Oil and Gas Well Drilling and Servicing eTool
Oil and Gas Well Drilling and Servicing » Glossary of Terms - D
† This is an abridged version of the Dictionary of Petroleum Terms provided by Petex and the University of Texas Austin. © Petex 2001
daily drilling report
n: a record made each day of the operations on a working drilling rig and, traditionally, phoned, faxed, emailed, or radioed in to the office of the drilling company and possibly the operator every morning.
dampener
n: an air or inert gas device that minimizes pressure surges in the output line of a mud pump. Sometimes called a surge dampener.
daylight tour
(pronounced "tower") n: in areas where three eight-hour tours are worked, the shift of duty on a drilling rig that starts at or about daylight. Compare evening tour, morning (graveyard) tour.
day tour
(pronounced "tower") n: in areas where two 12-hour tours are worked, a period of 12 hours, usually during daylight, worked by a drilling or workover crew when equipment is being run around the clock.
deadline
n: the drilling line from the crown block sheave to the anchor, so called because it does not move. Compare fast line.
deadline anchor
n: see deadline tie-down anchor.
deadline sheave
n: the sheave on the crown block over which the deadline is reeved.
deadline tie-down anchor
n: a device to which the deadline is attached, securely fastened to the mast or derrick substructure. Also called a deadline anchor.
deck
n: (nautical) floor.
degasser
n: the equipment used to remove unwanted gas from a liquid, especially from drilling fluid.
density
n: the mass or weight of a substance per unit volume. For instance, the density of a drilling mud may be 10 pounds per gallon, 74.8 pounds/cubic foot, or 1,198.2 kilograms/cubic meter. Specific gravity, relative density, and API gravity are other units of density.
density log
n: a special radioactivity log for open-hole surveying that responds to variations in the specific gravity of formations. It is a contact log (i.e., the logging tool is held against the wall of the hole). It emits neutrons and then measures the secondary gamma radiation that is scattered back to the detector in the instrument. The density log is an excellent porosity-measure device, especially for shaley sands. Some trade names are Formation Density Log, Gamma-Gamma Density Log, and Densilog.
derrick
n: a large load-bearing structure, usually of bolted construction. In drilling, the standard derrick has four legs standing at the corners of the substructure and reaching to the crown block. The substructure is an assembly of heavy beams used to elevate the derrick and provide space to install blowout preventers, casingheads, and so forth.
derrick floor
n: also called the rig floor.
derrickhand
n: the crew member who handles the upper end of the drill string as it is being hoisted out of or lowered into the hole. On a drilling rig, he or she may be responsible for the circulating machinery and the conditioning of the drilling or workover fluid.
derrickman
n: see derrickhand.
desander
n: a centrifugal device for removing sand from drilling fluid to prevent abrasion of the pumps. It may be operated mechanically or by a fast-moving stream of fluid inside a special cone-shaped vessel, in which case it is sometimes called a hydrocyclone.
desilter
n: a centrifugal device, similar to a desander, used to remove very fine particles, or silt, from drilling fluid to lower the amount of solids in the fluid.
diamond bit
n: a drill bit that has small industrial diamonds embedded in its cutting surface.
dies
n: a tool used to shape, form, or finish other tools or pieces of metal. For example, a threading die is used to cut threads on pipe.
die insert
n: a removable, hard-steel, serrated piece that fits into the jaws of the tongs and firmly grips the body of the drill pipe, drill collars, or casing while the tongs are making up or breaking out the pipe.
diesel-electric power
n: the power supplied to a drilling rig by diesel engines driving electric generators.
diesel engine
n: a high-compression, internal-combustion engine used extensively for powering drilling rigs. In a diesel engine, air is drawn into the cylinders and compressed to very high pressures; ignition occurs as fuel is injected into the compressed and heated air. Combustion takes place within the cylinder above the piston, and expansion of the combustion products imparts power to the piston.
diesel fuel
n: a light hydrocarbon mixture for diesel engines; it has a boiling range just above that of kerosene.
dipmeter log
n: see dipmeter survey.
