Glossary
Browse the IADC Lexicon alphabetically or by category. Get comprehensive definitions of drilling industry terms.
Service Life
Definition(s)
Service Life
Duration of time in which the equipment performs under the specified design conditions, i.e. time in active connected riser operations, excluding storage periods.- NOTE: The service life is normally a small fraction of the design life.
Service Life
Duration of time in which the equipment performs under the specified design conditions, i.e. time in active operation excluding storage periods.- NOTE: The service life is normally a small fraction of the design life.
Service Life
Specified time during which the umbilical system shall be capable of meeting the functional requirements. Source: API SPEC 17E, Specification for Subsea Umbilicals, Upstream Segment, Fourth Edition, October 2010. Global StandardsService Life
Period of time during which the flexible pipe fulfils all performance requirements. Source: API SPEC 17J, Specification for Unbonded Flexible Pipe, Third Edition, July 2008. Global StandardsSecure Status
Definition(s)
Secure Status
Establishment of two independent barriers between the reservoir and the environment. Source: API RP 17G, Recommended Practice for Completion/Workover Risers, Second Edition, July 2006 (Reaffirmed April 2011). Global StandardsSecondary Load
Definition(s)
Secondary Load
Load induced by structural deformation (or the prevention thereof) in the riser which is necessary to satisfy the laws of compatibility of strain and deformation. NOTE The internal forces induced by a secondary load diminish when yielding occurs. Secondary loads do not have to be taken into account where they do not affect the resistance of the member/component to resist other loads. Preload of bolts in flanges is an example. During make-up of a flange, the torque/tension applied by the tool on the bolts is primary, but after make-up, the residual bolt preload is secondary. EXAMPLE An example of a secondary load is the bending caused in the C/WO riser during operation within the drilling riser due to flex joint/ball joint angles. Bending moments that exceed yield, in this case, do not generally cause excessive yielding and failure. Other examples are differential temperature in restrained sections and residual stresses after welding. Source: API RP 17G, Recommended Practice for Completion/Workover Risers, Second Edition, July 2006 (Reaffirmed April 2011). Global StandardsWave Scatter Diagram
Definition(s)
Wave Scatter Diagram
Table listing occurrence of sea-states in terms of significant wave height and wave peak period or mean upcrossing period. 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 StandardsRotary Table
Definition(s)
Rotary Table
Device used to apply torque to the drill string during drilling and normally located in the centre of the drill floor. NOTE Can be rotated and can support wear bushing or spider. Source: API RP 17G, Recommended Practice for Completion/Workover Risers, Second Edition, July 2006 (Reaffirmed April 2011). Global StandardsRotary Table
A device through which passes the bit and drill string and that transmits rotational action to the kelly. Source: API RP 59, Recommended Practice for Well Control Operations, Second Edition, May 2006. Global Standards Source: API RP 64, Recommended Practice for Diverter Systems Equipment and Operations, Second Edition, November 2001 (March 1, 2007). Global StandardsRiser System
Definition(s)
Riser System
The riser and all integrated components, including subsea and surface equipment. Source: API Standard 2RD, Dynamic Risers for Floating Production Systems, Second Edition, September 2013. Global StandardsRiser System
Comprises the riser and all integrated components including subsea and surface equipment. EXAMPLE In tubing hanger mode, the system includes all components from tubing hanger to the top drive; in tree mode, the system includes all components from the wellhead to the top drive. Source: API RP 17G, Recommended Practice for Completion/Workover Risers, Second Edition, July 2006 (Reaffirmed April 2011). Global StandardsRiser System
The riser together with its supports, component parts and ancillary systems such as corrosion protection, mid water arch, bend stiffeners, buoyancy modules, bend restrictors, bend stiffener latching mechanisms, etc. Source: Rules and Regulations for the Classification of Mobile Offshore Units, Part 3, Functional Unit Types and Special Features, June 2013, Lloyd’s Register, Global StandardsRiser Pipe
Definition(s)
Riser Pipe
Seamless pipe which forms the principal conduit of the riser joint. EXAMPLE The riser pipe is the conduit for containing the production fluid flow from the well to the surface tree. Source: API RP 17G, Recommended Practice for Completion/Workover Risers, Second Edition, July 2006 (Reaffirmed April 2011). Global StandardsRiser Pipe
