Glossary

1. ton. 2. top of, used in drilling reports.

connection for transforming three-phase power using two transformers; a variation of the open-delta connection.

a ruler with a crosspiece or head at one end used in making parallel lines.

temporarily abandoned.

an instrument that measures the speed of rotation.

see hoist (def. 1) and block and tackle.

to touch an object downhole with the drill stem (as to tag the bottom of the hole or to tag the top of the fish).

in crane operations, a small wire rope attached to the bottom of a load suspended by the crane, which, when grasped by a crew member, allows the crew member to prevent rotation of the load.

running pipe or tubing and landing it on a downhole tool.

the ungraduated lower portion of a mercury-in-glass thermometer.

a short length of chain that is attached to the end of a winch line. It is usually provided with a special hook that fastens to objects.

the exit gas from a plant. Quantities of sulfur compounds that must be reduced before the dispersion of the gases to the atmosphere. The sulfur compounds in the tail gases are principally unreacted hydrogen sulfide (H2S) and sulfur dioxide with traces of carbonyl sulfide and carbon disulphide. See Claus process.

the point in a gas processing plant at which the residue gas is last metered, usually the allocation meter or the plant residue sales meter.

see guideline.

to pull the bottom end of a sucker rod away from a well when laying rods down.

1. a pipe run in a well below a packer. 2. a pipe used to exhaust gases from the muffler of an engine to the outside atmosphere.

a large roller located across the stern of an anchor-handling boat. Pendant lines travel over it when an anchor is being brought in or dropped.

in a ram blowout preventer, the steel rod, or shaft, that protrudes from each side of the preventer’s housing and to which the rams are attached. As the rams are operated, the tail shaft rotates to open or close the rams.

a gathering of personnel who are about to perform a task, the purpose of which is to discuss what the task involves, which person or persons are responsible for each part of the task, and to ensure that everyone involved in the tasks know precisely what they are to do, when they are to do it, and, if necessary, what personal protection equipment is required. So termed because, on land facilities, this meeting may occur at or near the tailgate of a pickup. Also called prejob meeting, safety meeting.

guiding a downhole tool into the wellbore or onto the rig floor.

a tropical cyclone in Haiti.

to begin to pull on a load.

to remove a joint or stand of pipe from the drill stem.

see in-kind.

the quantity of gas that a gas purchaser agrees to take, or to pay for if not taken.

a contract clause that guarantees payment to a seller for gas, even though the particular gas volume is not taken during a specified time period. Some contracts stipulate a time period for the buyer to take later delivery without penalty.

under Federal Energy Regulatory Commission Order No. 500, credits provided to a transporting pipeline by the producer of the natural gas that the pipeline can apply against any take-or-pay or take-and-pay obligations the pipeline might have to that producer under certain qualifying gas purchase contracts existing on June 23, 1987. Take-or-pay credits may only be received by a pipeline from a producer whose gas it transports and from whom the pipeline has received an “offer of credits” pursuant to Order No. 500. The many and complicated rules about take-or-pay credits are set out in detail in Order No. 500.

under a take-or-pay clause, the threshold quantity of product that the buyer is obligated to pay for, whether actually taken during the stated period of time. A take-or-pay quantity is usually stated in terms of an absolute quantity or a certain percentage of a total contract quantity over a specific period of time, usually a year.

usually prepared by an abstract company, a takeoff lists and briefly describes the documents relevant to the title of a given piece of property. It costs much less to prepare than an abstract of title and is similar to a landman’s run sheet.

under ESA, killing, capturing, hunting, harassing, or modifying or destroying the habitat so that breeding, feeding, or sheltering of a species is significantly impaired. Consequently, clearing an area that is the actual or potential habitat of an endangered or threatened species could constitute a violation of the act.

to measure and record the total length of pipe, casing, or tubing that is to be run in a well.

angular pieces of rock produced by weathering that come to rest in a steep slope at the bottom of a mountainside. The rock is broken loose from the larger mass by repeated freezing and thawing.

Technology Advancement of Multilaterals.

tangent.

a piece that provides an extension of an instrument (such as a file) and serves to form the handle or make a connection for the attachment of a handle.

in a right triangle, the ratio of the side opposite a given angle to the side adjacent to the angle.

a metal, plastic, or wooden container used to store a liquid. Three types include mud tanks for drilling, production tanks, and storage tanks.

a large, flat-bottomed vessel divided into compartments and used to carry crude or fuel oil.

a group of production tanks located in a field to store crude oil.

the settlings in the bottom of a storage tank. See basic sediment and water, bottoms.

see strap.

see calibration table.

a railroad car used to transport petroleum or petroleum products.

one circumferential ring of plates in a tank. See storage tank.

a structure erected to contain petroleum or a petroleum-fed fire in case a storage vessel ruptures or collapses. Usually a dike is built around the petroleum storage tank and a steel or stone wall is put up between the prime movers and the oil pumps in a pipeline pumping station. Also called fire wall.

a group of large tanks maintained by a pipeline and used to store oil after it has been transferred from the production tanks and before it is transported to the refinery.

an open or closed vessel of known capacity designed for the accurate determination of the volume of liquid delivered into or out of it during a meter-proving operation.

in offshore operations, a ship designed to transport oil when oil cannot be pipelined to shore.

settlings that collect at the bottom of storage tanks containing crude oils, residues, and other petroleum products. Such sludge usually contains water.

the person who measures a tank at various levels to see how much it will hold.

the obtaining of several measurements, such as ring circumference, gauge height, and tank height, to determine how much a tank will hold.

a table giving the number of barrels of fluid contained in a storage tank that correspond to the linear measurement on a gauge line. Tank tables are prepared from tank strapping measurements. See strap. Also called calibration table, tank capacity table.

a truck (tractor) whose specialty is hauling containers (tanks) that hold petroleum or petroleum products.

a truck designed to transport petroleum or petroleum products.

the total capacity of the number of tanks in a field.

a ship designed to transport oil, LPG, LNG, or SNG. Tankers whose capacity is 100,000 deadweight tons (90,720 deadweight tonnes) or more are supertankers, either very large crude carriers or ultralarge crude carriers. Also called a tank ship.

a spot sample taken from a suitable sample connection to the side of a tank.

the trademarked name for General American Transportation Company’s (GATX’s) system of interconnecting tank cars that can transport large volumes of bulk liquids. The TankTrain system consists of an entire string of cars that can be loaded or unloaded from a single system connection.

the active ingredient of quebracho and quebracho substitutes, such as mangrove bark, chestnut extract, and hemlock.

1. a tool for forming an internal screw thread. It consists of a hardened tool-steel male screw grooved longitudinally so as to have cutting edges. 2. a hole or opening in a line or vessel into which a gauge or valve may be inserted and screwed tight. v: 1. to form a female thread by means of a tap. 2. to extract or cause to flow by means of a borehole, e.g., to tap a reservoir.

a hole radially drilled in the wall of the meter tube or fitting, the inside edge of which is flush and without any burrs.

in tank sampling, withdrawing liquid samples through sample taps, at least three of which should be placed equidistant throughout the tank height and extending at least 3 feet (1 metre) inside the tank shell. A standard G-inch (0.64-centimetre) pipe with suitable valve is satisfactory.

a quick-release clamp that may be fitted around a strapping tape at any convenient position throughout its length.

in pipeline construction, a protective coating of polyethylene, polyvinyl, coal-tar-base, or butyl-mastic tape that is wrapped around pipe to prevent corrosion. Tape coatings are applied on the line, and any defects can be repaired relatively quickly and simply.

a guide that slides freely along strapping tape and that is used to pull and hold the tape in the correct position for taking measurements.

rolls of plastic sheeting with a preapplied adhesive that are used to coat pipelines to prevent corrosion after they are buried.

a tap with a gradually decreasing diameter from the top. It is used to retrieve a hollow fish such as a drill collar and is the male counterpart of a die collar. The taper tap is run into a hollow fish and rotated to cut enough threads to provide a firm grip and permit the fish to be pulled and recovered. See tap. Compare die collar.

a fitting, usually divided into two halves, that crew members place inside the master bushing to hold the slips.

