Definition(s)
Head
Height that a fluid column would reach in an open-ended pipe if the pipe were attached to the point of interest. NOTE The head at the bottom of a 300 m (1 000 ft) well is 300 m (1 000 ft), but the pressure at that point depends upon the density of the drilling fluid in the well.
Source: API RP 13C, Recommended Practice on Drilling Fluids Processing Systems Evaluation, Upstream Segment, Fourth Edition, December 2010. Global Standards
Head
Potential energy exerted by a column of liquid that has the ability to do work; expressed as the vertical height of the column.
Source: IADC UBO / MPD Glossary, December 2011. Global Standards