dipmeter survey
n: an oilwell-surveying method that determines the direction and angle of formation dip in relation to the borehole. It records data that permit computation of both the amount and direction of formation dip relative to the axis of the hole and thus provides information about the geologic structure of the formation. Also called dipmeter log or dip log.
directional drilling
n: 1. intentional deviation of a wellbore from the vertical. Although wellbores are normally drilled vertically, it is sometimes necessary or advantageous to drill at an angle from the vertical. Controlled directional drilling makes it possible to reach subsurface areas laterally remote from the point where the bit enters the earth.
directional hole
n: a wellbore intentionally drilled at an angle from the vertical. See directional drilling.
displacement fluid
n: in well cementing, the fluid, usually drilling mud or salt water, that is pumped into the well after the cement is pumped into it to force the cement out of the casing and into the annulus.
dissolved gas
n: natural gas that is in solution with crude oil in the reservoir.
dissolved-gas drive
n: a source of natural reservoir energy in which the dissolved gas coming out of the oil expands to force the oil into the wellbore. Also called solution-gas drive. See reservoir drive mechanism.
doghouse
n: a small enclosure on the rig floor used as an office and/or as a storehouse for small objects. Also, any small building used as an office or for storage.
dogleg
n: 1. an abrupt change in direction in the wellbore, frequently resulting in the formation of a keyseat. 2. a sharp bend permanently put in an object such as a pipe, wire rope, or a wire rope sling.
double
n: a length of drill pipe, casing, or tubing consisting of two joints screwed together.
downhole
adj, adv: pertaining to the wellbore.
downhole motor
n: a drilling tool made up in the drill string directly above the bit. It causes the bit to turn while the drill string remains fixed. It is used most often as a deflection tool in directional drilling, where it is made up between the bit and a bent sub (or, sometimes, the housing of the motor itself is bent). Two principal types of downhole motor are the positive-displacement motor and the downhole turbine motor.
drawworks
n: the hoisting mechanism on a drilling rig. It is essentially a large winch that spools off or takes in the drilling line and thus lowers or raises the drill stem and bit.
drawworks brake
n: the mechanical brake on the drawworks that can slow or prevent the drawworks drum from moving.
drawworks drum
n: the spool-shaped cylinder in the drawworks around which drilling line is wound or spooled.
drill
v: to bore a hole in the earth, usually to find and remove subsurface formation fluids such as oil and gas.
drillable
adj: pertaining to packers and other tools left in the wellbore to be broken up later by the drill bit. Drillable equipment is made of cast iron, aluminum, plastic, or other soft, brittle material.
drillable packer
n: a permanent packer that can only be removed by drilling it out.
drill ahead
v: to continue drilling operations.
drill bit
n: the cutting or boring element used in drilling oil and gas wells. Most bits used in rotary drilling are roller-cone bits. The bit consists of the cutting elements and the circulating element. The circulating element permits the passage of drilling fluid and utilizes the hydraulic force of the fluid stream to improve drilling rates.
drill collars
n: a heavy, thick-walled tube, usually steel, used between the drill pipe and the bit in the drill stem, used to stiffen the drilling assembly an put weight on the bit so that the bit can drill.
drill collar sub
n: a sub made up between the drill string and the drill collars that is used to ensure that the drill pipe and the collar can be joined properly.
driller
n: the employee normally in charge of a specific (tour) drilling or workover crew. The driller’s main duty is operation of the drilling and hoisting equipment, but this person may also be responsible for downhole condition of the well, operation of downhole tools, and pipe measurements.
driller’s position
n: the area immediately surrounding the driller’s console.
drill floor
n: also called rig floor or derrick floor. See rig floor.
drill in
v: to penetrate the productive formation after the casing is set and cemented on top of the pay zone.
drilling contract
n: an agreement made between a drilling company and an operating company to drill a well. It generally sets forth the obligation of each party, compensation, identification, method of drilling, depth to be drilled, and so on.
drilling crew
n: a driller, a derrickhand, and two or more helpers who operate a drilling or workover rig for one tour each day.
drilling engine
n: an internal-combustion engine used to power a drilling rig. These engines are used on a rotary rig and are usually fueled by diesel fuel, although liquefied petroleum gas, natural gas, and, very rarely, gasoline can also be used.
