Glossary
Browse the IADC Lexicon alphabetically or by category. Get comprehensive definitions of drilling industry terms.
Angle Beam
Definition(s)
Angle Beam
Term used to describe an angle of incidence or refraction other than normal to the surface of the test object. This includes shear waves and longitudinal (compression) waves. Source: API RP 5A5, Field Inspection of New Casing, Tubing, and Plain-end Drill Pipe, Reaffirmed August 2010. Global StandardsAmpere
Definition(s)
Ampere (A, I or amp)
Unit of electrical current. Source: API RP 5A5, Field Inspection of New Casing, Tubing, and Plain-end Drill Pipe, Reaffirmed August 2010. Global StandardsAlternating Current
Definition(s)
Alternating Current (AC)
Current that reverses its direction of flow at regular intervals. Source: API RP 5A5, Field Inspection of New Casing, Tubing, and Plain-end Drill Pipe, Reaffirmed August 2010. Global StandardsHigh Degree of Workmanship
Definition(s)
High Degree of Workmanship
Because of the difficulty in defining "well-contoured" and "high degree of workmanship", the owner's discretion shall govern (only with respect to the contour of the grind). Source: API RP 5A5, Field Inspection of New Casing, Tubing, and Plain-end Drill Pipe, Reaffirmed August 2010. Global StandardsPurge Gas
Definition(s)
Purge Gas
Flammable gas or noncondensable inert gas added to the flare header to mitigate air ingress and burnback.
Source: API STD 521, Pressure-relieving and Depressuring Systems, Sixth Edition, January 2014. Global StandardsPurge Gas
Fuel gas or non-condensable inert gas added to the flare header to mitigate air ingress and burnback. Source: API STD 521, Pressure-relieving and Depressuring Systems, Fifth Edition, January 2007 (Addendum May 2008). Global StandardsPurge Gas
"Purge gas" means gas used to maintain forward flow and positive pressure in a safety flare system. Source: Alaska Oil and Gas Conservation Commission, Definitions, Alaska Admin. Code tit. 20, § 25.990, December 7, 2012. RegulationsWell-Contoured
Definition(s)
Well-Contoured
Because of the difficulty in defining "well-contoured" and "high degree of workmanship", the owner's discretion shall govern (only with respect to the contour of the grind). Source: API RP 5A5, Field Inspection of New Casing, Tubing, and Plain-end Drill Pipe, Reaffirmed August 2010. Global StandardsPressure Tank or Process Vessel
Definition(s)
Pressure Tank or Process Vessel
Tank or vessel used for an integrated operation in petrochemical facilities, refineries, gas plants, oil and gas production facilities, and other facilities. cf. storage tank (3.74). NOTE A process tank or vessel used for an integrated operation can involve, but is not limited to, preparation, separation, reaction, surge control, blending, purification, change in state, energy content, or composition of a material. Source: API STD 521, Pressure-relieving and Depressuring Systems, Fifth Edition, January 2007 (Addendum May 2008). Global StandardsVTI
Definition(s)
VTI
Visual thread inspection. Source: API RP 5A5, Field Inspection of New Casing, Tubing, and Plain-end Drill Pipe, Reaffirmed August 2010. Global StandardsUTW
Definition(s)
UTW
Ultrasonic inspection, weld line. Source: API RP 5A5, Field Inspection of New Casing, Tubing, and Plain-end Drill Pipe, Reaffirmed August 2010. Global StandardsUTFL
Definition(s)
UTFL
Full-length ultrasonic inspection. Source: API RP 5A5, Field Inspection of New Casing, Tubing, and Plain-end Drill Pipe, Reaffirmed August 2010. Global StandardsUT
Definition(s)
UT
