Geomechanics and FracturingIn-Situ Stress and Rock Mechanics

Reservoir Stress Path from Biot Coefficient and Poisson Ratio Formula

A=\frac{\alpha(1-2\nu)}{1-\nu}

Reservoir Stress Path from Biot Coefficient and Poisson Ratio calculates stress path 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 (alpha, nu) 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, A equals 0.533333 dimensionless.

alphadimensionless

0.8

nudimensionless

0.25

Inputs

alpha

dimensionless

Biot Coefficient

nu

dimensionless

Poisson Ratio

Outputs

A

dimensionless

Stress Path

alpha

dimensionless

Biot Coefficient

nu

dimensionless

Poisson Ratio

Source and review

reviewed

Reservoir Geomechanics, Zoback, M.D. (2007)

Zoback, M.D. 2007. Reservoir Geomechanics, Cambridge University Press, Page 381.

Source