1. a condition wherein the hole diameter narrows with depth owing to wear on the bit gauge caused by drilling abrasive formations. 2. a wellbore whose diameter is larger near the surface than near the bottom.

drill pipe, tubing, sucker rods, and so forth with the diameter near the top of the well larger than the diameter below.

in pipeline construction, a machine that moves along the pipe, wrapping joints with tape in overlapping segments.

Trans-Alaska Pipeline System.

a sandstone that contains chiefly heavy, tarlike hydrocarbons. Tar sands are difficult to produce by ordinary methods; thus it is costly to obtain usable hydrocarbons from them.

the weight of an empty container subtracted from the gross weight of the container and that which is in the container to ascertain net weight.

a bull plug or a blind flange at the end of a tee to prevent erosion at a point where a change in flow direction occurs.

a meter that balances target force with a feedback force applied above a fulcrum.

said of a fluid piping system in which flow impinges on a lead-filled end (target) or a piping tee when fluid flow changes direction.

certain substances under TSCA that present “an unreasonable risk of injury to health or to the environment,” for example, asbestos and PCB.

the rate set by pipeline companies for moving oil.

a device on an instrument control panel that indicates the cause of a system shutdown or alarm signal.

see weephole.

a multileg spread mooring using components in a taut leg configuration.

a system for monitoring the position of a floating offshore drilling rig in relation to the subsea wellhead. A taut steel line is stretched from the rig to the ocean floor. An inclinometer measures the slope of the line at the rig, and, because the line is assumed to have been straight when stretched from the rig to the ocean floor, any angle in the line indicates that the rig has moved. The system’s weakness is that the tautline can be distorted by currents and thus give inaccurate readings. Compare acoustic position reference, position-reference system.

an interest in production that does not bear its portion of production taxes levied on production from the property. The tax applicable to this interest is borne by other interest owners in the property. Compare exempt interest.

trillion cubic feet.

trillion cubic feet per day.

tubing conveyed perforator.

total depth.

top dead center.

a truck driver; a person who drives a truck that hauls loads, especially one who does it as professionally.

see rig down.

in paint technology, the drops of paint that collect on the bottom edges of items that are painted by dipping the item into a container of paint.

an organization composedprimarily of North Sea operators with multilateral experience. TAML has developed a multilateral categorization system based on amount and type of junction support provided.

of or relating to the deformation of the earth’s crust, the forces involved in or producing such deformation, and the resulting rock forms.

a formation in which movements of the earth’s crust compress or stretch the formation. When a well is drilled into such a formation, the rock can collapse into the wellbore and cause the drill stem to become stuck. Maintaining the mud weight to a value high enough to offset the tectonic stresses on the formation can prevent formation collapse.

a pipe fitting that is shaped like the letter T. A pipe or other fitting can be attached to each end of the tee, since the tee ends are threaded.

totally enclosed fan-cooled motor.

triethylene glycol.

the process of gathering data by electronic or other kinds of sensing devices and transmitting those data to remote points. See downhole telemetry.

a device used in the marine riser system of a floating drilling rig to compensate for the vertical motion of the rig caused by wind, waves, or weather. It consists of an inner barrel attached beneath the rig floor and an outer barrel attached to the riser pipe and is an integrated part of the riser system. Also called slip joint.

see telescoping mast.

a portable mast that can be erected as a unit, usually by a tackle that hoists the wireline or by a hydraulic ram. The upper section of a telescoping mast is generally nested (telescoped) inside the lower section of the structure and raised to full height either by the wireline or by a hydraulic system. Erroneously but commonly called a telescoping derrick.

a sub with a telescoping joint used in dual or triple completions for running additional tail pipe.

terminology used to describe a screen that, when packed off by gels, will give a pressure rise at the surface, thereby “telling” the tool operator that the gel has reached a certain location. Also called tattletale.

a hole drilled into the space between rings of packing material used with a liner in a mud pump. When the liner packing fails, fluid spurts out of the telltale hole with each stroke of the piston, indicating that the packing should be renewed. See weephole.

used to regulate the force of the blow delivered to the drill bit on a cable-tool rig. Attached to the walking beam, it controls the feed rate of the drilling tools. Also called temple screw.

a measure of heat or the absence of heat, expressed in degrees Fahrenheit or Celsius. The latter is the standard used in countries on the metric system.

an instrument lowered into a well to record downhole temperature.

an expression of the amount resistance increases in a material as the temperature increases. It is stated as per degree Celsius per ohm.

a device on a meter that automatically converts the flowing temperature of the fluid through the meter to a standard temperature.

a factor for correcting volumes of oil or gas to the volume occupied at a specific reference temperature. The reference temperature most commonly used in the petroleum industry is 60°F (15.56°C).

a sensor, transmission medium, and readout equipment in an operating configuration used to determine the temperature of a liquid for measurement purposes.

the measuring error caused by the temperature of a measurement differing from the pertinent reference value.

1. the rate of change of temperature with displacement in a given direction. 2. the increase in temperature of a well as its depth increases.

a gauge that measures and monitors temperature.

a survey run in cased holes to locate the top of the cement in the annulus. Since cement generates a considerable amount of heat when setting, a temperature increase will be found at the level where cement is found behind the casing.

the range of ambient temperatures, given by their extremes, within which a transducer is intended to operate.

see thermostat.

the maximum temperature increase that any part of the motor winding or magnetic structure accessible for measurement with a thermometer will have when the motor is developing its full load.

a sensing element and its housing, if any, and defined as the part of a temperature device that is positioned in a liquid the temperature of which is being measured.

an operation used to determine temperatures at various depths in the wellbore. It is also used to determine the height of cement behind the casing and to locate the source of water influx into the wellbore.

in process control systems, a device that senses the process variable of temperature and converts it to a proportional electrical signal of, usually, 4 to 20 milliamperes. Transmitters can be reranged, or calibrated, over a specific temperature range for better resolution around the temperature of interest.

see temporary guide base.

see temper screw.

temporarily shut in but not plugged.

the initial piece of equipment lowered to the ocean floor once a floating offshore drilling rig has been posi­tioned on location. It serves as an anchor for the guidelines and as a foundation for the permanent guide base and has an opening in the center through which the bit passes. It is also called a drilling template.

a magnet usually made of soft iron that loses its magnetism shortly after the magnetizing force is removed from it.

same as an eight round, except ten threads per inch. See eight round.

the measured 10-minute gel strength of a fluid is the maximum reading (deflection) taken from a direct-reading viscometer after the fluid has been quiescent for 10 minutes. The reading is reported in pounds per 100 square feet (grams per 9.29 square metres). See gel strength.

see cotenants.

