1.
n. [Drilling]
A measure of the energy per unit of time that is being expended across the
bit nozzles. It is commonly calculated with the equation HHP=P*Q/1714, where P stands for
pressure in pounds per square in., Q stands for flow rate in gallons per minute, and 1714 is a conversion factor necessary to
yield HHP in terms of horsepower. Bit manufacturers often recommend that fluid hydraulics energy across the bit nozzles be in a particular HHP range, for example 2.0 to 7.0 HHP, to ensure adequate bit tooth and bottom-of-
hole cleaning (the minimum HHP) and to avoid premature
erosion of the bit itself (the maximum HHP).