Glossary

1. henry. 2. length. 3. litre.

a chart used in measuring gas with orifice meters on which are recorded differential and static pressures. It uses a logarithmic scale from 0 to 10. The readings must be converted, but it can be used on any flow recorder, regardless of range. Also called square-root chart.

cold ocean current that flows south along the Labrador coast through the Davis Strait to the Grand Banks, where it divides and flows into the North Atlantic and the Gulf of St. Lawrence.

lease automatic custody transfer.

an automated system for measuring, sampling, and transferring oil from a lease gathering system into a pipeline. See lease automatic custody transfer.

a collection of sediment in a lake at the point at which a river or stream enters. When the flowing water enters the lake, the encounter with still water absorbs most or all of the stream’s energy, causing its sediment load to be deposited.

a method used to describe the arrangement of electromechanical relays in a control system. Usually, a schematic drawing of such relays consists of vertical lines called rails and horizontal lines called rungs. Consequently, the schematic resembles the rails and rungs of a ladder.

lowest achievable emission rate.

the length of time it takes for an adjustment made on a surface choke to appear on the drill pipe (standpipe) pressure gauge when a well is shut in and a choke is being used to maintain back-pressure on the well. A rule of thumb for lag time is 1 second per 1,000 feet (300 metres). For example, in a 5,000-foot well, an adjustment made on the choke does not appear on the drill pipe pressure gauge until 10 seconds after the adjustment was made. The choke adjustment takes 5 seconds to reach the bottom and 5 seconds to reach the surface again. In underbalanced drilling with various fluids besides drilling mud, the rule of thumb does not hold because of the nature of the various gases, liquids, and mixtures of the two in the well. For example, in a 10,000-foot hole that is being drilled underbalanced, lag times can vary from 30 seconds to 60 minutes or more.

the positive-to-negative transition of an electric signal.

removable and interchangeable drum spool shells for changing hoist drum diameter to provide variation in rope speeds and line pulls.

a smooth flow of fluid in which no turbulence or cross flow of fluid particles occurs between adjacent stream lines. See Reynolds number.

1. the area of a partly machined surface (as with grooves or indentation) that is left smooth. 2. the area on a piston between the grooves into which the rings fit. v: to seat tubular goods (such as casing or tubing) into a special device designed to support them from the surface.

to attach casingheads and other wellhead equipment not already in place at the time of well completion.

to install casing so that it is supported in the casinghead by slips.

that section or unit of an oil company that seeks out and acquires oil and gas leases.

(RCRA) placement in or on the land; placement in a landfill, surface impoundment, waste pile, injection well, land treatment facility, salt dome formation, salt bed formation, underground mine or cave, or in a concrete vault or bunker intended for disposal purposes.

any drilling rig that is located on dry land. Compare offshore rig.

the price of imported crude oil at the port of discharge. Includes purchase price at the foreign port plus charges for transporting and insuring the crude oil from the purchase point to the port of discharge; does not include import tariffs or fees, wharfage charges, or demurrage costs.

a recognizable, naturally formed physical land feature having a characteristic shape, such as a plain, alluvial fan, valley, hill, or mountain.

the depth to which the lower end of casing extends in the hole when casing is landed.

any downhole tool placed in the tubing string that facilitates the later placement of special tools at that point.

a device machined internally to receive the movable locking devices used to position, lock, and seal subsurface production controls in tubing. A landing nipple provides a seat at a known depth into which various types of retrievable flow control equipment can be set. Also called a seating nipple.

oceangoing military ships used by land and water forces for landing troops and heavy equipment on beaches.

on conductor casing, a recessed, machined area on the conductor housing or similar fitting on which a wellhead is placed (landed).

offshore, to land the wellhead on casing beneath the water on the seafloor, it is run in a landing string (drill pipe or tubing) to seafloor or inside casing.

a person in the petroleum industry who negotiates with landowners for oil and gas leases, options, minerals, and royalties and with producers for joint operations relative to production in a field. Also called a leaseman.

an unstaffed earth-orbiting NASA satellite that transmits multispectral images to earth receiving stations; formerly called ERTS (Earth Resource Technology Satellite).

the process of disking, or tilling, low-toxicity wastes into surface soil; land farming.

a type of wire rope construction in which the wires that make up the wire rope strands are twisted in the same direction as the strands themselves. Compare regular lay.

the middle ring in a liner packing in a reciprocating pump. A notch on the lantern ring lines up with the grease fitting so that when lubricant is injected, the ring distributes it between the gland packing rings.

an interval in the cased hole where the top of a liner overlaps the bot­tom of a string of casing. See liner lap.

a relative term that implies the existence of a geologic formation bigger than is usual for a particular area.

launch and recovery system.

the last pipe thread that is actually screwed into the coupling thread in making up a joint of drill pipe, drill collars, tubing, or casing. If the pipe makes up perfectly, it is also the last thread cut on the pipe.

an electronic circuit that reverses and maintains its state each time power is applied.

to attach elevators to a section of pipe to pull it out of or run it into the hole.

a device, usually with segmented threads, run with seal subs on the bottom of a tubing string and latched into a permanent packer to prevent tubing movement.

the heat that changes the phase of a fluid.

in the oil industry, a borehole that is drilled off to the side of a vertical borehole. Usually, the hole is drilled straight to a given depth and then the hole is directionally drilled so that the hole goes off to the side of the vertical portion of the hole. Often, several laterals are drilled to efficiently exploit a reservoir.

in conventional electric logging, the curve drawn on the log by a device on an electric logging tool that is designed to measure formation resistivity about 36 feet (11 metres) from the wellbore.

see strike slip.

a resistivity log taken with a sonde that focuses an electrical current laterally, away from the wellbore, and into the formation being logged. Allows more precise measurement than was possible with earlier sondes. The lateral focus log is a useful means of distinguishing thin rock layers. Also called Laterolog™.

trade name for a Schlumberger guard or lateral focus resistivity log, but so commonly used as to be almost a generic term.

an oilwell cement composed of latex, cement, a surfactant, and water and characterized by its high-strength bond with other materials and its resistance to contamination by oil or drilling mud.

an imaginary line joining points on the earth’s surface that are of equal distance north or south of the equator.

the regular geometrical arrangement of points or objects over an area in space—for example, the arrangement of atoms in a crystal. See crystal.

boom of open construction with angular or tubular lacing between main corner members in the form of a truss.

a system that transports the bell from the mating trunk to the work site and back without damaging the equipment or causing injury to the occupants. Commonly referred to as the bell-handling system.

the northern part of the supercontinent Pangaea, comprising the future land masses of North America, Greenland, and Eurasia.

magma that reaches the surface of the earth.

the principle that energy cannot be created or destroyed, although it can be changed from one form to another, such as mechanical energy to electrical energy.

law that states that when, for two substances, any two ratios of pressure, temperature, or volume to their respective critical properties are equal, the third ratio must equal the other two.

see Dalton’s law.