1. the barge anchored alongside a relatively small offshore drilling platform. It usually contains living quarters, storage space, and the mud system. 2. a shipment of oil presented by a shipper to a pipeline for movement. 3. a form required by certain regulatory bodies in some states for their approval of products shipped from plants or other sources. 4. the person responsible for tending to a diver’s needs. 5. in naval architecture, the tendency of a floating vessel, such as an offshore rig, to heel easily from wind, current, and wave forces. Compare stiff.

a number assigned to a particular shipment, or tender, of petroleum or petroleum product.

steel tubes that attach a compliant platform to the seafloor. Called a tension-leg platform rig.

in a column of numbers having more than one digit, the column immediately to the left of the ones column. For example, in the number 3,284, 8 is in the tens column. It denotes that the number 3,284 contains 8 tens. Besides 8 tens, the number also contains 3 thousands, 2 hundreds, and 4 ones.

of or relating to tension.

the amount of longitudinal stress borne by an object or substance.

the greatest longitudinal stress that a metal can bear without tearing apart. A metal’s tensile strength is greater than its yield strength.

stress developed by a material bearing a tensile load. See stress.

a trial, or test, that determines a material’s reaction to pulling forces, which are applied to the material. As the material is pulled, its resistance to pull is determined, as well as how much it will elongate before breaking. Basically, tensile tests measure a material’s strength. Also known as a tension test.

the condition of a string, wire, pipe, or rod that is stretched between two points.

a device that measures and indicates the amount of pulling force (tension) being put on pipe, a tape measure, etc. In tank strapping, the strapping crew attaches a tension gauge to the measuring tape they use to determine a tank’s circumference. Knowing how much tension to apply to the tape is essential to accurate measurement because the same amount of tension must be applied to the tape each time they make a measurement.

on offshore production systems from floating surface facilities, a riser joint that is positioned directly below the surface joint. It applies additional tension to the riser from within the surface facility’s moon pool using the marine riser tensioning system. See surface joint.

a packer that is held in its set position by upstrain, or upward pull.

a device on a retrievable or drillable packer that allows the packer to be set with an upward pull (tension); it is often used when not enough pipe weight is available to set the packer by applying downward force (compression).

see tension-leg platform rig.

a compliant offshore drilling platform used to drill development wells. The platform, which resembles a semisubmersible drilling rig, is attached to the seafloor with tensioned steel tubes. The buoyancy of the platform applies tension to the tubes. See platform rig.

a set of devices installed on a floating offshore drilling rig to maintain constant tension on the riser pipe, despite any vertical motion made by the rig.

part of the riser tensioner system on a floating offshore drilling rig that uses a hydropneumatic cylinder assembly to which is attached the tensioning lines from the telescopic joint. High-pressure air and hydraulic fluid in the cylinder assembly provide tension on the lines as the rig moves up and down (heaves) with ocean movements.

totally enclosed nonventilated motor.

thermal enhanced oil recovery.

see habendum clause.

severed minerals acquired for a certain time and, generally, as long thereafter as production continues.

1. a point to which oil is transported through pipelines. It usually includes a tank farm and may include tanker-loading facilities. 2. a screw, soldering lug, or other point to which electric connections can be made. 3. one of the electrical input or output points of a circuit or component.

see termination spool.

a standard riser joint with a side entry to allow connection of a mud booster line. It is used to overcome a height restriction, and is the first riser joint connected to the lower marine riser package (LMRP). Some spools feature an automatic check valve that allows mud to flow only down the circulation line and up the riser string.

1. the use of improved oil recovery methods that not only restore formation pressure but also improve oil displacement or fluid flow in the reservoir. 2. the use of any improved recovery method to remove additional oil after secondary recovery. Compare primary recovery, secondary recovery.

the unit of magnetic-flux density in the metric system.

on choke and kill lines that are attached to a riser joint, a pressure-tight stopper (a cap) fitted on the top of the choke and kill lines. When the lines are capped, crew members can apply pressure to them and ensure that they do not leak as they run the riser pipe.

see theoretical gallons.

product analysis conducted under real conditions of the market.

vessels used as secondary standards for volume measurements.

when pressure testing a blowout preventer stack, a blocking device that is run and landed in the high-pressure wellhead housing. The plug isolates the casing string, which has a lower pressure rating than the blowout preventer stack, from blowout preventer test pressure.

the working pressure of a container or vessel times a safety factor. See working pressure.

an oil and gas separator that is used to separate relatively small quantities of oil and gas, which are diverted through the testing devices on a lease.

equipment that allows the kelly valves and top drive valves to be tested while testing the BOP stack.

in capacitors, voltage applied to a capacitor that is higher than the capacitor’s maximum working voltage rating. Test voltage is applied to ensure that a capacity can perform at its working voltage without failing. See maximum working voltage rating.

a wildcat well.

a person who tests pipe and casing for leaks.

diving in which an umbilical hose is used to connect a diver to the gas supply.

an ancient great ocean of 200 million years ago, between what will become Eurasia and Africa. More than half the world’s known petroleum accumulated along the margins of this ocean during a brief (30 million-year) interval.

an antiknock compound for motor gasoline. It is being phased out because lead is a pollutant.

a glycol used for water dew-point control and refrigeration.

the main load-bearing deck of an offshore drilling structure and the highest above the water, excluding auxiliary decks such as the helicopter landing pad. So called because it is the largest deck on the structure.

see full-opening safety valve.

through-the-flow-line. See through-the-flow-line equipment.

1. in geology, the line connecting the lowest points along a stream bed or valley. Also known as a valley line. 2. a line crossing all contour lines on a land surface perpendicularly.

the tendency of permafrost to sink when a heavy weight or structure is placed on it. When the structure is placed on frozen ground, any heat that thaws the soil causes it to become soft, so that the structure sinks or subsides into it.

an optical instrument used to track rising pilot balloons and thus obtain indications of wind directions and speeds above the earth’s surface.

the content of liquefiable hydrocarbons in a volume of gas, determined from analyses or tests of the gas.

the volume of residue that theoretically remains after volume reductions attributable to the processing of a volume of gas in a plant. It is determined by applying a factor from a table or calculation to the volume of gas delivered to the plant.

a unit of gross heating value equal to 100,000 Btu (1.055056108 joules).

a quantity indicator that measures current by the heating effect of the current on a thermocouple.

the process of making oils of low boiling range (100°–550°F, 37.8°–287.8°C), to be used for motor fuels and burning oils, from oils of high boiling range (550°–800°F, 287.8°–426.7°C), such as gas oil and fuel oil. All modern commercial methods get this breaking-down action by subjecting the high boiling oils to high temperatures. Pressure up to 1,000 pounds per square inch (6,895 kilopascals) is used for producing a dense system and for making sure of good contact within the desired temperature and in an apparatus of reasonable size.

proprietary name for a type of pulsed-neutron survey.

the breakdown of a compound or substance by temperature into simple substances or into constituent elements.

a method of increasing well productivity and recoverable oil by using heat, e.g., steam injection (the huff ‘n’ puff method), steam flood, or in situ combustion.

the achievement of equal temperatures in two or more substances.

neutron having an average energy level at room temperature of 0.025 electron volts.

the number of thermal neutrons around the neutron logging tool. The number of capture gamma rays present at any time is directly proportional to the thermal neutron population.

see thermal recovery.

a type of improved recovery in which heat is introduced into a reservoir to lower the viscosity of heavy oils and to facilitate their flow into producing wells. The pay zone may be heated by injecting steam (steam drive) or by injecting air and burning a portion of the oil in place (in situ combustion). See cyclic steam injection, in situ combustion, steam drive.

a relative measure of the ability of a substance to withstand heat without disintegrating.

the time required for a thermometer to indicate 63.2 percent of the magnitude of a change in the measured temperature.

