Glossary
Browse the IADC Lexicon alphabetically or by category. Get comprehensive definitions of drilling industry terms.
Structure
Definition(s)
Structure
Structure means any fixed, moveable or floating structure or installation, and includes a greenhouse gas pipeline, greenhouse gas pumping station, greenhouse gas tank station or greenhouse gas valve station. Source: Offshore Petroleum and Greenhouse Gas Storage Act 2006, Australia, amended 2012. LegislationStructure
Structure means any fixed, moveable or floating structure or installation, and includes a petroleum pipeline, petroleum pumping station, petroleum tank station or petroleum valve station. Source: Offshore Petroleum and Greenhouse Gas Storage Act 2006, Australia, amended 2012. LegislationStructure
Organized combination of connected components designed to withstand actions and provide adequate rigidity. [ISO 19900:2002]. Source: ISO 19901-7:2013, Petroleum and natural gas industries – Specific requirements for offshore structures – Part 7: Stationkeeping systems for floating offshore structures and mobile offshore units. Global Standards Source: ISO 19900:2013, Petroleum and natural gas industries – General requirements for offshore structures. Global StandardsStructure Decommissioning
Definition(s)
Structure Decommissioning
Removal of the deck, followed by removal of the jacket. All or part of the installation is usually removed from the site for disposal, recycle, use as an artificial reef, or reuse of platform components either onshore or offshore. Source: API RP 2SIM, Structural Integrity Management of Fixed Offshore Structures, First Edition, November 2014. Global StandardsStructure Orientation
Definition(s)
Structure Orientation
position of a structure in plan referenced to a fixed direction, such as true north. Source: ISO 19900:2013, Petroleum and natural gas industries – General requirements for offshore structures. Global StandardsStructure, Wrought
Definition(s)
Structure, Wrought
One that contains no cast dendritic structure. Source: API SPEC 16RCD, Specification for Drill Through Equipment—Rotating Control Devices, Upstream Segment, First Edition, February 2005. Global StandardsStrumming
Definition(s)
Strumming
See Vortex Induced Vibration. Source: API Specification 16Q, Design, Selection, Operation, and Maintenance of Marine Drilling Riser Systems, Second Edition, April 2017. Global Standards 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 StandardsStuck Pipe
Definition(s)
Stuck pipe
A condition in which the pipe sticks or hangs while in the hole and cannot be moved. Source: API RP 54, Recommended Practice for Occupational Safety for Oil and Gas Well Drilling and Servicing Operations, Third Edition, August 1999 (2007). Global StandardsStudded Block
Definition(s)
Studded Block
A solid block of metal bored and studded to accept flanges. Used for erosion points or high stress connections. Source: IADC UBO / MPD Glossary, December 2011. Global StandardsStudded Connection
Definition(s)
Studded Connection
Flanged end or outlet connection in which thread-anchored studs screwed into tapped holes replace the holes for bolt studs. Source: API SPEC 6A, Specification for Wellhead and Christmas Tree Equipment, Twentieth Edition, October 2010 (Addendum November 2012). Global StandardsStudded Connection
Connection in which thread-anchored studs are screwed into tapped holes. Source: API Specification 16A, Specification for Drill-through Equipment, Fourth Edition, April 2017. Global Standards Source: API SPEC 16A, Specification for Drill-through Equipment, Third Edition, June 2004 (Errata/Supplement November 2004). Global StandardsSu,plugbase
Definition(s)
Su,plugbase
Undrained shear strength corresponding to the level of the sand plug base.
Source: ABS Guidance Notes on Geotechnical Performance of Spudcan Foundations, January 2017. Global StandardsSu0
Definition(s)
Su0
Undrained shear strength at the lowest depth of the maximum plan area of spudcan.
Source: ABS Guidance Notes on Geotechnical Performance of Spudcan Foundations, January 2017. Global StandardsSua
Definition(s)
Sua
Undrained shear strength averaged from (h – ht) to (h + hplug).