1. the manner in which the wires in a strand or the strands in a rope are helically laid. 2. the distance measured parallel to the axis of the rope (or strand) in which a strand (or wire) makes one complete helical convoltion about the core (or center). Lay is also referred to as lay length or pitch.

a barge used in the construction and placement of underwater pipelines. Joints of pipe are welded together and then lowered off the stern of the barge as it moves ahead.

to pull drill pipe or tubing from the hole and place it in a horizontal position on a pipe rack. Compare set back.

a pipe-laying technique used in swamps and marshes in which the forward motion of the barge sends the pipe down a ramp and into the water. Also called marine lay.

a bed, or stratum, of rock.

the operation of laying down pipe. See lay down pipe.

pound.

pounds per barrel.

pounds per cubic foot.

a low-pass filter that smooths the DC output voltage of a rectifier. It consists of one or more sections in series, each section consisting of an inductor on one of the pair of conductors in series with a capacitor between the conductors. Also known as inductive filter, pi (π ) filter.

liquid crystal display.

lost circulation material.

local distribution company.

low-dosage hydrate inhibitor.

in geology, the removal of minerals from rock by solution in water or another solvent.

(pronounced “leed”) in electronics, a wire, usually insulated, which, when placed in an electrical circuit, connects two points in the circuit.

(pronounced “led”) a chemical element, the symbol of which is Pb, which is a heavy, soft, malleable, and ductile bluish white metal. It is often used in batteries, solder, and radioactivity shields.

a method for detecting the presence of hydrogen sulfide in a fluid by discoloration of paper that has been moistened with lead acetate solution.

see impression tool.

(pronounced “leed”) the pipe through which oil or gas flows from a well to additional equipment on the lease.

(pronounced “leed”) the pipe tongs suspended in the derrick or mast and operated by a chain or a wire rope connected to the makeup cathead or the breakout cathead. Personnel call the makeup tongs the lead tongs if pipe is going into the hole; similarly, they call the breakout tongs the lead tongs if pipe is coming out of the hole. Compare backup tongs.

a storage battery in which the electrodes are grids of lead and lead peroxide that change in composition during charging and discharging, and the electrolyte is dilute sulfuric acid.

an electrical device, often part of a battery, that consists of lead and lead peroxide plates immersed in a liquid solution (an electrolyte) that is usually sulfuric acid. Such a cell produces voltage and current.

(pronounced “leed”) the crew member who operates the lead tongs when drill pipe and drill collars are being handled. Also called lead-tong man.

see lead-tong hand.

the negative-to-positive transition of an electric signal.

kicking the bit in a direction not on the plan.

in a leak-off test, the pressure at which drilling mud begins to leak off, or enter, the formation from the borehole.

the rate at which a fracturing fluid leaves the fracture and enters the formation surrounding the fracture. Generally, it is desirable for fracturing fluids to have a low leak-off rate (i.e., very little fluid should enter the formation being fractured), so that the fracture can be better extended into the formation.

a gradual pressurizing of the casing after the blowout preventers have been installed to permit estimation of the formation fracture pressure at the casing seat.

in an electrical component, such as a capacitor, that employs a dielectric (insulator) to separate conductive elements in the component and prevent the flow of electricity between the conductive elements, the relatively small amount of electricity that flows between the conductors because no dielectric is a perfect insulator. Consequently, some current flows, or leaks, from one conductive element to another.

in a coil, or winding, in which electrical current is flowing, the current that escapes, or leaks, from it. This leakage, in turn, tends to hold back, or impede, the flow of current through the winding. In this case, the impedance to flow is termed reactance.

amine solution that has been stripped of absorbed acid gases, giving a solution suitable for recirculation to the contactor.

1. residue gas remaining after recovery of natural gas liquids in a gas processing plant. 2. unprocessed gas containing few or no recoverable natural gas liquids. Also called dry gas.

glycol from which water has been removed. It can be reused by pumping it back into the absorber.

a hydrocarbon liquid, usually lighter in weight than kerosene and heavier than paint thinner. In a gas processing plant, lean oil is used in an absorber to remove heavier hydrocarbons from natural gas.

an increased yield process that separates the various saleable products in natural gas.

1. a legal document executed between a landowner, as lessor, and a company or individual, as lessee, that grants the right to exploit the premises for minerals or other products; the instrument that creates a leasehold or working interest in minerals. 2. the area where production wells, stock tanks, separators, LACT units, and other production equipment are located.

see lease (def. 1).

the measurement, sampling, and transfer of oil from the producer’s tanks to the connected pipeline on an automatic basis without a representative of either the producer or the gathering company having to be present. See LACT unit.

see lease automatic custody transfer.

usually, the cash consideration that is paid by the lessee for the execution of an oil and gas lease by a landowner. It is usually based on a per acre basis.

an independent landman who may work with several operators or companies.

a natural gas liquid recovered from gas well gas in lease separators or natural gas field facilities. Consists primarily of pentanes and heavier hydrocarbons. Usually blended with crude oil for refining.

facility such as a dehydrator, compressor, or separator installed to serve only a single lease.

a person who works on a lease; a pumper. See lease operator.