the process of reducing the energy of neutrons to thermal energy levels.

a kind of industrial diamond and binding agent that are heated to a high temperature and very high pressure to blend (sinter) them. A TSP diamond has extremely high wear resistance and high thermal stability.

a special type of fixed-head bit that has synthetic diamond cutters that do not disintegrate at high temperatures. Compare polycrystalline diamond compact.

a temperature-sensitive element with variable resistivity for overload protection in motors.

a device consisting of two dissimilar metals bonded together, with electrical connections to each. When the device is exposed to heat, an electrical current is generated, the magnitude of which varies with the temperature. It is used to measure temperatures higher than those that can be measured by an ordinary thermometer, such as those in engine exhausts.

property of a system that is in mechanical, chemical, and thermal equilibrium.

a chemical injected into natural gas that lowers the temperature of hydrate formation.

an electrical component that directly converts heat into electrical energy or directly converts electrical energy into heat.

a combination hydrometer-thermometer designed to measure gravity and temperature of a liquid.

an instrument that measures temperature. Thermometers provide a way to estimate temperature from its effect on a substance with known characteristics (such as a gas that expands when heated). Various types of thermometers measure temperature by measuring the change in pressure of a gas kept at a constant volume, the change in electrical resistance of metals, or the galvanic effect of dissimilar metals in contact. The most common thermometer is the mercury-filled glass tube, which indicates temperature by the expansion of the liquid mercury.

the length of mercury in the capillary of a mercury-in-glass thermometer, which indicates the temperature.

any of a variety of materials often used in pipe coatings, the molecular structure of which allows them to soften repeatedly when heated and harden when cooled.

a device whose electrical resistance changes with temperature. One thermoresistive element in process control is a resistance temperature detector (RTD) that is constructed of platinum, nickel, or copper.

plastics that solidify when first heated under pressure, but whose original characteristics are destroyed when remelted or remolded.

a device for assisting in controlling the direction of thermal currents in an indirect heater.

a control device used to regulate temperature.

a well in a process vessel or line used as a thermometer or thermocouple holder.

see polymer.

the amount of time required for cement to reach an API-established degree of consistency, or thickness. Thickening time begins when the slurry is mixed.

a device that is lowered into a tank to take an oil sample at any depth. The sample will subsequently be used to determine the quality and S&W content of the oil in the tank. v: to obtain a sample of oil from a tank using a thief.

1. a formation that absorbs drilling fluid as it is circulated in the well. Lost circulation is caused by a thief formation. Also called a thief sand or a thief zone. 2. a low pressure reservoir or zone that “steals” fluids from a higher pressure reservoir or zone and prevents their production to the surface.

a lidded opening on top of a stock tank. It allows access for measuring the oil level and for taking samples with a device that is lowered into a tank to take an oil sample at any depth. The sample will subsequently be used to determine the quality and sediment and water content of the oil in the tank.

see tube sample.

the process of using a thief (a special graduated tube) to capture a sample of oil or oil product from a storage tank. See thief.

see thief formation.

see thief formation.

a grooved metal or synthetic fitting to protect the eye or the fastening loop of a wire or synthetic rope. The thimble conforms to the inside shape of the rope’s eye and covers the wire rope’s strands.

to add a substance such as water or a chemical to drilling mud to reduce its viscosity.

a special chemical or combination of chemicals that, when added to a drilling mud, reduces its viscosity.

small rod-shaped bacteria living in oxidizing sulfur created from hydrogen sulfide accumulations.

a blend of portland cement and calcium sulfate hemihydrate designed primarily for cementing lost circulation zones and porous or fractured formations.

a paint in which brushing or stirring lowers its viscosity.

the property exhibited by a fluid that is in a liquid state when flowing and in a semisolid, gelled state when at rest. Most drilling fluids must be thixotropic so that cuttings will remain in suspension when circulation is stopped.

a radioactive metallic element found combined in minerals.

a measure of wire diameter stated in thousands of circular mils. See circular mil.

a continuous helical rib, as on a screw or pipe.

see dope.

see dope.

a device to measure the amount of wear or stretch on pipe threads.

a metal or plastic device that is screwed onto or into pipe threads to protect them from damage when the pipe is not in use.

a type of connector that has threads on each end, making it possible to screw two pieces of pipe together. Compare pressure coupling. See also coupling.

a species that is likely to become endangered.

information gathered by seismic equipment that, after being processed, can display the height, width, and length of subsurface strata. Such 3D displays allow explorationists to see formations and structures as a whole, rather than in the form of a flat cross section. Compare two dimensional (2D) seismic data, four dimensional (4D) seismic data.

complex well trajectory plans that include studies on dynamic vibration, buckling, drill string component stresses, and drill string and casing wear analyses. Also called designer wells.

an instrument that continuously measures the value of signals generated by three variable quantities or conditions and acts to control any deviation from a desired preset value.

a separator that separates well fluids into oil or emulsion, gas, and water, or, in a glycol dehydration unit, into gas, condensate, and glycol.

voltage generated in a circuit that is energized by alternating-current voltages that differ in phase by one-third of a cycle, or 120 degrees.

the average concentration of toxic gas in a breathing atmosphere in which a normal person can be exposed safely for 8 hours per day, 5 days per week; usually established by a regulatory agency such as OSHA.

EPA minimum quantities of extremely hazardous substances under SARA that may not be exceeded without meeting reporting requirements. Under SARA (section 302), companies must notify and coordinate emergency plans with the SERC and the LEPC when a facility reaches or exceeds the EPA-stipulated TPQ for any EHS. For example, hydrofluoric acid is an EHS with a TPQ of 100 pounds. If a facility has 100 pounds or more of hydrofluoric acid, it must notify the SERC and the LEPC.

a stand of pipe made up of three joints and handled as a unit. Compare double, fourble, single.

the name used for the derrickhand’s working platform, the monkeyboard, when it is located at a height in the derrick equal to three lengths of pipe joined together. Compare double board, fourble board.

tubing hanger running and orientation tool.

the choking or failing that occurs when a mud pump fails to deliver a full amount of fluid through one or more of its valves. Throttling is usually caused by improper valve lift.

in process control, the full range of control over which the final control element in a process can be operated. See proportional band.

a valve, usually only partially open or closed, used to regulate the rate of flow.

any equipment designed to be pumped down a completed well to effect a repair, modify the well’s flow, or for other reasons.

the volume of fluid that has flowed through a meter during a specific amount of time.

the distance from the centerline of the main bearing of a crankshaft to the centerline of the connecting-rod journal. Two times the throw equals the stroke.

to flip the spinning chain up from a tool joint box so that the chain wraps around the tool joint pin after it is stabbed into the box. The stand or joint of drill pipe is turned or spun by a pull on the spinning chain from the cathead on the drawworks.

