Geomechanics and FracturingIn-Situ Stress and Rock Mechanics

Formation Compressibility from Hydrofrac Data Formula

\beta=\frac{1}{V_s}\frac{dV_s}{dP}

Formation Compressibility from Hydrofrac Data calculates formation compressibility 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 (Vs, dVs, dP) 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, beta equals 0.000005 psi^-1.

Vsbbl

1000

dVsbbl

dPpsi

1000

Inputs

Vs

bbl

Hydrofrac Test Volume

dVs

bbl

Change in Hydrofrac Volume

dP

psi

Change in Pressure

Outputs

beta

psi^-1

Formation Compressibility

dVs

bbl

Change in Hydrofrac Volume

dP

psi

Change in Pressure

Vs

bbl

Hydrofrac Test Volume

Source and review

reviewed

Zoback, M.D. Reservoir Geomechanics. Cambridge University Press, Page 221.

Source