Glossary
Browse the IADC Lexicon alphabetically or by category. Get comprehensive definitions of drilling industry terms.
Substructure
Definition(s)
Substructure
Structure on which the derrick sits. The substructure may provide space for wellhead and well control equipment. Source: API RP 54, Recommended Practice for Occupational Safety for Oil and Gas Well Drilling and Servicing Operations, Third Edition, August 1999 (2007). Global StandardsSubstructure
“Substructure” means a structure that surrounds the wellbore at the surface and provides the working area for certain employees. It may contain the rotary table. [Mich. Admin. Code R 408 (2013)]. Source: Oil and Gas Drilling and Servicing Operations, Michigan Administrative Code R 408, February 8, 2013. RegulationsSubstructure
Refer to Drill Floor Substructure. Source: API RP 64, Recommended Practice for Diverter Systems Equipment and Operations, Second Edition, November 2001 (March 1, 2007). 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 StandardsStrand
Definition(s)
Strand
The largest component of the rope, which is twisted, braided, or otherwise assembled together to form the finished rope, and which is formed by twisting or otherwise assembling rope yarns together, generally with an opposite twist direction to that of the yarns. Source: API RP 2SM Design, Manufacture, Installation, and Maintenance of Synthetic Fiber Ropes for Offshore Mooring, Second Edition, July 2014. Global Standards Source: API RP 2SM, Design, Manufacture, Installation, and Maintenance of Synthetic Fiber Ropes for Offshore Mooring, First Edition, July 2014. Global StandardsStrand
Several round or shaped wires helically laid about an axis. Source: API RP 54, Recommended Practice for Occupational Safety for Oil and Gas Well Drilling and Servicing Operations, Third Edition, August 1999 (2007). Global StandardsStand of Pipe
Definition(s)
Stand of pipe
One, two, or three joints of pipe screwed together, and sometimes referred to as a single, double, or triple, respectively. Source: API RP 54, Recommended Practice for Occupational Safety for Oil and Gas Well Drilling and Servicing Operations, Third Edition, August 1999 (2007). Global StandardsStabbing Board
Definition(s)
Stabbing Board
A platform in the derrick on which personnel work while casing is being run to aid in guiding a tubular joint into another tubular joint for makeup. Source: API RP 54, Recommended Practice for Occupational Safety for Oil and Gas Well Drilling and Servicing Operations, Third Edition, August 1999 (2007). Global StandardsStabbing Board
A readily movable platform used in the derrick or on a mast which workmen stand on to perform work of a temporary nature and not normally performed from a fixed inside derrick platform or monkey board, or a fixed working platform on a mast. Source: Petroleum Safety Orders--Drilling and Production, Definitions, California Code of Regulations, 8 CCR § 6505, December 2012. RegulationsStabbing Board
“Stabbing board” means a temporary elevated platform erected in a derrick mast. [Mich. Admin. Code R 408 (2013)]. Source: Oil and Gas Drilling and Servicing Operations, Michigan Administrative Code R 408, February 8, 2013. RegulationsSnubbing
Definition(s)
Snubbing
Pulling or running pipe under pressure through a sealing element where special equipment is used to apply external force to push the pipe into the well, or to control the pipe movement out of the well. Source: API RP 54, Recommended Practice for Occupational Safety for Oil and Gas Well Drilling and Servicing Operations, Third Edition, August 1999 (2007). Global StandardsSnubbing
Conducting tripping operations when the force acting on the drill string or coiled tubing from the wellbore pressure equals or exceeds the drill string or coiled tubing weight. Source: IADC UBO / MPD Glossary, December 2011. Global StandardsSnubbing
“Snubbing” means pulling or running pipe under pressure through a resilient sealing element where special equipment is used to apply external force to push the pipe into the well or to control the pipe movement out of the well. [Mich. Admin. Code R 408 (2013)]. Source: Oil and Gas Drilling and Servicing Operations, Michigan Administrative Code R 408, February 8, 2013. RegulationsSnubbing
Snubbing units as mentioned in the last subsection, means mobile units that are installed so that forces are transferred directly to the wellhead. Source: Guidelines Regarding the Facilities Regulations, Norway, updated December 2012. Regulatory GuidanceSnubbing
Intervention using jointed pipe and where the primary well control is at surface. Source: NORSOK D-002, Well intervention equipment, Rev. 2, June 2013. Global StandardsSingle
Definition(s)
Single
One joint of drill pipe, rod, or other tubular goods. Source: API RP 54, Recommended Practice for Occupational Safety for Oil and Gas Well Drilling and Servicing Operations, Third Edition, August 1999 (2007). Global StandardsSimultaneous Operations
Definition(s)
Simultaneous operations
Two or more of the following activities: production, drilling, completion, workover, wireline (except routine operations), and major construction 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 StandardsSimultaneous operations
