Hydrostatic Pressure (HP)

**Hydrostatic pressure using ppg and feet as the units of measure**

HP = mud weight, ppg x 0.052 x true vertical depth (TVD),ft

Example: mud weight = 13.5ppg

true vertical depth (TVD)= 12,000ft

HP = 13.5ppg x 0.052 x 12,000ft

HP = 8424psi

HP = 8424psi

**Hydrostatic pressure, psi, using pressure gradient, psi/ft**

HP = psi/ft x true vertical depth, ft

Example: pressure gradient = 0.624 psi/ft

true vertical depth = 8500ft

HP = 0.624psi/ft x 8500ft

HP = 5304psi

HP = 0.624psi/ft x 8500ft

HP = 5304psi

**Hydrostatic pressure, psi, using mud weight, lb/ft**

^{3}HP = mud weight, lb/ft3 x 0.006944 x TVD, ft

Example: mud weight = 90lb/ft

true vertical depth = 7500ft

HP = 90lb/ft

HP = 4687psi

^{3}true vertical depth = 7500ft

HP = 90lb/ft

^{3}x 0.006944 x 7500ftHP = 4687psi

**Hydrostatic pressure, psi, using meters as unit of depth**

HP = mud weight, ppg x 0.052 x TVD, m x 3.281

Example: mud weight = 12.2ppg

true vertical depth = 3700 meters

HP = 12.2ppg x 0.052 x 3700 x 3.281

HP = 7701psi

true vertical depth = 3700 meters

HP = 12.2ppg x 0.052 x 3700 x 3.281

HP = 7701psi

**Metric calculations**

Hydrostatic pressure, bar = drilling fluid density, kg/l x 0.0981 x true vertical depth, m

**S.I. units calculations**

Hydrostatic pressure, kPa = (drilling fluid density, kg/m

^{3 }: 102) x true vertical depth, m