drilling engineer
n: an engineer who specializes in the technical aspects of drilling.
drilling fluid
n: circulating fluid, one function of which is to lift cuttings out of the wellbore and to the surface. It also serves to cool the bit and to counteract downhole formation pressure.
drilling hook
n: the large hook mounted on the bottom of the traveling block and from which the swivel is suspended.
drilling mud
n: a specially compounded liquid circulated through the wellbore during rotary drilling operations. See drilling fluid, mud.
drill pipe
n: the heavy seamless tubing used to rotate the bit and circulate the drilling fluid. Joints of pipe are generally approximately 30 feet long are coupled together by means of tool joints.
drill stem
n: all members in the assembly used for rotary drilling from the swivel to the bit, including the kelly, the drill pipe and tool joints, the drill collars, the stabilizers, and various specialty items. Compare drill string.
drill stem test (DST)
n: a method of formation testing. The basic drill stem test tool consists of a packer or packers, valves or ports that may be opened and closed from the surface, and two or more pressure-recording devices. The tool is lowered on the drill string to the zone to be tested. The packer or packers are set to isolate the zone from the drilling fluid column.
driller's console
n: the control panel, where the driller controls drilling operations.
drilling line
n: a wire rope hoisting line, reeved on sheaves of the crown block and traveling block (in effect a block and tackle), the primary purpose of which is to hoist or lower drill pipe or casing from or into a well.
drilling out
n: the operation during the drilling procedure when the cement is drilled out of the casing.
drill string
n: the column, or string, of drill pipe with attached tool joints that transmits fluid and rotational power from the kelly to the drill collars and the bit. Often, the term is loosely applied to include both drill pipe and drill collars.
drive bushing
n: see kelly bushing.
drive chain
n: a chain by means of which a machine is propelled.
drive-in unit
n: a type of portable service or workover rig that is self-propelled, using power from the hoisting engines. The driver's cab and steering wheel are mounted on the same end as the mast support; thus the unit can be driven straight ahead to reach the wellhead.
drive pipe
n: see conductor casing.
drum (rope)
n: a rotating cylinder with side flanges on which wire or other rope used in machine operation is wrapped.
dry hole
n: any well that does not produce oil or gas in commercial quantities. A dry hole may flow water, gas, or even oil, but not in amounts large enough to justify production.
dual completion
n: a single well that produces from two separate formations at the same time. Production from each zone is segregated by running two tubing strings with packers inside the single string of production casing, or by running one tubing string with a packer through one zone while the other is produced through the annulus. In a miniaturized dual completion, two separate casing strings are run and cemented in the same wellbore.
dump bailer
n: a bailing device with a release valve, usually of the disk or flapper type, used to place, or spot, material (such as cement slurry) at the bottom of the well.
Annular Blowout Preventer
A large valve, usually installed above the ram preventers, that forms a seal in the annular space between the pipe and well bore. If no pipe is present, it forms a seal on the well bore itself. See blowout preventer.†
† This is an abridged version of the Dictionary of Petroleum Terms provided by Petex and the University of Texas Austin. © Petex 2001
Annulus
The space around a pipe in a well bore, the outer wall of which may be the wall of either the bore hole or the casing; sometimes termed the annular space.†
† This is an abridged version of the Dictionary of Petroleum Terms provided by Petex and the University of Texas Austin. © Petex 2001
Blowout Preventer
One or more valves installed at the wellhead to prevent the escape of pressure either in the annular space between the casing and the drill pipe or in open hole (for example, hole with no drill pipe) during drilling or completion operations. See annular blowout preventer and ram blowout preventer.†
† This is an abridged version of the Dictionary of Petroleum Terms provided by Petex and the University of Texas Austin. © Petex 2001
Ram Blowout Preventer
