Mud weight converter
Convert drilling mud density between ppg, specific gravity and the pressure gradient it produces down the hole.
That's about the same as a typical drilling mud. At 1,000 m depth that column would exert about 117.5 bar.
What it means
How heavy is that mud?
Gradients are for a vertical well. In a deviated hole the pressure depends on true vertical depth, not on how much pipe is in the ground.
Every unit
Your mud weight in every unit
Learn
Three things worth knowing
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psi/ft = ppg × 0.052
A 10 ppg mud gives 0.52 psi for every foot of depth, so at 10,000 ft the bottom sees 5,200 psi. That 0.052 is the most used number on a rig.
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Weight as a pressure
What matters downhole is not density but the pressure the column produces, so the industry quotes both and treats them as the same quantity.
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Water is 8.33, not 8
Rounding fresh water to 8 ppg understates the gradient by 4%, which at 15,000 feet is more than 250 psi of error.
Shortcuts
Popular mud weight conversions
Background
About mud weight
Drilling mud has one job above all others: to be heavy enough that its column holds the formation back, and light enough not to fracture it. Too light and the well flows; too heavy and you lose the mud into the rock.
US rigs work in pounds per gallon, where fresh water is 8.33. The rest of the world uses specific gravity or kg/m³.