Glossary
Browse the IADC Lexicon alphabetically or by category. Get comprehensive definitions of drilling industry terms.
Straight Sub
Definition(s)
Straight Sub
Sub with no outside diameter change. Source: API RP 7G-2, Recommended Practice for Inspection and Classification of Used Drill Stem Elements, First Edition, August 2009. Global StandardsStraight-Through Function
Definition(s)
Straight-Through Function
Subsea function that is directly operated by a pilot signal without interface with a podmounted pilot-operated control valve. Source: API SPEC 16D, Specification for Control Systems for Drilling Well Control Equipment and Control Systems for Diverter Equipment, Upstream Segment, Second Edition, July 2004. Global StandardsStraightness
Definition(s)
Straightness
Degree to which the longitudinal axis of a length of OCTG is parallel to a straight line. Source: API RP 5A5, Field Inspection of New Casing, Tubing, and Plain-end Drill Pipe, Reaffirmed August 2010. Global StandardsStrain
Definition(s)
Strain
The ratio of elongation to the gauge length over which the elongation takes place. 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 StandardsStrain-based Design
Definition(s)
Strain-based Design
Design where total nominal strain in any direction (excluding strain concentration) due to installation and operations exceeds 0.5 % at the OD surface. Source: API Standard 2RD, Dynamic Risers for Floating Production Systems, Second Edition, September 2013. Global StandardsStrakes
Definition(s)
Strakes
Helically wound appendages attached to the outside of the riser to suppress vortex induced vibrations. 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 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 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 StandardsStrand Assembly Checklist
Definition(s)
Strand Assembly Checklist
A document completed during the strand assembly process which states the nominal values and records the actual values for each set-up of each step of the process of assembling strands. Source: API RP 2SM, Design, Manufacture, Installation, and Maintenance of Synthetic Fiber Ropes for Offshore Mooring, First Edition, July 2014. Global StandardsStrategic Foresight
Definition(s)
Strategic Foresight
Range of activities associated with longer range planning and alternative futures analysis. Sample Usage: The organization’s strategic foresight initiative called for horizon scanning and analysis of the long-term implications of security policies. Annotation: Strategic foresight can be applied to activities such as scenario development, critical thinking and brainstorming about long-term trends, Delphi sessions, workshops, trend analysis and gaming (or "war-gaming"). Source: DHS Risk Lexicon, U.S. Department of Homeland Security, 2010 Edition. September 2010 Regulatory GuidanceStrategic Planning and Policy Development
Definition(s)
Strategic Planning and Policy Development
In the NICE Workforce Framework, cybersecurity work where a person: Applies knowledge of priorities to define an entity. From: NICE Workforce Framework. Source: NICCS™ Portal Cybersecurity Lexicon, National Initiative for Cybersecurity Careers and Studies (https://niccs.us-cert.gov/glossary) as of 11 November 2015, Global StandardsStrategic Risk
Definition(s)
Strategic Risk
Risk that affects an entity’s vital interests or execution of chosen strategy, whether imposed by external threats or arising from flawed or poorly implemented strategy. Sample Usage: An analysis of the organization's strategic risk considered threats to carrying out its essential mission functions. Annotation:- Managing strategic risk is associated with the ability to recognize future trends, challenges, and threats and match these with appropriate operational concepts, capabilities, competencies, and capacity.
- Strategic risk can arise from three basic sources. First, strategic risk can arise from the actions of adversaries, from natural hazards or from non-adversarial human actions, such as accidents. These can be thought of as imposed risks. Second, strategic risk can be created by the unintended consequences of the strategies we adopt in response to imposed risks. These can be thought of as self-imposed risks. Finally, strategic risk can arise from obstacles to successful implementation of an adopted strategy. These obstacles can be either imposed (e.g., the actions of an adaptive adversary to counter a security measure or to exploit an unintended vulnerability created by a security measure) or self-imposed (e.g., failure to adequately resource, or to prematurely abandon, a strategy or course of action that would otherwise be beneficial.
