Tradequip Glossary & Abbreviations


A B C D E F G H I J K L M
N O P Q R S T U V W X Y Z
A
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AAQS
Ambient Air Quality Standards

Abandon
To temporarily or permanently cease production from a well or to cease further drilling operations.

ABF
Aquatic Base Flow

Abrasion
Wearing away by friction.

Abrasion Test
A laboratory test to evaluate drilling-grade weighting material for potential abrasiveness.

Abrasive Jetting
A wellbore treatment in which a fluid laden with solid particles is used to remove deposits from the surface of wellbore tubulars and completion components.

ABS
American Bureau of Shipping

Absolotue Volume
The volume a solid occupies or displaces when added to water divided by its weight, or the volume per unit mass.

Absolute Filter
A type of high-specification fluid filter frequently used to remove small solid particles from workover or treatment fluids that may be injected into, or placed adjacent to, the reservoir formation.

abst
Abstract

AC
Alternating Current

Accelerator
A downhole tool used in conjunction with a jar to store energy that is suddenly released when the jar is activated.

Accumulator
The storage device for nitrogen pressuried hydraulic fluid, which is used in operating the blowout preventers.

Acetic Acid
An organic acid compound sometimes used to acidize oilwells.

ACHARR
Advisory Committee on Hydrocarbons Additional Recovery Research

Acid Fracture
To part or open fractures in limestone formations by using fluid under hydraulic pressure.

Acidize
Treat oil-bearing limestone or other formations with acid to increase production.

Adapter Flange
Any flange that will connect between two other flanges that would otherwise not connect.

Aeration
The introduction of air or gas into a liquid.

AESC
Association of Energy Service Companies. A trade association that represents the interests of members of the energy service segment of the oil and gas industry.

Afterflow
The flow associated with wellbore storage following a surface shut-in.

Air Drilling
A drilling technique whereby gases (typically compressed air or nitrogen) are used to cool the drill bit and lift cuttings out of the wellbore instead of the more conventional use of liquids.

Air Hoist
A hoist operated by compressed air; a pheumatic hoist. Air Hoists are often mounted on the rig floor and may be used to lift joints of pipe and other heavy objects.

Ambient Temperature
The temperature at a point or area expressed as an average of the surrounding areas or materials.

Amp
Ampere

Annubar
A device that uses pitot tubes to measure the gas flow rate within a pipeline. The gas volume is calculated from the difference between the flowing pressure and the static pressure of the gas.

Annular Blowout Prev
A well control device, usually installed above the ram preventers, that forms a seal in the annular space between the pipe and well bore or, if no pipe is present, over the well bore itself.

Annular Flow
A multiphase flow regime in which the lighter fluid flows inthe center of the pipe, and the heavier fluid is contained in a thin film on the pipe wall.

Annular Gas Flow
A flow of the formation gas in the annulus between a casing string andthe borehole wall. Annular gas flows occur when there is insufficient hydrostatic pressure to restrain the gas.

Annular Production
Production of formation fluid through the casing-tubing annulus.

Annulus
In a borehole, the space between the drill pipe and the borehole, between tubing and casing, or between casing and formation.

ANSI
American National Standards Institute. A trade association and standards organization that represents the interests of the oil and gas industry.

AOG
Australasian Oil & Gas Exhibition & Conference

API
American Petroleum Institute. An oil industry organization that is the leading standard-setting body for oilfield equipment and products.

API Gravity
American Petroleum Institute measure of specific gravity of crude oil or condensate in degrees. An arbitrary scale expressing the gravity or density of liquid petroleum products.

Aquifer
Any water-bearing formation encountered while drilling.

Armor
The metal strands on the outside of a wireline logging cable.

Artificial Lift
Any method used to raise oil to the surface after a well ceases to flow.

ATCE
Annual Technical Conference & Exhibition

B
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Back Off
To unscrew one threaded piece (such as a section of pipe) from another.

Back-In Unit
A portable servicing or workover rig that is self-propelled, using the hoisting engines for motive power.

Bail
A cylindrical steel bar (similar to the handle or bail of a bucket, only much larger) that supports the swivel and conncets it to the hook.

Bailer
A long, cylindrical container fitted with a valve at its lower end, used to remove water, sand mud, drilling cuttings or oil from a well in cable-tool drilling.

Ball-Out
To plug open perforations by using ball sealers.

Barium Sulfate
A chemical compound of barium, sulfur, and oxygen which may form a tenacious scale that is very drfficult to remove. Also called barite.

Barrel
42 U.S. gallons.

Basket
A device placed in a drill or work string that catches debris when a drillable object is being milled or drilled downhole.

Bbbl
Billion Barrels

Bbl
Barrel(s) of Oil

Bcf
Billion Cubic Feet

Bcfd
Billions Cubic Feet per Day

Bcfe
Billion Cubic Feet of Gas Equivalent

BDV
Blow Down Valve

Bell Nipple
Pipe extension atop the BOP used to discharge returning drilling mud to shakers,seperators & pits.

Belt
A flexible band or cord connecting and wrapping around each of two or more pulleys to transmit power or impart motion.

Bent Sub
A short cylindrical device (generally angular) installed in the drill stem between the bottommost drill collar and a downhole motor.

BHA
Bottom Hole Assembly (toolstring on coiled tubing or drill pipe)

BHP
Bottom Hole Pressure

Bit
The cutting or boring element used in drilling oil and gas wells.

Bit Whirl
The motion a bit makes when it does not rotate about its center, but in a spiral motion. Usually occurs in soft formations, it results in an over gauge (bigger than the bit) hole & excessive bit wear.

Bleed
To drain off liquid or gas, generally slowly, through a valve called a bleeder, to release pressure slowly from a well or from pressurized equipment.

Block
One or more pulleys, or sheaves, mounted into a common framework in order to rotate on a common axis.

Blowout
An uncontrolled flow of gas, oil or other well fluids from the well.

BOE
Barrels of Oil Equivalent

BOP
Blowout Preventer

BOP Stack
The assembly of well control equipment including preventers, spools, valves and nipples connected to the top of the wellhead.

BOPD
Barrels Of Oil Per Day

BOPM
Barrels of Oil Per Month

Bore
The inside diameter of a pipe or a drilled hole.

BOSIET
Basic Offshore Safety Induction and Emergency Training

Bottom Plug
A cement wiper plug that precedes cement slurry down the casing. The plug wipes drilling mud off the walls of the casing and prevents it from contaminating the cement.

Bottomhole
The lowest or deepest part of a well.

Bottomhole Assembly
The portion of the drilling assembly below the drill pipe.

Bottomhole Plug
A bridge plug or cement plug placed near the bottom of the hole to shut off a depleted, water-producing or unproductive zone.

Bottomhole Pump
Any of the rod pumps, high-pressure liquid pumps or centrifugal pumps located at or near the bottom of the well and used to lift the well fluids.

BPD
Barrels Per Day

BPH
Barrels Per Hour

BPV
Back Pressure Valve

BR
Building Rig or Building Road

Brake
The braking device on the drawworks or airhoist to stop a load being lifted.

Brake Band
A part of the brake mechanism consisting of a flexible steel band lined with a material that grips a drum when tightened.

Brakeout Block
A plate that fits in the rotary table and holds the drill bit while it is being unscrewed from the drill collar.

Break-Out
To unscrew one section of pipe from another, especially drill pipe while it is being withdrawn from the wellbore. During this operation the tongs are used to start the unscrewing operation.

Breakout Cathead
A device attached to the catshaft of the drawworks that is used as a power source for the tongs used in unscrewing drill pipe; usually located opposite the driller's side of the drawworks.

Bridge Plug
A downhole tool, composed primarily of slips, a plug mandrel and a rubber sealing element, that is run and set in casing to isolate a lower zone while an upper section is being tested or cemented.

British Thermal Unit
The quantity of heat required to raise the temperature of 1 lb. of liquid water by 1 degree Fahrenheit at the temperature at which water has its greatest density (approximately 39 degrees Fahrenheit).

Brown Fields
Fields beyond their production plateau but are still producing

BRT
Below Rotary Table

BS&W
Basic Sediment & Water

BSW
Barrels Salt Water

BTI
British Trade International

BTU
British Thermal Unit

Buck Up
To tighten up a threaded connection (such as two joints of drill pipe).

Bulk Tank
On a drilling rig, a large metal bin that usually holds a large amount of a certain mud additive, such as bentonite, that is used in large quantities in the makeup of the drilling fluid.

Bull Plug
Threaded, cylindrical device with a rounded closed end, used to seal off the casing string or instrument barrel to ensure pressure integrity.

