Glossary
Browse the IADC Lexicon alphabetically or by category. Get comprehensive definitions of drilling industry terms.
Electrical Classification of Areas
Definition(s)
Electrical classification of areas
For the purpose of this document, locations are classified according to API RP 500: Classification of Locations for Electrical Installations at Petroleum Facilities; or API RP 505: Classification of Locations for Electrical Installations at Petroleum Facilities Classified as Class I, Zone O, Zone 1, and Zone 2. Source: API RP 54, Recommended Practice for Occupational Safety for Oil and Gas Well Drilling and Servicing Operations, Third Edition, August 1999 (2007). Global StandardsElectrical classification of areas
Locations are classified according to API RP 500 or API RP 505. Source: API RP 74, Recommended Practice for Occupational Safety for Onshore Oil and Gas Production Operation, First Edition, October 2001 (March 2007). Global StandardsDrive Pipe
Definition(s)
Drive pipe
A relatively short string of large diameter pipe driven or forced into the ground to function as conductor pipe. Source: API RP 54, Recommended Practice for Occupational Safety for Oil and Gas Well Drilling and Servicing Operations, Third Edition, August 1999 (2007). Global Standards Source: API STD 53, Blowout Prevention Equipment Systems for Drilling Wells, Upstream Segment, Fourth Edition, November 2012. Global StandardsDrive Pipe
A relatively short string of large diameter pipe usually set in a drilled hole in onshore operations; it is normally washed, driven, or forced into the ground in bottom-supported offshore operations; sometimes referred to as structural pipe. Source: API RP 59, Recommended Practice for Well Control Operations, Second Edition, May 2006. Global StandardsDrive Pipe
A relatively short string of large diameter pipe usually set in a drilled hole in onshore operations; it is normally washed, driven, or forced into the ground in bottom-supported offshore operations; sometimes referred to as structural pipe. Source: API RP 64, Recommended Practice for Diverter Systems Equipment and Operations, Second Edition, November 2001 (March 1, 2007). Global StandardsDrive Pipe
“Drive pipe” means a casing string that is driven through unconsolidated sediment to stabilize the wellbore and isolate associated groundwater. Source: Division of Mineral Resources Management - Oil and Gas, Ohio Administrative Code, Chapter 1501:9, January 2012. RegulationsDrill String
Definition(s)
Drill string
Several sections or joints of drill pipe joined together. May also refer to sections or joints of threaded tubing or casing joined together to be used for drilling. Source: API RP 54, Recommended Practice for Occupational Safety for Oil and Gas Well Drilling and Servicing Operations, Third Edition, August 1999 (2007). Global StandardsDrill string element
Drill pipe with tool joints attached. Source: API RP 7G, Recommended Practice for Drill Stem Design and Operating Limits, Upstream Segment, Sixteenth Edition, August 1998 (Addendum 2: September 2009). Global StandardsDrill String
Several sections or joints of drill pipe with the tool joints that are joined together. Source: API RP 7G-2, Recommended Practice for Inspection and Classification of Used Drill Stem Elements, First Edition, August 2009. Global StandardsDrill Stem Test
Definition(s)
Drill Stem Test
A test taken by means of special testing equipment run into the wellbore on the drill string (work string) to determine the producing characteristics of a formation. Source: API RP 54, Recommended Practice for Occupational Safety for Oil and Gas Well Drilling and Servicing Operations, Third Edition, August 1999 (2007). Global StandardsDrill Stem Test (DST)
A test conducted to determine production flow rate and/or formation pressure prior to completing the well. Source: API RP 59, Recommended Practice for Well Control Operations, Second Edition, May 2006. Global StandardsDrill Stem Test
A procedure to determine the productive capacity, pressure, permeability or extent (or a combination of these) of a hydrocarbon reservoir. While several different proprietary hardware sets are available to accomplish this, the common idea is to isolate the zone of interest with temporary packers. Next, one or more valves are opened to produce the reservoir fluids through the drillpipe and allow the well to flow for a time. Finally, the operator kills the well, closes the valves, removes the packers and trips the tools out of the hole. The test may be short (one hour or less) or long (several days or weeks) depending on the requirements and goals. Also there might be more than one flow and pressure buildup periods. Source: IADC UBO / MPD Glossary, December 2011. Global StandardsDrill Stem Test