Stratigraphic Test Well
Definition(s)
Stratigraphic Test Well
"Stratigraphic test well" means a hole drilled for the sole purpose of gaining structural or stratigraphic information to aid in exploring for oil and gas. Source: Alaska Oil and Gas Conservation Commission, Definitions, Alaska Admin. Code tit. 20, § 25.990, December 7, 2012. RegulationsStratigraphic Test Well
"Stratigraphic test well" means any well or hole, except a seismograph shot hole, drilled for the purpose of gathering information in connection with the oil and gas industry with no intent to produce oil or gas from such well. Source: Oil and gas Conservation, North Dakota Administrative Code, Chapter 43-02-03, April 2012. RegulationsStratigraphic Well
Definition(s)
Stratigraphic Well
STRATIGRAPHIC WELL means a well drilled for stratigraphic information only. Wells drilled in a delineated field to known productive horizons shall not be classified as “stratigraphic.” Neither the term “well” nor “stratigraphic well” shall include seismic holes drilled for the purpose of obtaining geophysical information only. Source: Oil and Gas Conservation Commission, Practice and Procedure, Code of Colorado Regulations, 2 CCR 404-1, February 2013. RegulationsStratum
Definition(s)
Stratum
“Stratum” means a layer of rock more or less similar through out a lithological unit. Source: The Petroleum and Natural Gas Rules, 1959 (As amended from time to time), India, as amended as of May 2013. RegulationsStrength
Definition(s)
Strength
Mechanical property of a material, usually given in units of stress. 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 StandardsStrength Retrogression
Definition(s)
Strength Retrogression
Reduction in compressive strength and increase in permeability of a cement caused by exposure to temperatures exceeding 110 °C (230 °F). Source: API RP 10B-2, Recommended Practice for Testing Well Cements, First Edition, July 2005 (Reaffirmed: July 2010). Global StandardsStress
Definition(s)
Stress
Load per unit area. Source: API RP 5A5, Field Inspection of New Casing, Tubing, and Plain-end Drill Pipe, Reaffirmed August 2010. Global StandardsStress Amplification Factor
Definition(s)
Stress amplification factor
Equal to the 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.
Source: API Specification 16Q, Design, Selection, Operation, and Maintenance of Marine Drilling Riser Systems, Second Edition, April 2017. Global StandardsStress amplification factor
The ratio of the localized stress to the stress in adjacent material. Source: API RP 96, Deepwater Well Design and Construction, First Edition, March 2013. Global StandardsStress amplification factor
Equal to the local peak alternating stress in a component (including welds) divided by the nominal alternating stress in a defined reference section somewhere in the system (e.g. through wall section of the wellhead above or below the locking profile).- NOTE: This factor is used to account for the increase in the stresses caused by geometric stress amplifiers which occur in connector components.
Stress amplification factor (SAF)
Equal to the 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. This factor is used to account for the increase in the stresses caused by geometric stress amplifiers which occur in riser components. 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 StandardsStress Amplification Factor
Value equal to the 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 riser components.
Stress Concentration Factor
Definition(s)
Stress Concentration Factor
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 StandardsStress Concentration Factor (SCF)
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.
Stress Concentration Factor (SCF)
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, which occur in the riser component.
Stress Concentration Factor
Factor relating a nominal stress to the local stress at a detail. NOTE Adapted from ISO 19902:2007, definition 3.50. Source: ISO 19905-1:202, Petroleum and natural gas industries – Site-specific assessment of mobile offshore units – Part 1: Jack-ups. Global StandardsStress Corrosion Cracking (SCC)
Definition(s)
Stress Corrosion Cracking (SCC)
Cracking of metal involving anodic processes of localized corrosion and tensile stress (residual and/or applied) in the presence of water and H2S. NOTE Chlorides and/or oxidants and elevated temperature can increase the susceptibility of metals to this mechanism of attack. [ISO 15156-1]. Source: API SPEC 14A, Specification for Subsurface Safety Valve Equipment, Eleventh Edition, October 2005 (Reaffirmed June 2012). Global StandardsStress Corrosion Cracking
The cracking which results from a combination of corrosion and stress. Source: API SPEC 16C, Specification for Choke and Kill Systems, First Edition, January 1993 (Reaffirmed 2001). Global StandardsStress Corrosion Cracking
