Reservoir EngineeringPressure Transient Analysis
Estimation of Average Reservoir Pressure – MDH Method Formula
Estimation of Average Reservoir Pressure – MDH Method calculates average reservoir pressure for pressure transient analysis workflows in reservoir engineering.
How engineers use this formula
Use this formula when the listed inputs (p_ws, m, p_DMDH) 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_r equals 3,043.429167 psi.
p_wspsi
3000
mpsi/cycle
50
p_DMDHdimensionless
1
Inputs
p_ws
psiShut-In Pressure
m
psi/cycleSemi-log Slope of MDH Plot
p_DMDH
dimensionlessMDH Pressure
Outputs
P_r
psi
Average Reservoir Pressure
p_ws
psi
Shut-In Pressure (rearranged)
m
psi/cycle
Semi-log Slope (rearranged)
p_DMDH
dimensionless
Dimensionless MDH Pressure (rearranged)
Source and review
reviewedAhmed, T., McKinney, P.D. (2005). Advanced Reservoir Engineering. Gulf Publishing Company, Chapter 1, Page 59.
Source