(slang) a landman who procures leases on tracts of land for petroleum exploration and production.

the point on a lease where the volume of oil produced from the lease is measured, usually automatically.

the oil company employee who attends to producing wells. He or she attends to any number of wells, ensures steady production, prepares reports, tests, gauges, and so forth. Also called a custodian, pumper, or switcher.

an agreement between companies for the purchase by one company of a block of the other’s leases. Also used between lease brokers and companies.

special stipulations, or requirements, that are often included in OCS oil and gas leases in response to concerns raised by coastal states, fishing groups, federal agencies, and others. The stipulations may require biological surveys of sensitive seafloor habitats, environmental training for operations personnel, special waste-discharge procedures, archaeological resource reports to determine the potential for the encounter of historic or prehistoric resources, special operating procedures near military bases or their zones of activity, and other restrictions on OCS oil and gas operations. Lease stipulations are legally binding, contractual provisions.

the oil company employee who supervises one or more lease operators.

see production tank.

see lessee.

the estate in real property created by a lease. A leasehold is held by a lessee, usually for a fixed period.

all or a fractional part of the interest of a lessee (grantee) under an oil and gas lease. Such interest includes the lessee’s right to search for, drill, and produce oil and gas from a lease tract subject to royalty payments. The term usually refers to the remaining leasehold or working interest exclusive of any nonoperating interests created and assigned therefrom, such as overriding royalty interests and production payments. Also called operating interest, working interest.

see landman.

light-emitting diode.

a wellbore irregularity caused by penetration of alternating layers of hard and soft formations, where the soft formation is washed out and causes a change of diametrical size.

the side of a ship, vessel, or floating offshore rig away from the source of the wind. For example, if the wind is blowing from the north, the lee is on the south side of the ship, vessel, or rig. Compare windward.

the side of a rig that is away from the effects of wind and waves. Also called downwind.

in crane operations, a single length of wire-rope sling, one end of which is attached to the load and the other end of which is attached to the crane’s hook. Usually, but not always, slings with at least two legs are used.

in an oil and gas lease, the clause that binds the parties and declares the lease effective for the lessor when he or she signs the instrument.

1. the distance along something, such as a line, from one end to the other. 2. a measure of the distance along something.

1. a porous, permeable, irregularly shaped sedimentary deposit surrounded by impervious rock. 2. a lenticular sedimentary bed that pinches out, or comes to an end, in all directions.

a hydrocarbon reservoir consisting of a porous, permeable, irregularly shaped sedimentary deposit surrounded by impervious rock. See lens.

see lens-type trap.

a rule that states that an induced electromotive force (voltage) generates a current that induces a counter magnetic field that opposes the magnetic field generating the current.

a naturally occurring oxidized lignite. See lignins.

Local Emergency Planning Committee.

the recipient of a lease (such as an oil and gas lease). Also called leasee.

the conveyor of a lease (such as an oil and gas lease).

an agreement in which a party receiving gas sales proceeds agrees to refund part of such proceeds in the event FERC orders the party to return part of the gas sales proceeds to the purchaser because a portion of the rate is deemed unjustified.

a letter issued by any participant in a custody transfer citing any condition with which issue is taken. This serves as a written record that a particular action or finding was questioned at the time of occurrence. Also called notice of apparent discrepancy.

an MMS document sent to offshore lessees and operators to clarify or supplement operational guidelines.

1. an embankment that lies along the sides of a sea channel, a canyon, a river, or a valley. 2. the low ridge sometimes deposited by a stream along its sides.

1. the height or depth at which the top of a column of fluid is located (the level of fluid in a well). 2. horizontally even surface. 3. a device used to determine whether a surface is horizontal.

in a tank or vessel containing a liquid, a method of maintaining the height or depth of the liquid within specified limits. It is accomplished with sensors that monitor the incoming or outgoing liquid and which, in turn, activate a switch to turn the flow either on or off.

a piece of equipment, usually attached to a wire winch, that allows the wraps of wire to be spooled on uniformly.

a system of devices whose purpose is to maintain the volume of liquid in a tank or vessel at a predetermined height.

the act of a coat of paint flowing over the surface to which it is applied in a manner that produces a coat of uniform thickness.

low gravity solids.

a license and certification obtained by those who work at sea from the Liberian Maritime Registry System, which adheres to STCW standards. See Standards of Training, Certification, and Watchkeeping.

a very buoyant raft designed to be used by people forced into the water; made of a metal tube covered with wood or canvas, balsa wood, or of rubber which may be automatically inflated.

someone who holds the exclusive right to possess and use property during his or her lifetime but who cannot devise or bequeath the property. Compare remainderman.

a group of devices that allow a human being to survive under water or in a hyperbaric environment.

an individual who is trained extensively in the mixing and handling of gases and techniques for hyperbaric life support. They must fulfill classroom and field experience requirements and take assessments to be certified through the ADCI.

a small boat hoisted on davits or carried on one of the upper decks of a vessel which can be quickly lowered into the water in case of an emergency.

a line attached to a diver’s helmet by which he or she is lowered and raised in the water.

a device in an engine against which a cam rotates as the engine runs. As the high point of the cam rotates, it pushes against (lifts) the lifter. The lifter, in turn, actuates a push rod or other device to open a valve or similar device. Sometimes called a cam follower.

a tank whose roof rises and falls with the changes of pressure in the tank but does not float on the product stored in it.

the costs of producing oil from a well or a lease.

a short piece of pipe with a pronounced upset, or shoulder, on the upper end, screwed into drill pipe, drill collars, or casing to provide a positive grip for the elevators. Also called a lifting sub or a hoisting plug.

an arrangement of special hooks that fit into receptacles in a master bushing or an insert bowl and chains or wire rope that are connected to a rig’s air hoist, all of which enables crew members to insert or remove the master bushing and insert bowls as required.

also called hoisting plug or lifting nipple. See lifting nipple.

a crude oil of relatively high API gravity (usually 40° or higher).

on mobile offshore drilling rigs, the weight of the rig with all permanently attached equipment but without fuel, supplies, crew, ballast, drill pipe, and so forth.

components of a hydrocarbon liquid mixture that are low boiling and easily evaporated. Compare heavy ends.

fuels, such as gasoline, that have relatively high volatility.

the low molecular weight hydrocarbons such as methane, ethane, propane, and butanes.

see protium.

petroleum fractions, such as ethylene, that are relatively light in molecular weight.

a semiconductor device that has two electrodes or terminals (a diode) and emits light when voltage is applied to it. LEDs are used in electronic displays such as calculators, wrist watches, and so on.

a hole cut into a strengthening member that reduces its weight but does not significantly affect its strength.

a large, usually flat-bottomed, barge used in unloading or loading ships. v: to convey by a lighter.

a device incorporated into an electrical system to prevent damage by heavy surges of high-voltage electricity, such as a stroke of lightning or voltage surges resulting from mishaps in operations.

the weight of the steel structure of an offshore rig and its fixed equipment, but without ballast, fuel, consumables, deck loads, bulk material, stores, drilling tubulars, loose equipment, and the like.