1. a force applied to an object to move it in the desired direction. 2. the force exerted in any direction by a powered screw (propeller) or a fluid jet.

see reverse fault.

a load or pressure parallel to or in the direction of the shaft.

a special propulsion device used on offshore floating drilling rigs such as drill ships and semisubmersibles that is located on the hull of the vessel and is actuated by a sensing system. A computer to which the system feeds signals directs the thrusters to maintain the rig on location.

a hydraulically operated hammer used in obtaining a seismograph in oil exploration. It is mounted on a vehicle and, when dropped, creates shock waves in the subsurface formations, which are recorded and interpreted to reveal geological information.

see cumulonimbus.

a virtually obsolete electrical device, similar to a vacuum tube, that is a hot-cathode gas tube in which one or more control electrodes initiate but do not limit anode current except under certain operating conditions. Solid-state devices that perform the same function have replaced thyratrons.

a solid-state silicon diode that behaves as an insulator up to its rated voltage, and as a conductor above its rated voltage. It protects components in AC circuits from voltage surges.

a transistor that initiates but does not limit anode current except under certain operating conditions. As collector current is increased to a critical value, a thyristor gives a high-speed triggering action.

temperature indicator.

total installation cost.

the horizontal movement of the tide as it rises and falls and moves toward and away from the shore.

the difference in height between a low tide and a high tide.

any unusually high and generally destructive sea wave along a shore. Compare tsunami.

the periodic rising and falling of the surface of the oceans and water bodies connected with the oceans (gulfs and bays).

an instrument that measures the height of tides.

in oceanography, a long-period wave associated with the tide-producing forces of the sun and the moon, and identified with the rising and falling of tide. Also called a tidal wave. See tide.

casing that is run from the top of a liner to the surface.

a device to which a guy wire or brace may be attached, such as the anchoring device for the deadline of a hoisting-block arrangement.

a collective term for the construction tasks bypassed by regular crews on pipeline construction. Tie-in includes welding road and river crossings, valves, portions of the pipeline left disconnected for hydrostatic testing, and other fabrication assemblies, as well as taping and coating the welds.

workers responsible for tie-in tasks in the construction of a pipeline.

a reference point used in calculating well trajectory where measured depth, inclination, azimuth or direction, vertical depth, and coordinates N-S and E-W are known. See tie-in.

a federal form used by companies or individuals for submitting annual inventory data on hazardous chemicals or extremely hazardous substances. See SARA Title III.

Tungsten Inert Gas.

an emulsion that is relatively difficult to break. Compare loose emulsion.

a petroleum- or water-bearing formation of relatively low porosity and permeability.

see tight sand.

1. a well about which information is restricted for security or competitive reasons. 2. a section of the hole that, for some reason, is undergauge. For example, a bit that is worn undergauge will drill a tight hole.

sand or sandstone formation with low permeability.

a section of a borehole in which excessive wall cake has built up, reducing the hole diameter and making it difficult to run the tools in and out. Compare keyseat.

a well that produces from a reservoir of low permeability and thus stabilizes slowly. Such wells show slow buildup of bottomhole pressure on a buildup test, and the flowing pressure does not stabilize quickly at a constant value on a flow test.

to add oil to a system, which causes the oil to break out and rise to the surface.

1. the dimension of the physical universe which, at a given place, orders the sequence of events. 2. a designated instant in this sequence, as the time of day.

an automatic sample usually obtained from a pipeline and taken at regular timed intervals.

feature built into oilfield inhibitors that allows them to be introduced into production systems and their active ingredients to be released at timed intervals.

a layer of rock, with or without facies variations, deposited during a distinct geologic time interval. Compare rock stratigraphic unit.

the worth of a given amount of money adding in a given amount of interest that the money earns over a given time. For example, $100 invested today for one year that earns 5 percent interest will be worth $105 after one year. Therefore, $100 paid now or $105 paid one year from now have the same value to the recipient who assumes 5 percent interest; using time value of money terminology, $100 invested for one year at 5 percent interest has a future value of $105.

the movement of sound (a pressure wave) through a medium, such as rock or water, the strength of which changes, or varies, over a given time.

the relationship of all moving parts in an engine. Each part depends on another, so all parts must operate in the right relation with each other as the engine turns.

a source of accurately timed pulses, used in synchronizing a digital computer or as a time base in a transmission system. Also called a clock.

see timing gear train.

a set of gears in an engine, driven by the crankshaft, set to drive the equipment necessary for the engine’s operation. Engine equipment driven by the timing gears includes the oil pump, intake and exhaust valve mechanisms, fuel injectors, and magnetos.

see Geronimo.

drill pipe made from a metal alloy containing a large amount of titanium. Even though it is more expensive, titanium drill pipe is much stronger (has a higher tensile strength) than conventional steel pipe. Further, in horizontal drilling applications, titanium is almost twice as flexible as steel, which means that titanium pipe can be bent more than conventional pipe without being permanently deformed.

a term standing for those facts that, if proved, will enable a person to regain or retain possession of property.

see SARA Title III.

the written opinion of a title examiner on the status of the title to a given piece of property. Compare division order opinion, drill site opinion.

a process of chemical analysis by which drops of a standard solution are added to another solution or substance to obtain a desired response-color change, precipitation, or conductivity change-for measurement and evaluation.

Texas Iron Works valve.

inside blowout preventer (so named for one company that manufactured it, Texas Iron Works).

taut leg mooring.

threshold limit value.

on offshore installations with grated decks or floors, a flat bar attached flat against the outer edge of a grating or the edge of a stair tread that projects above the top surface of the grating or tread to form a lip or curb.

the range of variation permitted in maintaining a specific dimension in machining a part. For example, a shaft measurement could be 2.000 inches 0.001 (50 millimetres 0.025). This means that any measurement from 1.999 inches to 2.001 inches (49.975 millimetres to 50.025 millimetres) would be acceptable.

a liquid aromatic hydrocarbon, C7H8, that resembles benzene but is less volatile, flammable, and toxic.

1. (nautical) a volume measure equal to 100 square feet applied to mobile offshore drilling rigs. 2. a measure of weight equal to 2,000 pounds. 3. (metric) a measure of weight equal to 1,000 kilograms. Usually spelled “tonne.”

the unit of service given by a hoisting line in moving 1 ton of load over a distance of 1 mile. The SI measurement is the megajoule.

the part of the tongs that extends behind the tong jaws, and to which the jaws are attached. A snub line is attached to the end of the tong arm to prevent the tong from turning too far when it is being used to make up, break out, or back up pipe.

a weight placed in the derrick or under the rig floor that is attached by means of wire rope to the tong hanger. Each set of tongs has a counterbalance to ensure that they hang at a convenient height above the rig floor.

very hard and brittle pieces of serrated steel that are installed in the tongs and that grip or bite into the tool joint of drill pipe when the tongs are latched onto the pipe.

the member of the drilling crew who handles the tongs.

a relatively long narrow steel projection bolted to the tong arm to which wire rope is attached; suspends the tongs in the derrick.

on a set of tongs, one of two hinged devices that crew members latch around elements of the drill stem to make up or break out such elements. Tong jaws normally have replaceable serrated inserts (dies) to grip the pipe.

a length of wire rope one end of which is connected to the end of the tongs and the other end of which is connected to the automatic cathead on the drawworks. When the driller actuates the cathead, it takes in the tong line and exerts force on the tong to either make up or break out drill pipe.

the member of the drilling crew who handles the tongs.

the large wrenches used for turning when making up or breaking out drill pipe, casing, tubing, or other pipe; variously called casing tongs, pipe tongs, and so forth, according to the specific use. Power tongs or power wrenches are pneumatically or hydraulically operated tools that serve to spin the pipe up tight and, in some instances, to apply the final makeup torque.

the size of a ship or vessel or the spaces within a ship or vessel as measured in tons.

a mass unit in the metric system equal to 1,000 kilograms.

in the SI system of measurement, the weight in tonnes that must be loaded or discharged from a floating offshore drilling rig to change the average draft of the rig in seawater by one centimetre. See draft (def. 1).

in the English, or conventional, system of measurement, the weight in short tons that must be loaded or discharged from a floating offshore drilling rig to change the average draft of the rig in seawater by 1 inch. See draft (def. 1).

a driller’s helper on a cable-tool rig, once responsible for sharpening or dressing the drill bit. Sometimes called a toolie.

the part of a deflection tool-usually marked with a scribe line-that is oriented in a particular direction to make a predetermined deflection of the wellbore.

a worker on a well service or workover rig who helps run packers and other tools into the well.

a heavy coupling element for drill pipe made of special alloy steel. Tool joints have coarse, tapered threads and seating shoulders designed to sustain the weight of the drill stem, withstand the strain of frequent coupling and uncoupling, and provide a leakproof seal. The male section of the joint, or the pin, is attached to one end of a length of drill pipe, and the female section, or the box, is attached to the other end. The tool joint is usually friction welded to the end of the pipe or screwed on or both. A hard metal facing is often applied in a band around the outside of the tool joint to enable it to resist abrasion from the walls of the borehole.

a building for storing tools.

