Technical Thesaurus
oil & gas
Letter
LACT unit
An automated
system for measuring and transferring oil from a lease gathering system into a
pipeline. See lease automatic custody transfer.
Lagging
Insulation
material which is a bad conductor of heat used to cover pipes, reactors,
boilers, etc., to reduce loss of heat.
Landed price
The actual cost of
oil to a refiner, taking into account all costs from the place of production or
purchase to the refinery.
Landing nipple
Internally
profiled tubing nipple with locking and locating recesses and a polished bore
in which a mandrel can, by wireline method, be landed, locked and sealed.
Laser
Light
amplification by stimulated emission of radiation. A device that produces an
intense beam of monochromatic, spatially coherent light.
LAT
Lowest
Astronomical Tide (Datum).
Latch on
To attach
elevators to a section of drill pipe.
Latent heat
The amount of heat
required to change the state of unit mass of a substance from solid to liquid
or liquid to gas without any change in temperature; e.g., the latent heat of
fusion of ice is 80 cal/g and the Jatent heat of vapourisation of water is 540
cal/g.
Laterolog
A formation
resistivity measuring device utilising electrodes to focus a direct current
into the formation. Knowing voltage, resistivity can be computed. It is best
suited for measuring formation resistivity in wells drilled with more saline
drilling muds.
Latitude
(astronomical)
Angular distance
between the direction of gravity and the plane of the Equator. Astronomical
latitude is the latitude which results directly from observations on celestial
bodies, uncorrected for deflection of the vertical.
Latitude
(geodetic)
The angle which
the normal at a point on the spheroid makes with the plane of the geodetic
equator.
Lay barge
A specially
designed barge used to lay an underwater pipeline; also called a pipe laying
barge.
Lay days
Days allowed by
charter for loading or discharging cargo.
Lay-down rack
A storage area for
tubing and drill pipe that are removed from a well and laid down rather than
set back and racked vertically in the derrick.
LBL
Logging Baseline.
Generally used to define long range acoustic positioning systems.
Lead line
A line passing
through two or more clearly defined charted objects, and along which a vessel
can approach safely.
Lead tongs
(Pronounced “Ieed"). The pipe tongs suspended in the derrick
or mast and operated by a wireline connected to the break-out cathead. Also called
break-out tongs.
Leak-off test
The process of
applying pressure to the formation below the casing seat to test the quality of
cementing and to determine the fracture pressure in the permeable zone
immediately below the casing seat.
Lease
2. The area where
production wells, stock tanks, separators, LACT units, and other production
equipment are located. See LACT unit and lease automatic custody transfer.
Lease automatic
custody transfer
The measurement
and transfer of oil from the producer's tanks to the connected pipeline on an
automatic basis without a representative of either having to be present. See
LACT unit.
Least depth
The shoalest
sounding value obtained on a feature.
Licence
An authority to
explore for or produce oil or gas in a particular area issued to a company by
the governing State. See exploration licence, production licence.
Licence area
The area for which
a licence to recover petroleum has been granted by the Designated Authority.
Licence block
A section of
continental shelf area in a particular national sector bounded by latitude and
longitude lines, generally at one-degree intervals; a licence block is usually
sub-divided into a smaller area.
Licence round
A stage in the
allocation of offshore licences in which a State places a number of specified
areas in its sector on offer to oil companies at one time.
Lifting ends
The more volatile
products of petroleum refining, e.g., butane, propane, gasoline. Also called
light ends.
Light crude
Crude oil with a
low specific gravity and high API gravity due to the presence of a high
proportion of light hydrocarbon fractions.
Light fractions
The
low-molecular-weight, low-boiling point fractions that emerge from the upper
part of a fractionating column during the oil refining process.
Limestone
A bedded
sedimentary deposit consisting chiefly of calcium carbonate.
Liner
Small-diameter
casing that extends into the production layer from just above the casing seat
and is perforated when production starts.
Liquefied natural
gas (LNG):
Natural gas that
has been liquefied by refrigeration or pressure in order to facilitate storage
or transport; it generally consists mainly of methane.
Liquefied
petroleum gas (LPG)
A mixture of light
hydrocarbons derived from oil-bearing strata which is gaseous at normal
temperatures but which has been liquefied by refrigeration or pressure in order
to facilitate storage or transport; it generally consists mainly of propane and
butane. Sometimes known as condensate.
Liquid product
(hydrocarbon)
A sales product in
liquid form produced as a result of further processing by the onshore plant,
e.g. condensate, LPG.
Liquid returned
Total mass of a
liquid product returned after being loaded as a cargo.
Live oil
Crude oil which
contains dissolved natural gas when produced.
LNG
Liquefied Natural
Gas
Loan capital
Capital raised by
borrowing money rather than from retained income or from issuing shares for
sale on the stock market.
Loan spread
The difference
between the interest rate a bank charges a borrower and the rate at which the
bank borrows the money itself.
Location
The place where a
well is drilled.
Log
A tabular or
graphic description of drilling conditions or sub-surface features prepared
during the drilling of a well or its subsequent evaluation.
Log analysis
Determination of
the nature and fluid content of a reservoir formation from wireline tools,
which are lowered into the well to measure the physical properties of rocks.
Log sheets
Detailed operating
records. Normally containing written information regarding the operation as
well as recorded data.
Log/logging
1. Mass storage of
records; examples: disk or tape navigation logging, paper ships Log or Survey's
Log. 2. Towed ship's speed measurement device.
Logger's depth
The depth of a
well (vertical or deviated) as measured via the along hole length of the cable
used to run electric log tools.
Long string
The longest tubing
string in a multiple string completion.
Longitude
Angular distance,
along a primary great circle, from the adopted reference point.
Longitude (geodetic)
The angle between
the plane of the geodetic meridian and the plane of an initial meridian,
arbitrarily chosen.
LOP
Line of Position
(of a beacon); several together determine the "angle of cut", a
schematic of the geometry of beacons in relation to a given position, used to
determine the error inherent in the computed position.
Lost circulation
The loss of
substantial quantities of drilling mud into a formation; also called loss of
returns.
Lost time
Time in which no
work is possible on an operation due to bad weather, industrial dispute, etc.
Lubricant
A substance
(generally based on heavy liquid hydrocarbons) used to reduce friction in an
engine or machine.
Lump sum freight
A fixed freight
rate, regardless of how much cargo is loaded.
Lutite
Sediment or
sedimentary rock consisting principally of clay or clay and silt-sized
particles i.e., silts and/or clays and their various associated materials
which, when mixed with water, form mud.
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