reduce the weight of the slurry so the cement can flow past low-pressure zones or soft formations without losing part of the slurry or damaging the wellbore.

a cement or cement system that handles stable slurries having a density less than that of neat cement. Lightweight cements are used in low-pressure zones where the hydrostatic pressure of long columns of neat cement can fracture the formation and result in lost circulation.

all diving equipment less complex than the standard dress. This equipment employs face masks or helmets, protective clothing, and swim fins or boots.

a measure of a ship or offshore floating rig’s actual displacement (in long tons) when it is not carrying cargo or expendable supplies and equipment. A rig’s lightweight is made up of the hull and upper deck as well as fixed equipment, meaning equipment that is part of the structure and is not normally removed, such as a derrick or crane.

naturally occurring special lignites, e.g., leonardite, that are produced by strip mining from special lignite deposits. Used primarily as thinners and emulsifiers.

an organic drilling fluid additive derived from by-products of a paper-making process using sulfite. It minimizes fluid loss and reduces mud viscosity.

a hole cut in a structural member of a ship or offshore drilling rig, usually in a tank, to allow water to pass through freely.

a caustic solid that consists primarily of calcium oxide (CaO). Many forms of CaO are called lime, including the various chemical and physical forms of quicklime, hydrated lime, and even calcium carbonate. Limestone is sometimes called lime.

an alkaline chemical also known as lime, slaked lime, or calcium hydroxide, Ca (OH)2.

1. a calcite-rich sediment that may give rise to shaly limestone. 2. a drilling mud that is treated with lime to provide a source of soluble calcium in the filtrate to obtain desirable mud properties for drilling in shale or clay formations.

a sedimentary rock rich in calcium carbonate that sometimes serves as a reservoir rock for petroleum.

a generic term to describe certain types of packers where the packing element is positioned in such a fashion as to limit wellbore media exposed to the tool’s setting or releasing mechanisms.

a fracturing method in which fracturing fluid is injected into the formation through a limited number of perforations (i.e., fluid is not injected through all the perforations at once; rather, injection is confined to a few selected perforations). This special technique can be useful when long, thick, or multiple producing zones are to be fractured.

see clipper.

see clipper.

1. any length of pipe through which liquid or gas flows. 2. rope or wire rope. 3. electrical wire.

petroleum or other liquid delivered through a pipeline system into a receiving vessel or tank to ensure that the section of pipeline from the source tank to the receiving tank is full in order to minimize the amount of air in the pipeline.

control device that makes and breaks the power circuit to the motor.

an operation to replace previous material in a pipeline.

in waterflooding, a straight-line pattern of injection wells designed to advance water to the producing wells in the form of a nearly linear frontal movement. See waterflooding.

opening (venting to atmosphere) in a vessel’s piping system so as to allow, to the extent possible, drainage into a tank where the material may be gauged and accounted for.

1. the reduction in the quantity of natural gas flowing through a pipeline that results from leaks, venting, and other physical and operational circumstances. 2. the reduction in (or the loss of) electrical energy that occurs when electricity flows through a conductor (a line).

see line press.

see parts of line.

a steel or plastic pipe used in pipelines, gathering systems, flow lines, and so forth.

the recorded difference in a tank’s gauges taken both while the tank’s valves are closed (off-line), and while the tank’s valves are opened (on-line) into a closed system. All downstream valves of the line section to be pressed are opened while the terminating valves remain closed. Also called line pack.

the force per unit area exerted on a pipe wall by a fluid inside the pipe.

the rate of flow of a fluid through a line.

see pig.

an instrument calibrated to show the speed in feet per minute at which wireline is raised or lowered in the hole. The line speed indicator may be driven mechanically by the measuring wheel and placed next to the depth odometer, or it may be driven by a motor.

a device fitted on the drawworks and used to cause the fastline to reverse its direction on the drawworks drum or spool when a layer of line is completed on the drum and the next layer is started.

in pipeline construction, the coating applied to pipe over the ditch. Coal tar enamels are particularly effective.

used to align the ends of pipe prior to welding.

where the end of a joint of pipe is aligned with the joint ahead of it.

a linear topographic or tonal feature on the terrain and on images and maps of the terrain that is thought to indicate a zone of subsurface structural weakness.

see caliper.

a direct-reading chart used on the flow recorder of an orifice metering system on which are recorded static and differential pressures during a particular time period. It must have the same static and differential ranges as the flow recorder.

the flow range over which the meter factor does not deviate from specified limits.

a technique used to measure instantaneous corrosion rates by changing the electrical potential of a structure that is corroding in a conductive fluid and measuring the current required for that change.

in a potentiometer with multiple windings, the uniform winding of the resistance wire that makes up the potentiometer’s control. A linear taper provides the potentiometer with directly proportional control—that is, turning the potentiometer’s control directly varies the potentiometer’s resistance. For example, turning the control one-fourth turn decreases or increases the resistance by one fourth. Compare logarithmic taper.

in electronics, the relationship between two quantities that occurs when a change in one of the quantities produces a directly proportional change in the other quantity.

an expression of a meter’s deviation from accuracy.

1. a string of pipe used to case open hole below existing casing. A liner extends from the setting depth up into another string of casing, usually overlapping about 100 feet (30.5 metres) above the lower end of the intermediate or the oil string. Liners are nearly always suspended from the upper string by a hanger device. 2. a relatively short length of pipe with holes or slots that is placed opposite a producing formation. Usually, such liners are wrapped with specially shaped wire that is designed to prevent the entry of loose sand into the well as it is produced. They are also often used with a gravel pack. 3. in jet perforation guns, a conically shaped metallic piece that is part of a shaped charge. It increases the efficiency of the charge by increasing the penetrating ability of the jet. See jet. 4. a replaceable tube that fits inside the cylinder of an engine or a pump. See cylinder liner.

a pump barrel used for either tubing pumps or rod (insert) pumps. A full-cylinder barrel consists of a steel jacket inside of which is a full-length tube of cast iron or special alloy. The inner surface of the barrel is polished to a mirrorlike finish to permit a fluid-tight seal between it and the plunger. In a sectional liner barrel, the tube placed inside the steel jacket consists of a series of sections placed end to end and held firmly in place by means of threaded collars on the ends of the steel jacket.

the process of cementing a liner string in the hole. See cementing, liner.

a well completion in which a liner is used to obtain communication between the reservoir and the wellbore.