(slang) tool dresser.

Canadian term for toolpusher. See toolpusher.

an employee of a drilling contractor who is in charge of the entire drilling crew and the drilling rig. Also called a drilling foreman, rig superintendent, or rig supervisor.

the angle on a storage tank where the side wall is joined to the roof of the tank; it is usually 90°.

the position of a piston when it is at the highest point possible in the cylinder of an engine; often marked on the flywheel.

a device similar to a power swivel that is used in place of the rotary table to turn the drill stem. It also includes power tongs. Modern top drives combine the elevator, the tongs, the swivel, and the hook. Even though the rotary table assembly is not used to rotate the drill stem and bit, the top-drive system retains it to provide a place to set the slips to suspend the drill stem when drilling stops.

a mechanism, located at the top of the working barrel, for anchoring a sucker rod pump to the tubing. Compare bottom hold-down.

a lease acquired while a mineral lease to the same property is still in effect. The top lease (held by a different company) replaces the existing lease when it expires or is terminated.

to fill a wellbore with fluid up to the surface.

to finish filling a tank.

a cement wiper plug that follows cement slurry down the casing. It goes before the drilling mud used to displace the cement from the casing and separates the mud from the slurry. See cementing, wiper plug.

a flat steel piece (a plate) that houses the choke and kill line connections to the lower marine riser package (LMRP), the blowout preventer’s control system receptacles, and the LMRP’s guidance devices.

in tank sampling, a spot sample obtained 6 inches (150 millimetres) below the top surface of the oil.

in a ram blowout preventer, a piece of synthetic rubber that is molded to the upper and lower steel antiextrusion plates of the ram block.

a component of a packer to which the tubing is connected.

a device placed in the cementing head and run down the casing behind cement to clean the cement off the walls of the casing and to prevent contamination between the cement and the displacement fluid.

see top drive.

horizontal representation of land elevations as a series of contour lines, each line connecting points of equal elevation.

the configuration of a land surface, including its natural and artificial features with their relative positions and elevations.

a part of a marine delta that is nearest the shore and that is composed of the heavier, coarser particles carried by the river.

the main deck of a ship.

the technique of placing topsoil in a spoil bank separate from the rest of the materials excavated during pipeline construction so that it can be replaced in its original stratum during back-filling operations.

a usually destructive funnel-shaped rotating column of air that passes over a narrow path of land. Compare cyclone.

the turning force that is applied to a shaft or other rotary mechanism to cause it to rotate or tend to do so. Torque is measured in foot-pounds, joules, newton-metres, and so forth.

a hydraulic device connected between an engine and a mechanical load such as a compound. Torque converters are characterized by an ability to increase output torque as the load causes a reduction in speed. Torque converters are used on mechanical rigs that have compounds.

an instrument that measures the amount of torque (turning or twisting action) applied to the drill or casing string. The amount of torque applied to the string is important when joints are being made up.

an instrument that measures and makes a record of the amount of torque (turning or twisting action) applied to the drill or casing string.

on a portable top-drive unit, the steel rail that is mounted in the derrick and to which the top drive is attached. The top drive moves up or down on the track and, because it is firmly joined to the track, cannot turn as its drive shaft rotates the drill stem. Compare guide rails, torque tube. See also top drive.

a large cylindrical tube mounted in the derrick to which a top drive is attached and on which it can move up and down. Like guide rails, a torque tube prevents the top drive from turning when it is connected to the drill stem and is rotating it. Compare guide rails. See also top drive.

twisting deformation of a solid body about an axis in which lines that were initially parallel to the axis become helices. Torsion is produced when part of the pipe turns or twists in one direction while the other part remains stationary or twists in the other direction.

one of the earliest gravitational instruments invented; first marketed commercially in 1922.

the amount of twisting force that a pipe can withstand before twisting off.

the relative degree of crookedness of a hydrocarbon flow path through a reservoir.

the total volume of all petroleum liquids and sediment and water, corrected by the appropriate temperature correction (Ctl) for the observed temperature and API gravity, relative density, or density to a standard temperature such as 60°F or 15°C, and also corrected by the applicable pressure factor (Cpl) and meter factor and all free water measured at observed temperature and pressure. Total calculated volume is equal to the gross standard volume plus free water volume.

the maximum depth reached in a well.

on a floating offshore vessel, the lightship displacement plus the maximum allowed variable load. See lightship displacement.

sum of crude oil input to refineries, crude oil exports, crude oil burned as fuel, and crude oil losses.

a thermometer that is designed for the whole length of mercury column to be immersed in liquid. An emergent stem correction has to be applied to the reading to correct for that part of the column that is above the liquid surface during reading.

the cost of installing something (as equipment).

the total measured volume of all petroleum liquids, sediment and water, and free water at observed temperature and pressure.

see absolute porosity.

see apparent power.

the pressure on the surface at which a flowing fluid is brought to rest in excess of the pressure on it when the fluid is not flowing. Also called stagnation pressure.

a figure that a company uses to compare its accident rate with other companies. To determine it, the total number of injuries are multiplied by 200,000; the result is then divided by the number of hours worked by all employees. The figure 200,000 represents the number of hours 100 employees working 40 hours per week, 50 weeks per year, would be. The number provides a standard base for calculating accident rates.

all sediment and water in a vessel’s cargo tanks, whether settled or suspended.

in diesel engine fuel tanks, the full capacity of the tank; usually, not all the fuel in the tank is usable. Compare useful volume.

the sum of the dissolved, entrained, and free water in the cargo or the parcel.

a meter register that receives signals from several other meters and displays or records the sum of the readings from the other meters.

a motor with no provision for the entrance of outside air; heat must be conducted away through the frame. It may be fan-cooled.

measure of steel’s ability to withstand a crack or flaw without fracturing. It can be altered by changing chemical composition, microstructure, and heat treatment. Also called ductility. Compare brittleness.

(pronounced “tower”) a working shift for drilling crew or other oilfield workers. Some tours are 8 hours; the three daily tours are called daylight, evening (or afternoon), and graveyard (or morning). Often, 12-hour tours are used, especially on offshore rigs; they are called simply day tour and night tour.

a water gel explosive often used as a substitute for dynamite. It is less toxic and less hazardous to manufacture, transport, and store. Tovex is widely used by companies for seismic exploration.

to draw or pull behind by attaching a chain, cable, or line. n: 1. the condition of being towed, as a tugboat with a barge in tow. 2. something, such as a tugboat, that tows. 3. something, such as a barge or an offshore drilling rig, that is being towed. 4. a rope, cable, or chain that is used in towing.

a tractor used to tow equipment up steep grades.

a relatively flat-bottomed boat with a square bow that can push a string of barges carrying tons of petroleum products over great distances.

in offshore seismic surveying, the gathering of seismic data by a boat’s deployment of several lines (streamers) to which are attached the devices that sense and transmit seismic reflections from the formations being surveyed.

