Geomechanics and FracturingIn-Situ Stress and Rock Mechanics

Classic Breakdown Pressure for a Vertical Wellbore Formula

P_b=3S_{hmin}-S_{Hmax}-P_p+T_o

Classic Breakdown Pressure for a Vertical Wellbore calculates breakdown pressure for in-situ stress and rock mechanics workflows in geomechanics and fracturing.

Calculate

How engineers use this formula

Use this formula when the listed inputs (S_hmin, S_Hmax, P_p, T_o) are known and the assumptions behind the cited in-situ stress and rock mechanics 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_b equals 5,700 psi.

S_hminpsi

5000

S_Hmaxpsi

6500

P_ppsi

3500

T_opsi

700

Inputs

S_hmin

psi

Minimum Horizontal Stress

S_Hmax

psi

Maximum Horizontal Stress

P_p

psi

Pore Pressure

T_o

psi

Rock Tensile Strength

Outputs

P_b

psi

Breakdown Pressure

S_hmin

psi

Minimum Horizontal Stress

S_Hmax

psi

Maximum Horizontal Stress

P_p

psi

Pore Pressure

T_o

psi

Rock Tensile Strength

Source and review

reviewed

TU Bergakademie Freiberg. Hydraulic Fracturing lecture notes, Eq. 1.27, conventional breakdown model.

Source