Bushing
A pipe fitting on which the external thread is larger than the internal thread to allow two pipes of different sizes to be connected.

BWPD
Barrels of Water Per Day

Bypassed Footage
Bypassed footage is the footage in that section of hole that is abandoned as the result of remedial sidetrack drilling operations.

C
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C (cent.)
Centigrade

C/H
Cased Hole

Cable
A rope of wire, hemp or other fibers.

Carrier Rig
A specially designed, self-propelled workover or drilling rig that is driven directly to the well site. A carrier rig may be a back-in type or a drive-in type.

Cased Hole
A wellbore in which casing has been run.

Casing
Steel pipe placed in an oil or gas well to prevent the wall of the hole from caving in, to prevent movement of fluids from one formation to another and to aid in well control.

Casing Centralizer
A device secured around the casing at regular intervals to center it in the hole.

Casing Coupling
Also called casing collar: a tubular section of pipe that is threaded inside and used to connect two joints of casing.

Casing Cutter
A heavy cylindrical body, fitted with a set of knives, used to cut and free a section of casing in a well.

Casing Hanger
A circular device with a frictional gripping arrangement of slips and packing rings used to suspend casing from a casing head in a well.

Casing Head
A flanged steel fitting connected to the first string of casing. It allows suspension of intermediate and production strings of casing and is the means for sealing off the annulus.

Casing Point
The depth in a well at which casing is set, generally the depth at which the casing shoe rests.

Casing String
The entire length of all the joints of casing run in a well.

Casing-Tubing Annulu
In a wellbore, the space between the inside of the casing and the outside of the tubing.

Casinghead Gas
Natural gas produced along with crude oil from oil wells. It contains either dissolved or associated gas or both.

Cathead
A spool-shaped attachment on the end of the catshaft, around which rope for hoisting and moving heavy equipment on or near the rig floor is wound.

Catline Boom
A hoisting or pulling line powered by the cathead and used to lift heavy equipment on the rig. A structural framework erected near the top of the derrick for lifting material.

Catwalk
The elevated work area adjacent to the vdoor and ramp on a drilling rig where pipe is laid to be lifted to the derrick floor by the catline or by an air hoist. Also any elevated walkway.

CBL
Cable

Cellar
A pit in the ground to provide additional height between the rig floor and well head to accommodate the installation of BOP's. ratholes, and so forth.

Cement
A powder consisting of alumina, silica, lime and other substances.

Cement Bond
The adherence of casing to cement and cement to formation. When casing is run in a well, it is set, or bonded, to the formation by means of cement.

Cement Casing
To fill the annulus between the casing and wall of the hole with cement to support the casing and prevent fluid migration between permeable zones.

Cementing
The application of a liquid slurry of cement and water to various points inside or outside the casing.

centr
Centrifugal

Centrifuge
A machine that uses centrifugal force to separate substances of varying densities.

Cf
Cubic Feet

Cfs
Cubic Feet per Second

Chain Tongs
A hand tool used to tighten or loosen pipe, consisting of a handle and chain that resembles the chain on a bicycle.

Chemical Cutter
A fishing tool that uses high-pressure jets of chemicals to sever casing, tubing or drill pipe stuck in the hole.

Chemical Inhibitor
Liquid chemical compounds injected into lines carrying fluids that contain H2S. Most inhibitors coat surfaces to isolate them from corrosive substances. Some react to produce less-destructive compound

Choke
Pressure control equipment that restricts & regulates pressure & flow rates of well fluids.

Choke Manifold
Assembly of valves, fittings & chokes to regulate & control flow of high pressure fluid from a well.

CHP
Casing Hanger Pressure (pressure in an annulus as measured at the casing hanger)

Christmas Tree
Assembly of equipment topping off wellhead to regulate & control flow of oil & gas during production

Circulating Head
An accessory attached to the top of the drill pipe or tubing to form a connection with the mud system to permit circulation of the drilling mud.

Class
Category in Classification Register

CNG
Compressed Natural Gas

CO
Carbon Monoxide

CO2
Carbon Dioxide

Coiled Tubing
Long sections of small-diameter tubulars in rolls & used to replace jointed pipe.

Collar
A device used to join two lengths of pipe.

Completion
Technology used to bring a well to production.

Compressor
An engine used to increase the pressure of natural gas so that it will flow more easily through a pipeline.

Conductor Pipe
Generally, the first string of casing in a well.

Connection
A section of pipe or fitting used to join pipe to pipe or to a vessel. Also the action of adding a joint of pipe to the drill stem as drilling progresses.

Conventional Product
Wireline well logs run in vertical production wells to determin wellbore oil, water & gas inflow.

Coring Services
Coring is the removal of sample formation material from a wellbore.

CPI
Consumer Price Index

cplg
Coupling

CPS
Cycles Per Second

Crossover Sub
A sub that allows different sizes and types of drill pipe or other components to be joined.

Crown Block
An assembly of sheaves mounted on beams at the top of the derrick or mast.

csg
Casing

CT
Coiled Tubing

CTCO
Coiled Tubing Clean Out

CTM
Cable Tool Measurement

Cuttings
The fragments of rock dislodged by the bit and brought to the surface in the drilling mud. Washed and dried cuttings samples are analyzed to obtain information about the formations drilled.

D
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D&C
Drilling and Completions

Dampener
An air or inert gas device that minimizes pressure surges in the output line of a mud pump. Sometimes called a surge dampener.

DB
Decibles

DC
Drill Collar(s)

DDM
Derrick Drilling Machine (a.k.a. Top Drive)

Deadline
The drilling line from the crown block sheave to the anchor, so called because it does not move.

Degasser
The equipment used to remove unwanted gas from a liquid, especially from drilling fluid.

depl
Depletion

Derrick
A large load-bearing structure, usually of bolted construction. In drilling, the standard derrick has 4 legs standing at the corners of the subsctructure and reaching to the crown block.

Derrick Floor
Another name for the rig floor.

Desander
A centrifugal device for removing sand from drilling fluid to prevent pump abrasion.

Desilter
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.

Development Well
A well drilled within the proved area of an oil or gas reservoir to the depth of a stratigraphic horizon known to be productive.

Diamond Bit
A drill bit that has small industrial diamonds embedded in its cutting surface.

Die Insert
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

Dies
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.

Diesel Engine
A high-compression, internal-combustion engine used extensively for powering drilling rigs.

Diesel Fuel
A light hydrocarbon mixture for diesel engines; it has a boiling range just above that of kerosene.

Directional Drilling
The method of guiding a well along a predetermined path to a specific target.

Directional Hole
A wellbore intentionally drilled at an angle from the vertical.

Displacement Fluid
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.

Diverter
Specialized annular BOP used with large diameter flow valves, to close & divert gas during drilling

DOE
US Department of Energy

Doghouse
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.

DOT
US Department of Transportation

Double
A length of drill pipe, casing or tubing consisting of two joints screwed together.

Downhole Motor
A tool directly above the drill bit in a drill string that converts the hydraulic energy of circulating drilling fluid into mechanical energy to turn the bit independently of drill string rotation.

Downhole Oil/Water S
A system comprising a downhole hydrocyclone and electrical submersible pump that separates oil from water downhole, reinjects water, and produces oil to the surface.

DP
Drill Pipe

DR
Development Redrill (sidetrack)

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 lowers or raises the drill stem and bit.

Drill
To bore a hole in the earth, usually to find and remove subsurface formation fluids such as oil and gas.

Drill Bit
the component at the end of the drill string that cuts the rock and makes hole.

Drill Collar
Heavy-walled sections of pipe included at the bottom of the drill string to apply weight to the drill bit during drilling.

Drill Collar Sub
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.

Drill In
To penetrate the productive formation after the casing is set and cememted on top of the pay zone.

Drill Stem
All components in a rotary drilling assembly from the swivel to the bit.

Drill String
The total string of drill pipe with attached tools and bit.

Drillable
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.

Drilling Engine
An internal-combustion engine used to power a drilling rig.

Drilling Fluid
Fluid used in the wellbore to lubricate & cool the bit, control bottom-hole pressures, and remove cuttings.

Drilling Line
A wire rope hoisting line, reeved on sheaves of the crown block and traveling block, the primary purpose of which is to hoist or lower drill pipe or casing from or into a well.

Drive Chain
A chain by means of which a machine is propelled.

drk
Derrick

drl
Drill

Drum (rope)
A rotating cylinder with side flanges on which wire or other rope used in machine operation is wrapped.

Dry Gas
The volume of gas remaining after all water and natural gas liquids have been removed.

Dry Hole
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.