1. a vertical vessel such as an absorber, fractionator, or still. 2. a cooling tower.

a gas separation system that reduces the amount of required equipment. Various types include bubble cap, valve, sieve, and perforated. See separation tower, valve trays.

see city gate station.

1. the north-south lines of the rectangular survey system. 2. the square, 6 miles on each side, that is the major unit of land in the rectangular survey scheme of measurement. Compare range.

a north-south line of the rectangular survey system.

a report required under SARA (section 313) that quantifies all releases of toxic chemicals that a facility has had throughout the year. Currently, E&P facilities are not subject to the toxic chemical release reporting requirement, since it is applied only to manufacturers with standard industrial classification codes of 20 through 39.

a congressional act that regulates the manufacture, processing, distribution in commerce, use, and disposal of chemical substances.

the ability of a substance to be poisonous if inhaled, swallowed, absorbed, or introduced into the body through cuts or breaks in the skin.

tubing pressure; used in drilling reports.

tonnes-per-centimetre.

tons-per-inch.

threshold planning quantities.

the relation of a prover or a transducer calibration, through a step-by-step process, to an instrument or group of instruments calibrated and certified by a national or international primary standard.

a substance added to reservoir fluids to permit the movements of the fluid to be followed or traced. Dyes and radioactive substances are used as tracers in underground water flows and sometimes helium is used in gas. When samples of the water or gas taken some distance from the point of injection reveal signs of the tracer, the route of the fluids can be mapped.

a survey that uses a radioactive tracer such as a gas, liquid, or solid having a high gamma ray emission. When the material is injected into any portion of the wellbore, the point of placement or movement can be recorded by a gamma ray instrument. The tracer log is used to determine channeling or the travel of squeezed cement behind a section of perforated casing. Also called tracer survey.

see tracer log.

a rare type of bit-tooth wear occurring when the pattern made on the bottom of the hole by all three cones of a rock bit matches the bit-tooth pattern to such an extent that the bit follows the groove or channel of the pattern and drills ahead very little.

a direct current electric motor normally found in railway use, but frequently adapted to power certain drilling rigs.

a type of winch in which a small drum on deck only holds one layer of wire. The bulk of the wire is stored on a take-up reel generally located lower in the boat’s hull. This style of winch can apply constant force to the mooring line regardless of the amount of wire paid out.

in an electromagnet, the force of attraction that exists between an iron (or other ferrous material) bar placed close to the poles of the electromagnet.

a powerful truck (tractor), usually with ten wheels, that pulls an attached container (trailer), usually with eight wheels, in which goods are loaded. The trailer typically has a set of eight rear wheels but no front wheels; instead, the front of the trailer is attached to the back of the tractor, which supports the front of the trailer.

a prevailing tropical wind blowing toward the equator from the northeast in the northern hemisphere or from the southeast in the southern hemisphere.

a wheeled unpowered vehicle in or on which cargo may be loaded and which is towed by a tractor (truck).

a rig mounted on a wheeled and towed trailer. It has a mast, a rotary, and one or two engines. The rig systems are powered by a prime mover.

a well service and workover rig that has a tractor (truck) built into it. Most of the rig components are built onto the trailer and the trailer is an integral part of the tractor (truck).

a series of units functioning together to complete a complex process.

the path of the wellbore.

a metal rod of precise length used to measure distance between two points where accessibility is limited. It is often used to mark crankshaft positions on engines.

the largest long-distance, big-inch pipeline in the non-Communist world. Stretching approximately 800 miles (1,288 kilometres) from Deadhorse (near Prudhoe Bay) to Valdez, Alaska, the 48-inch pipeline was completed in 1977 at a cost of $8 billion. Today, it transports from 1 million to 2 million barrels (159 million to 318 million litres) of oil a day from fields on the North Slope of Alaska to tank farms in Valdez.

pollution that crosses political or governmental or geographical boundaries.

a substance or a device, such as a piezoelectric crystal, a microphone, or a photoelectric cell, that converts input energy of one form into output energy of another. For example, a telephone receiver receives electric power and supplies acoustic power.

a computer- generated readout of a quantity of gas measured by the computer system.

to lower pipe or tubing onto a down­hole tool so that all or part of the pipe’s or tubing’s weight is transferred from the traveling block’s hook to the tool.

in an electronic circuit, the delay that occurs between the time the circuit receives an electrical signal and the time the circuit produces a modified form of this signal at its output.

an agreement regarding change of production ownership that indemnifies the pipeline company or the purchaser.

the use of a master meter to calibrate positive-displacement and turbine meters measuring gas flow.

a pump that pressures the crude oil from the stock tank through a LACT unit.

a bell clamps onto the transfer chamber by its bottom or side trunking and allows divers to pass between chambers through a small tube with hatches on both sides.

a strike-slip fault caused by relative movement between crustal plates.

a device that uses the principle of induction to convert variations of current in a primary circuit into variations of current and voltage in a secondary circuit. It typically consists of two coils with different numbers of turns around a single iron core.

a small electronic device containing a small block of semiconducting material to which at least three electrical contacts are made, usually two rectifying contacts and one ohmic, or nonrectifying contact. A transistor is used in circuits as an amplifier, detector, or switch. Physicists at Bell Laboratories, who invented the device in the late 1940s, coined the term by combining the words transfer and resistor-that is, a transistor transfers a signal across a resistor. See semiconductor.

on a semisubmersible rig, the draft of the pontoons in a deballasted condition. For a ship-shaped drilling rig, the transit draft varies. Compare operational draft, survival draft.

see foamed mist.

1. the area in which underground pressures begin to change from normal to abnormally high as a well is being deepened. 2. the areas in the drill stem near the point where drill pipe is made up on drill collars.

the movement of molecules.

the gear or chain arrangement by which power is transmitted from the prime mover to the drawworks, the mud pump, or the rotary table of a drilling rig.

the seller of natural gas.

1. a high-voltage line used to transmit electric power from one place to another. 2. a pipeline used to transmit natural gas or other fluids.

in instrumentation, an instrument or a transducer that converts a process variable such as temperature, pressure, level, or flow into a proportional electrical current or voltage.

an agreement setting forth the terms and conditions applicable to transportation service. For interstate pipelines, this contract is usually a Form of Service Agreement stated in the pipeline’s FERC gas tariff.

the sum of the fixed costs and variable costs of moving gas or oil.

see distance-velocity lag.

the pipeline company that transports natural gas for a shipper.

something, such as a bar or a beam, that lies crossways (is transverse). adj: situated or lying across; crosswise.

on offshore installations with grated decks or floors, a length of steel strip fixed at right angles to the load-bearing bars to provide lateral restraint.

a body of permeable oil-bearing rock surrounded or overlain by an impermeable barrier that prevents oil from escaping. The types of traps are structural, stratigraphic, or a combination of these.

in well control and underbalanced drilling, pressure that occurs in the BOP stack when the well is closed in at the flow line or choke line without first relieving the pressure in the BOP stack. Closing a ram or an annular can trap high pressure between the closed blowout preventers because the annular and rams displace a certain amount of volume as they are closed. If the fluid in the stack is all or mostly liquid, high pressures can occur that may cause valve failure or incomplete ram closure.