Source: ABS Guidance Notes on Geotechnical Performance of Spudcan Foundations, January 2017. Global StandardsSub
Definition(s)
Sub
Short, threaded piece of pipe used to connect parts for the drilling assembly for various reasons, such as crossing over to a different connection, or to save wear and tear on more expensive elements. Source: API RP 7G-2, Recommended Practice for Inspection and Classification of Used Drill Stem Elements, First Edition, August 2009. Global StandardsSub-Area
Definition(s)
Sub-Area
Sub-Area means a sub-division of a METAREA in which a number of countries have established a coordinated system for the promulgation of marine meteorological information. The delimitation of such areas is not related to and should not prejudice the delimitation of any boundaries between States. Source: IMO resolution A.1051(27), IMO/WMO Worldwide Met-Ocean Information and Warning Service ‒ Guidance Document, 20 December 2011, International Maritime Organization. Regulatory GuidanceSub-Contractor
Definition(s)
Sub-Contractor
"Sub-Contractor" means any person and/or employer (see definition of “person” and/or “employer”) who contracts to perform any part of oil and gas well drilling from contractor. Source: State of Wyoming Occupational Safety and Health Rules and Regulations for Oil and Gas Well Drilling, Revised January 8, 2013. RegulationsSubassembly
Definition(s)
Subassembly
Subordinate unit consisting of two or more components assembled for incorporation as an integral portion of a tool, which may be independently performance tested before its integration.
Source:API SPECIFICATION 19TT, Specification for Downhole Well Test Tools and Related Equipment, First Edition, October 2016. Global StandardsSubcontractor
Definition(s)
Subcontractor
Subcontractor means a person engaged (otherwise than as an employee) by any contractor or subcontractor to do for gain or reward any work the contractor or subcontractor has been engaged (as contractor or subcontractor) to do. Source: Health and Safety in Employment Act 1992, Public Act 1992 No 96, New Zealand, as of 1 July 2011. LegislationSubdivision Length (Ls)
Definition(s)
Subdivision Length (Ls)
Subdivision length (Ls) of the ship is the greatest projected moulded length of that part of the ship at or below deck or decks limiting the vertical extent of flooding with the ship at the deepest subdivision draught. <Chapter II-1, regulation 2>. Source: IMO Resolution MSC.216(82), amendments to the International Convention for the Safety of Life at Sea, 1974, as amended, 8 December 2006, International Maritime Organization. LegislationSubject
Definition(s)
Subject
An individual, process, or device causing information to flow among objects or a change to the system state. Extended Definition: An active entity. Adapted from: NIST SP 800-53 Rev 4., CNSSI 4009. Source: NICCS™ Portal Cybersecurity Lexicon, National Initiative for Cybersecurity Careers and Studies (https://niccs.us-cert.gov/glossary) as of 11 November 2015, Global StandardsSubject Matter Expert ω:
Definition(s)
Subject Matter Expert ω:
Individual with in-depth knowledge in a specific area or field. Sample Usage: A subject matter expert was consulted to inform team members on improvised nuclear devices. Annotation: Structured techniques for the elicitation of expert judgment are key tools for risk assessment. Subject matter experts are also used to supplement empirical data when needed, or to provide input on specialized subject areas for the purposes of designing and executing risk assessments. Frequently abbreviated as SME. Source: DHS Risk Lexicon, U.S. Department of Homeland Security, 2010 Edition. September 2010 Regulatory GuidanceSubject Tract
Definition(s)
Subject Tract
“Subject tract or drilling unit” means a tract upon which a person proposes to drill, reopen, deepen, plug back, or re-work a well for producing oil and natural gas. Source: Division of Mineral Resources Management - Oil and Gas, Ohio Administrative Code, Chapter 1501:9, January 2012. RegulationsSubject Tract
“Subject tract” means a tract upon which a person proposes to drill, reopen, deepen, plug back, or rework a well for the injection of fluids. Source: Division of Mineral Resources Management - Oil and Gas, Ohio Administrative Code, Chapter 1501:9, January 2012. RegulationsSubject Tract
“Subject tract” means a tract upon which a person proposes to drill, reopen, deepen, plug back, or rework a well for the injection of saltwater. Source: Division of Mineral Resources Management - Oil and Gas, Ohio Administrative Code, Chapter 1501:9, January 2012. RegulationsSubjective Probability
Definition(s)
Subjective Probability
Interpretation or estimate of probability as a personal judgment or ―degree of belief‖ about how likely a particular event is to occur, based on the state of knowledge and available evidence Sample Usage: Analysts use their knowledge of terrorist strategies, objectives, and capabilities in combination with evidence from operations to estimate a subjective probability of 10 percent for an attack to occur within the next five years. Annotation:- Like all probabilities, subjective probability is conventionally expressed on a scale from zero to one where zero indicates the event is impossible and one indicates the event has or certainly will occur.