Ultrasonic testing. Source: API STANDARD 16AR, Standard for Repair and Remanufacture of Drill-through Equipment, First Edition, April 2017. Global Standards Source: API Standard 2RD, Dynamic Risers for Floating Production Systems, Second Edition, September 2013. Global Standards Source: API RP 5A5, Field Inspection of New Casing, Tubing, and Plain-end Drill Pipe, Reaffirmed August 2010. Global Standards Source: API RP 2SIM, Structural Integrity Management of Fixed Offshore Structures, First Edition, November 2014. Global Standards Source: API RP 8B, Recommended Practice for Procedures for Inspections, Maintenance, Repair and Remanufacture of Hoisting Equipment, Seventh Edition, March 2002 (Reaffirmed: August 2012). Global Standards Source: API RP 17G, Recommended Practice for Completion/Workover Risers, Second Edition, July 2006 (Reaffirmed April 2011). Global Standards Source: API SPEC 5CRA, Specification for Corrosion Resistant Alloy Seamless Tubes for Use as Casing, Tubing and Coupling Stock, Upstream Segment, First Edition, February 2010 (Errata August 2011). Global Standards Source: API SPEC 5CT, Specification for Casing and Tubing, Upstream Segment, Ninth Edition, July 2011 (Errata September 2012). Global Standards Source: API SPEC 5DP, Specification for Drill Pipe, First Edition, August 2009. Global Standards Source: API SPEC 7-1, Specification for Rotary Drill Stem Elements, First Edition, March 2006 (Addendum April 2011). Global Standards Source: API SPEC 17E, Specification for Subsea Umbilicals, Upstream Segment, Fourth Edition, October 2010. Global Standards Source: Rules for Classification – Offshore units, DNVGL-OU-0101, Offshore drilling and support units, DNV GL, July 2015. Global StandardsUT
Ultrasonic inspection. Source: API RP 7G-2, Recommended Practice for Inspection and Classification of Used Drill Stem Elements, First Edition, August 2009. Global StandardsUT
Usability Testing. Source: IMO MSC.1/Circ.1512, Guideline on Software Quality Assurance and Human-Centred Design for e-navigation, 8 June 2015, International Maritime Organization. Regulatory GuidanceUT
Evaluation methods and techniques used to support Human-Centred Design (HCD) and used for the purpose of increasing the usability of a system. Source: IMO MSC.1/Circ.1512, Guideline on Software Quality Assurance and Human-Centred Design for e-navigation, 8 June 2015, International Maritime Organization. Regulatory GuidanceUCMPI
Definition(s)
UCMPI
Unattached coupling magnetic particle inspection. Source: API RP 5A5, Field Inspection of New Casing, Tubing, and Plain-end Drill Pipe, Reaffirmed August 2010. Global StandardsTESTED
Definition(s)
TESTED
Hydrostatically pressure-tested. Source: API RP 5A5, Field Inspection of New Casing, Tubing, and Plain-end Drill Pipe, Reaffirmed August 2010. Global StandardsT&C
Definition(s)
T&C
Threaded and coupled. Source: API RP 5A5, Field Inspection of New Casing, Tubing, and Plain-end Drill Pipe, Reaffirmed August 2010. Global Standards Source: API RP 5C5, Recommended Practice on Procedures for Testing Casing and Tubing Connections, Third Edition, July 2003 (Reaffirmed August 2010). Global Standards Source: API SPEC 5CT, Specification for Casing and Tubing, Upstream Segment, Ninth Edition, July 2011 (Errata September 2012). Global StandardsPressure-Relief Valve
Definition(s)
Pressure-Relief Valve
A flow-control device installed as part of the circulating system able to open and shut in response to operating conditions in order to maintain preset limits for pressure applied to parts of the circulating system to prevent over pressurization.
Source: ABS Guide for Classification and Certification of Managed Pressure Drilling Systems, September 2017. Global StandardsPressure-Relief Valve
Valve designed to open and relieve excess pressure and to reclose and prevent the further flow of fluid after normal conditions have been restored.- NOTE: Other terms used for pressure-relief valve (PRV) include pressure safety valve (PSV), relief valve, safety valve, and safety relief valve.
Pressure Relief Valve (PRV)
A valve that opens automatically to relieve the line pressure that is above the safe operating limit. Source: IADC UBO / MPD Glossary, December 2011. Global StandardsPressure-Relief Valve
Valve designed to open and relieve excess pressure and to reclose and prevent the further flow of fluid after normal conditions have been restored.- NOTE: In ISO 4126-1, this is termed a safety valve.