the time it takes for sound to travel from one receiver on an acoustic sonde to another receiver on the sonde.

a sucker rod insert pump in which the working barrel travels and the plunger remains stationary. The working barrel is connected to the sucker rod string through a connector and the traveling valve; the standing valve is connected to the top of the plunger, which in turn is connected to the bottom hold-down.

an arrangement of pulleys, or sheaves, through which drilling line is reeved and which moves up and down in the derrick or mast. See block.

see snubber (def. 1).

one of the two valves in a sucker rod pumping system. It moves with the movement of the sucker rod string. On the upstroke, the ball member of the valve is seated, supporting the fluid load. On the downstroke, the ball is unseated, allowing fluid to enter into the production column. Compare standing valve.

a computerized drawing created during well planning that shows the intersection of wells to aid in assessing the risk of collision during directional drilling at multiwell locations. Survey results can be plotted directly on the diagram, enabling an immediate visual risk assessment.

a horizontal device in a tower that holds liquid and provides a vapor-liquid contact step. Several common types are bubble-cap, perforated, or valve trays.

a vessel wherein gas and liquid, or two miscible liquids, contact on trays, usually countercurrently.

on offshore installations with grated decks or floors, the grated panel on which personnel step to ascend or descend the stairway.

the diameter of the sheave of a drilling block, measured from groove bottom to groove bottom. It is the diameter of the circle around which the wire rope is bent.

to subject a substance to a process or to a chemical to improve its quality or to remove a contaminant.

a vessel in which oil is treated for the removal of S&W or other objectionable substances by the addition of chemicals, heat, electricity, or all three.

see treat.

a plant that removes contaminants from natural gas to render the gas marketable.

acids and other fluids used to stimulate reservoirs. See acidize, fracturing.

a depth, time, and breathing gas profile designed to treat a diver for gas embolism or decompression sickness.

a facility that treats, stores, or disposes of hazardous waste above certain volume limits and beyond certain time periods. If hazardous waste is stored or collected for shipment, generators need to be aware that exceeding volume and time limits can cause a generator site to be classed as a TSD facility. RCRA places rigorous controls on TSD facilities and they must have permits.

short for Christmas tree, which is the valves and fittings placed on top of a flowing well to control production.

a tubular device employed as an isolation tool inside the Christmas tree that protects the tree from the very high pressures that occur during well stimulation.

tetraethylene glycol.

the directional line of a rock bed or petroleum deposit.

a type of thyristor that switches current to high levels from a low-level control signal in AC and DC circuits. While triacs are similar to silicon-controlled rectifiers, triacs, unlike SCRs, are capable of conducting current in both directions in the circuit; SCRs can conduct current only in one direction.

a rarely used form of sidewall coring that uses a wall corer with saw-type blades set at 45° angles to cut triangular-shaped cores.

a method used to calculate the combined loads that a casing or tubing string may experience throughout the service life of the well.

land within an Indian reservation or owned by an Indian tribe, group, or band.

the continuous flow of direct current electricity into a cell or battery at a low rate to either recharge the cell or battery or to maintain a charge as the cell or battery is used.

a type of bit in which three cone-shaped cutting devices are mounted in such a way that they intermesh and rotate together as the bit drills. The bit body may be fitted with nozzles, or jets, through which the drilling fluid is discharged.

a liquid chemical used in gas processing to remove water from the gas. An organic compound with the formula HO(C2H4O)3H, used to dehydrate natural gas to inhibit the formation of hydrates. See glycol, glycol dehydrator.

in mathematics, the relationship, or function, such as the sine, cosine, secant, cosecant, tangent, and cotangent of an arc or angle expressed as the ratios of pairs of the sides of a right triangle. See function.

one of a class of extinct Paleozoic arthropods.

1. the difference between fore and aft draft readings on a marine vessel or an offshore drilling rig. 2. the use of special corrosion-resistant metals in blowout preventers, valves, and other oilfield devices to minimize the effects of hydrogen sulfide. v: 1. to minimize the difference between fore and aft readings. 2. to install H2S corrosion-resistant materials in oilfield equipment used in H2S environments.

a correction applied to cargo ullages when the vessel is not on an even keel. Valid only when liquid completely covers the tank bottom and is not in contact with the underside of the deck.

the movement of a floating vessel’s bow or stern either higher or lower in the water, which is created by shifting weight on the vessel toward the bow or stern.

a virtually obsolete electrical component, which is a three-electrode vacuum tube that contains an anode, a cathode, and a control electrode. Triode transistors have almost completely replaced triode tubes.

the operation of hoisting the drill stem from and returning it to the wellbore. v: 1. to insert or remove the drill stem into or out of the hole. Shortened form of “make a trip.” See make a trip, overspeed governor. 2. pulling the anchor out backwards with line tied to the crown, releasing the anchor from the bottom.

gas that enters the wellbore when the mud pump is shut down and pipe is being pulled from the wellbore. The gas may enter because of the reduction in bottomhole pressure when the pump is shut down, because of swabbing, or because of both.

to go in the hole.

the small amount of additional mud weight carried over that needed to balance formation pressure to overcome the pressure-reduction effects caused by swabbing when a trip out of the hole is made.

to come out of the hole.

the stem on the end of a core thief that can be bumped or tapped to close and thus catch a sample in the thief.

a record of the measured drilling fluid that displaces the drill string as one pulls the pipe out of the hole or runs the pipe into the hole. See trip tank.

a small mud tank with a capacity of 10 to 15 barrels (1 to 3 cubic metres), often with 1-barrel or H-barrel (decalitre or litre) divisions, used to ascertain the amount of mud necessary to keep the wellbore full with the exact amount of mud that is displaced by drill pipe. When the bit comes out of the hole, a volume of mud equal to that which the drill pipe occupied while in the hole must be pumped into the hole to replace the pipe. When the bit goes back in the hole, the drill pipe displaces a certain amount of mud, and a trip tank can be used again to keep track of this volume.

a device installed on a trip tank that shows the amount of mud being removed from or added to the trip tank.

see thribble.

a drilling rig with a mast or derrick tall enough to allow crewmembers to set back stands made up of three joints of drill pipe or drill collars. See thribble.

a reciprocating pump with three pistons or plungers.

a device with three extensions (legs) that is suspended over a manway or other vertical access into a space. It supports hoisting gear and cables used to pull a person from a confined space.

the operation of hoisting the drill stem out of and returning it to the wellbore. See make a trip.

see trip out

an isotope of hydrogen with three atoms of three times the mass of ordinary hydrogen atoms, designated 1H3.

a line of latitude that is 23.5 degrees north of the equator.

a line of latitude that is 23.5 degrees south of the equator.

a tropical cyclonic storm with wind speeds of 65 knots or greater. See baguio, cordonazo, cyclone, hurricane, taino, typhoon, willy-willy.

a tropical cyclonic system with wind speeds from 28 to 34 knots.

a tropical cyclonic system with wind speeds of up to 27 knots.

a tropical cyclonic system with wind speeds from 35 to 64 knots.

disturbances on the intertropical convergence zone that travel from east to west. Low-pressure areas travel in tropical waves.

the lowest and densest layer of the atmosphere, which extends from the surface to about 6 to 12 miles (10 to 20 kilometres) and in which most of the earth’s weather occurs.

rocks having characteristics that make drilling difficult or risky. For example, a reservoir containing high-pressure fluids that, once penetrated, might cause a blowout.

1. in meteorology, a zone or belt of relatively low pressure. 2. in oceanography, the lowest point of the water surface level between crests.