DS
Drill Stem

DSC
Dangerous Goods, Solid Cargoes and Containers

DST
Drill Stem Test

dstl
Distillate

Dump Bailer
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.

dwks
Drawworks

DWT
Deadweight Tons or Deadweight Tester

E
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EC
European Community

EHV
Extra High Voltage

Elastomer
An elastic synthetic rubber or plastic material – often the main component of packing material in downhole packers.

Electric Rig
A drilling rig on which the energy from the power source - usually diesel engines - is changed to electricity by generators mounted on the engines.

Electric Sub Pumping
A form of artificial lift that utilizes an electric submersible multistage centrifugal pump. Electric power is conducted to the pump by a cable attached to the tubing.

elev
Elevator

Elevator Links
Cylindrical bars that support the elevators and attach them to the hook.

Elevators
On rotary rigs and top drive rigs, hinged steel devices with manual operating handles that crew members latch onto a tool joint (or a sub).

EMF
Electromotive Force

EMI
Electromagnetic Inspection

Emulsifier
A material that causes water and oil to form an emulsion, i.e.; fine oil droplets suspended in the water.

eng
Engine

Engine
A machine for converting the heat content of fuel into rotary motion that can be used to power other machines.

EOFL
End of Field Life

EOR
Enhanced Oil Recovery

EPA
Environmental Protection Act

equip
Equipment

ERD
Extended Reach Drilling

ESD
Emergency Shut Down

ESP
Electric Submersible Pump

EU
European Union

External Cutter
A fishing tool containing metalcutting knives that is lowered into the hole and over the outside of a length of pipe to cut it. The severed part of the pipe can then be brought to the surface.

F
Back To Top

Fastline
The end of the drilling line that is affixed to the drum or reel of the drawworks, so called because it travels with greater velocity than any other portion of the line.

FC
Float Collar

FCV
Flow Control Valve

Fingerboard
A rack that supports the stands of pipe being stacked in the derrick or mast. It has steel fingerlike projections that form slots to place a stand of pipe or collars after being pulled from the hole.

Fish
An object that is left in the wellbore during drilling or workover operations and must be recovered before work can proceed.

Fishing
The process of recovering equipment lost or stuck in the wellbore. Tools & services that perform specialty & repair work downhole. Retrieving lost tools & repairing wellbore damage.

FJ
Flush Joint

Flange
Single disc or protruding disc on a body with holes to accept bolts used to join pressure equipment

Float Collar
A special coupling device inserted one or two joints above the bottom of the casing string that contains a check valve to permit fluid to pass downward but not upward through the casing.

Float Equipment
Check valves that permit fluid to pass downward, but not upward through the casing. A float collar is a special coupling device inserted one or two joints above the bottom of the casing string.

Flood
To drive oil from a reservoir into a well by injecting water under pressure into the reservoir formation. Also to drown out a well with water.

Flow Line
The surface pipe through which oil or gas travels from a well to processing equipment or to storage.

Flowing Well
A well that produces oil or gas by its own reservoir pressure rather than by use of artificial means (such as pumps).

Fluid Injection
Injection of gases or liquids into a reservoir to force oil toward and into producing wells.

Fluid Loss
The unwanted migration of the liquid part of the drilling mud or cement slurry into a formation, often minimized or prevented by the blending of additives with the mud or cement.

FO
Fuel Oil

FPF
Floating Production Facility

FPS
Feet Per Second

Fracturing (frac)
A method of stimulation production by opening new flow channels in the rock surrounding a production well by pumping proppant and fluid into the well at high pressure and volume.

Friction
Resistance to movement created when two surfaces are in contact. When friction is present, movement between the surfaces produces heat.

FRSB
Fast Response Spill Boat

FST
Forged Steel

Ft
Foot (feet)

FTC
US Federal Trade Commission

FTP
Final (Flowing) Tubing Pressure

Full-Gauge Bit
A bit that has maintained its original diameter.

Full-Gauge Hole
A wellbore drilled with a full-gauge bit. Also called a true-to-gauge hole.

FWV
Flow Wing Valve

G
Back To Top

G
Gas

G/L
Gathering Line

Gal
Gallon

GAPP
Generally Accepted Accounting Principles

Gas Anchor
A tubular, perforated device attached to the bottom of a suckerrod pump that helps to prevent gas lock. The device works on the principle that gas, being lighter than oil, rises.

Gas Cap
A free-gas phase overlying an oil zone and occurring within the same producing formation as the oil.

Gas Drive
The use of the energy that arises from the expansion of compressed gas in a reservoir to move crude oil to a wellbore. Also called depletion drive.

Gas Injection
The injection of gas into a reservoir to maintain formation pressure by gas drive and to reduce the rate of decline of the original reservoir drive.

Gas Lift
The process of raising or lifting fluid from a well by injecting gas down the well through tubing or through the tubing-casing annulus.

Gas-Cap Drive
Drive energy supplies naturally (as a reservoir is produced) by the expansion of the gas cap. In such a drive, the gas cap expands to force oil into the well and to the surface.

Gas-Lift Well
A well in which reservoir fluids are artificially lifted by the injection of gas.

Gasket
Any material (such as paper, cork, asbestos, stainless steel or other types of metal, or rubber) used to seal two essentially stationary surfaces.

Gauge
The diameter of a bit or the hole drilled by the bit.

GB
Gun Barrel

GBT
Gravity Base Tank

GL
Gas Lift or Ground Level

GLM
Gas Lift Mandrel

GLR
Gas Liquid Ratio

GLV
Gas Lift Valve

GOC
Gas Oil Contact

GOM
Gulf of Mexico

Gooseneck
The curved connection between the rotary hose and the swivel.

GOR
Gas Oil Ratio

Gravel Pack
A completion technique used to control production of sand from loosely consolidated formations.

Gravel Packing
A method of well completion in which a slotted or perforated liner, often wire-wrapped, is placed in the well and surrounded by gravel.

GRV
Grooved or Gravel

GT
Geothermal

GT&C
General Terms and Conditions

GTL
Gas To Liquid

GTW
Gas To Wire

Guide Shoe
A short, heavy, cylindrical section of steel filled with concrete and rounded at the bottom, which is placed at the end ot the casing string.

Guy Line Anchor
A buried weight or anchor to which a guy line is attached.

Guy Wire
A rope or cable used to steady a mast or polst.

GW
Gallons Water, Gas Well, or Geothermal Wildcat

Gwh
Gigawatt-Hour

H
Back To Top

H2S
Hydrogen Sulfite

Hammer Unions
Connections that allow quick make-up & break-out of pipe & fittings used in temporary flow lines.

Hang Rods
To suspend sucker rods in a derrick or mast on rod hangers rather than to place them horizontially on a rack.

HARP
Hydrocarbons Additional Recovery Program

HAZMAT
Hazardous Materials Response Division of NOAA

Head
The measure of fluid at the bottom of a column of fluid in a well bore.

HEX
Heat Exchanger

HL
Hook Load

Hoist
An arrangement of pulleys and wire rope used for lifting heavy objects; a winch or similar device.

Hoisting Components
Drawworks, drilling line, and traveling and crown blocks. Auxiliary hoisting components include catheads, catshaft, and air hoist.

Hoisting Drum
The large, flanged spool in the drawworks on which the hoisting cable is wound.

Hook
A large, hook-shaped device from which the elevator bails or the swivel is suspended. It turns on bearings in its supporting housing.

Hook Load
The weight of the drill stem and associated components that are suspended from the hook.

Horizontal Drilling
Deviation of the borehole from vertical so that the borehole penetrates a productive formation in a manner parallel to the formation.

Horsehead
The generally horsehead-shaped steel piece at the front of the beam of a pumping unit to which the bridle is attached in sucker rod pumping.

HP
Horse Power

HPHT
High Pressure High Temperature

HSC
Health & Safety Commision

HVDC
High Voltage Direct Current

HVI
High Viscosity Index

HWDP
Heavy-Weight Drill Pipe (sometimes spelled Hevi-Wate)

Hydraulic
Of or relating to water or other liquid in motion. Operated, moved or effected by water or liquid.

Hydraulic Force
Force resulting from pressure on water or other hydraulic fluid.

Hydraulic Fracturing
An operation in which a specially blended liquid is pumped down a well and into a formation under pressure high enough to cause the formation to crack open, and allowing oil to flow into the wellbore.

Hydraulic Jar
A type of mechanical jar in which a fluid moving through a small opening slows the piston stroke while the crew stretches the work string.

Hydrocyclone
A cone-shaped device for separating mixed liquids (i.e., oil and water).