Seamless or electric-welded pipe that forms the principal conduit of the riser joint. NOTE The riser main tube is the conduit for guiding the drillstring and containing the return fluid flow from the well. 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 StandardsRiser Model
Definition(s)
Riser Model
Structural model which is established from the tabulated data of the riser, to describe the actual riser, and used in global analysis of the riser system. Source: API Standard 2RD, Dynamic Risers for Floating Production Systems, Second Edition, September 2013. Global StandardsRiser Model
Structural model, established from the tabulated data of the riser, to describe the actual riser, and used in a global analysis of the riser system. Source: API RP 17G, Recommended Practice for Completion/Workover Risers, Second Edition, July 2006 (Reaffirmed April 2011). Global StandardsReturn Period
Definition(s)
Return Period
Average period of time between occurrences of a given event. NOTE The inverse of return period expressed in years is the statistical probability of such an event occurring in any given year Source: API Standard 2RD, Dynamic Risers for Floating Production Systems, Second Edition, September 2013. Global StandardsReturn Period
Average period of time between occurrences of a given event. NOTE The inverse of the return period is the statistical probability of such an event occurring in any given year. Source: API RP 17G, Recommended Practice for Completion/Workover Risers, Second Edition, July 2006 (Reaffirmed April 2011). Global StandardsReturn Period
Average period between occurrences of an event or of a particular value being exceeded. NOTE The offshore industry commonly uses a return period measured in years for environmental events. The return period is equal to the reciprocal of the annual probability of exceedance of the event. [ISO 19901-1:2005] Source: API RP 2MET, Derivation of Metocean Design and Operating Conditions, First Edition, November 2014. Global Standards 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 StandardsReturn Period
Average period between occurrences of an event or of a particular value being exceeded. NOTE The offshore industry commonly uses a return period measured in years for environmental events. The return period in years is equal to the reciprocal of the annual probability of exceedance of the event. [ISO 19901-1:2005, definition 3.23]. Source: ISO 19905-1:202, Petroleum and natural gas industries – Site-specific assessment of mobile offshore units – Part 1: Jack-ups. Global StandardsRetainer Valve
Definition(s)
Retainer Valve
Valve assembly in the C/WO riser used to retain fluid within the riser and hence preventing its escape to the environment during a riser disconnect operation. NOTE Typically located just above the disconnect point. Source: API RP 17G, Recommended Practice for Completion/Workover Risers, Second Edition, July 2006 (Reaffirmed April 2011). Global StandardsResistance
Definition(s)
Resistance
Mechanical property of a component, a cross-section, or a member of the structure, e.g. bending resistance, local buckling resistance. 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 StandardsResistance
Capacity of a structure, a component or a cross-section of a component to withstand action effects without exceeding a limit state. NOTE This definition is at variance with that specified in 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 StandardsResistance
capacity of a component, or a cross-section of a component, to withstand action effects without failure Source: ISO 19900:2013, Petroleum and natural gas industries – General requirements for offshore structures. Global StandardsRe-Entry Spool
Definition(s)
Re-Entry Spool
Uppermost part of a subsea tree to which the C/WO riser is attached to gain vertical well access or the uppermost part of a lower workover riser package to which an emergency disconnect package connector is attached to provide a single disconnect point. Source: API RP 17G, Recommended Practice for Completion/Workover Risers, Second Edition, July 2006 (Reaffirmed April 2011). Global StandardsRe-Entry Spool
Tree upper connection profile, which allows remote connection of a tree running tool, LWRP or tree cap. 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 StandardsRatcheting
Definition(s)
Ratcheting
Progressive inelastic deformation or strain which can occur in a component that is subjected to variations of mechanical stress, thermal stress, or both (thermal stress ratcheting is partly or wholly caused by thermal stress). NOTE Ratcheting results in a plastic deformation, which increases by about the same amount at each cycle and quickly leads to an unacceptable value. Source: API RP 17G, Recommended Practice for Completion/Workover Risers, Second Edition, July 2006 (Reaffirmed April 2011). Global StandardsPrying
