Geomechanics and FracturingIn-Situ Stress and Rock Mechanics

Velocity of Bulk Compressional Waves Formula

V_b=\sqrt{\frac{E}{\rho}\frac{1-\nu}{(1+\nu)(1-2\nu)}}

Velocity of Bulk Compressional Waves calculates velocity of bulk compressional waves for in-situ stress and rock mechanics workflows in geomechanics and fracturing.

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How engineers use this formula

Use this formula when the listed inputs (E, rho, 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, V_b equals 2,000 ft/s.

Elbf/ft^2

500000000

rholbm/ft^3

150

nudimensionless

0.25

Inputs

E

lbf/ft^2

Young Modulus

rho

lbm/ft^3

Density

nu

dimensionless

Poisson Ratio

Outputs

V_b

ft/s

Velocity of Bulk Compressional Waves

E

lbf/ft^2

Young Modulus

rho

lbm/ft^3

Density

Source and review

reviewed

Formation Evaluation and Petrophysics, Core Laboratories (2005)

Core Laboratories. 2005. Formation Evaluation and Petrophysics, Page 23.

Source