Hydrostatic pressure is pressure created by fluid column and two factors affecting hydrostatic pressure are mud weight and True Vertical Depth.

You can read full details about hydrostatic pressure from this article, Understand Hydrostatic Pressure.

In this article, it will demonstrate how to calculate hydrostatic pressure in different oilfield and metric unit.

### 1. Calculate hydrostatic pressure in psi by using mud weight in pound per gallon (ppg) and feet as the units of True Vertical Depth.

Hydrostatic pressure equation:

Hydrostatic Pressure (HP) = 0.052 × Mud Weight × True Vertical Depth (TVD)Where;

Mud Weight in ppg

True Vertical Depth in ft

**Example;**

Mud Weight = 12.0 ppg

True Vertical Depth (TVD) = 10,000 ft

Hydrostatic Pressure (HP) = 0.052 × 12.0 × 10,000

Hydrostatic Pressure (HP) = 6,240 psi

### 2. Calculate hydrostatic pressure in psi by using pressure gradient in psi/ft and feet as the units of True Vertical Depth.

Hydrostatic pressure equation:

Hydrostatic Pressure (HP) = Pressure gradient in psi/ft × True Vertical Depth (TVD)Where;

Pressure gradient in psi/ft

True Vertical Depth in ft

**Example;**

Pressure Gradient = 0.5 psi/ft

True Vertical Depth (TVD) = 10,000 ft

Hydrostatic Pressure (HP) = 0.5 psi/ft × 10,000 ft

Hydrostatic Pressure (HP) = 5,000 psi

### 3. Calculate hydrostatic pressure in psi by using mud weight in lb/ft^{3} and feet as the units of True Vertical Depth.

Hydrostatic pressure equation:

Hydrostatic Pressure (HP) = 0.006944 × Mud Weight × True Vertical Depth (TVD)Where;

Mud Weight in lb/ft

^{3}True Vertical Depth in ft

**Example;**

Mud Weight = 80 lb/ft^{3}

True Vertical Depth (TVD) = 10,000 ft

Hydrostatic Pressure (HP) = 0.006944 × 80 lb/ft^{3} × 10,000 ft

Hydrostatic Pressure (HP) = 5,555 psi

### 4. Calculate hydrostatic pressure in psi by using mud weight in PPG and meters as unit of True Vertical Depth.

Hydrostatic pressure equation:

Hydrostatic Pressure (HP) = Mud Weight × 0.052 × TVD in meters x 3.281Where;

Mud Weight in ppg

True Vertical Depth in meter

**Example:**

Mud Weight = 12.0 ppg

True Vertical Depth (TVD) = 5000 meters

Hydrostatic Pressure (HP) = 12.0 × 0.052 × 5000 × 3.281

Hydrostatic Pressure (HP) = 10,237 psi

### 5. Calculate hydrostatic pressure in Pascal by using mud weight in kg per cu-meter (kg/m^{3}) and __meter (m) __as the units of True Vertical Depth.

Hydrostatic Pressure (HP) = 9.81 × Mud Weight × True Vertical Depth (TVD)Where;

Mud Weight in kg/m

^{3}True Vertical Depth in meter

**Example;**

Mud Weight = 1,000 kg/m3

True Vertical Depth (TVD) = 100 m

Hydrostatic Pressure (HP) = 9.81 × 1,000 × 100

Hydrostatic Pressure (HP) = 981,000 pascal

### 6. Calculate hydrostatic pressure in bar by using mud weight in kg per cu-meter (kg/m^{3}) and __meter (m) __as the units of True Vertical Depth.

Hydrostatic Pressure (HP) = 9.81 × Mud Weight × True Vertical Depth (TVD) ÷ 100,000Where;

Mud Weight in kg/m

^{3}True Vertical Depth in meter

**Example;**

Mud Weight = 1,000 kg/m^{3}

True Vertical Depth (TVD) = 100 m

Hydrostatic Pressure (HP) = 9.81 × 1,000 × 100 **÷** 100,000

Hydrostatic Pressure (HP) = 9.81 bar

### 7ุ. Calculate hydrostatic pressure in atm by using mud weight in kg per cu-meter (kg/m^{3}) and __meter (m) __as the units of True Vertical Depth.

Hydrostatic Pressure (HP) = 9.81 × Mud Weight × True Vertical Depth (TVD) × 9.8692 × 10^{-6}Where;

Mud Weight in kg/m

^{3}True Vertical Depth in meter

**Example;**

Mud Weight = 1,000 kg/m3

True Vertical Depth (TVD) = 100 m

Hydrostatic Pressure (HP) = 9.81 × 1,000 × 100 **× **9.8692 × 10^{-6}

Hydrostatic Pressure (HP) = 9.6817 atm

**Download Free Excel Spread Sheet**

** Download the Excel sheet for calculating hydrostatic pressure – This is 2020 update with Metric Unit**

**Ref books: **

Lapeyrouse, N.J., 2002. Formulas and calculations for drilling, production and workover, Boston: Gulf Professional publishing.

Bourgoyne, A.J.T., Chenevert , M.E. & Millheim, K.K., 1986. SPE Textbook Series, Volume 2: Applied Drilling Engineering, Society of Petroleum Engineers.

Mitchell, R.F., Miska, S. & Aadny, B.S., 2011. Fundamentals of drilling engineering, Richardson, TX: Society of Petroleum Engineers.