Hydrostatic Pressure
The force exerted by a body of fluid at rest. It increases directly with the density and depth of the fluid and is expressed in many different units, including pounds per square inch or kilopascals.

Hz
Hertz (cycles per second)

I
Back To Top

I:P
Injector To Producer Ratio

IADC
International Association of Drilling Contractors

ICV
Internal Control Vavle

ID
Inner Diameter

IFO
Intermediate Fuel Oil

Impeller
A set of mounted blades used to impart motion to a fluid air or gas (such as, the rotor of a centrifugal pump).

Impermeable
Preventing the passage of fluid. A formation may be porous yet impermeable if there is an absence of connecting passages between the voids within it.

Impression Block
A block with lead or another relatively soft material on its bottom. It indicates the position of the lost object and allows the correct fishing tool to be selected.

IN.
Inch

Inflatable Packer
A packer with an element that inflates by means of gas or liquid pumped from the surface through a line. They are used when a temporary packer is needed in a hole.

Injection Gas
A high-pressure gas injected into a formation to maintain or restore reservoir pressure. Gas injected in gas-lift operations.

Injection Water
Water that is introduced into a reservoir to help drive hydrocarbons to a productin well.

Injection Well
A well through which fluids are injected into an underground stratum to increase reservoir pressure and to displace oil. Also called input well.

Injector Head
A control head for injecting coiled tubing into a well that seals off the tubing and makes a pressure tight connection.

Inland Barge Rig
An off shore drilling structure consisting of a barge on which the drilling equipment is constructed. It is positioned on location, then the barge is sunk.

Insert Pump
A sucker rod pump that is run into the well as a complete unit.

Intake Valve-Engine
The mechanism on an engine through which air and sometimes fuel are admitted to the cylinder.

Intake Valve-Pump
On a mud pump, the valve that opens to allow mud to be drawn into the pump by the pistons moving in the liners.

Internal Cutter
A fishing tool containing metal-cutting knives that is lowered into the inside of a length of pipe stuck in the hole to cut the pipe. The severed portion of the pipe is then returned to the surface.

ISO
International Standards Organization

Isotropic
Of equal physical properties in all directions.

IW
Injection Well

J
Back To Top

Jackup Drill Rig
A mobile, bottom-supported offshore drilling structure that is essentially a barge with legs. The platform is raised or adjusted by moving up or down on the legs.

Jar
A percussion tool operated manually or hydraulically to deliver a heavy upward or downward blow to fish stuck in the borehole. To apply a heavy blow to the drill stem by use of a jar or bumper sub.

Jar Accelerator
A hydraulic tool used in conjunction with a jar and made up on the fishing string above the jar to increase the power of the jarring force.

Jerk Line
A wire rope, one end of which is connected to the end of the tongs and the other end of which is attached to the cathead.

Jet Cutoff
A procedure for severing pipe stuck in a well by detonating special shaped charge explosives similar to those used in jet perforating.

Jet Cutter
A fishing tool that uses shaped charges to sever casing, tubing or drill pipe stuck in a hole.

Jet-Gun
In a perforating gun using shaped charges, a highly penetrating, fast-moving stream of exploded particles that forms a hole in the casing, cement and formation.

Jet-Perforate
To create holes through the casing with a shaped charge of high explosives instead of a gun that fires projectiles.

Jet-Pump
A hydraulic device operated by a centrifugal pump used to clean the mud pits, or tanks, and to mix mud components.

Joint of Pipe
A length of drill pipe or casing. Both come in various lengths.

Journal Bearing
A machine part in which a rotating shaft (a journal) revolves or slides. Also called a plain bearing.

JTS
Joints (number of)

JU
Jackup

Junk
Metal debris lost in a hole. Junk may be a lost bit, pieces of a bit or pipe, wrenches, or any relatively small object that impedes drilling and must be fished out of the hole.

Junk Basket
A device made up on the bottom of the drill stem or on a wireline to catch pieces of junk from the bottom of the hole.

Junk Mill
A mill used to grind up junk in the hole.

JV
Joint Venture

K
Back To Top

KB
Kelly Bushing

Kelly
The heavy square or hexagonal steel member suspended from the swivel through the rotary table and connected to the topmost joint of drill pipe to turn the drill stem as the rotary table turns.

Kelly Bushing
A device fitted to the rotary table through which the kelly passes and the means by which the torque of the rotary table is transmitted to the kelly and the drill stem.

Kelly Bypass
A system of valves and piping that allows drilling fluid to be circulated without the use of the kelly.

Kelly Cock
A valve installed at one or both ends of the kelly. When a high-pressure backflow occurs inside the drill stem, the valve is closed to keep pressure off the swivel and rotary hose.

Kelly Driver
A device that fits inside the head and inside of which the kelly fits. The kelly driver rotates with the kelly.

Kelly Saver Sub
A heavy and relatively short length of pipe that fits in the drill stem between the kelly and the drill pipe. The threads of the drill pipe mate with those of the sub, minimizing wear on the kelly.

Kelly Spinner
A pheumatically operated device mounted on top of the kelly that, when actuated, causes the kelly to turn or spin.

kHz
Kilohertz

Kick Off
To bring a well into production; used most often when gas is injected into a gas lift well to start production. In workover operations, to swab a well to restore it to production.

Kickoff Point (KOP)
The depth in a vertical hole at which a deviated or slant hole is started; used in directional drilling.

Kill-Drilling
In drilling, to control a kick by taking suitable preventive measures (as in to shut in the well with the blowout preventers, circulate the kick out, and increase the weight of the drilling mud).

Kill-Production
In production, to stop a well from producing oil and gas so that reconditioning of the well can proceed.

KOP
Kick Off Point (directional drilling)

KV
Kilovolt

KVA
Kilovolt-Ampere

Kw
Kilowatt

KWH
Kilowatt-Hour

L
Back To Top

LAGCOE
Louisana Gulf Coast Oil Exposition

Land Rig
Any drilling rig that is located on dry land.

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

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

Lateral Bore
Normally referred to as the deviated or horizontal extension in the drilling of a horizontal well or multilateral well.

Lay
The spiral of strands in a wire rope either to the right or the left, as viewed from above.

Lay Down Pipe
To pull drill pipe or tubing from the hole and place it in a horizontal position on a pipe rack.

Lead Tongs
(Pronounced "leed") The pipe tongs suspended in the derrick or mast and operated by a chain or a wire rope connected to the makeup cathead or the breakout cathead.

Lead-Tong Hand
(Pronounced "leed") The crew member who operates the lead tongs when drill pipe and drill collars are being handled.

LGR
Liquid Gas Ratio

Lifting Sub
A threaded device placed in the end of tubulars, such as drill collars to aid in lifting; also called hoisting plug.

Liner
A string of pipe used to case open hole below existing casing, overlapping inside the upper string and held in place by a liner hanger packer.

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

Liner Hanger
A slip device that attaches the liner to the casing.

LKO
Lowest Known Oil

LNG
Liquified Natural Gas

Log A Well
To run any of the various logs used to ascertain downhole information about a well.

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

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

Lost Circulation
The quantities of whole mud lost to a formation, usually in cavernous, pressured, or coarsely permeable beds.

Lost Pipe
Drill pipe, drill collars, tubing or casing that has become separated in the hole from the part of the pipe reaching the surface, necessitating its removal before normal operations can proceed.

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

LOT
Leak Off Test

LP
Low Pressure

LPG
Liquefied Petroleum Gas

LST
Local Standard Time

Lubricator
A specially fabricated length of casing or tubing usually placed temporarily above a valve on top of the casing head or tubing head.

LW
Load Water

LWD
Logging While Drilling

M
Back To Top

M
Meter

M/V
Motor Vessel

Macaroni String
A string of tubing or pipe, usually 3/4 inch or 1 inch (1.9 or 2.54 centimeters) in diameter.

Main Bore
The main casing string from which subsequent directional drilling operations or openhole operations are initiated.

Make A Connection
To attach a joint or stand of drill pipe onto the drill stem suspended in the wellbore to permit deepening the wellbore by the length of the pipe.

Make Up A Joint
To screw a length of pipe into another length of pipe.

Make-Up
To assemble and join parts to form a complete unit (for example, to make up a string of drill pipe). To screw together two threaded pieces. To mix or prepare (for example, to make up a tank of mud).

Makeup
Added to a system (for example, makeup water used in mixing mud).

Makeup Cathead
A device that is attached to the shaft of the drawworks and used as a power source for making up joints of pipe. It is usually located on the sriller's side of the drawworks.

Makeup Tongs
Tongs used for screwing one length of pipe into another for making up a joint.