Two or more of the following activities being performed in close proximity: production, drilling, completion, workover, wireline (except routine operations), major construction operations, well testing and maintenance. Source: API RP 74, Recommended Practice for Occupational Safety for Onshore Oil and Gas Production Operation, First Edition, October 2001 (March 2007). Global StandardsSimultaneous operations
Two or more of the following activities: production, drilling, completion, workover, wireline (except routine operations as defined in 30 CFR 250.91), and major construction operations. 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 StandardsSimultaneous operations
Two or more independent operations (such as drilling, workover, wire!ine, facilities construction, etc.) conducted under common operational control in which the activities of any one operation may impact the safety of personnel, equipment and/or the environment of the other(s). NOTE Failure to coordinate can result in the potential clash of activities that can cause an undesired event or set of circumstances. Source: API Bulletin 97, Well Construction Interface Document Guidelines, First Edition, December 2013. Global StandardsStabbing Valve
Definition(s)
Safety valve (stabbing valve)
A full opening valve available for quick installation in the pipe string to prevent flow. Source: API RP 54, Recommended Practice for Occupational Safety for Oil and Gas Well Drilling and Servicing Operations, Third Edition, August 1999 (2007). Global StandardsSafety Valve
Definition(s)
Safety Valve
Spring-loaded pressure-relief valve actuated by the static pressure upstream of the valve and characterized by rapid opening or pop action.- NOTE: A safety valve is normally used with compressible fluids.
Safety Valve (stabbing valve)
A full opening valve available for quick installation in the pipe string to prevent flow. Source: API RP 54, Recommended Practice for Occupational Safety for Oil and Gas Well Drilling and Servicing Operations, Third Edition, August 1999 (2007). Global StandardsSafety Valve
“Safety valve” means a valve available for quick installation in the pipe string to prevent flow. [Mich. Admin. Code R 408 (2013)]. Source: Oil and Gas Drilling and Servicing Operations, Michigan Administrative Code R 408, February 8, 2013. RegulationsSucker Rod
Definition(s)
Rod (sucker rod)
A length of steel, aluminum, fiberglass, or other suitable material, a number of which are screwed together to make up the mechanical link (rod string) from the surface pumping unit to the pump in the well. Source: API RP 54, Recommended Practice for Occupational Safety for Oil and Gas Well Drilling and Servicing Operations, Third Edition, August 1999 (2007). Global StandardsSulfur Dioxide
Definition(s)
Sulfur dioxide
Chemical formula is SO2. A toxic product of combustion of hydrogen sulfide, normally heavier than air. CAUTION: Inhalation at certain concentrations can lead to injury or death. Refer to Appendix B. Source API RP 49, Recommended Practice for Drilling and Well Servicing Operations Involving Hydrogen Sulfide, Third Edition, May 2001. Global StandardsSpecial Operations
Definition(s)
Special operations
Any service performed on or in a well other than the normal drilling or service operations that are accomplished in their entirety by a drilling or servicing rig. Source: API RP 49, Recommended Practice for Drilling and Well Servicing Operations Involving Hydrogen Sulfide, Third Edition, May 2001. Global StandardsSO2
Definition(s)
SO2
Sulfur dioxide. Source: API RP 49, Recommended Practice for Drilling and Well Servicing Operations Involving Hydrogen Sulfide, Third Edition, May 2001. Global Standards Source: Resolution MEPC.184(59), 2009 Guidelines for exhaust gas cleaning systems, 17 July 2009, International Maritime Organization. Regulatory GuidanceShould
Definition(s)
Should
For the purposes of this publication, the term should denotes a RP a) where a safe comparable alternative practice is available; b) that may be impractical under certain circumstances; or c) that may be unnecessary under certain circumstances or applications. This word indicates that the rule is a recommendation, the advisability of which depends on the facts in each situation. Sources: API RP 2D, Operation and Maintenance of Offshore Cranes, Sixth Edition, May 2007. Global StandardsShould
As used in a standard, “should” denotes a recommendation or that which is advised but not required in order to conform to the specification. Sources: API RP 17L2, Recommended Practice for Flexible Pipe Ancillary Equipment, First Edition, March 2013. Global Standards Sources: API RP 13C, Recommended Practice on Drilling Fluids Processing Systems Evaluation, Upstream Segment, Fourth Edition, December 2010. Global StandardsShould
“Should” is used to state that a provision is not mandatory, but is recommended as good practice. Sources: API RP 17L2, Recommended Practice for Flexible Pipe Ancillary Equipment, First Edition, March 2013. Global StandardsShould
Denotes a “recommended practice(s)”- Where a safe comparable alternative practice(s) is available;
- That may be impractical under certain circumstances; or
- That may be unnecessary under certain circumstances.