“Drill stem test” means a method of gathering data on the potential productivity of a formation by permitting the flow of formation fluids through the drill pipe. [Mich. Admin. Code R 408 (2013)]. Source: Oil and Gas Drilling and Servicing Operations, Michigan Administrative Code R 408, February 8, 2013. RegulationsDrill Stem
Definition(s)
Drill stem
The entire drilling assembly from the swivel to the bit composed of the kelly, drill string (work string), subs, drill collars. and other downhole tools such as stabilizers and reamers. This assembly is used to rotate the bit and carry the drilling fluid to the bit. Source: API RP 54, Recommended Practice for Occupational Safety for Oil and Gas Well Drilling and Servicing Operations, Third Edition, August 1999 (2007). Global StandardsDrill stem
All members between the swivel or top drive and the bit; includes drill string. Source: API RP 7G-2, Recommended Practice for Inspection and Classification of Used Drill Stem Elements, First Edition, August 2009. Global StandardsDrill stem
“Drill stem” means the entire drilling assembly from the swivel to the bit composed of the kelly, drill string, subs, drill collars, and other downhole tools such as stabilizers and reamers. [Mich. Admin. Code R 408 (2013)]. Source: Oil and Gas Drilling and Servicing Operations, Michigan Administrative Code R 408, February 8, 2013. RegulationsDrilling Rig
Definition(s)
Drilling Rig
Equipment and machinery assembled primarily for the purpose of drilling or boring a hole in the ground. Source: API RP 54, Recommended Practice for Occupational Safety for Oil and Gas Well Drilling and Servicing Operations, Third Edition, August 1999 (2007). Global StandardsDrilling Rig
“Drilling rig” means the plant used to make a well by boring or other means, and includes a derrick, draw-works, rotary table, mud pump, blowout preventer, accumulator, choke manifold, dependent personnel accommodation and other associated equipment, including power, control and monitoring systems (appareil de forage). Source: Atlantic Canada Offshore Petroleum Industry, Standard Practice for the Training and Qualifications of Personnel, 2013, Canadian Association of Petroleum Producers, Global Standards Source: Canada Oil and Gas Installations Regulations, SOR/96-111, Canada, current to May 1, 2014. Regulations Source: Canada Oil and Gas Installations Regulations, SOR/96-118, February 2013. Regulations Source: Nova Scotia Offshore Certificate of Fitness Regulations, SOR/95-187, Canada, current to May 31, 2012. Regulations Source: Nova Scotia Offshore Petroleum Installations Regulations, SOR/95-191, Canada, current to May 31, 2012. RegulationsDrilling Rig
“Drilling rig” means the plant and associated support equipment used to make a hole or well by boring or other means for geophysical, exploration or production purposes (appareil de forage). Source: Canada Oil and Gas Occupational Safety and Health Regulations, SOR/87-612, February 2013. Regulations Source: Nova Scotia Offshore Petroleum Occupational Health & Safety Requirements, Canada-Nova Scotia Offshore Petroleum Board, Canada, December 2000. Regulations Source: Oil and Gas Occupational Safety and Health Regulations, SOR/87-612, Canada, current to April 29, 2013. RegulationsDrilling Rig
Drilling rig In these Regulations, “drilling installation”, “drilling rig”, “drilling unit”, “drill site”, “installation”, “production installation”, “production operation”, “production site” and “subsea production system” have the same meaning as in subsection 2(1) of the Canada Oil and Gas Installations Regulations. Source: Canada Oil and Gas Drilling and Production Regulations, SOR/2009-315, February 2013. Regulations Source: Nova Scotia Offshore Petroleum Drilling and Production Regulations, SOR/2009-317, Canada, current to May 31, 2012. RegulationsDrilling Rig
“Drilling rig” means the equipment and machinery assembled primarily for the purpose of drilling or boring a hole in the ground. [Mich. Admin. Code R 408 (2013)]. Source: Oil and Gas Drilling and Servicing Operations, Michigan Administrative Code R 408, February 8, 2013. RegulationsHoisting Line
Definition(s)
Drilling (hoisting) line