STC
Definition(s)
STC
Short round thread casing connection. Source: API RP 5A5, Field Inspection of New Casing, Tubing, and Plain-end Drill Pipe, Reaffirmed August 2010. Global StandardsSMLS
Definition(s)
SMLS
Seamless casing or tubing (including attached couplings). Source: API RP 5A5, Field Inspection of New Casing, Tubing, and Plain-end Drill Pipe, Reaffirmed August 2010. Global StandardsSEA
Definition(s)
SEA
End area inspection (formerly called special end area inspection). Source: API RP 5A5, Field Inspection of New Casing, Tubing, and Plain-end Drill Pipe, Reaffirmed August 2010. Global StandardsPTL
Definition(s)
PTL
Perfect thread length. Source: API RP 5A5, Field Inspection of New Casing, Tubing, and Plain-end Drill Pipe, Reaffirmed August 2010. Global StandardsOCTG
Definition(s)
OCTG
Oil country tubular goods. Source: API RP 5A5, Field Inspection of New Casing, Tubing, and Plain-end Drill Pipe, Reaffirmed August 2010. Global Standards Source: API RP 5C5, Recommended Practice on Procedures for Testing Casing and Tubing Connections, Third Edition, July 2003 (Reaffirmed August 2010). Global StandardsNU
Definition(s)
NU
Non-upset tubing connection. Source: API RP 5A5, Field Inspection of New Casing, Tubing, and Plain-end Drill Pipe, Reaffirmed August 2010. Global StandardsNU
API Spec 5B non-upset tubing connection. Source: API SPEC 5CT, Specification for Casing and Tubing, Upstream Segment, Ninth Edition, July 2011 (Errata September 2012). Global StandardsPressure-Design Code
Definition(s)
Pressure-Design Code
Standard to which the equipment is designed and constructed.- EXAMPLE ASME Boiler and Pressure Vessel Code, Section VIII: Rules for Construction of Pressure Vessels
Pressure-Design Code
Standard to which the equipment is designed and constructed.- EXAMPLE ASME Section VIII, Division 1 [20].
Pool Fire
Definition(s)
Pool Fire
Burning pool of liquid. Source: API STD 521, Pressure-relieving and Depressuring Systems, Sixth Edition, January 2014. Global Standards Source: API STD 521, Pressure-relieving and Depressuring Systems, Fifth Edition, January 2007 (Addendum May 2008). Global StandardsPool Fire
Turbulent diffusion fire burning above a horizontal pool of vaporizing hydrocarbon fuel under conditions where the fuel has zero or very low initial momentum. Source: ISO 13702:2015, Petroleum and natural gas industries — Control and mitigation of fires and explosions on offshore production installations — Requirements and guidelines, Second Edition, August 2015. Global StandardsPin Device
Definition(s)
Pin Device
Non-reclosing pressure-relief device actuated by static pressure and designed to function by buckling or breaking a pin that holds a piston or a plug in place; upon buckling or breaking of the pin, the piston or plug instantly moves to the fully open position. Source: API STD 521, Pressure-relieving and Depressuring Systems, Fifth Edition, January 2007 (Addendum May 2008). Global StandardsPilot Burner
Definition(s)
Pilot Burner
Small, continuously operating burner that provides ignition energy to light the flared gases. Source: API STD 521, Pressure-relieving and Depressuring Systems, Fifth Edition, January 2007 (Addendum May 2008). Global StandardsOverpressure (Relieving Device)
Definition(s)
Overpressure (Relieving Device)
Pressure increase over the set pressure of a relieving device.- NOTE: In the latter context, overpressure is the same as accumulation (3.1) only when the relieving device is set to open at the MAWP of the vessel.
Overpressure (Relieving Device)
Pressure increase over the set pressure of a relieving device.- NOTE: In the context of a relieving device, overpressure is the same as accumulation (3.1.1) only when the relieving device is set to open at the MAWP of the vessel.