a slip device that attaches the liner to the casing. See liner.

the distance that a liner extends into the bottom of a string of casing. See lap.

a stressed-steel corrugated tube that is lowered into existing casing in a well to repair a hole or leak in the casing. The patch is cemented to the casing with glass fiber and epoxy resin.

a casing shoe attached to liner rather than to casing.

a completion tool installed at the top of a production liner that isolates the reservoir from the tubing and can hold pressure both from the tubing or from the reservoir.

see magnetic lines of force.

a steel projection on the drilling hook by means of which the elevator links are attached to the hook.

on a drilling rig’s hook, a device that firmly secures and locks the elevator link into the link ear’s opening.

a bolt that secures elevators in the bail. Manufactured with the nut end toward the derrickhand so that workers can monitor the nut pins when latching and unlatching elevators during a trip.

on a top drive, a device that, when actuated by the driller, tilts the unit’s built-in elevators into a position to make it easy for crew members to latch the elevators onto a joint of pipe stored in the mousehole. See top drive.

Louisiana Independent Oil and Gas Association.

a substance usually colloidal and easily wet by oil.

having an affinity for lipids, a class of compounds that includes most hydrocarbons.

the process whereby a substance in its gaseous or solid state is liquefied.

hydrocarbon components of natural gas that can be extracted and saved in liquid form.

a liquid composed chiefly of natural gas (i.e., mostly methane). Natural gas is liquefied to make it easy to transport if a pipeline is not feasible (as across a body of water). Not as easily liquefied as LPG, LNG must be put under low temperature and high pressure or under extremely low (cryogenic) temperature and close to atmospheric pressure to liquefy.

a vessel such as a ship used to transport liquefied natural gas.

a mixture of heavier, gaseous, paraffinic hydrocarbons, principally butane and propane. These gases, easily liquefied at moderate pressure, may be transported as liquids and converted to gases on release of the pressure. Thus, liquefied petroleum gas is a portable source of thermal energy that finds wide application in areas where it is impractical to distribute natural gas. It is also used as a fuel for internal-combustion engines and has many industrial and domestic uses. Principal sources are natural and refinery gas, from which the liquefied petroleum gases are separated by fractionation. Also called LP-gas.

liquid propane or butane produced by a crude oil refinery. It may differ from LP gas in that propylene and butylene may be present.

a state of matter in which the shape of the given mass depends on the containing vessel, but the volume of the mass is independent of the vessel. A liquid is a fluid that is almost incompressible.

the measurable material remaining on board a vessel after a discharge. Includes measurable sludge, sediment, oil, and water or oil residue lying on the bottom of the vessel’s cargo compartments and in associated lines and pumps.

a method of determining a tank’s capacity by filling and withdrawing from the tank accurately determined volumes of liquid.

an electronic digital display that consists of two sheets of glass separated by a sealed-in, normally transparent, liquid crystal material. The outer surface of each glass sheet has a transparent conductive coating etched into character-forming segments that have leads going to the edges of the display. Voltage applied between front and back electrode coatings disrupts the orderly arrangement of molecules, which darkens the liquid enough to form visible characters although no light is generated.

the mark on the gauger’s tape indicating the height of the liquid.

a hygroscopic liquid, such as glycol, used to remove water from other fluids.

the crude oil or product that is forced into the hatch or up around the edges of a floating roof by the weight of the roof.

in underbalanced drilling, the use of a liquid drilling fluid (mud) to drill the well. See underbalanced drilling.

the condition in which a liquid is heated and free to expand in all directions. Same as volume expansion.

the hydrostatic pressure of the liquid in a stock or holding tank, which causes the shell to expand and contract as liquid is added or removed from the tank.

liquids that have been extracted from natural gas, such as propanes, butanes, pentanes, and heavier products. Liquid hydrocarbons extracted in gas processing plants are often referred to as “plant products.”

the height, or depth, of a liquid in a tank or vessel; liquid level is controlled by level controllers, measured with liquid-level gauges, and viewed with liquid-level indicators.

nitrogen that occurs as a liquid at atmospheric pressure but at a temperature of –383°F (–195°C). Under normal conditions of pressure and temperature, nitrogen occurs as a gaseous fluid. Liquid nitrogen is sometimes transported to the rig and used as a drilling fluid in underbalanced drilling. See underbalanced drilling.

in drilling fluids, that part of the fluid that is liquid. Normally, the liquid phase of a drilling fluid is water, oil, or a combination of water and oil.

in plant processing, that portion of the fluids being processed that is not gas but liquid.

a vessel used to separate a vapor-liquid mixture.

a type of thermometer in which the sensitive part of the instrument consists of a liquid like mercury or alcohol contained in an envelope of glass.

any device used to control the liquid level in a tank by actuating electric or pneumatic switches that open and close the discharge valve or the intake valve, thus maintaining the liquid at the desired level.

any device that indicates the level or quantity of liquid in a container.

a device connected to a vessel and coupled with either a float in the vessel or directly with the fluid therein. It is calibrated to give a visual indication of the liquid level.

where participants resell their positions.

notice that a suit has been filed in a court of law and that the property owned by the defendant may be liable to judgment.

the position of a ship or offshore drilling rig that heels to one side because of a shift in cargo, machinery, or supplies. Also called heel.

the correction applied to the volume or gauge observed in a vessel’s tank when the vessel is listing, provided that liquid is in contact with all bulkheads in the tank. List correction may be accomplished by referring to the list correction tables for each of the vessel’s tanks or by mathematical calculation.

a list published periodically in the Federal Register that names endangered and threatened wildlife and plants.

the unit of capacity in the metric system. It is equal to about 0.9464 quarts. Also spelled litre in the SI system.

the conversion of unconsolidated deposits into solid rock.

a facies map showing lithologic variations within a formation. It shows the variations of selected lithologic characteristics within a stratigraphic unit.