A blowout preventer that uses rams to seal off pressure on a hole that is with or without pipe. It is also called a ram preventer. Ram-type preventers have interchangeable ram blocks to accommodate different O.D. drill pipe, casing, or tubing.†
† This is an abridged version of the Dictionary of Petroleum Terms provided by Petex and the University of Texas Austin. © Petex 2001
Brake Bands
The braking device on the drawworks to stop a load being lifted.†
† This is an abridged version of the Dictionary of Petroleum Terms provided by Petex and the University of Texas Austin. © Petex 2001
Bulk Mud Components Storage
Hopper type tanks for storage of drilling fluid components.†
† This is an abridged version of the Dictionary of Petroleum Terms provided by Petex and the University of Texas Austin. © Petex 2001
Casing Head
A heavy, flanged steel fitting connected to the first string of casing. It provides a housing for slips and packing assemblies, allows suspension of intermediate and production strings of casing, and supplies the means for the annulus to be sealed off. Also called a spool.†
† This is an abridged version of the Dictionary of Petroleum Terms provided by Petex and the University of Texas Austin. © Petex 2001
Cathead
A spool-shaped attachment on a winch around which rope for hoisting and pulling is wound.†
† This is an abridged version of the Dictionary of Petroleum Terms provided by Petex and the University of Texas Austin. © Petex 2001
Catline Boom and Hoist Line
A structural framework erected near the top of the derrick for lifting material.†
† This is an abridged version of the Dictionary of Petroleum Terms provided by Petex and the University of Texas Austin. © Petex 2001
Catwalk
The ramp at the side of the drilling rig where pipe is laid to be lifted to the derrick floor by the catline or by an air hoist.†
† This is an abridged version of the Dictionary of Petroleum Terms provided by Petex and the University of Texas Austin. © Petex 2001
Cellar
A pit in the ground to provide additional height between the rig floor and the well head to accommodate the installation of blowout preventers, ratholes, mouseholes, and so forth. It also collects drainage water and other fluids for disposal.†
† This is an abridged version of the Dictionary of Petroleum Terms provided by Petex and the University of Texas Austin. © Petex 2001
Choke Manifold
The arrangement of piping and special valves, called chokes, through which drilling mud is circulated when the blowout preventers are closed to control the pressures encountered during a kick.†
† This is an abridged version of the Dictionary of Petroleum Terms provided by Petex and the University of Texas Austin. © Petex 2001
Conductor Pipe
The largest diameter casing and the topmost length of casing. It is relatively short and encases the topmost string of casing.†
† This is an abridged version of the Dictionary of Petroleum Terms provided by Petex and the University of Texas Austin. © Petex 2001
Crown Block and Water Table
An assembly of sheaves or pulleys mounted on beams at the top of the derrick. The drilling line is run over the sheaves down to the hoisting drum.†
† This is an abridged version of the Dictionary of Petroleum Terms provided by Petex and the University of Texas Austin. © Petex 2001
Degasser
The equipment used to remove unwanted gas from a liquid, especially from drilling fluid.†
† This is an abridged version of the Dictionary of Petroleum Terms provided by Petex and the University of Texas Austin. © Petex 2001
Desander
A centrifugal device for removing sand from drilling fluid to prevent abrasion of the pumps. It may be operated mechanically or by a fast-moving stream of fluid inside a special cone-shaped vessel, in which case it is sometimes called a hydrocyclone.†
† This is an abridged version of the Dictionary of Petroleum Terms provided by Petex and the University of Texas Austin. © Petex 2001
Desilter
A centrifugal device, similar to a desander, used to remove very fine particles, or silt, from drilling fluid. This keeps the amount of solids in the fluid to the lowest possible level.†
† This is an abridged version of the Dictionary of Petroleum Terms provided by Petex and the University of Texas Austin. © Petex 2001
Doghouse
A small enclosure on the rig floor used as an office for the driller or as a storehouse for small objects. Also, any small building used as an office or for storage.†
† This is an abridged version of the Dictionary of Petroleum Terms provided by Petex and the University of Texas Austin. © Petex 2001
Drawworks
The hoisting mechanism on a drilling rig. It is essentially a large winch that spools off or takes in the drilling line and thus raises or lowers the drill stem and bit.†
