20 October 2021

Underbalanced (UB)

A well construction or maintenance activity employing appropriate equipment and controls where the pressure exerted in the wellbore is intentionally less than the pore pressure in […]
18 July 2017


To enlarge a drill hole below the casing.
18 July 2017

Unit operator

The oil company in charge of development and production in an oilfield in which several companies have joined to produce the field.
25 July 2017

Upper racking arm

Functionally replaces the derrickman in guiding pipe from the set-back to the travelling equipment. Some systems have hoist mechanisms and some work in conjunction with an […]