The wire rope used in the rig’s main hoisting system. Source: API RP 54, Recommended Practice for Occupational Safety for Oil and Gas Well Drilling and Servicing Operations, Third Edition, August 1999 (2007). Global StandardsDrilling Line
Definition(s)
Drilling (Hoisting) Line
The wire rope used in the rig’s main hoisting system. Source: API RP 54, Recommended Practice for Occupational Safety for Oil and Gas Well Drilling and Servicing Operations, Third Edition, August 1999 (2007). Global StandardsDrilling (Hoisting) Line
“Drilling line” sometimes called a hoisting line, means the wire line used in the main rig hoisting system, one end of which is attached to the hoisting drum. This line does not include a tugger line. [Mich. Admin. Code R 408 (2013)]. Source: Oil and Gas Drilling and Servicing Operations, Michigan Administrative Code R 408, February 8, 2013. RegulationsDeadman
Definition(s)
Ground anchor (deadman)
Static holding device installed in the ground separate from the rig structure and to which guyline(s) may be attached. Source: API RP 54, Recommended Practice for Occupational Safety for Oil and Gas Well Drilling and Servicing Operations, Third Edition, August 1999 (2007). Global StandardsDriller
Definition(s)
Driller
First line supervisor whose main duties are to control the activities of his crew and to train those crew members in the proper way to perform their assigned tasks. The driller is responsible for operation of the drilling and hoisting equipment. This person is also referred to as the “crew chief” or “rig operator” in well servicing operations. Source: API RP 54, Recommended Practice for Occupational Safety for Oil and Gas Well Drilling and Servicing Operations, Third Edition, August 1999 (2007). Global StandardsMast
Definition(s)
Derrick (mast)
The steel lower component of a drilling or well servicing rig that supports the crown block, traveling block, and hoisting lines. Derricks and masts may be stationary structures normally requiring dismantling and disassembly when moved from location to location, or may be portable with the capability of being laid down and raised to and from ground level fully assembled. Source: API RP 54, Recommended Practice for Occupational Safety for Oil and Gas Well Drilling and Servicing Operations, Third Edition, August 1999 (2007). Global StandardsMast
A structural frame, extending above the machinery deck or upper-structure to which the boom support ropes are reeved Source: API RP 2D, Operation and Maintenance of Offshore Cranes, Seventh Edition, December 2014. Global StandardsMast
The tower component of a drilling or well servicing rig that supports the crown block assembly, travelling block and hoisting lines. Derricks and masts may be stationary structures normally requiring dismantling and disassembly when moved from location to location, or may be portable with the capability of being laid down and raised to and from ground level fully assembled. Source: Petroleum Safety Orders--Drilling and Production, Definitions, California Code of Regulations, 8 CCR § 6505, December 2012. RegulationsDerrick
Definition(s)
Derrick (mast)
The steel lower component of a drilling or well servicing rig that supports the crown block, traveling block, and hoisting lines. Derricks and masts may be stationary structures normally requiring dismantling and disassembly when moved from location to location, or may be portable with the capability of being laid down and raised to and from ground level fully assembled.1Source(s)
1. API RP 54, Recommended Practice for Occupational Safety for Oil and Gas Well Drilling and Servicing Operations, Third Edition, August 1999 (2007). Global Standards
Critical Equipment
Definition(s)
Critical equipment
Equipment and other systems determined to be essential in preventing the occurrence of, or mitigating the consequences of an uncontrolled event. Such equipment may include vessels, machinery, piping, blowout preventers, wellheads and related valving, flares, alarms, interlocks, fire protection equipment, and other monitoring, control, and response systems. Source: API RP 54, Recommended Practice for Occupational Safety for Oil and Gas Well Drilling and Servicing Operations, Third Edition, August 1999 (2007). Global StandardsCritical equipment
Equipment and other systems determined to be essential in preventing the occurrence of, or mitigating the consequences of an uncontrolled event. Source: API RP 74, Recommended Practice for Occupational Safety for Onshore Oil and Gas Production Operation, First Edition, October 2001 (March 2007). Global StandardsCritical equipment