Male Connection
A pipe, coupling, or tool that has threads on the outside so that it can be joined to a female connection.

Mandrel
A cylindrical bar, spindle or shaft around which other parts are arranged or attached or that fits inside a cylinder or tube.

Manifold
Assembly of valves & fittings to regulate & control the flow of high pressure fluid from a well bore

MAP
Maximum Allowable Pressure

Mast
A portable derrick that is capable of being raised as a unit, as distinguished from a standard derrick, which cannot be raised to a working position as a unit.

Master Bushing
A device that fits into the rotary table to accommodate the slips and drive the kelly bushing so that the rotating motion of the rotary table can be transmitted to the kelly.

Master Valve
A large valve located on the Christmas tree and used to control the flow of oil and gas from a well. Also called a master gate.

MAWP
Maximum Allowable Working Pressure

Mbbls
Thousand Barrels

Mbod
Thousand Barrels of Oil Per Day

MCC
Master Control Center

Mcf
Thousand Cubic Feet (of Gas)

MCFD
Thousand Cubic Feet Per Day

MCFPD
One Thousand Cubic Feet of Gas Per Day

MCT
Multi-Cycle Tool

MD
Measured Depth

Mechanical Jar
A percussion tool operated mechanically to give an upward thrust to a fish by the sudden release of a tripping device inside the tool.

Mechanical Rig
A drilling rig in which the source of power is one or more internal-combustion engines and in which the power is distributed to rig components through mechanical devices. Also called a power rig.

Mgd
Million Gallons Per Day

MH
Manhole

Mill
A downhole tool with rough, sharp, extremely hard cutting surfaces for removing metal, packers, cement, sand, or scale by grinding or cutting.

Miscible Drive
A method of enhanced recovery in which various hydrocarbon solvents or gases are injected into the reservoir to reduce interfacial forces between oil and water in the pore channels.

Mix Mud
To prepare drilling fluids.

Mixing Tank
Any tank or vessel used to mix components of a substance (as in the mixing of additives with drilling mud).

MMbd
Million Barrels Per Day

MMcf
Million Cubic Feet

MMS
Minerals Management Service

MODU
Mobile Offshore Drilling Unit

Monitor
An instrument that reports the performance of a control device or signals if unusual conditions appear in a system.

Motor
Any of various power units, such as a hydraulic, internal combustion, air, or electric device, that develops energy or imparts motion.

Motorhand
The crew member on a rotary drilling rig, who is responsible for the care and operation of drilling engines. Also called motorman.

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.

Mousehole Connection
The procedure of adding a length of drill pipe or tubing to the active string.

Mpd
Thousand Barrels Per Day

MSDS
Materials Safety Data Sheet

MTLP
Mini Tension Leg Platform

mtr
mtr = Meter or MTR = motor

MTR's
Material Test Report or Manufactuers Test Results

Mud Acid
A mixture of hydrochloric and/or hydrofluoric acids and surfactants used to remove wall cake from the wellbore.

Mud Cake
The sheath of mud solids that forms on the wall of the hole when liquid from mud filters into the formation. Also called filter cake or wall cake.

Mud Centrifuge
A device that uses centrifugal force to separate small solid components from liquid drilling fluid.

Mud Cleaner
A cone-shaped device, a hydrocyclone, designed to remove very fine solid particles from the drilling mud.

Mud Line
A mud return line.

Mud Logging
The recording of information derived from examination and analysis of formation cuttings made by the bit and of mud circulated out of the hole.

Mud Pump
A large, high-pressure reciprocating pump used to circulate the mud on a drilling rig.

Mud Return Line
A trough or pipe that is placed between the surface connections at the wellbore and the shale shaker.

Mud Tank
One of a series of open tanks, usually made of steel plate, through which the drilling mud is cycled to remove sand and fine sediments.

Mud Weight
A measure of the density of a drilling fluid expressed as pounds per gallon, cubic foot, or kilograms per cubic metre.

Mud-Gas Separator
A device that removes gas from the mud coming out of a well when a kick is being circulated out.

Mud/Drill Fluid
Fluid used in the wellbore to lubricate & cool the bit, control bottom-hole pressures and remove cuttings.

Multiple Completion
An arrangement for producing a well in which one wellbore penetrates two or more petroleum-bearing formations.

MUX
Make Up Crossover

MVA
Megavolt-Amperes

MW
Megawatts

MWD
Measurement While Drilling

N
Back To Top

Natural Gas
A highly compressible, highly expansible mixture of hydrocarbons with a low specific gravity and occurring naturally in a gaseous form.

Natural Reservoir...
Natural Reservoir Pressure is the energy within an oil or gas reservoir that causes the oil or gas to rise to the earth's surface when the reservoir is penetrated by an oil or gas well.

NE
Northeast

NEB
National Energy Board

Neutron Log
A radioactivity well log used to determine formation porosity.

NG
Natural Gas

NGL
Natural Gas Liquids

Nipple
A tubular pipe fitting threaded on both ends used for making connections between pipe joints and other tools.

Nipple Up
In drilling, to assemble the blowout preventer stack on the wellhead at the surface.

Nitro Shooting
A formation-stimulation process first used about 100 years ago in Pennsylvania. Nitroglycerine is placed in a well and exploded to fracture.

NM
Nautical Mile

NO2
Nitrogen Dioxide

NOAA
National Oceanic and Atmospheric Administration

Normal Circulation
The smooth, uninterrupted circulation of drilling fluid down the drill stem, out the bit, up the annular space between the pipe and the hole, and back to the surface.

NOX
Nitrogen Oxides

Nozzle
A passageway through jet bits that causes the drilling fluid to be ejected from the bit at high velocity.

NRV
Non Return Valve

NT
Net Tonnage

Nuclear Tracer
A gas, liquid, or solid material that emits gamma rays.

O
Back To Top

O
Oil

O-Ring
A circular seal common in the oil field; made of elastomer, rubber, plastic, or stainless steel. To seal they all require enough pressure to make them deform against a sealing surface.

O/B
On Board

OAL
Overall Length

OCTG
Oil Country Tubular Goods

OD
Outer Diameter

ODT
Oil Down To

off-sh
Off-Shore

OGA
Oil & Gas Asia

OIAC
Oil Industry Advisory Committe

Oil
A simple or complex liquid mixture of hydrocarbons that can be refined to yield gasoline, kerosene, diesel fuel, and various other products.

Oil Mud
A drilling mud, such as oil-base mud and invert-emulsion mud, in which oil is the continuous phase, useful in drilling certain formations that may be difficult or costly to drill with waterbase mud.

Oil Sand
A sandstone that yields oil.

Oil Saver
A gland arrangement that mechanically or hydraulically seals by pressure; used to prevent leakage and waste of gas, oil or water around a wireline (as when swabbing a well).

Oil Spotting
Pumping oil, or a mixture of oil and chemicals, to a specific depth in the well to lubricate stuck drill collars.

Oil String
The final string of casing set in a well after the productive capacity of the formation has been determined to be sufficient. Also called the long string or production casing.

Oil Zone
A formation or horizon of a well from which oil may be produced. The oil zone is usually immediately under the gas zone and on top of the water zone if all three fluids are present and segregated.

Oil-Base Mud
A drilling or workover fluid in which oil is the continuous phase and which contains from less than 2% and up to 5% water. This water is spread out in the oil as small droplets.

Oil-Emulsion Mud
A water-based mud in which water is the continuous phase and oil is the dispersed phase.

Oilfield
The surface area overlying an oil reservoir or reservoirs. The term usually includes not only the surface area, but also the reservoir, the wells, and the production equipment.

OOE
Offshore Operations Engineer (senior technical authority on an offshore oil platform)

OPEC
Organization of Petroleum Exporting Countries

Open Formation
A petroleum-bearing rock with good porosity and permeability.

Open Hole
Any wellbore in which casing has not been set. Open or cased hole in which no drill pipe or tubing is suspended.

Open-Hole Completion
A method of preparing a well for production in which no production casing or liner is set opposite the producing formation. Reservoir fluids flow unrestricted into the open wellbore.

Open-Hole Fishing
The procedure of recovering lost or stuck equipment in an uncased wellbore.

OSHA
Occupational Safety and Health Administration

OTC
Offshore Technology Conference

OTL
Operations Team Leader

Out-Of-Gauge Bit
A bit that is no longer of the proper diameter.

Out-Of-Gauge Hole
A hole that is not in gauge; that is, it is smaller or larger than the diameter of the bit used to drill it.

