
k
mDPermeability
h
ftNet pay thickness
t_p
hProducing time before shut-in
delta_t
hShut-in time
Outputs
P_ws
Shut-in bottomhole pressure on Horner straight line
P_i
Initial or extrapolated reservoir pressure
Q_o
Stabilized oil rate before shut-in
B_o
Oil formation volume factor
mu_o
Oil viscosity
k
Permeability
h
Net pay thickness
t_p
Producing time before shut-in
delta_t
Shut-in time
Source and review
reviewedAhmed, T. and McKinney, P. D. 2005. Advanced Reservoir Engineering, Gulf Publishing of Elsevier, Chapter 1, Page 54.
Source