# Principal stress due to petro-static pressure (hydraulic fracturing)

## Input(s)

$\gamma$ : Average Specific Weight of Formation $\left(\mathrm{p} / \mathrm{cm}^{3}\right)$

$h$: Depth $(\mathrm{m})$

## Output(s)

$\sigma_{z}$: Principal Stress in z-axis $\left(\mathrm{kp} / \mathrm{cm}^{2}\right)$

## Formula(s)

$\sigma_{z}=\frac{\gamma \cdot h}{10}$## Reference(s)

Saydam, T., (1967). Principles of Hydraulic Fracturing, ARI Publishing Co., Page: 5.