Equipment and other systems determined to be essential in preventing the occurrence of or mitigating the consequences of an uncontrolled release. Such equipment may include vessels, machinery, piping, blowout preventers, wellheads and related valving, flares, alarms, interlocks, fire protection equipment and other monitoring, control and response systems. Source: API RP 75, Recommended Practice for Development of a Safety and Environmental Management Program for Offshore Operations and Facilities: Upstream Segment, Third Edition, May 2004. Global StandardsCritical equipment
Critical equipment refers to vessels, machinery, piping, alarms, interlocks, and controls determined by the management to be vital to preventing the occurrence of a catastrophic release. Source: API RP 750, Management of Process Hazards, First Edition, January 1990. Global StandardsBlowout Preventer (BOP)
Definition(s)
Blowout Preventer
Equipment installed at the wellhead to contain wellbore pressure either in the annular space between the casing and the tubulars or in an open hole during drilling, completion, testing, or workover operations.
Source: API STANDARD 16AR, Standard for Repair and Remanufacture of Drill-through Equipment, First Edition, April 2017. Global StandardsBlowout Preventer
Large, specialized valve used to seal, control, and monitor an oil and gas well. Source: API RP 16Q, Recommended Practice for Design, Selection, Operation and Maintenance of Marine Drilling Riser Systems, First Edition, November 1993 (Reaffirmed August 2001). Global StandardsBlowout Preventer
A device attached immediately above the casing, which can be closed to shut in the well. Source: API RP 16Q, Recommended Practice for Design, Selection, Operation and Maintenance of Marine Drilling Riser Systems, First Edition, November 1993 (Reaffirmed August 2001). Global Standards Source: ISO 13624-1:2009, Petroleum and natural gas industries – Drilling and production equipment – Part 1:Design and operation of marine drilling riser equipment. Global StandardsBlowout Preventer (Annular Type)
A remotely controlled device which can form a seal in the annular space around any object in the wellbore or upon itself. Compression of a reinforced elastomer packing element by hydraulic pressure effects the seal. Source: API RP 16Q, Recommended Practice for Design, Selection, Operation and Maintenance of Marine Drilling Riser Systems, First Edition, November 1993 (Reaffirmed August 2001). Global StandardsBlowout Preventer (BOP)
Device installed at the wellhead to contain well-bore pressure either in the annular space between the casing and the tubulars or in an open hole during drilling, completion, testing or workover. Source: API RP 17G, Recommended Practice for Completion/Workover Risers, Second Edition, July 2006 (Reaffirmed April 2011). Global StandardsBlowout Preventer (BOP)
A device attached to the wellhead or Christmas tree that allows the well to be closed in with or without a string of pipe or wireline in the borehole. Source: API RP 54, Recommended Practice for Occupational Safety for Oil and Gas Well Drilling and Servicing Operations, Third Edition, August 1999 (2007). Global StandardsBlowout Preventer (BOP)
A device attached to the casinghead that allows the well to be sealed to confine the well fluids to the well bore. Source: API RP 59, Recommended Practice for Well Control Operations, Second Edition, May 2006. Global StandardsBlowout Preventer
Equipment installed at the wellhead or wellhead assemblies to contain wellbore fluids, either in the annular space between the casing and the tubulars or in an open hole during drilling, completion, testing, or workover operations. Source: API Specification 16A, Specification for Drill-through Equipment, Fourth Edition, April 2017. Global StandardsBlowout Preventer (BOP)
Equipment installed on the wellhead or wellhead assemblies to contain wellbore fluids either in the annular space between the casing and the tubulars, or in an open hole during well drilling, completion and testing operations.- NOTE: BOPS are not: gate valves, workover/ intervention control packages, subsea shut-in devices, well control components (per API 16ST), intervention control packages, diverters, rotating heads, rotating circulating devices, capping stacks, snubbing or stripping packages, or non-sealing rams.