† This is an abridged version of the Dictionary of Petroleum Terms provided by Petex and the University of Texas Austin. © Petex 2001
Drill Bit
The cutting or boring element used in drilling oil and gas wells. Most bits used in rotary drilling are roller-cone bits. The bit consists of the cutting elements and the circulating element. The circulating element permits the passage of drilling fluid and uses the hydraulic force of the fluid stream to improve drilling rates.†
† This is an abridged version of the Dictionary of Petroleum Terms provided by Petex and the University of Texas Austin. © Petex 2001
Drill Collar
A heavy, thick-walled tube, usually steel, used between the drill pipe and the bit in the drill stem. It is used to put weight on the bit so that the bit can drill.†
† This is an abridged version of the Dictionary of Petroleum Terms provided by Petex and the University of Texas Austin. © Petex 2001
Drill Pipe
The heavy seamless tubing used to rotate the bit and circulate the drilling fluid. Joints of pipe 30 feet long are coupled together with tool joints.†
† This is an abridged version of the Dictionary of Petroleum Terms provided by Petex and the University of Texas Austin. © Petex 2001
Drillers Console
The control panel, located on the platform, where the driller controls drilling operations.†
† This is an abridged version of the Dictionary of Petroleum Terms provided by Petex and the University of Texas Austin. © Petex 2001
Drilling Line
A wire rope hoisting line, reeved on sheaves of the crown block and traveling block (in effect a block and tackle). Its primary purpose is to hoist or lower drill pipe or casing from or into a well. Also, a wire rope used to support the drilling tools.†
† This is an abridged version of the Dictionary of Petroleum Terms provided by Petex and the University of Texas Austin. © Petex 2001
Electric Cable Tray
Supports the heavy electrical cables that feed the power from the control panel to the rig motors.†
† This is an abridged version of the Dictionary of Petroleum Terms provided by Petex and the University of Texas Austin. © Petex 2001
Electric Control House
On diesel electric rigs, powerful diesel engines drive large electric generators. The generators produce electricity that flows through cables to electric switches and control equipment enclosed in a control cabinet or panel. Electricity is fed to electric motors via the panel.†
† This is an abridged version of the Dictionary of Petroleum Terms provided by Petex and the University of Texas Austin. © Petex 2001
Elevators
A set of clamps that grips a stand, or column, of casing, tubing, drill pipe, or sucker rods, so the stand can be raised or lowered into the hole.†
† This is an abridged version of the Dictionary of Petroleum Terms provided by Petex and the University of Texas Austin. © Petex 2001
Fuel Tanks
Fuel storage tanks for the power generating system.†
† This is an abridged version of the Dictionary of Petroleum Terms provided by Petex and the University of Texas Austin. © Petex 2001
Hoisting Line
A wire rope used in hoisting operations. Must conform to the API standards for its intended uses.†
† This is an abridged version of the Dictionary of Petroleum Terms provided by Petex and the University of Texas Austin. © Petex 2001
Hook
A large, hook-shaped device from which the elevator bails or the swivel is suspended. It is designed to carry maximum loads ranging from 100 to 650 tons and turns on bearings in its supporting housing.†
† This is an abridged version of the Dictionary of Petroleum Terms provided by Petex and the University of Texas Austin. © Petex 2001
Kelly
The heavy square or hexagonal steel member suspended from the swivel through the rotary table. It is connected to the topmost joint of drill pipe to turn the drill stem as the rotary table turns.†
† This is an abridged version of the Dictionary of Petroleum Terms provided by Petex and the University of Texas Austin. © Petex 2001
Kelly Bushing
A device fitted to the rotary table through which the kelly passes. It is the means by which the torque of the rotary table is transmitted to the kelly and to the drill stem. Also called the drive bushing.†
† This is an abridged version of the Dictionary of Petroleum Terms provided by Petex and the University of Texas Austin. © Petex 2001
Kelly Spinner
A device for spinning the drill pipe. Replaces the spinning chain.†
† This is an abridged version of the Dictionary of Petroleum Terms provided by Petex and the University of Texas Austin. © Petex 2001
Mast