Overshot
A fishing tool that is attached to tubing or drill pipe and lowered over the outside wall of pipe or sucker rods lost or stuck in the wellbore.

Overthrust Fault
A low-dip angle (nearly horizontal) reverse fault along which a large displacement has occurrred. Some overthrusts represent slippages of many miles.

OWC
Oil Water Contact

P
Back To Top

P & A
(Plug and Abandon) To place cement plugs into a dry hole and abandon it.

Pack Off
To place a packer in the wellbore and activate it so that is forms a seal between the tubing and the casing.

Pack-Off
A device with an elastomer packing element that depends on pressure below the packing to effect a seal in the annulus. Used primarily to run or pull pipe under low or moderate pressures.

Packer
A piece of downhole equipment that consists of a sealing device, a holding or setting device, and an inside passage for fluids.

Packer Fluid
A liquid, usually salt water or oil, but sometimes mud, used in a well when a packer is between the tubing and the casing.

Packing
A material used in a cylinder on rotating shafts of an engine or pump in the stuffing box of a valve, or between flange joints to maintain a leak proof seal.

Packing Assembly
The arrangement of the downhole tools used in running and setting a packer.

Packing Elements
The set of dense rubber, washer-shaped pieces encircling a packer, which are designed to expand against casing or formation face to seal off the annulus.

Paraffin (Oil)
A light-colored, wax-free oil obtained by pressing paraffin distillate.

Paraffin Scraper
A tube with guides around it to keep it centered in the hole, and a cylindrical piece with blades attached. Spaces between the blades allow drilling fluid to pass through and carry away the scrapings.

Parallel Strings
In a multiple completion, the arrangement of a separate tubing string for each zone produced, with all zones isolated by packers.

Parted Rods
Sucker rods that have been broken and separated in a pumping well because of corrosion, improper loading, damaged rods, and so forth.

PBU
Pressure Build Up

PCV
Pressure Control Valve

PDC Drill Bits
A special type of diamond drilling bit that does not use roller cones.

PDG
Permanent Downhole Gauge

PE
Petroleum Engineer

Perforate
To open holes through casing walls and cement into a formation so that fluids can flow into or out of the borehole.

Perforated Completio
A well completion method in which the producing zone or zones are cased through, cemented and perforated to allow fluid flow into the wellbore.

Perforated Liner
A liner that has had holes shot in it by a perforating gun.

Perforated Pipe
Sections of pipe (such as casing, liner, and tail pipe) in which holes or slots have been cut before it is set.

Perforating Gun
A device fitted with shaped charges or bullets that is lowered into a well and fired to create penetrating holes in casing, cement and formation.

Perforation
A hole made in the casing, cement, and formation through which formation fluids enter a wellbore. Usually several perforations are made at a time.

Permanent Packer
A nonretrievable type of packer that must be drilled or milled out for removal.

Permeability
A measure of the ease with which a fluid flows through the connecting pore spaces of a formation or cement. The unit of measurement is the millidarcy.

Petroleum
A substance occurring naturally in the earth in solid, liquid or gaseous state and composed mainly of mixtures of chemical compounds of carbon and hydrogen, with or without other nonmetallic elements.

PF
Per Foot or Power Factor

Pick Up
To use the drawworks to lift the bit (or other tool) off bottom by raising the drill stem. To use an air hoist to lift a tool, a joint of drill pipe or other piece of equipment.

Pilot
A rodlike or tubelike extension below a downhole tool, such as a mill, that serves to guide the tool into or over another downhole tool or fish.

Pilot Bit
A bit placed on a special device that serves to guide the device into an already existing hole that is to be opened (made larger in diameter).

Pilot Mill
A special mill that has a heavy tubular extension below it called a pilot or stinger. The pilot mill is designed to go inside drill pipe or tubing that is lost in the hole.

Pin
The male threaded section of a tool joint. On a bit, the threaded bit shank.

Pipe
A long, hollow cylinder, usually steel, through which fluids are conducted. Oilfield tubular goods are casing (including liners), drill pipe, tubing or line pipe.

Pipe Racks
Horizontal supports for tubular goods.

Pipe Ram
A sealing component for a blowout preventer that closes the annular space between the pipe and the blowout preventer or wellhead.

Pipe Ram Preventer
A blowout preventer that uses pipe rams as the closing elements.

Pipe Ramp
An angled ramp for dragging drill pipe, casing and other materials up to the drilling floor or bringing such equipment down. Also called pipe on rack.

Pipe Upset
That part of the pipe that has an abrupt increase of dimension.

Pipe Wiper
A flexible disk-shaped device usually made of rubber, with a hole in the center thru which drill pipe or tubing passes. It is used to wipe off any liquid from the pipe as it is pulled from the hole.

Pit Level
Height of drilling mud in the mud tanks or pits.

Pit-Level Indicator
One of a series of devices that continuously monitor the level of the drilling mud in the mud tanks.

Pitman
The arm that connects the crank to the walking beam on a pumping unit by means of which rotary motion is converted to reciprocating motion.

PJ
Pump Jack

PLATF
Platform

Plug
Any object or device that blocks a hole or passageway (such as a cement plus in a borehole).

Plug Back
To place cement in or near the bottom of a well to exclude bottom water, to sidetrack or to produce from a formation higher in the well.

Plug-Back Cementing
A secondary cementing operation in which a plug of cement is positioned at a specific point in the well and allowed to set.

Plunger
A basic component of the sucker rod pump that serves to draw well fluids into the pump. The rod that serves as a piston in a reciprocating pump.

PM
Particulate Matter

PMS
Planned Maintenance System

POB
Plug on Bottom or Pump on Beam

Pole Mast
A portable mast constructed of tubular members. A pole mast may be a single pole or a double pole.

Polished Rod
The topmost portion of a string of sucker rods. It is used for lifting fluid by the rod-pumping method.

Polymer
A substance used in the oilfield to thicken drilling fluids, fracturing fluids, acid and other liquids.

POOH
Pull Out Of Hole

Porosity
The condition of being porous (such as a rock formation). The ratio of the volume of empty space to the volume of solid rock in a formation, indicating how much fluid a rock can hold.

Portable Mast
A mast mounted on a truck and capable of being erected as a single unit.

Possum Belly
A receiving tank situated at the end of the mud return line. The flow of mud comes into the bottom of the device and travels to control mud flow over the shale shaker.

POV
Pressure Operated Valve

Power Generator Sys
A diesel, LPG, natural gas, or gasoline engine along with a mechanical transmission or generator for producing power for the drilling rig.

Power Wrench
A wrench that is used to make up or break out drill pipe, tubing or casing on which the torque is provided by air or fluid pressure.

PPG
Pounds Per Gallon

PPM
Parts Per Million

Pressure Depletion
The method of producing a gas reservoir that is not associated with a water drive. Gas is removed and reservoir pressure declines until all the recoverable gas has been expelled.

Primary Recovery
The first stage of oil production in which natural reservoir drives are used to recover oil, although some form of artificial lift may be required to exploit declining reservoir drives.

Production
The phase of the petroleum industry that deals with bringing the well fluids to the surface and separating them and storing, gauging and otherwise preparing the product for delivery.

Production Casing
The last string of casing set in a well, inside of which is usually suspended a tubing string.

Production Packer
Any packer designed to make a seal between the tubing and the casing during production.

Production Rig
A portable servicing or workover unit, usually mounted on wheels and self-propelled. A wellservicing unit consists of a hoist and engine mounted on a wheeled chassis with a self-erecting mast.

Production Test
A test of the well's producing potential usually done during the initial completion phase.

Production Tubing
A string of tubing used to produce the well.

Production Well
In fields in which improved recovery techniques are being applied, the well through which oil is produced.

Proppant
Sized particles mixed with fracturing fluid to hold fractures open after a hydraulic fracturing treatment. Sand grains, resin-coated sand or high-strength ceramic materials may also be used.

Propping Agent
A granular substance (sand grains, ect) that is carried in suspension by the fracturing fluid and that serves to keep the cracks open when fracturing fluid is withdrawn after a fracture treatment.

PSE
Pressure Safety Element

PSI
Pounds Per Square Inch

PSIA
Pounds Per Square Inch Atmospheric

Pulling Unit
A well-servicing outfit used in pulling rods and tubing from the well.

Pump
A device that increases the pressure on a fluid or raises it to a higher level.

Pump Barrel
The cylinder or liner in which the plunger of a sucker rod pump reciprocates.

Pump Jack
A surface unit similar to a pumping unit but having no individual power plant. Usually, several pump jacks are operated by pull rods or cables from one central power source.