Cracking induced by a combination of stress and corrosion. Source: IADC UBO / MPD Glossary, December 2011. Global StandardsStress Corrosion Cracking
Cracking of metal involving anodic processes of localized corrosion and tensile stress (residual and/or applied). NOTE 1 Parameters that influence the susceptibility to SCC are temperature, pH, chlorides, dissolved oxygen, H2S and CO2. NOTE 2 The above definition differs from that of the same term given in ISO 15156-1:2009, definition 3.21, since it includes external environments. Source: ISO 21457:2010, Petroleum and natural gas industries — Materials selection and corrosion control for oil and gas production systems, First Edition,September 2010. Global StandardsStress Cracking
Definition(s)
Stress Cracking
Stress corrosion cracking, or sulfide stress cracking, or both. NOTE Adapted from NACE MR0175: Jan 2003. Source: API SPEC 14A, Specification for Subsurface Safety Valve Equipment, Eleventh Edition, October 2005 (Reaffirmed June 2012). Global StandardsStress Intensification Factor
Definition(s)
Stress Intensification Factor
Ratio of the actual or effective longitudinal stress in a component or fitting under external load to the nominal stress in that component or fitting as determined based on a straight pipe run with the same MPRxx as the component fitting. Source: ISO 14692-1:2017, Petroleum and natural gas industries — Glass-reinforced plastics (GRP) piping — Part 1: Vocabulary, symbols, applications and materials, Second Edition, August 2017. Global StandardsStress Intensity Factor
Definition(s)
Stress Intensity Factor
Term used in fracture mechanics to define the local conditions of stress and strain around a crack tip, in terms of global parameters such as of loads, geometry and crack size. Source: API Standard 2RD, Dynamic Risers for Floating Production Systems, Second Edition, September 2013. Global StandardsStress Intensity Factor (Fracture Mechanics)
Factor used to define the local conditions of stress and strain around a crack tip in terms of global parameters such as of loads, geometry and crack size. Source: API RP 17G, Recommended Practice for Completion/Workover Risers, Second Edition, July 2006 (Reaffirmed April 2011). Global StandardsStress Joint
Definition(s)
Stress Joint
Specialized riser joint designed with a tapered cross-section to control curvature and reduce local bending stresses. Source: API Standard 2RD, Dynamic Risers for Floating Production Systems, Second Edition, September 2013. Global StandardsStress Joint
Specialized riser joint designed with a tapered cross-section, in order to control curvature and reduce local bending stresses. NOTE It is the lowermost riser joint in the riser string when configured for workover. Source: API RP 17G, Recommended Practice for Completion/Workover Risers, Second Edition, July 2006 (Reaffirmed April 2011). Global StandardsStress Range
Definition(s)
Stress Range
The difference between stress maximum and stress minimum in a stress cycle. 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 StandardsStress Relaxation
Definition(s)
Stress Relaxation
The time-dependent reduction in stress of a component when subjected to a constant strain (see creep). Source:API SPECIFICATION 7K, Drilling and Well Servicing Equipment, Sixth Edition, December 2015. Global StandardsStress Relief
Definition(s)
Stress Relief
Controlled heating of material to a predetermined temperature for the purpose of reducing any residual stresses after welding. Source: API SPEC 6A, Specification for Wellhead and Christmas Tree Equipment, Twentieth Edition, October 2010 (Addendum November 2012). Global Standards Source: API SPEC 16C, Specification for Choke and Kill Systems, First Edition, January 1993 (Reaffirmed 2001). Global StandardsStress Relief
Controlled heating of material to a predetermined temperature for the purpose of reducing any residual stresses. Source: API Specification 16A, Specification for Drill-through Equipment, Fourth Edition, April 2017. Global Standards Source: API STANDARD 16AR, Standard for Repair and Remanufacture of Drill-through Equipment, First Edition, April 2017. Global Standards Source: API SPEC 14A, Specification for Subsurface Safety Valve Equipment, Eleventh Edition, October 2005 (Reaffirmed June 2012). Global Standards Source: API SPEC 16A, Specification for Drill-through Equipment, Third Edition, June 2004 (Errata/Supplement November 2004). Global Standards Source: API SPEC 16RCD, Specification for Drill Through Equipment—Rotating Control Devices, Upstream Segment, First Edition, February 2005. Global StandardsStress Relieving
Definition(s)
Stress Relieving
Controlled heating of material to a predetermined temperature for the purpose of reducing any residual stresses.
Source:API SPECIFICATION 19TT, Specification for Downhole Well Test Tools and Related Equipment, First Edition, October 2016. Global Standards