Calculate overburden pressure, bulk density, or true vertical depth from any two inputs with ppg or kg/m³, ft or m, and psi, kPa, or MPa.
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Overburden Pressure Formula
The calculator estimates total vertical stress from a depth-weighted average bulk density using the conventional rounded oilfield factor 0.052. It does not calculate pore pressure, effective stress or a safe mud pressure. It converts all entries to base units first: bulk density in ppg, true vertical depth in feet, and pressure in psi.
- P = overburden pressure, in psi
- ρb = average overburden bulk density, in ppg
- TVD = true vertical depth, in ft
- 0.052 = conversion factor for ppg and ft to psi
If you select overburden pressure, the calculator multiplies bulk density, depth, and 0.052 to find pressure.
If you select bulk density, it divides pressure by depth and 0.052 to find the average overburden density.
If you select true vertical depth, it divides pressure by bulk density and 0.052 to find the depth.
When you select metric units, the calculator converts them internally before applying the formula, then converts the result back to your selected output unit.
Typical Overburden Gradients and Unit Conversions
Overburden pressure is often discussed as a pressure gradient. In this calculator, the gradient in psi/ft is equal to bulk density in ppg multiplied by 0.052.
| Average Bulk Density | Equivalent Gradient | General Interpretation |
|---|---|---|
| 18 ppg | 0.936 psi/ft | Lower average overburden density |
| 20 ppg | 1.040 psi/ft | Common approximate sedimentary overburden gradient |
| 22 ppg | 1.144 psi/ft | Higher average overburden density |
| Quantity | Conversion Used |
|---|---|
| Bulk density | 1 ppg ≈ 119.826427 kg/m³ (US gallon) |
| Depth | 1 m ≈ 3.280839895 ft; 1 ft = 0.3048 m exactly |
| Pressure | 1 psi ≈ 6.894757293 kPa ≈ 0.006894757293 MPa |
Example Calculations
Example 1: Calculate overburden pressure
You have an average overburden bulk density of 20 ppg and a true vertical depth of 10,000 ft.
The overburden pressure is 10,400 psi.
Example 2: Calculate average bulk density
You have an overburden pressure of 9,000 psi at a true vertical depth of 8,000 ft.
The average overburden bulk density is 21.6346 ppg.
FAQ
What is overburden pressure?
Overburden pressure is the vertical pressure caused by the weight of the rock and fluids above a given depth. In drilling and geomechanics, it is also called vertical stress. It is based on true vertical depth, not measured depth along a deviated wellbore.
Why does the formula use 0.052?
The factor 0.052 converts mud weight or density in ppg and depth in feet into pressure in psi. The same factor is commonly used for hydrostatic pressure calculations in oilfield units.
Should I use measured depth or true vertical depth?
Use true vertical depth. Overburden pressure depends on the vertical height of the material above the point of interest. Measured depth can be longer than true vertical depth in directional or horizontal wells and would overstate the pressure if used directly.