Pump Rate
The speed, or velocity, at which a pump is run. In drilling, the pump rate is usually measured in strokes per minute.

Pump-Down
Descriptive of any tool or device that can be pumped down a wellbore. Pump-down tools are not lowered into the well on wireline; instead, they are pumped down the well with the drilling fluid.

Pumping Unit
The machine that imparts reciprocating motion to a string of sucker rods extending to the positive displacement pump at the bottom of a well.

Pup Joint
A length of drill or line pipe, tubing, or casing shorter than range 1 (18 feet or 6.26 meters for drill pipe) in length.

PV
Pressure/Vacuum

PVT
Pressure Volume Temperature

PW
Producing Wwll

PWV
Production Wing Valve

Q
Back To Top

QA
Quality Assurance

QC
Quality Control

R
Back To Top

R&D
Research and Development

R&T
Rods & Tubing

Rack
Framework for supporting or containing a number of loose objects, such as pipe. To place on a rack or to use as a rack.

Ram
The closing and sealing component on a blowout preventer. The three types are blind, pipe or shear.

Ram BOP
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.

Range of Load
In sucker rod pumping, the difference between the polished rod peak load on the upstroke and the minimum load on the downstroke.

Rate of Penetration
(ROP) A measure of the speed at which the bit drills into formations, usually expressed in feet (meters) per hour or minutes per foot (meter).

Rathole
A hole in the rig floor, some 30-40 feet (9-12 meters) deep, which is lined with casing that projects above the floor into which the kelly & swivel are placed when hoisting operations are in progress.

Rathole Connection
The addition of a length of drill pipe or tubing to the active string using the rathole instead of the mousehole, which is the more common connection.

Rathole Rig
A small, usually truck-mounted rig, used to drill ratholes for regular drilling rigs that will be moved later. It may also drill the top part of the hole before the main rig arrives on location.

RE
Reservoir Engineer

Ream
To enlarge the wellbore by drilling it again with a special bit.

Reamer
A tool used in drilling to smooth the wall of a well, enlarge the hole to the specified size, help stabilize the bit, straighten the wellbore if needed, and drill directionally.

Reciprocating Pump
A pump consisting of a piston that moves back and forth or up and down in a cylinder. The cylinder is equipped with inlet (suction) and outlet (discharge) valves.

Recompletion
After the initial completion of a well, the action and techniques of reentering the well and redoing or repairing the original completion to restore the well's productivity.

Reeve (the line)
To string a wire rope drilling line through the sheaves of the traveling and crown blocks to the hoisting drum.

Refinery
An installation that manufactures finished petroleum products from crude oil, unfinished oils, natural gas liquids, other hydrocarbons and oxygenates.

Reinjected
The forcing of gas under pressure into an oil reservoir in an attempt to increase recovery.

Reserve Tank
A special mud tank that holds mud that is not being actively circulated. A reserve tank usually contains a different type of mud from that which the pump is currently circulating.

Reserves
The unproduced but recoverable oil or gas in a formation that has been proved by production.

Reservoir
A subsurface, porous, permeable or naturally fractured rock body in which oil or gas are stored. Most reservoir rocks are limestone, dolomite, sandstone, or a combination of these.

Resistivity
A measurement of a formation's resistance to electrical current used to determine whether the formation holds hydrocarbons or water.

RF
Rig Floor

RIH
Run In Hole

RKB
Rotary Kelly Bushing (a datum for measuring depth in an oil well)

ROI
Return On Investment

ROP
Rate of Penetration

Rotary Drilling
The method of drilling oil and gas wells in which the entire drill string is rotated from the surface to turn the drill bit, and cuttings are removed from the hole by circulating fluid.

Rotary Steerable Sys
A drilling system that can perform directional drilling operations without interrupting drill string rotation, using a downhole guidance system that continually adjust the drill bit's course.

ROV
Remotely Operated Vehicle

RPM
Revolutions Per Minute

RTU
Remote Terminal Unit

Run In
To go into the hole with tubing, drill pipe, tools or other devices.

S
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Saddle
For pipe, a fitting made in parts to clamp on to a pipe to stop a leak or provide an outlet.

Safety Clamp
A clamp placed tightly around a drill collar that is suspended in the rotary table by drill collar slips.

Safety Joint
An accessory to a fishing tool, placed above it. If the tool can't be disengaged from the fish, the safety joint permits easy disengagement of the string of pipe above the safety joint.

Safety Slide
A device normally mounted near the monkey board to afford the derrickhand a means of quick exit to the surface in case of emergency.

Safety Valves
Fail-safe shut-off devices located at the surface and/or subsurface which shut off the produced flow in the event of a catastrophic event.

Sand
An abrasive material composed of small quartz grains formed from the disintegration of pre-existing rocks.

Sand Consolidation
Any one of several methods by which the loose, unconsolidated grains of a producing formation are made to adhere to prevent a well from producing sand but permit it to produce oil and gas.

Sand Control
Any method by which large amounts of sand in a sandy formation are prevented from entering the wellbore. Sand in the wellbore can cause plugging and premature wear of well equipment.

Sandfrac
Method of fracturing subsurface rock formations by injecting fluid and sand under high pressure to increase permeability. Fractures are kept open by the grains of sand.

Sandline
A wireline used on drilling rigs and well-servicing rigs to operate a swab or bailer, to retrieve cores or to run logging devices; usually 9/16 inch in diameter and several thousand feet long.

Sandstone
A sedimentary rock composed of individual mineral grains of rock fragments between 0.06 & 2 millimeters (0.002 & 0.079 inches) in diameter and cemented together by silica, calcite, iron oxide etc.

Saver Sub
An expendable substitute device made up in the drill stem to absorb much of the wear between the frequently broken joints (such as between the kelly or top drive and the drill pipe).

SBM
Synthetic Base Mud

Scale
A mineral deposit (for example, calcium carbonate) that precipitates out of water and adheres to the inside of pipes, heaters, and other equipment.

Scraper
Any device that is used to remove deposits (such as scale or paraffin) from tubing, casing, rods, flow lines or pipelines.

Scratcher
A device that is fastened to the outside of casing to remove mud cake from the wall of a hole to condition the hole for cementing.

Screening Effect
The tendency of proppants to separate from fracture fluid when the speed, or velocity, of the fluid is low.

SDV
Shut Down Valve

SEMI
Semisubmersible

Semi-Submersible Rig
A mobile offshore drilling unit that floats on the water's surface above the subsea wellhead and is anchored in place, using partially filled pontoons to steady the rig over the well.

sep
Separator

Service Company
A company that provides a specialized service, such as a well-logging service or a directional drilling service.

Service Well
A nonproducing well used for injecting liquid or gas into the reservoir for enhanced recovery.

Set Back
To place stands of drill pipe and drill collars in a vertical position to one side of the rotary table in the derrick or mast of a drilling or workover rig.

Set Casing
To run and cement casing at a certain depth in the wellbore. Sometimes called set pipe.

Shale
A fine-grained sedimentary rock composed mostly of consolidated clay or mud. Shale is the most frequently occurring sedimentary rock.

Shale Shaker
A vibrating screen used to remove cuttings from the circulating fluid in rotary drilling operations. Also called a shaker.

Shaped Charge
A small container of high explosive that is loaded into a perforating gun used to penetrate the casing, cement and formation.

SHDP
Slim Hole Drill Pipe

Shear Ram
The component in a blowout preventer that cuts, or shears through drill pipe and forms a seal against well pressure.

Shear Ram BOP
A blowout preventer that uses shear rams as closing elements.

Sheave
A grooved pulley. Also a support wheel over which tape, wire or cable rides.

Shoulder
The flat portion machined on the base of the bit shank that meets the shoulder of the drill collar and serves to form a pressure-tight seal between the bit and the drill collar.

Shut In
To close the valves on a well so that is stops production. To close in a well in which a kick has occurred.

SI
Shut In

SIBHP
Shut-In Bottomhole Pressure. The pressure at the bottom of a well when the surface valves on the well are completely closed. It is caused by formation fluids at the bottom of the well.

Sidetrack
To use a whipstock, turbodrill, or other mud motor to drill around the original planned path of the well.

Single-Pole Rig
A well-servicing unit whose mast consists of but one steel tube, usually about 65 feet (19.8 meters) long.

Sliding Sleeve
A flow-control device that can be opened or closed to allow or prevent production to flow into the well.

slur
Slurry

SNG
Synthetic Natural Gas

Snubbing
The process of removing or installing pipe into a pressurized well bore, using specialized equipment

SO2
Sulfur Dioxide

SO3
Oxides of Sulfur

SPE
Society of Petroleum Engineers

SPP
Stand Pipe Pressure

SS
Stainless Steel

SSV
Surface Safety Valve

STB
Stock Tank Barrel

Steerable Motor
A downhole motor used for directional drilling which can turn the drill bit independently of drill string rotation.