1. the study of rocks, usually macroscopic. 2. the individual character of a rock in terms of mineral composition, structure, and so forth.

see geostatic pressure.

a water soluble blue powder obtained from various lichens, but especially Variolaria lecanora and V. rocella. Litmus turns red in acid solutions and blue in base (alkaline) solutions and is therefore often used as an acid-base indicator.

an acceptable unit of measure in the SI system of capacity equal to the volume occupied by 1 kilogram of water at 4°C and at the standard atmospheric pressure of 760 millimetres. It is spelled litre in the SI system.

a 20-inch (50.8-centimetre) products line constructed during the same period as Big Inch as part of the World War II effort. See Big Inch.

the end of a flexible steel brake band that is attached to a brake lever by means of a linkage. Moving the brake lever pulls the live end down, and the whole band tightens around the flange. This slows or stops the drum by friction.

crude oil that contains gas and has not been stabilized or weathered. It can cause gas cutting when added to mud and is a potential fire hazard.

an assembly of multiple swing rollers free to roll between the revolving superstructure and the mounting.

a diving operation involving the use of a boat or vessel that is under way.

an on-site patented fire-suppressor system that uses monoammonium phosphate to put out the fire on a burning well.

an independent risk management organization that provides risk assessment and risk mitigation solutions and management systems certification around the world. Their goal is to improve their clients’ quality, safety, environmental, and business performance. Founded in 1760. Address: 71 Fenchurch Street, London EC3M 4BS, UK; www.lr.org.

lime; used in drilling reports.

lower marine-riser package.

used to remotely connect the BOP assembly to the wellhead, and the LMRP to the BOP.

liquefied natural gas.

liquefied natural gas carrier.

in electronics, a probe that attenuates (reduces) the strength of a signal being measured by the probe. See attenuation probe.

1. in mechanics, the weight or pressure placed on an object. The load on a bit refers to the amount of weight of the drill collars allowed to rest on the bit. See weight on bit. 2. in reference to engines, the amount of work that an engine is doing; for example, 50 percent load means that the engine is putting out 50 percent of the power that it is able to produce. 3. the amount of gas delivered or required at any specified point or points on a system; load originates primarily at the gas-consuming equipment of the customer. 4. in electronics, a device that consumes electric power. v: 1. to engage an engine so that it works. Compare idle. 2. to set a governor to maintain a given pressure as the rate of gas flow through the governor varies. Compare demand.

a chain or cable with a latching device, used to secure loads (usually of pipe) on trucks. Also called a boomer.

see hook block.

the amount of weight a device can safely carry or support.

see guy line.

the wireline attached to a mast or derrick to provide the main support for the structure. Compare wind guy line.

a brand of bolted-flange connector used in marine riser systems to join (connect) riser pipe. This connector is designed for drilling in water depths of 7,000 feet (2,000 metres) or deeper, and has a tensile load rating of 3.5 million pounds (1.6 million kilograms). See riser pipe.

a line, painted or cut on the outside of a floating rig or ship’s hull, which marks the maximum waterline when the rig or ship is loaded with the greatest amount of cargo that it can safely carry.

1. loss from a cargo of oil. Usually the losses occur because the light ends escape during transport. 2. in a transformer, the reduction (loss) of electrical energy that occurs when the transformer is loaded—that is, when electricity is being drawn from it.

the crude or refined oil used in fracturing a formation to stimulate a well, as distinguished from the oil normally produced by the well.

the shipboard procedure of collecting and settling water and oil mixtures. It results from ballasting and tank-cleaning operations (usually in a special slop tank or tanks) and the subsequent loading of cargo on top and the pumping of the mixture ashore at the discharge port. v: to commingle on-board quantity with cargo being loaded.

the total calculated volume (TCV) by vessel measurement on sailing, less onboard quantity (OBQ), divided by the TCV by shore measurement at loading: LVR = TCV sailing volume + OBQ/TCV received from shore at loading.

see voltage drop.

see LOT (loaded on top) procedure.

the individual who handles the filling of tank cars, ships, barges, or transport trucks.

occurs when the amount of water or condensate production is too great to be lifted by the velocity of the gas.

see suction line.

the equipment used for transferring crude oil or petroleum products into tank cars or trucks.

a rounded blade on a displacement meter that separates the liquid stream into discrete quantities.

location; used in drilling reports.

a company that sells natural gas to homes, offices, and businesses in towns, cities, or relatively small rural areas.

a local community committee required under SARA. Committee members are approved by the SERC and include elected state and local officials; police, fire, and public health officials; environmental advocates; hospital and transportation officials; industry representatives; community groups; and the media. The function of the LEPC is to develop an emergency response plan that will be implemented if a hazardous material is released in the community.

the place where a well is drilled. Also called well site.

compensation paid to the surface owner for actual and potential damage to the surface and crops in the drilling and operation of a well.

a device, larger than the bore of a permanent packer, which is run with seal subs on the bottom of a tubing string and used to locate the top of a permanent packer.

a device made up in the tubing string and run inside a packer to prevent fluid and pressure from escaping between the tubing and the packer.

see kelly bushing lock assembly.

a special type of threaded fastener (a nut) that, when screwed down firmly against another nut or a washer, fastens (locks) firmly in place.

a device to lock a packer’s mandrel to its dragblock housing.

a dial-indicating temperature instrument with an automatic locking device for the indicator, which ensures that the indication cannot change until the reading has been taken and the instrument reset.

on the telescopic joint of a floating offshore rig, a mechanism that secures (locks) the joint’s inner barrel to its outer barrel in a fully retracted position. Locking the joint fully retracted allows for easier handling when it is being shipped, when it is being picked up on the rig, and when the blowout preventer stack is being run or retrieved.

on a lower marine riser package’s connector, a device with a tapered locking profile on its inside diameter that mates with a tapered locking profile on the outside diameter of the wellhead.

slickline tools with slips and rubber cups to contain pressure and pack-off tubing in wells not equipped with landing nipples.

a personnel protection system in which a padlock is placed on the power switch for motor- or engine-driven machinery so that the switch cannot be turned on without unlocking and removing the padlock. A note—the tag—is also attached to the switch that explains that the equipment the motor or engine drives is being worked on and should not be energized (turned on).

a trademark for a packer with bidirectional slips used in completion.

a kind of naturally occurring iron oxide that has magnetic properties and therefore attracts iron or steel. Also called magnetite.

unstratified, homogeneous accumulation of silt, often containing small amounts of clay or sand and redeposited by wind from glacial outwash or deserts.

a systematic recording of data, such as a driller’s log, mud log, electrical well log, or radioactivity log. Many different logs are run in wells to discern various characteristics of downhole formation. v: to record data.

logarithm.

to run any of the various logs used to ascertain downhole information about a well.

a cross section of a reservoir or part of a reservoir constructed with electric or radioactivity logs.

the movement of the curve on a log away from a reference, or base, line.