A portable derrick capable of being erected as a unit, as distinguished from a standard derrick, which cannot be raised to a working position as a unit.†
† This is an abridged version of the Dictionary of Petroleum Terms provided by Petex and the University of Texas Austin. © Petex 2001
Monkeyboard
The derrickman's working platform. Double board, tribble board, fourable board; a monkey board located at a height in the derrick or mast equal to two, three, or four lengths of pipe respectively.†
† This is an abridged version of the Dictionary of Petroleum Terms provided by Petex and the University of Texas Austin. © Petex 2001
Mousehole
Shallow bores under the rig floor, usually lined with pipe, in which joints of drill pipe are temporarily suspended for later connection to the drill string.†
† This is an abridged version of the Dictionary of Petroleum Terms provided by Petex and the University of Texas Austin. © Petex 2001
Mud Gas Separator
A device that removes gas from the mud coming out of a well when a kick is being circulated out.†
† This is an abridged version of the Dictionary of Petroleum Terms provided by Petex and the University of Texas Austin. © Petex 2001
Mud Pits
A series of open tanks, usually made of steel plates, through which the drilling mud is cycled to allow sand and sediments to settle out. Additives are mixed with the mud in the pit, and the fluid is temporarily stored there before being pumped back into the well. Mud pit compartments are also called shaker pits, settling pits, and suction pits, depending on their main purpose.†
† This is an abridged version of the Dictionary of Petroleum Terms provided by Petex and the University of Texas Austin. © Petex 2001
Mud Pump
A large reciprocating pump used to circulate the mud (drilling fluid) on a drilling rig.†
† This is an abridged version of the Dictionary of Petroleum Terms provided by Petex and the University of Texas Austin. © Petex 2001
Mud Return Line
A trough or pipe, placed between the surface connections at the well bore and the shale shaker. Drilling mud flows through it upon its return to the surface from the hole.†
† This is an abridged version of the Dictionary of Petroleum Terms provided by Petex and the University of Texas Austin. © Petex 2001
Pipe Ramp
An angled ramp for dragging drill pipe up to the drilling platform or bringing pipe down off the drill platform.†
† This is an abridged version of the Dictionary of Petroleum Terms provided by Petex and the University of Texas Austin. © Petex 2001
Pipe racks
A horizontal support for tubular goods.†
† This is an abridged version of the Dictionary of Petroleum Terms provided by Petex and the University of Texas Austin. © Petex 2001
Engine Generator Sets
A diesel, Liquefied Petroleum Gas (LPG), natural gas, or gasoline engine, along with a mechanical transmission and generator for producing power for the drilling rig. Newer rigs use electric generators to power electric motors on the other parts of the rig.†
† This is an abridged version of the Dictionary of Petroleum Terms provided by Petex and the University of Texas Austin. © Petex 2001
Rathole
A hole in the rig floor 30 to 35 feet deep, lined with casing that projects above the floor. The kelly is placed in the rathole when hoisting operations are in progress.†
† This is an abridged version of the Dictionary of Petroleum Terms provided by Petex and the University of Texas Austin. © Petex 2001
Mousehole
Shallow bores under the rig floor, usually lined with pipe, in which joints of drill pipe are temporarily suspended for later connection to the drill string.†
† This is an abridged version of the Dictionary of Petroleum Terms provided by Petex and the University of Texas Austin. © Petex 2001
Reserve Pits
A mud pit in which a supply of drilling fluid has been stored. Also, a waste pit, usually an excavated, earthen-walled pit. It may be lined with plastic to prevent soil contamination.†
† This is an abridged version of the Dictionary of Petroleum Terms provided by Petex and the University of Texas Austin. © Petex 2001
Rotary Hose
The hose on a rotary drilling rig that conducts the drilling fluid from the mud pump and standpipe to the swivel and kelly; also called the mud hose or the kelly hose.†
† This is an abridged version of the Dictionary of Petroleum Terms provided by Petex and the University of Texas Austin. © Petex 2001
Rotary Table
The principal component of a rotary, or rotary machine, used to turn the drill stem and support the drilling assembly. It has a beveled gear arrangement to create the rotational motion and an opening into which bushings are fitted to drive and support the drilling assembly.
