# Normal stress in tangential direction at wellbore wall (hoop stress)

## Input(s)

Shmax: Maximum Principal Stress in reservoir (psi)

Shmin: Minimum Principal Stress in reservoir (psi)

Po: Pore Pressure (psi)

\(S d t\): Stress induced due to temperature (psi)

\(d P\): Difference between Wellbore Pressure and Mud Weight (psi)

\(\theta\): Angle from \(S_{\text {hmax }}\) at which stress is measured (degrees)

## Output(s)

sig \(_{\text {th }}\): Hoop Stress in Tangential Direction at Wellbore Wall (psi)

## Formula(s)

\[
\operatorname{sig}_{\mathrm{th}}=(\operatorname{Shmax}+\mathrm{Shmin})-2 *(\text { Shmax }-\operatorname{Shmin}) * \cos \left(2 * \theta * \frac{3.142}{180}\right)-2 * \text { Po }-\mathrm{dP}-\mathrm{Sdt}
\]

## Reference(s)

Mark D. Zoback, Reservoir Geomechanics, Cambridge University Press, UK, Page: 102.