18 July 2017

Maximum anticipated surface pressure (MASP)

MASP is the calculated maximum internal pressure that the blow-out preventer (BOP) and related equipment will be subject to while conducting well operations. MASP establishes pressure […]
18 July 2017

Mechanical rig

A drilling rig in which the source of power is one or more internal-combustion engines and in which the power is distributed to rig components through […]
18 July 2017

Mechanized roughneck

A machine that integrates the function of a spinning wrench and a torque wrench to make up and break out drill pipe connections. These machines evolved […]
18 July 2017

Metocean

Meteorological and oceanographic data, such as wind, wave, water current, and tidal condition measurements.
18 July 2017

Mill

A downhole tool with rough, sharp, extremely hard cutting surfaces for removing metal by grinding or cutting. Mills are run on drill pipe or tubing to […]
18 July 2017

Mix mud

To prepare drilling fluids from a mixture of water or other liquids and any one or more of the various dry mud making materials (such as […]
20 October 2021

Mobile offshore drilling unit (MODU)

A vessel capable of engaging in drilling operations for the exploration for or exploitation of resources beneath the seabed such as liquid or gaseous hydrocarbons, sulphur […]
25 July 2017

Monkeyboard

The derrickman’s working platform. As pipe or tubing is run into or out of the hole, the derrickman must handle the top end of the pipe, […]
18 July 2017

Motorman

The crew member on a rotary drilling rig, usually the most experienced rotary helper, who is responsible for the care and operation of drilling engines. Compare […]
18 July 2017

Mouse hole

A shallow cased hole close to the rotary table through the derrick floor in which a joint of drill string can be suspended to facilitate connecting […]
18 July 2017

Mousehole connection

The procedure of adding a length of drill pipe or tubing to the active string. The length to be added is placed in the mousehole, made […]