for pipelines, a daily report sheet on which operating data are entered by gaugers, dispatchers, and station operators.

the exponent that indicates the power to which a number is raised to produce a given number. For example, the logarithm of 100 to the base 10 is 2.

of or pertaining to a logarithm, as a logarithmic scale. See logarithm.

a range of values—a scale—on which actual distances from the origin are proportional to the logarithms of the corresponding scale numbers. Unlike an arithmetic scale, where distances from the origin relate directly to the number, values on a logarithmic scale indicate a proportional relation. For example, the Richter scale of earthquake intensity is logarithmic; thus, an earthquake with an intensity of 4.0 on the Richter scale is much more than twice as intense as an earthquake with an intensity of 2.0.

in a potentiometer, the winding of the resistance wire in such a manner that turning the potentiometer’s control knob varies the resistance nonproportionately. That is, turning the control knob one-quarter turn increases or decreases the resistance by a factor different from one-fourth—for example, two or four times more. Compare linear taper.

a book used by station engineers, dispatchers, and gaugers for keeping notes on current operating data.

any of several electrical, acoustical, mechanical, or radioactivity devices that are used to measure and record certain characteristics or events that occur in a well that has been or is being drilled.

logging measurements obtained by measurement-while-drilling techniques as the well is being drilled.

1. the study of the principles of reasoning, especially of the structure of propositions as distinguished from their content; logic also includes the study of method and validity in deductive reasoning. 2. the nonarithmetic operations performed by a computer, such as sorting, comparing, and matching that involve yes-no decisions.

an electronic circuit that provides the action of comparing, selecting, making references, matching, sorting, and merging where yes-or-no (logic) quantities are involved.

a process in logical reasoning whereby two related statements, or premises, must be true before a correct conclusion can be drawn. For example, if one premise is “that dog is panting,” and the other premise is that “the temperature is 98°,” then the conclusion, “when the temperature is 98°, that dog pants,” may be correctly drawn.

a process in logical reasoning whereby a true statement is made false by making a false statement.

a process in logical reasoning whereby if either or both of two statements, or premises, are true, then a correct conclusion can be drawn. For example, the statement that “if 50 tons of iron or 50 tons of coal overloads a truck, then the truck is overloaded,” is a correct conclusion. Either 50 tons of iron or 50 tons of coal overload the truck.

slips designed to fit a square-drive master bushing, and whose taper length is 813/16   inches (224 millimetres). Compare extra-long rotary slips. See also slips, square-drive master bushing.

1. the last string of casing set in a well. 2. the string of casing that is set at the top of or through the producing zone, often called the oil string or production casing.

the failure of the adhesion (bond) between the tungsten carbide stud and the tungsten carbide of a polycrystalline diamond compact (PDC) bit cutter. As a result, the PDC layer and the tungsten carbide layer below the PDC layer fall off, leaving only the tungsten carbide stud on the bit.

any one of two types of thread that are cut on casing as standardized by API. The other is the short thread.

a unit of measure of mass (weight) that is equal to 2,240 pounds (1,016.06 kilograms). Compare short ton.

displacing fluid from the tubing up the annulus. Compare short way.

a weather forecast covering more than a week in advance (sometimes for a month or a season).

energy that is emitted from a source in the form of waves the lengths of which are longer than 545 metres. Long-wave radiation is not visible. Compare shortwave radiation.

the arc or portion of the earth’s equator intersected between the meridian of a given place and the prime meridian (at Greenwich, England) and expressed either in degrees or in time.

movement of seawater parallel to the shore.

that portion of the gauge housing that contains a shielded or glassed-in opening through which a gauge is observed.

Louisiana Offshore Oil Port.

the technique of laying an additional pipeline alongside an existing one when additional capacity is needed.

an emulsion that is relatively easy to break. Compare tight emulsion.

see lost circulation.

friction loss. See pressure-drop loss.

a rock layer that takes excessive amounts of drilling mud as it is being drilled.

the quantities of whole mud lost to a formation, usually in cavernous, fissured, or coarsely permeable beds. Evidenced by the complete or partial failure of the mud to return to the surface as it is being circulated in the hole. Lost circulation can lead to a blowout and, in general, can reduce the efficiency of the drilling operation. Also called lost returns. See blowout.

materials added to the mud in varying amounts to control or prevent lost circulation. Classified as fiber, flake, or granular.

a substance added to cement slurries or drilling mud to prevent the loss of cement or mud to the formation. See bridging materials.

cement set across a formation that is taking excessively large amounts of drilling fluid during drilling operations.

a well that cannot be drilled further or produced because of a blowout, unsuccessful fishing job, and so forth.

drill pipe, drill collars, tubing, or casing that has become separated in the hole from the part of the pipe reaching the surface, necessitating its removal before normal operations can proceed; i.e., a fish.

see lost circulation.

an incident in the workplace that results in an injury serious enough that causes the person injured to be unable to work for a day or more.

a procedure in which tank-cleaning operations are carried out on board ships and the resulting water/oil mixture is collected in a tank and allowed to separate. The relatively clean water is then pumped out of the vessel, and part of the next cargo is loaded on top of the remaining cargo/water-cleaning residue. This residue is called slops.

lockout-tagout.

a group of independent oil producers and persons who own royalties from oil and gas wells in Louisiana. Address: PO Box 4069, Baton Rouge, LA 70821-4069; 800-443-1433.

a deepwater oil gathering system located off the coast of Louisiana in the Gulf of Mexico. It is located near the town of Port Fourchon. Large tanker ships, which usually carry oil produced overseas, can tie up to LOOP and offload their cargo. LOOP temporarily stores the oil before it is sent through a pipeline to shore for further handling. Most tankers offloading at LOOP are too large for U.S. inland ports.

heavily weighted muds whose high solids content (a result of the large amounts of barite added) necessitates the reduction of clay solids.

the drawworks drum drive used when hoisting loads are heavy.

in drilling, nonreactive particles in the drilling fluid that are either intentionally added to give the drilling fluid desirable properties or are picked up by the drilling fluid from a formation being drilled. Usually, low gravity solids that get into the drilling fluid as a formation is drilled are removed by mud cleaning equipment at the surface.

see permeability.

a tide at its lowest level or the time of day when it occurs. Compare high tide. See tide.

a liquid that, at the measurement or proving temperature of the meter, has a vapor pressure less than atmospheric pressure. Compare high vapor pressure liquid.

