Oil and Gas Terms Beginning with “M” — Page 2

Mafic is a descriptive term in petrology (the study of rocks) for igneous rocks or minerals that are rich in magnesium and iron (Fe), with the term being a portmanteau of "ma" from magnesium and "fic" from the Latin… Read more →

Magma is the molten rock within the Earth that can either rise to the surface as lava and form extrusive igneous rock or cool more slowly within the crust to form intrusive, or plutonic, igneous rock. It is a complex… Read more →

The magnesium test in drilling fluid analysis is a volumetric titration method used to measure the total concentration of divalent cations (primarily magnesium ions Mg2+ and calcium ions Ca2+) in a drilling mud filtrate… Read more →

Magnetic mud in drilling operations refers to a drilling fluid that contains sufficient ferromagnetic material to interfere with magnetic azimuth measurements taken by MWD (measurement while drilling) or conventional… Read more →

What Is Magnetic Resonance Logging? Magnetic resonance logging (also called nuclear magnetic resonance logging, or NMR logging) is a petrophysical measurement technique that applies pulsed magnetic fields to the… Read more →

(noun) A non-destructive inspection technique used to detect corrosion, pitting, and metal loss in ferromagnetic tubulars and pipelines. The method works by magnetising the pipe wall and measuring distortions in the… Read more →

Magnetics is the geophysical study of the Earth's magnetic field — a branch of geophysics that began with the foundational observation by British scientist William Gilbert (1544-1603) that the Earth itself acts as a… Read more →

An instrument used to measure the strength or direction of the Earth's magnetic field. Read more →

What Is the Magnetotelluric Method? The magnetotelluric (MT) method (also called magnetotellurics or MT surveying) is a passive electromagnetic geophysical exploration technique that measures natural variations in the… Read more →

What Is Making a Connection? Making a connection (also called a pipe connection or simply a connection) is the drilling operation of temporarily stopping rotation and circulation to add a new joint or stand of drill… Read more →

To deepen a wellbore with the drill bit. To drill ahead. Read more →

Make-up in oilfield operations refers to the act of connecting (assembling) two threaded tubular components by rotating one relative to the other to engage and tighten the threaded connection, with "making up" a… Read more →

Make-up water is the water added to a water-based drilling mud system to maintain volume during operations or to dilute the mud system for solids control management — added in volumes calculated to compensate for water… Read more →

Make-up water is the water added to a water-based drilling mud system to maintain volume during operations or to dilute the mud system for solids control management — added in volumes calculated to compensate for water… Read more →

A makeup cathead is a clutched, rotating spool or drum mounted on the end of the catshaft of a drawworks on a drilling rig that enables the driller to use the drawworks motor to apply a controlled tension load to a… Read more →

What Is Makeup Gas? Makeup gas (also spelled make-up gas) is natural gas that a pipeline seller delivers to a buyer, or that a buyer has the right to receive in future periods, to correct an imbalance arising under a… Read more →

(noun) Large hydraulic or manual wrenches used on a drilling rig to apply torque to threaded connections when assembling (making up) joints of drillpipe, casing, or tubing. Makeup tongs grip the pipe body or coupling… Read more →

A mandrel in oil and gas well technology is a cylindrical bar, shaft, or tubular body around which other components are arranged, assembled, or activated, serving as a structural core or central element to which… Read more →

A manifold in oil and gas production and drilling operations is a piping assembly with a common header (main pipe) connected to multiple branch lines through valves, allowing fluid from multiple sources to be combined… Read more →

The mantle is the intermediate compositional layer of the Earth located between the crust above and the core below, extending from the base of the crust (at approximately 5 to 70 kilometers depth, defined by the… Read more →

A map in petroleum geology and reservoir engineering is a two-dimensional representation of subsurface or surface data on a spatial coordinate system — including structural maps (depicting the depth or elevation of… Read more →

A well that, for reasons of depletion or natural low productivity, is nearing the limits of viable production and profitability. Read more →

Pertaining to sediments or environments in seas or ocean waters, between the depth of low tide and the ocean bottom. Read more →

(noun) A stratigraphic surface that records a significant increase in water depth across a sedimentary basin, marking a transgressive event in which marine conditions advance landward over previously non-marine or… Read more →

A marker bed (also called a key bed or correlation horizon) is a distinctive, laterally persistent geological stratum that can be reliably identified in well logs, seismic data, outcrops, and core samples across a broad… Read more →

A marker joint in petroleum drilling and completion operations is a specially identified joint of drill pipe, casing, or tubing that is placed at a known position in the string to serve as a depth reference — allowing… Read more →

A marketing agreement is a commercial contract under which one party, the marketer or aggregator, sells a producing company's oil, natural gas, or natural gas liquids on its behalf and then remits the sale proceeds back… Read more →

An environment from which water rarely drains that supports primarily grassy vegetation and does not form peat. Read more →

A massif in geology is a compact, relatively elevated structural and topographic feature composed predominantly of crystalline basement rocks (igneous or metamorphic, such as granite, gneiss, granulite, or amphibolite)… Read more →

A mast in drilling operations is the portable, self-erecting structural tower mounted on a land drilling rig that serves the same purpose as a fixed derrick — providing the vertical height and load capacity needed to… Read more →