- Source: API Specification 16Q, Design, Selection, Operation, and Maintenance of Marine Drilling Riser Systems, Second Edition, April 2017. Global Standards
Blowout Preventer (BOP)
Equipment (or valve) installed at the wellhead to contain wellbore pressure either in the annular space between the casing and the tubulars or in an open hole during drilling, completion, testing or workover operations. Source: API SPEC 16A, Specification for Drill-through Equipment, Third Edition, June 2004 (Errata/Supplement November 2004). Global StandardsBlowout Preventer (BOP)
A device attached to the casing head that allows the well to be sealed to confine the well fluids in the wellbore. Refer to API RP 53 or other relevant standards for further information. Source: API STD 65 – Part 2, Isolating Potential Flow Zones During Well Construction, Upstream Segment, Second Edition, December 2010. Global StandardsBlowout Preventer (BOP)
“Blowout preventer” means a casing-head control fitted with special gates or rams that can be closed around the drill pipe and completely close the top of the casing if the pipe is withdrawn (dispositif anti-éruption). Source: Canada Oil and Gas Drilling and Production Regulations, C.R.C., c. 1517, February 2013. RegulationsBlowout Preventer
"Blowout preventer" means a heavy casinghead control fitted with special gates and/or rams which can be closed around the drill pipe or which completely closes the top of the casing. Source: Corporation Commission, Oil and Gas Conservation, Oklahoma Administrative Code 165:10, February 2013. RegulationsBlowout Preventer (Annular Type)
Remotely controlled device which can form a seal in the annular space around any object in the wellbore or upon itself. NOTE Compression of a reinforced elastomer packing element by hydraulic pressure effects the seal. Source: ISO 13624-1:2009, Petroleum and natural gas industries – Drilling and production equipment – Part 1:Design and operation of marine drilling riser equipment. Global StandardsBlowout Preventer
“Blowout preventer” means a device attached to the wellhead that allows the well to be sealed to confine the well fluids in the wellbore. Source: Oil and Gas Drilling and Servicing Operations, Michigan Administrative Code R 408, February 8, 2013. RegulationsBlowout Preventer
A device attached to a casing head that allows the well to be sealed to confine the well fluid in the well bore. Source: Petroleum Safety Orders--Drilling and Production, Definitions, California Code of Regulations, 8 CCR § 6505, December 2012. RegulationsAuthorized Person
Definition(s)
Authorized person
A person assigned by an employer to perform or supervise the performance of a specific type of duty or duties at the work site. Source: API RP 54, Recommended Practice for Occupational Safety for Oil and Gas Well Drilling and Servicing Operations, Third Edition, August 1999 (2007). Global StandardsAuthorized person
A qualified person assigned by an employer to perform or supervise the performance of a specific type of duty or duties at the work site. Source: API RP 74, Recommended Practice for Occupational Safety for Onshore Oil and Gas Production Operation, First Edition, October 2001 (March 2007). Global StandardsAcidizing
Definition(s)
Acidizing
“Acidizing” means the act of pumping an acidic solution into a wellbore to remove any materials from the perforations, pipe, and walls of the producing formation and includes the act of pumping the substance into formations to improve permeability. Source: Oil and Gas Drilling and Servicing Operations, Michigan Administrative Code R 408, February 8, 2013. RegulationsAcidizing
The act of pumping an acidic solution into a wellbore to remove materials from the perforations, pipe, and walls of the producing formation or pumping the solution into formations to improve permeability. Source: API RP 54, Recommended Practice for Occupational Safety for Oil and Gas Well Drilling and Servicing Operations, Third Edition, August 1999 (2007). Global StandardsHole
Definition(s)
Hole
Common term that usually refers to the wellbore.1Source(s)
1. API RP 54, Recommended Practice for Occupational Safety for Oil and Gas Well Drilling and Servicing Operations, Third Edition, August 1999 (2007). Global Standards