Geomechanics and FracturingIn-Situ Stress and Rock Mechanics

Drilling-Induced Tensile Fracture Margin Formula

M_T=\sigma_{\theta\theta}+T_s

Drilling-Induced Tensile Fracture Margin calculates tensile fracture stability margin 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_Hmax, S_hmin, P_p, P_W, T_s, sigma_DT) 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, M_T equals 610 psi.

S_Hmaxpsi

6300

S_hminpsi

4300

P_ppsi

3080

P_Wpsi

3710

T_spsi

800

sigma_DTpsi

Inputs

S_Hmax

psi

Total Maximum Horizontal Stress

S_hmin

psi

Total Minimum Horizontal Stress

P_p

psi

Pore Pressure

P_W

psi

Wellbore Mud Pressure

T_s

psi

Rock Tensile Strength

sigma_DT

psi

Thermally Induced Hoop Stress

Outputs

M_T

psi

Tensile Fracture Stability Margin

sigma_theta_min

psi

Minimum Hoop Stress at Tensile-Fracture Azimuth

T_s_req

psi

Tensile Strength Required for Neutral Margin

Source and review

reviewed

Introduction to Energy Geomechanics, Espinoza, D.N.

Espinoza, D.N. Introduction to Energy Geomechanics, Chapter 6.4, Eqs. 6.16-6.17.

Source