String
A length of tubulars such as drillpipe, casing or tubing composed of many individual sections that have been screwed or fastened together.

SU
Submersible

Substructure
Base of fabricated steel beams or columns that supports the working floor & mast of a drilling rig.

SW
Southwest

SWD
Salt Water Disposal

SWDW
Salt Water Disposal Well

SWE
Senior Well Engineer

Sweet
Crude oil or natural gas without appreciable amounts of sulfur or sulfur compounds.

SWL
Safe Working Load

SWU
Salt Water Unit

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

Tcf
Trillion Cubic Feet

TD
Total Depth

TDS
Total Dissolved Solids

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.

Tension-Leg Platform
An offshore drilling platform attached to the seafloor with tensioned steel tubes.

Tertiary Recovery
The use of improved recovery methods that not only restore formation pressure but also improve oil displacement or fluid flow in the reservoir.

Through-Tubing
Operations performed from inside the production tubing of an existing well.

Throw the Chain
To jump the spinning chain up from a box end tool joint so that the chain wraps around the pin end tool joint after it is stabbed into the box. The pipe is spun by a pull on the chain from the cathead

Tight Formation
A petroleum-bearing or water-bearing formation of relatively low porosity and permeability.

Tight Sand
Sand or sandstone formation with low permeability.

Tight Spot
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.

tk
Tank

TLP
Tension Leg Platform

Tongs
The large wrenches used for turning when making up or breaking out drill pipe, casing, tubing, or other pipe; also called casing tongs, rotary tongs, and so forth according to the specific use.

Top Drive
A device similar to a power swivel that is used in place of the rotary table to turn the drill stem.

Top Plug
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.

TOU
Time-Of-Use

Trailer Rig
A rig mounted on a wheeled and towed trailer. It has a mast, a rotary, and one or two engines.

Transmission
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.

Traveling Block
An assembly of sheaves mounted in a framework that allows the block to move up and down by use of the drilling line that is reeved over the crown block sheaves and through the traveling block sheaves.

Traveling Valve
One of the two valves in a sucker rod pumping system. It moves with the movement of the sucker rod string.

Trip
To remove the drill stem from the wellbore to perform one or more operations, such as changing bits, and then return the drill stem to the wellbore.

Truck-Mounted Rig
A well-servicing and workover rig that is mounted on a truck chassis.

Tubing
Pipe suspended in a well bore, inside the casing, used to produce fluid or gas from the well.

Tubing Coupling
A special connector used to connect lenghts of tubing.

Tubing Hanger
An arrangement of slips and packing rings used to suspend tubing from the tubing head.

Tubing Head
A flanged fitting that supports the tubing string, seals off pressure between the casing and the outside of the tubing, and provides a connection that supports the Christmas tree.

Tubing Pump
A sucker rod pump in which the barrel is attached to the tubing

Tubular Goods
Any kind of pipe. Oilfield tubular goods include tubing, casing, drill pipe, drill collars and line pipe. Also called tubulars.

Tungsten Carbide
A fine, very hard, gray crystalline powder, a compound of tungsten and carbon, which is bonded with cobalt or nickel in cemented carbide compositions and used for cutting tools, abrasives and dies.

Tungsten Carbide Bit
A type of roller cone bit with inserts made of tungsten carbide. Also called tungsten carbide insert bit.

TVD
True Vertical Depth

U
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UCT
Underground Construction Technology

Ultra Deepwater
Generally defined as operations in water depths of 5000 ft. or greater.

Ultrasonic Testing
Non-destructive examination of solid bodies utilizing high-frequency sound waves to find anomalies

UMV
Upper Master Valve (from a Xmas Tree)

Undergauge Bit
A bit whose outside diameter is worn to the point at which it is smaller than it was when new. A hole drilled with an undergauge bit is said to be undergauge.

Unloading a Well
Removing fluid from the tubing in a well, often by means of a swab, to lower the bottomhole pressure in the wellbore at the perforations and induce the well to flow.

Upper Kelly Cock
A valve installed above the kelly that can be closed manually to protect the rotary hose from high pressure that may exist in the drill stem.

UTFL
Ultrasonic Inspection Full Length

UV
Ultra-Violet

V
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V-Belt
A belt with a trapezoidal cross section, made to run in sheaves, or pulleys, with grooves of corresponding shape.

V-Door
An opening at floor level in a side of a derrick or mast. The V-door is opposite the drawworks and is used as an entry to bring in drill pipe, casing, and other tools from the pipe rack.

Valve
Pressure controlling equipment used to stop and seal off any flow through the bore or pipe.

VRS
Vapor Recovery System

VRU
Vapor Recovery Unit

W
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WAG
Water Alternating Gas

Wash Over
To release pipe that is stuck in the hole by running washover pipe.

Washover Pipe
An accessory used in fishing operations to go over the outside of tubing or drill pipe stuck in the hole because of cuttings, mud, and so forth, that have collected in the annulus.

Washover String
The assembly of tools run into the hole during fishing to perform a washover. A typical washover string consists of a washover back-off connector, several joints of washoverpipe, and a rotary shoe.

Water Drive
The reservoir drive mechanism in which oil is produced by the expansion of the underlying water and rock, which forces the oil into the wellbore.

Weight Indicator
A device for measuring the weight of the drill string.

Weight on Bit
The amount of downward force placed on the bit.

Well
The hole made by the drilling bit, which can be open, cased, or both. Also called borehole, hole, or wellbore.

Well Completion
The activities & methods of preparing a well for the production of oil and gas or for other purposes, such as injection.

Well Control
The methods used to control a kick and prevent a well from blowing out.

Well Fluid
The fluid, usually a combination of gas, oil, water, and suspended sediment, that comes out of a reservoir. Also called a well stream.

Well Logging
The recording of information about subsurface geologic formations, including records kept by the driller & records of mud & cutting analyses, core analysis, drill stem tests, & electric procedures.

Well Servicing
The maintenance work performed on an oil or gas well to improve or maintain the production from a formation already producing.

Well Stimulation
Any of several operations used to increase the production of a well, such as acidizing or fracturing.

Well-Servicing Rig
A portable rig, truck-mounted, trailer-mounted, or a carrier rig, consisting of a hoist and engine with a self-erecting mast. Compare workover rig.

Wellhead
That portion of the completed well at, and above, the ground surface or sea floor.

WH
Well Head

Whipstock
A long steel tool that uses an inclined plane to cause the bit to deflect from the original borehole at a slight angle.

WHM
Wellhead Maintenance

WHP
Wellhead Pressure

WI
Water Injection

Wickers
Broken or frayed strands of the steel wire that makes up the outer wrapping of wire rope.

Wildcat
A Well Drilled in an area where no oil or gas production exists.

Window
A slotted opening or a full section removed in the pipe lining (casing) of a well, usually made to permit sidetracking.

Wire Rope
A cable composed of steel wires twisted around a central core of fiber or steel wire to create a rope of great strength and considerable flexibility.

Wireline
A slender rod-like small-diameter piece of metal used to lower tools into a well.

Wireline Log
Any log that is run on wireline.

Wireline Operations
The lowering of mechanical tools, such as valves and fishing tools, into the well for various purposes.

Wireline Survey
A general term used to refer to any type of log being run in a well.

Wireline Tools
Special tools or equipment made to be lowered into and retrieved from the well on a wireline, for example, packers, swabs, gas-lift valves, measureing devices.

wkor
Workover Rig

WOB
Weight on Bit

WOE
Well Operations Engineer (a key person of well services)

Work String
In drilling, the string of drill pipe or tubing suspended in a well to which is attached a special tool or device that is used carry out a certain task, such as squeeze cementing or fishing.

Workover
Process of re-entering an existing well to perform remedial action to restore or improve production

Workover Fluid
A special drilling mud used to keep a well under control while it is being worked over. A workover fluid is compounded carefully so that it will not cause formation damage.

Workover Rig
Specialized unit that can hoist well production tubing & perform other services.

WP
Wash Pipe, Well Pad, or Working Pressure

WSS
Well Services Supervisor (leader of well services at the wellsite)

WT
Watertight

WTI
West Texas Intermediate

WY
Water Year

X
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XO
Cross-Over

Xtree
Christmas Tree

Y
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Yield Strength
When material elongates so that when stress is removed the material will not return to normal size

YP
Yield Point

Z
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ZD
Zone Description