Note the pipe spinner (in red) on the side of the swivel.†
† This is an abridged version of the Dictionary of Petroleum Terms provided by Petex and the University of Texas Austin. © Petex 2001
Shale Shaker
A series of trays with sieves or screens that vibrate to remove cuttings from circulating fluid in rotary drilling operations. The size of the openings in the sieve is selected to match the size of the solids in the drilling fluid and the anticipated size of cuttings. Also called a shaker.†
† This is an abridged version of the Dictionary of Petroleum Terms provided by Petex and the University of Texas Austin. © Petex 2001
Slips
Wedge-shaped pieces of metal with teeth or other gripping elements that are used to prevent pipe from slipping down into the hole or to hold pipe in place. Rotary slips fit around the drill pipe and wedge against the master bushing to support the pipe. Power slips are pneumatically or hydraulically actuated devices that allow the crew to dispense with the manual handling of slips when making a connection. Packers and other down hole equipment are secured in position by slips that engage the pipe by action directed at the surface.†
† This is an abridged version of the Dictionary of Petroleum Terms provided by Petex and the University of Texas Austin. © Petex 2001
Spinning Chain
A relatively short length of chain attached to the tong pull chain on the manual tongs used to make up drill pipe. The spinning chain is attached to the pull chain so that a crew member can wrap the spinning chain several times around the tool joint box of a joint of drill pipe suspended in the rotary table. After crew members stab the pin of another tool joint into the box end, one of them then grasps the end of the spinning chain and with a rapid upward motion of the wrist "throws the spinning chain"-that is, causes it to unwrap from the box and coil upward onto the body of the joint stabbed into the box. The driller then actuates the makeup cathead to pull the chain off of the pipe body, which causes the pipe to spin and thus the pin threads to spin into the box.†
† This is an abridged version of the Dictionary of Petroleum Terms provided by Petex and the University of Texas Austin. © Petex 2001
Stairways
Stairs leading from one level to another. Protected with handrails.†
† This is an abridged version of the Dictionary of Petroleum Terms provided by Petex and the University of Texas Austin. © Petex 2001
Standpipe
A vertical pipe rising along the side of the derrick or mast. It joins the discharge line leading from the mud pump to the rotary hose and through which mud is pumped going into the hole.†
† This is an abridged version of the Dictionary of Petroleum Terms provided by Petex and the University of Texas Austin. © Petex 2001
Substructure
The foundation on which the derrick or mast and usually the drawworks sit; contains space for storage and well control equipment.†
† This is an abridged version of the Dictionary of Petroleum Terms provided by Petex and the University of Texas Austin. © Petex 2001
Swivel
A rotary tool that is hung from the rotary hook and traveling block to suspend and permit free rotation of the drill stem. It also provides a connection for the rotary hose and a passageway for the flow of drilling fluid into the drill stem.†
† This is an abridged version of the Dictionary of Petroleum Terms provided by Petex and the University of Texas Austin. © Petex 2001
Tongs
The large wrenches used for turning when making up or breaking out drill pipe, casing, tubing, or other pipe; variously called casing tongs, rotary tongs, and so forth according to the specific use. Power tongs are pneumatically or hydraulically operated tools that spin the pipe up and, in some instances, apply the final makeup torque.†
† This is an abridged version of the Dictionary of Petroleum Terms provided by Petex and the University of Texas Austin. © Petex 2001
Top Drive
The top drive rotates the drill string end bit without the use of a kelly and rotary table. The top drive is operated from a control console on the rig floor.†
† This is an abridged version of the Dictionary of Petroleum Terms provided by Petex and the University of Texas Austin. © Petex 2001
Traveling Block
An arrangement of pulleys or sheaves through which drilling cable is reeved, which moves up or down in the derrick or mast.†
† This is an abridged version of the Dictionary of Petroleum Terms provided by Petex and the University of Texas Austin. © Petex 2001
Walkways
An area cleared for moving through by personnel and protected with a handrail.†
† This is an abridged version of the Dictionary of Petroleum Terms provided by Petex and the University of Texas Austin. © Petex 2001
Water Tank
Is used to store water that is used for mud mixing, cementing, and rig cleaning.†
† This is an abridged version of the Dictionary of Petroleum Terms provided by Petex and the University of Texas Austin. © Petex 2001
Weight Indicator
A device for measuring the weight of the drill string. Monthly calibration to calculated drill string weight is required by API.†
† This is an abridged version of the Dictionary of Petroleum Terms provided by Petex and the University of Texas Austin. © Petex 2001