- Within the subjective probability interpretation, it is possible to estimate probabilities of events (using experts or models) that have not previously occurred or that have only rarely occurred, such as acts of terrorism. However, because subjective probabilities incorporate historical or trial data when available, the subjective probability will approximate the frequentist probability as data becomes more plentiful.
- Subjective probability is currently one of the most common uses of probability among statisticians and the risk analysis community.
- Bayesian probability is colloquially used as a synonym for subjective probability. In statistical usage, Bayesian probabilistic inference is an approach to statistical inference that employs Bayes’ theorem to revise prior information using evidence.
Submerged Weight
Definition(s)
Submerged Weight
In-air weight minus buoyancy due to water displacement.- NOTE: 1 The submerged weight of a riser string depends on the mode of operation, i.e. connected or suspended. For a connected riser and a suspended riser, internal and external pressures act on internal and external surfaces of the pipe and buoyancy.
- NOTE: 2 For a suspended riser, pressure end loads occur at the exposed areas at the bottom of the riser string
Submerged Weight
See Apparent Weight. 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 StandardsSubmerged Weight
Submerged weight including content minus buoyancy. Source: API RP 17G, Recommended Practice for Completion/Workover Risers, Second Edition, July 2006 (Reaffirmed April 2011). Global StandardsSubmerged Weight
Weight minus buoyancy. NOTE Apparent weight is commonly referred to as weight in water, wet weight, submerged weight, or effective weight. 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 StandardsSubmerged Wetland Area
Definition(s)
Submerged Wetland Area
Submerged Wetland Area―a wetland area which is normally inundated with water and where only levee material is available for mixing with waste fluids during closure of a pit. Source: Natural Resources, Office of Conservation – General Operations, Louisiana Administrative Code, Title 43, Part XIX, March 2013. RegulationsSubmerged Zone
Definition(s)
Submerged Zone
The part of the unit which is below the splash zone, including buried parts. Source: Offshore Standard DNV-OS-C101, Design of Offshore Steel Structures, General (LRFD Method, Det Norske Veritas, April 2011. Global StandardsSubmerged Zone
That part of the external structure below the maximum design operating draught . Source: Rules and Regulations for the Classification of Mobile Offshore Units, Part 8, Corrosion Controls, June 2013, Lloyd’s Register, Global StandardsSubmersible Pump
Definition(s)
Submersible pump
Downhole submersible pumps are basically multistage progressing cavity pumps driven either by an electric motor or a hydraulic turbine. Source: API RP 17A, Design and Operation of Subsea Production Systems—General Requirements and Recommendations, Fourth Edition, Reaffirmed 2011. Global StandardsSubmit
Definition(s)
Submit (a document)
Formally transmit a document to NOPSEMA for the purpose of assessment under one of the listed laws, leading to an enforcement decision concerning its acceptability. Any other documents provided to or obtained by NOPSEMA or its OHS inspectors are not regarded as submitted and are not assessed. Source: NOPSEMA Guideline – Glossary – Regulatory Operations, N-09000-GL0326, Australia, Revision 5, December 2011. Regulatory GuidanceSubnormal Pressure
Definition(s)
Subnormal Pressure
"Subnormal pressure" means the formation pore pressure, proportional to depth, which is less than a hydrostatic pressure gradient of .465 psi/ft. Source: Corporation Commission, Oil and Gas Conservation, Oklahoma Administrative Code 165:10, February 2013. RegulationsSubrope Splicing
Definition(s)
Subrope Splicing
Subrope splicing is defined here as the replacement of one subrope for another by any means, such as overlapping, tucking, intertwining, or interbraiding. Subrope splicing should only be done to repair damage during assembly of the rope.
Source: API RP 2SM Design, Manufacture, Installation, and Maintenance of Synthetic Fiber Ropes for Offshore Mooring, Second Edition, July 2014. Global Standards