Definition(s)
Prying
Magnification of an external load by a pseudo-lever action when the load is an eccentric tensile load. Source: API RP 17G, Recommended Practice for Completion/Workover Risers, Second Edition, July 2006 (Reaffirmed April 2011). Global StandardsProcess Shutdown
Definition(s)
Process Shutdown
Controlled sequence of events that ensures that the well is secured against accidental release of hydrocarbons to the environment. Source: API RP 17G, Recommended Practice for Completion/Workover Risers, Second Edition, July 2006 (Reaffirmed April 2011). Global StandardsPeak Stress
Definition(s)
Peak Stress
Part of stress, which is additive to the respective primary and secondary stresses, to form the total stress. NOTE Peak stresses do not cause any noticeable distortion and are only important to fatigue and brittle fracture in conjunction with primary and secondary stresses. Source: API RP 17G, Recommended Practice for Completion/Workover Risers, Second Edition, July 2006 (Reaffirmed April 2011). Global StandardsPeak Stress
A peak stress is a highly localized stress that exists at a discontinuity in the load path. An example of a peak stress is the high localized stress at the root of a thread in a bolt. Source: API SPEC 16R, Specification for Marine Drilling Riser Couplings, Exploration and Production Department, First Edition, January 1997. Global StandardsQualified Personnel
Definition(s)
Qualified Personnel
Individuals with characteristics or abilities gained through theory and training and/or experience as measured against the manufacturer’s established requirements. Source: API RP 17G, Recommended Practice for Completion/Workover Risers, Second Edition, July 2006 (Reaffirmed April 2011). Global StandardsQualified Personnel
Individual with characteristics or abilities gained through training, experience, or both, as measured against the established requirements of the manufacturer/purchaser/this International Standard. Source: API SPEC 6A, Specification for Wellhead and Christmas Tree Equipment, Twentieth Edition, October 2010 (Addendum November 2012). Global StandardsQualified Personnel
Individual with characteristics or abilities gained through training, experience or both, as measured against the manufacturer's established requirements. Source: API SPEC 16A, Specification for Drill-through Equipment, Third Edition, June 2004 (Errata/Supplement November 2004). Global StandardsQualified Personnel
Individuals with characteristics or abilities gained through training, experience, or both, as measured against the manufacturer/user/API established requirements. Source: API SPEC 16C, Specification for Choke and Kill Systems, First Edition, January 1993 (Reaffirmed 2001). Global StandardsOut-of-Roundness
Definition(s)
Out-of-Roundness
Deviation of the circumference from a circle. NOTE This can be an ovalization, i.e. an elliptic cross-section, or a local out-of-roundness, e.g. flattening. The numerical definition of out-of-roundness and ovalization is the same. 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 StandardsOut-of-Roundness
Difference between the maximum and minimum diameters of the bar or tube, measured in the same crosssection, and not including surface finish tolerances outlined in 8.1.4. Source: API SPEC 7-1, Specification for Rotary Drill Stem Elements, First Edition, March 2006 (Addendum April 2011). Global StandardsOperating Mode
Definition(s)
Operating Mode
Conditions that arise from the use and application of the equipment or riser system. Source: API Standard 2RD, Dynamic Risers for Floating Production Systems, Second Edition, September 2013. Global StandardsOperating Mode
Condition that arises from the use and application of the equipment or riser system. NOTE Typical operating modes are racking of riser components, running/retrieval, landing/connecting, overpull to verify lockdown, system pressure testing, normal operation, surface shut-in, subsea shut-in, disconnecting, hang-off, overpull to retrieve tubing hanger, failure of dynamic positioning system, failure of tensioner system and failure of anchors or anchor lines. Source: API RP 17G, Recommended Practice for Completion/Workover Risers, Second Edition, July 2006 (Reaffirmed April 2011). Global StandardsOperating Envelope
Definition(s)
Operating Envelope
Limited range of parameters in which operations will result in safe and acceptable equipment performance. Source: API RP 17G, Recommended Practice for Completion/Workover Risers, Second Edition, July 2006 (Reaffirmed April 2011). Global StandardsNotch Stress Range
Definition(s)
Notch Stress Range
