PetroCalcHubFree
Browse
Geomechanics and FracturingIn-Situ Stress and Rock Mechanics

Rotation of Maximum Principal Stress Zoback Day Lewis Calculator

γ=12tan⁡−1(Aqsin⁡2Δ1+Aqcos⁡2Δ)\gamma=\frac{1}{2}\tan^{-1}\left(\frac{Aq\sin 2\Delta}{1+Aq\cos 2\Delta}\right)

Enter the required inputs, confirm the units, and run the calculator to solve gamma_rad. Review the formula source and assumptions before using the result in engineering work.

Tabular solver

Inputs

Defaults provide a quick field-unit example for the equation.

3 variables

Calculation runs locally with the shared TypeScript engine.

Formula reference

Rotation of Maximum Principal Stress Zoback Day Lewis calculates stress rotation for in-situ stress and rock mechanics workflows in geomechanics and fracturing.

View formula, units, and source

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.

Common mistakes

  • Mixing unit systems without converting the inputs.
  • Using default example values as field recommendations.
  • Applying the formula outside the source assumptions.