a carbon steel generally containing not more than about 1% carbon and small amounts of one or more of the following: manganese, nickel, chromium, molybdenum, and vanadium. Low-alloy steels have good hardenability—that is, they can be hardened, which improves other properties of the steel. Low-allow also steels resist corrosion when used in certain environmental conditions.

see lo-cap probe.

chemicals injected into natural gas to prevent hydrate formation.

see near-balance drilling.

an area of low atmospheric pressure.

a system in which the gas pressure in the mains and the service lines is substantially the same as that delivered to the customers’ appliances; ordinarily, a pressure regulator is not required on individual service lines.

a squeeze cementing technique in which the pressure used to place the cement always remains below fracture pressure. See squeeze cementing.

see low-solids mud.

a drilling mud that contains a minimum amount of solid material (sand, silt, and so on) and that is used in rotary drilling when possible because it can provide fast drilling rates.

separation of a hydrocarbon fluid mixture into components by fractionation, wherein the reflux condenser is operated at temperatures requiring refrigeration. See pod (Podbielniak) analysis.

gas processing conducted below ambient temperatures.

a process where natural gas cools down as pressure is reduced; lowering pressure lowers the temperature to –32°C. Water and the higher hydrocarbons and mercury condense, leaving the natural gas.

a separator that removes water vapor from (dehydrates) gas by expanding the gas, which lowers its temperature. The low temperature makes the water vapor in the gas condense to liquid water, which falls to the bottom of the separator for removal.

commercial clay chiefly of the calcium montmorillonite type and having a yield of approximately 15 barrels per ton (2,385 litres per tonne).

a wire or chain fairlead that is mounted on a lower column of a semisubmersible.

the part of a semisubmersible rig that is always submerged or mainly submerged below the waterline. Ballast, drill water, and fuel oil are stored in the lower hull.

on rigs that use a kelly and rotary table system to rotate the bit and drill stem, a heavy-duty valve installed between the kelly and the first joint of drill pipe. Usually, the valve is open so that drilling fluid can flow out of the kelly and down the drill stem. When the mud pump is stopped, the valve can be manually closed with a special wrench to prevent pressurized fluids in the drill string from flowing into the kelly. When closed, the valve also prevents mud in the kelly from spilling onto the rig floor when the kelly is broken out of the drill string. Also called a drill stem safety valve, mud saver valve.

see drill stem safety valve, lower kelly cock.

the equipment that attaches the bottom part of the marine riser to the subsea blowout preventer (BOP) stack. It includes the BOP connector, a flexible joint to compensate for side-to-side movement, and the marine riser connector. See riser connector, riser pipe, subsea blowout preventer.

a hydraulically actuated device that is used to remotely connect the blowout preventer stack to the wellhead, and the lower marine riser package to the blowout preventer stack.

in instrumentation, the measure of a process variable, such as pressure or temperature, over the desired range of measurement at its minimum point. Compare upper range value.

in tank sampling, a spot sample obtained at a level of fi/§ the depth of liquid below the surface.

a category of oil production for purposes of price control. It refers to old oil, i.e., oil contained in reservoirs that were being produced during 1972.

the part of the earth’s atmosphere that starts at sea level and extends to an altitude of about 18,000 to 19,000 feet (about 5.5 to 5.8 kilometres).

the process of laying pipe in a ditch in pipeline construction. Pipe can be lowered into the ditch as part of the coating operation or lowered separately by a lowering-in crew.

in pipeline construction, the process of raising pipe and placing it on vertical support members in parts of the world where frozen earth prevents normal burial of the line. Lowering-up is the counterpart of lowering-in in more temperate climates.

an air emission standard determined by the states on a case-by-case basis. LAER is applied in nonattainment areas, which do not meet NAAQS, and is more stringent than the BACT applied in attainment areas. Consequently, cost and economic impact are not taken into consideration in determining LAER.

liquefied petroleum gas.

liquefied refinery gas.

lower range value.

limestone; used in drilling reports.

lease; used in drilling reports.

life-support technician.

Landing Ship Tanks.

Letter to Lessees and Operators.

low-temperature separation.

low-temperature separator. A mechanical separator that uses refrigeration obtained by expansion of gas from high pressure to low pressure to increase recovery of gas-entrained liquids.

see lubricate-and-bleed method.

a substance—usually petroleum-based—that is used to reduce friction between two moving parts.

1. to apply grease or oil to moving parts. 2. to lower or raise tools in or out of a well with pressure inside the well. The term comes from the fact that a lubricant (grease) is often used to provide a seal against well pressure while allowing wireline to move in or out of the well.

in well control, a method used to lower the pressure exerted by gas in a well. Usually, the well has kicked, which has allowed gas to enter the wellbore. In some cases, the pressure of the gas may be so high that normal well-control methods cannot be used because the high pressure could fracture a formation and cause an underground blowout. In the lubricate-and-bleed method, mud is pumped into the well, which increases hydrostatic pressure. After pumping in a given volume of mud, time is given for the pressure to stabilize. Then, pressure is released (bled) from the well in an amount equal to the increase in hydrostatic pressure caused by the mud pumped into the well. This pumping of mud into the well (called lubing, or lubricating) and bleeding of pressure continues until the pressure of the gas is low enough to allow conventional well-control methods to be used. Also called lube-and-bleed process.

a specially fabricated length of casing or tubing usually placed temporarily above a valve on top of the casinghead or tubing head. It is used to run swabbing or perforating tools into a producing well and provides a method for sealing off pressure and thus should be rated for highest anticipated pressure.

see lubricator.

positioned just below the slash zone. Its function is to provide pressure containment of the landing string production bore when wireline or coil tubing activities are being deployed through the surface tree swab valve.

the ability to lubricate; an oily smoothness.

a projection on a casting to which a bolt or other part may be fitted.

the torque, or turning power, delivered to the flywheel of a diesel engine.

that portion of a tide that is due to the gravitational attraction of the moon on the earth.

load vessel ratio.

logging while drilling.

sensors capable of reading the rock properties in different directions of the wellbore. The results are normally shown in an image log where the formation change direction and dip can be seen.

having an affinity for the suspending medium, such as bentonite in water.

a colloid that is not easily precipitated from a solution and is readily dispersible after the precipitation by an addition of the solvent. See colloid.

a colloid that is readily precipitated from a solution and cannot be redispersed by an addition of the solution. See colloid.