Technical
Thesaurus oil & gas
Letter
Magma
Molten material originating from deep within the
Earth's crust; the material from which igneous rocks form.
Magnetic
brake
Also called an electrodynamic brake. See
electrodynamic brake.
Magnetic
survey
This measures variations in the Earth's magnetic field
caused by the presence of rock structures and is used to detect sedimentary
areas. This type of survey is usually carried out by air.
Magnetometer
Towed sensor for detection of sea-bed or buried ferrous
masses (e.g. pipelines, anchors, wreckers).
Magnetometer
survey
A geological survey method in which sedimentary basins
are identified and their size determined by measuring the magnetic properties
of the underlying igneous rocks.
Make hole
To deepen the hole made by the bit; to drill ahead.
Make up
1. To assemble and join parts to form a complete unit
(as to make up a string of casing). 2. To screw together two threaded pieces.
3. To mix or prepare (as to make up a tank of mud). 4. To compensate for (as to
make up for lost time).
Make up
cathead
A device attached to the shaft of the drawworks that
is used as a power source for screwing together joints of pipe; usually located
on the driller's side of the drawworks. See cathead.
Make up
torque
The power necessary to screw a joint of pipe into
another sufficiently tight to hold and seal and not loosen under working
conditions.
Making a
connection
The act of screwing a length of drill pipe onto a
drill string suspended in a well bore, i.e. lengthening the drill string by one
section of pipe during a drilling operation.
Making up a
joint
The act of screwing individual sections of pipe
together to form a longer length.
Making-a trip
See round trip.
Male end
A pipe, rod, or coupling with threads cut on the
outside. See pin end.
Man hours
The total hours required/used to complete a job
assuming one man only is performing the job.
Mandrel
Wireline mandrel. A piece of wireline equipment which
locates, locks and often seals in landing nipples installed at predetermined
depths in tubing strings. Control equipment to be placed in the tubing string,
e.g. plug, choke, safely valve, etc., is connected to the bottom of the
mandrel.
Manifest
A document issued by a shipper covering oil or products
to be transported.
Manifold
Piping arrangement which allows one stream of liquid
or gas to be divided into two or more streams.
Manometer
An instrument used for the measurement of gaseous
pressures or pressure differentials in a system.
Manway
A port in the wall or cover of a tank or reactor, for
inspection purposes or for charging the vessel with raw materials or additives.
Marginal
field
A field that mayor may not produce enough net income
to make it worth developing at a given time, should technical or economical
conditions change such a field may subsequently become commercial.
Marginal
riser
The pipe which connects an exploration rig, drilling
platform or production platform to a subsea wellhead or subsea pipeline during
drilling or production operations.
Marine riser
The pipe which connects an exploration rig, drilling
platform or production platform to a sub-sea wellhead or sub-sea pipeline
during drilling or production operations.
Mass balance
A reconciliation of the masses of petroleum or
petroleum products entering and leaving a system. Losses and own usage within
the system are accounted for.
Massif
A consolidated mass of rock forming part of a
continent or mountain range which has relatively uniform characteristics.
Mast
A portable derrick capable of being erected as a unit,
as distinguished from a standard derrick that cannot be raised to a working
position as a unit. For transporting by land, the mast can be divided into two
or more sections to avoid excessive length extending from truck beds on the
highway. Compare derrick.
Master
bushing
A device that fits into the rotary table. It
accommodates the slips and drives the kelly bushing so that the rotating motion
of the rotary table can be transmitted to the kelly. Also called rotary
bushing. See slips and kelly.
Master
schedule
An overall graphical time schedule for the various
activities related to a project.
Maturation
The effect of temperature and time on potential source
rock, with respect to hydrocarbon generation. Immature -not yet at the
generation stage. Mature -capable of generation. Over mature -beyond the stage
when liquid hydrocarbons have broken down into gaseous hydrocarbons. It is dependant
on the geological history of the area in terms of burial, deformation and
erosion.
MD
The linear distance of a well measured along its
drilled projection.
Mean high
water (MHW)
The average height of the high waters at a place over
a 19-year period.
Mean low
water (MLW)
The average height of all low waters at a place over a
19-year period.
Mean sea
level (MSL)
The average height of the surface of the sea at a tide
station for all stages of the tide over a given period, usually determined from
hourly height readings measured from a fixed predetermined reference level
(datum).
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 mechanical devices (as chains, sprockets, clutches, and
shafts), It is also called a power
Median line
The dividing line between two national sectors of an
ocean or sea; the focus of points equidistant from the territorial boundaries
of the countries concerned.
Mercaptans
Compounds of carbon, hydrogen and sulphur found in
sour crude and gas; the lower mercaptans have a strong, repulsive odour and are
used, among other things, to odourise natural gas.
Mesozoic era
The era of geological time (comprising the Triassic,
Jurassic and Cretaceous Periods) which began roughly 230 million years ago and
ended roughly 60 million years ago; the era in which many oil and gas producing
source rocks were laid down in the North Sea and in the
Metallurgist
A scientist whose work relates to the study of the
properties of metals and ores.