Should
Denotes a recommended practice:- Where a safe comparable alternative practice is available;
- That may be impractical under certain circumstances: or
- That may be unnecessary for personnel safety under certain circumstances.
Should
Denotes a recommended practice(s) a) where a safe comparable alternative practice(s) is available; b) that may be impractical under certain circumstances; or c) that may be unnecessary under certain circumstances or applications. Sources: API RP 59, Recommended Practice for Well Control Operations, Second Edition, May 2006. Global StandardsShould
As used in a standards, “should” denotes a recommendation or that which is advised but not required in order to conform to the specification. Sources: API RP 67, Recommended Practice for Oilfield Explosives Safety, Upstream Segment, Second Edition, May 2007. Global StandardsShould
For the purpose of this document, should denotes a recommended practice(s)- Where a safe comparable alternative practice(s) is available;
- That may be impractical under certain circumstances; or
- That may be unnecessary for personnel safety under certain circumstances.
Should
The term “should” denotes a recommendation or that which is advised but not required in order to conform to the recommended practice. Sources: API RP 96, Deepwater Well Design and Construction, First Edition, March 2013. Global StandardsShould
SHOULD is used to indicate that a provision is not mandatory, but RECOMMENDED as good practice. Sources: 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 Sources: API SPEC 5DP, Specification for Drill Pipe, First Edition, August 2009. Global StandardsShould
As used in a standard, “should” denotes a recommendation or that which is advised but not required in order to conform to the specification. Sources: 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 Sources: API SPEC 5CT, Specification for Casing and Tubing, Upstream Segment, Ninth Edition, July 2011 (Errata September 2012). Global Standards Sources: API SPEC 17D, Design and Operation of Subsea Production Systems—Subsea Wellhead and Tree Equipment, Upstream Segment, Second Edition May 2011 (Errata September 2011). Global StandardsShould
Should: As used in a standard, "should" denotes a recommendation or that which is advised but not required in order to conform to the specification. Sources: API SPEC 6A, Specification for Wellhead and Christmas Tree Equipment, Twentieth Edition, October 2010 (Addendum November 2012). Global Standards Sources: API SPEC 10A, Specification for Cements and Materials for Well Cementing, Twenty-fourth Edition, December 2010. Global Standards Sources: API SPEC 11D1, Packers and Bridge Plugs, Upstream Segment, Second Edition, July 2009. Global Standards Sources: API SPEC 13A, Specification for Drilling Fluids Materials, Eighteenth Edition, February 2010. Global Standards Sources: API SPEC 17E, Specification for Subsea Umbilicals, Upstream Segment, Fourth Edition, October 2010. Global StandardsShould
Refers to a recommended method which provides an example of how an operator can meet an expectation, but does not prevent an operator from selecting alternative best practices. Source: Incident Reporting and Investigation Guidelines, The Canada-Nova Scotia Offshore Petroleum Board and Canada-Newfoundland and Labrador Offshore Petroleum Board, Canada, November 30, 2012. Regulatory GuidanceShould
Indicates a recommendation that a certain course of action is preferred or particularly suitable. Alternative courses of action are allowable under the standard where agreed between contracting parties but shall be justified and documented. Sources: Offshore Standard DNV-OS-C101, Design of Offshore Steel Structures, General (LRFD Method, Det Norske Veritas, April 2011. Global StandardsShould
"Should" means recommended. Sources: State of Wyoming Occupational Safety and Health Rules and Regulations for Oil and Gas Well Drilling, Revised January 8, 2013. RegulationsShould
“Should”, means the authorities' recommended way of fulfilling the functional requirement. Alternative solutions with documented corresponding functionality and quality can be used without having to present this to the authorities. Source: Guidelines Regarding the Framework Regulations, Norway, updated December 2012. Regulatory GuidanceShould
Verbal form used to indicate that among several possibilities one is recommended as particularly suitable, without mentioning or excluding others, or that a certain course of action is preferred, but not necessarily required. Source: NORSOK D-002, Well intervention equipment, Rev. 2, June 2013. Global StandardsShould
Should is a recommendation. Alternative solutions having the same functionality and quality are acceptable. Source: NORSOK D-007, Well Testing Systems, Rev. 1, January 1996. Global StandardsShould