Sum of the primary stress range plus the secondary stress range plus the peak stress range, forming the total stress range (see Annex C), as applied to fatigue assessment of unwelded parts. Source: API RP 17G, Recommended Practice for Completion/Workover Risers, Second Edition, July 2006 (Reaffirmed April 2011). Global StandardsNominal Value
Definition(s)
Nominal Value
Dimensional value specified as nominal on the drawings and specifications. 3.1.62 Source: API Standard 2RD, Dynamic Risers for Floating Production Systems, Second Edition, September 2013. Global StandardsNominal Value
Dimensions as specified on the drawings and specifications. Source: API RP 17G, Recommended Practice for Completion/Workover Risers, Second Edition, July 2006 (Reaffirmed April 2011). Global StandardsNominal Value
The value assigned to a basic variable determined on a non-statistical basis, typically from acquired experience or physical conditions [ISO 32]. Source: API RP 2FB, Recommended Practice for the Design of Offshore Facilities Against Fire and Blast Loading, First Edition, April 2006. Global StandardsNominal Value
value assigned to a basic variable determined on a non-statistical basis, typically from acquired experience or physical conditions Source: ISO 19900:2013, Petroleum and natural gas industries – General requirements for offshore structures. Global StandardsMill/FAT Test Pressure
Definition(s)
Mill/FAT Test Pressure
Hydrostatic test pressure applied to riser components upon completion of manufacture and fabrication to test the riser components for strength and/or leak tightness. Source: API Standard 2RD, Dynamic Risers for Floating Production Systems, Second Edition, September 2013. Global StandardsMill/FAT Test Pressure
Hydrostatic test pressure applied to riser components upon completion of manufacture and fabrication to test the riser components for strength and/or tightness. Source: API RP 17G, Recommended Practice for Completion/Workover Risers, Second Edition, July 2006 (Reaffirmed April 2011). Global StandardsMean Static Offset
Definition(s)
Mean Static Offset (of vessel)
Mean static offset includes static offset due to steady forces from current, wind and wave, offset due to low-frequency motions and active positioning of the vessel. Source: API RP 17G, Recommended Practice for Completion/Workover Risers, Second Edition, July 2006 (Reaffirmed April 2011). Global StandardsManufacturing Procedure Specification
Definition(s)
Manufacturing Procedure Specification
Document prepared by the manufacturer to demonstrate how the specified properties can be achieved and verified through the proposed manufacturing route. Source: API RP 17G, Recommended Practice for Completion/Workover Risers, Second Edition, July 2006 (Reaffirmed April 2011). Global StandardsLubricator Valve
Definition(s)
Lubricator Valve
Valve assembly typically situated below the surface tree and used to isolate the reservoir from the environment when deploying long wireline/coiled tubing tool assemblies. Source: API RP 17G, Recommended Practice for Completion/Workover Risers, Second Edition, July 2006 (Reaffirmed April 2011). Global StandardsLower Workover Riser Package
Definition(s)
Lower Workover Riser Package
Lowermost equipment package in the riser string when configured for subsea tree installation/workover and including any equipment between the riser stress joint and the subsea tree, and typically consisting of a lower riser package and emergency disconnect package. NOTE The lower workover riser package permits well control and ensures a safe operating status whilst performing coiled tubing/wireline and well servicing operations. Source: API RP 17G, Recommended Practice for Completion/Workover Risers, Second Edition, July 2006 (Reaffirmed April 2011). Global StandardsLower Marine Riser Package
Definition(s)
Lower Marine Riser Package
Upper section of a subsea BOP stack that interfaces between the lower stack and drilling riser, typically consisting of a hydraulic connector, annular BOP, ball/flex joint, riser adapter, jumper lines for the choke, kill, and auxiliary lines, and subsea control pods.
Source: API Specification 16Q, Design, Selection, Operation, and Maintenance of Marine Drilling Riser Systems, Second Edition, April 2017. Global StandardsLower Marine Riser Package (LMRP)
Upper section of a two-section subsea BOP stack consisting of the hydraulic connector, annular BOP, ball/flex joint, riser adapter, jumper hoses for the choke, kill and auxiliary lines and subsea control modules.- NOTE: The LMRP interfaces with the BOP stack.
Lower Marine Riser Package
Upper section of a two-section subsea BOP stack consisting of a hydraulic connector, annular BOP, flex joint, riser adapter, jumper hoses for the choke, kill and auxiliary lines, and subsea control pods.- NOTE: This interfaces with the lower subsea BOP stack.