Technical
Thesaurus oil & gas
L
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.