Indicates a preferred course of action or recommended practice to be adopted. Source: Approved Code of Practice for Managing Hazards to Prevent Major Industrial Accidents, Health and Safety in Employment Act 1992, Department of Labour, New Zealand, July 1994. Regulatory GuidanceShould
verbal form used to indicate that among several possibilities one is recommended as particularly suitable, without mentioning or excluding others, or that a certain course of action is preferred but not necessarily required . Source: Rules for Classification and Construction, IV Industrial Services, 6 Offshore Technology, 9 Guideline for Personnel Transfers by Means of Lifting Appliances, Edition 2011, Germanischer Lloyd SE, Global StandardsShould
Indicates that among several possibilities, one is recommended as particularly suitable, without mentioning or excluding others, or that a certain course of action is preferred but not necessarily required. Other possibilities may be applied subject to agreement. Source: Verification of Lifting Appliances for the Oil and Gas Industry, DNV-OSS-308, October 2010, Det Norske Veritas AS, Global StandardsSTEL
Definition(s)
Short term exposure limit (STEL)
A 15-minute TWA exposure that should not be exceeded at any time during a workday. Source: API RP 49, Recommended Practice for Drilling and Well Servicing Operations Involving Hydrogen Sulfide, Third Edition, May 2001. Global StandardsSTEL
short-term exposure limit. Source: API RP 98, Personal Protective Equipment Selection for Oil Spill Responders, First Edition, August 2013. Global StandardsSTEL
Fifteen-minute TWA exposure limit that shall not be exceeded at any time during a workday unless another time limit is established. Source: API RP 98, Personal Protective Equipment Selection for Oil Spill Responders, First Edition, August 2013. Global StandardsShort Term Exposure Limit
Definition(s)
Short term exposure limit (STEL)
A 15-minute TWA exposure that should not be exceeded at any time during a workday. Source: API RP 49, Recommended Practice for Drilling and Well Servicing Operations Involving Hydrogen Sulfide, Third Edition, May 2001. Global StandardsShelter-in-place
Definition(s)
Shelter-in-place
The concept of providing the public protection from exposure to toxic gas or vapor releases to the environment by having residents stay indoors until emergency evacuators arrive or the emergency is over. Source: API RP 49, Recommended Practice for Drilling and Well Servicing Operations Involving Hydrogen Sulfide, Third Edition, May 2001. Global StandardsSERC
Definition(s)
SERC
State Emergency Response Commission. Source: API RP 49, Recommended Practice for Drilling and Well Servicing Operations Involving Hydrogen Sulfide, Third Edition, May 2001. Global StandardsSCF
Definition(s)
SCF
"Scf" means standard cubic feet. Source: Alaska Oil and Gas Conservation Commission, Definitions, Alaska Admin. Code tit. 20, § 25.990, December 7, 2012. RegulationsSCF
Stress concentration factor. Source: API Technical Report 17TR7, Verification and Validation of Subsea Connectors, 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 17G, Recommended Practice for Completion/Workover Risers, Second Edition, July 2006 (Reaffirmed April 2011). Global Standards Source: API SPEC 17D, Design and Operation of Subsea Production Systems—Subsea Wellhead and Tree Equipment, Upstream Segment, Second Edition May 2011 (Errata September 2011). Global Standards Source: ISO 19905-1:202, Petroleum and natural gas industries – Site-specific assessment of mobile offshore units – Part 1: Jack-ups. Global Standards Source: Offshore Standard DNV-OS-C101, Design of Offshore Steel Structures, General (LRFD Method, Det Norske Veritas, April 2011. Global Standards Source: Rules for Classification – Offshore units, DNVGL-OU-0101, Offshore drilling and support units, DNV GL, July 2015. Global Standards Source: Verification of Lifting Appliances for the Oil and Gas Industry, DNV-OSS-308, October 2010, Det Norske Veritas AS, Global StandardsSCF
Equal to the local peak stress in a component (including welds) divided by the nominal stress in the component cross-section at the location of the local peak stress
Source: API Technical Report 17TR7, Verification and Validation of Subsea Connectors, First Edition, April 2017. Global StandardsSCF
Standard cubic feet. Source: API RP 49, Recommended Practice for Drilling and Well Servicing Operations Involving Hydrogen Sulfide, Third Edition, May 2001. Global StandardsSCF
Local peak alternating stress in a component (including welds) divided by the nominal alternating stress in the pipe wall at the location of the component.- NOTE: This factor is used to account for the increase in the stresses caused by geometric stress amplifiers that occur in the riser component.