Metamorphic
rocks
Rocks changed considerably from their original
composition and structure by heat and pressure.
Methane
The hydrocarbon with the lightest molecule (CH4); the
first member of the paraffin (alkane) series -a gas under normal conditions.
Methyl
tertiary-butyl ether (MTBE)
A lead-free, anti-knock compound added to petrol.
Metric tonne
Equivalent to 1000 kilos, 2204.61 Ibs., or .9842 tons.
Microwave
link
A communications system between two points involving
the use of a beamed carrier wave in the microwave region of the electromagnetic
spectrum.
Middle
distillate
A phrase used to denote those distillates in the
boiling point range immediately below that of kerosene and to include diesel
fuel and the various gas oil cuts. It is frequently but incorrectly used to
denote the whole range of distillates at atmospheric pressure other than LPG,
gasolines and naphthas.
Milling
To remove a packer or junk, or to cut a
"window" in a well's casing with a milling tool lowered into the hole
on the drill string.
Milling tool
A grinding or cutting tool used on the end of the
drill pipe to pulverise a piece of downhole equipment or to cut the casing.
Mineral
rights
The ownership of any minerals that may exist in the
strata beneath a particular area.
Miscible
Descriptive of substances, usually liquids, which mix
together to form a homogeneous mixture.
Mist
Airborne particles of a liquid which have condensed on
dust particles.
Mixing mud
The preparation of drilling mud by mixing water or
other fluids with clays and dry chemicals.
Mixture
A co-mingling of two or more substances in which each
substance retains its chemical nature and identity.
Navigation receiver, usually offshore (beacon).
Mobilisation
(mob)
The initial stage of survey or other work: often
involves lump sum payment for acceptance trials, transit, costs, calibrations etc.
Module
A package of plant, equipment, etc., installed on (or
for installation on) an offshore structure such as a production platform.
Molecular
weight
A measure of the mass of the molecule of a chemical
compound.
Molecule
The smallest particle of a compound that is capable of
independent existence while retaining its individual properties.
Monkeyboard
A high-level platform in the derrick on which the
derrick man works.
Monomer
A simple molecular unit (such as ethylene or styrene)
from which a polymer can be made.
Moonpool
The open hole in the centre of the hull of a drillship
through which drilling takes place. Also called moonwell.
Motor oil
Refined lubricating oil, usually containing additives,
used as a lubricant in internal combustion engines.
Motor spirit
The light fuel used in spark ignition engines in cars,
motor cycles etc.; often referred to as petrol or gasoline.
Motorman
The man responsible for the care and operation of the
drilling engines.
Mouse hole
A shallow hole in the drilling floor near the drilling
table in which the kelly joint and other stands of pipe are temporarily stored
while making a connection; sometimes called the rat hole.
Mouse hole
connection
The procedure of adding a length of drill pipe or
tubing to the active string in which the length to be added is placed in the
mouse hole, made up to the kelly, then pulled out of the mouse hole, and
subsequently made up into the string.
Mud
See drilling mud.
Mud cake
The sheath of mud solids that forms on the wall of the
hole when the liquid from the mud filters into the formation; also called wall
cake or filter cake.
Mud
circulation
The act of pumping mud downwards to the bit and back
up to the surface by normal circulation or reverse circulation. See normal
circulation and reverse circulation.
Mud engineer
(mud man)
The service man in charge of maintaining the mud
systems on a drilling rig to the specifications set out in the drilling
programme.
Mud gun
A pipe that shoots a jet of drilling mud under high
pressure into the mud pit to mix additives with the mud.
Mud logging
The recording of information derived from examination
and analysis of formation cuttings made by the bit and mud circulated out of
the hole. A portion of the mud is diverted through a gas-detecting device.
Cuttings brought up by the mud are examined under ultraviolet light to detect
the presence of oil or gas. Mud logging is often carried out in a portable
laboratory set up at the well.
Mud pits
Large steel storage pits through which the drilling
mud is circulated.
Mud polymer
A chemical compound produced by the polymerisation
process used as an additive to drilling mud to obtain a specific property such
as an emulsion, low filtration losses, high/low viscosity, prevent foaming,
block small pore spaces etc.
Mud pumps
Pumps used to circulate drilling mud at the desired
pressure and flow rate; also called slush pumps.
Mud return
line
A trough or pipe placed between the surface
connections at the well bore and the shale shaker, through which drilling mud
flows upon its return to the surface from the hole.
Mud screen
See shale shaker.
Mud weight
The density of the drilling mud -usually recorded in
pounds per gallon; the mud weight is changed by varying the concentration of
solids in the mud.
Multinational
A company that has investments in more than one
country and is organised on an international basis.
Multiple
completion
The completion of a well in more than one producing
formation. Each production zone will either have its own tubing installed
(multiple string multiple completion), extending up to the christmas tree, or
all zones produce through one tubing string (single string multiple completion).
Multiservice vessel (MSV)
A support vessel designed to provide a variety of
construction, fabrication, diving, emergency and other services to offshore
installations.
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