Glossary
Browse the IADC Lexicon alphabetically or by category. Get comprehensive definitions of drilling industry terms.
Casing Head
Definition(s)
Casing Head (or Braden Head)
A heavy steel fitting connected to the uppermost end of the surface casing. It provides a pressure seal for subsequent casing strings placed in the well and allows suspension of intermediate casing strings and the production casing. It also provides outlets to release any pressure that might accumulate between casing strings. The casing head is usually connected to the surface casing by a threaded connection, but in deep wells it may be attached by welding. Source: API BULLETIN E3, Environmental Guidance Document: Well Abandonment and Inactive Well Practices for U.S. Exploration and Production Operations, First Edition, January 1993 (Reaffirmed June 2000). Global StandardsBullhead Squeeze
Definition(s)
Bullhead Squeeze
The process by which hydraulic pressure is applied to a workstring or tubing to force fluids, such as cement, outside the wellbore. Annular flow (returns) is prevented by a packer set in the casing above the perforated and/or open hole interval. The packer shields the inner casing wall from exposure to the pumping pressures. Source: API BULLETIN E3, Environmental Guidance Document: Well Abandonment and Inactive Well Practices for U.S. Exploration and Production Operations, First Edition, January 1993 (Reaffirmed June 2000). Global StandardsBridge Plug
Definition(s)
Bridge Plug
A downhole tool (composed primarily of slips, a plug mandrel, and a rubber sealing element) that is run and set in casing to isolate a lower zone while an upper section is tested, cemented, stimulated, produced, or injected into. In order to facilitate removal by drilling, a bridge plug is often made of cast iron and is commonly referred to as a cast iron bridge plug (CIBP). Source: API BULLETIN E3, Environmental Guidance Document: Well Abandonment and Inactive Well Practices for U.S. Exploration and Production Operations, First Edition, January 1993 (Reaffirmed June 2000). Global StandardsBridge Plug
Mechanical device installed in, and used for blocking fluid (liquid or gas) communication in, the conduit and not installed in a designed receptacle. Source: API SPEC 11D1, Packers and Bridge Plugs, Upstream Segment, Second Edition, July 2009. Global StandardsBradenhead Squeeze
Definition(s)
Bradenhead Squeeze
The process by which hydraulic pressure is applied to a casing, workstring, or tubing, to force fluids, such as cement, outside the wellbore. Annular returns may be prevented by closing the casinghead valves. A packer is not run in the well. Therefore, the inner casing wall is exposed to the pumping pressures. Source: API BULLETIN E3, Environmental Guidance Document: Well Abandonment and Inactive Well Practices for U.S. Exploration and Production Operations, First Edition, January 1993 (Reaffirmed June 2000). Global StandardsBorehole
Definition(s)
Borehole
The hole made by drilling a well. Where casing is run in the well, the borehole is the space between the exterior of the casing and the formations. After the casing has been installed, the borehole is normally filled with various materials such as cement, drilling mud, sloughing formations, and water. Source: API BULLETIN E3, Environmental Guidance Document: Well Abandonment and Inactive Well Practices for U.S. Exploration and Production Operations, First Edition, January 1993 (Reaffirmed June 2000). Global StandardsBalanced Cement Plug
Definition(s)
Balanced Cement Plug
The result of pumping cement through drill pipe, workstring, or tubing until the level of cement outside is equal to that inside the drill pipe/ workstring/ tubing. The pipe is then pulled slowly from the Cement slurry, leaving the plug in place. The technique is used in both open hole and cased hole applications when the wellbore fluids are in static equilibrium. Source: API BULLETIN E3, Environmental Guidance Document: Well Abandonment and Inactive Well Practices for U.S. Exploration and Production Operations, First Edition, January 1993 (Reaffirmed June 2000). Global StandardsControl Station/Panel, Remote
Definition(s)
Control Station/Panel, Remote
A panel containing a series of controls that will operate the BOP functions from a location that is remote from the hydraulic control manifold, or central processor in the case of a MUX or Multiplex control system. NOTE: The control station for a discrete hydraulic system is at the HPU. Source: API STD 53, Blowout Prevention Equipment Systems for Drilling Wells, Upstream Segment, Fourth Edition, November 2012. Global StandardsControl Panel, Remote
A panel containing a series of controls that will operate the valves on the control manifold from a remote point. Source: API RP 59, Recommended Practice for Well Control Operations, Second Edition, May 2006. Global StandardsWPS
Definition(s)
WPS
Welding procedure specification. Source: API 570, Piping Inspection Code: In-service Inspection, Rating, Repair, and Alteration of Piping Systems, Fourth Edition, February 2016, with Addendum May 2017. Global Standards Source: API Specification 16A, Specification for Drill-through Equipment, Fourth Edition, April 2017. Global Standards Source:API SPECIFICATION 19TT, Specification for Downhole Well Test Tools and Related Equipment, First Edition, October 2016. Global Standards Source: API SPEC 5DP, Specification for Drill Pipe, First Edition, August 2009. Global Standards Source: API SPEC 6A, Specification for Wellhead and Christmas Tree Equipment, Twentieth Edition, October 2010 (Addendum November 2012). Global Standards Source: API SPEC 16A, Specification for Drill-through Equipment, Third Edition, June 2004 (Errata/Supplement November 2004). Global StandardsWPS
Weld procedure specification. Source: API STANDARD 16AR, Standard for Repair and Remanufacture of Drill-through Equipment, First Edition, April 2017. Global Standards Source: API STD 53, Blowout Prevention Equipment Systems for Drilling Wells, Upstream Segment, Fourth Edition, November 2012. Global StandardsWPS
Written welding procedure that is qualified to provide direction for welding in accordance with requirements of this standard and describing the specific essential, nonessential, and supplementary essential variables required for each welding process.- NOTE: These variables and their meanings are defined in ASME BPVC Section IX, Article II and Article IV.
WPS
Document providing the required welding variables for a specific application to assure repeatability by properly trained welders and welding operators.- NOTE: These variables and their meanings are defined, respectively, in Article II of the ASME Boiler & Pressure Vessel Code, Section IX—Welding and Brazing Qualifications.
WPS
Welding Procedure Specifications. Source: API SPEC 16C, Specification for Choke and Kill Systems, First Edition, January 1993 (Reaffirmed 2001). Global Standards 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 Standards Source: API SPEC 16RCD, Specification for Drill Through Equipment—Rotating Control Devices, Upstream Segment, First Edition, February 2005. Global Standards Source: Verification of Lifting Appliances for the Oil and Gas Industry, DNV-OSS-308, October 2010, Det Norske Veritas AS, Global StandardsWell Control Equipment
Definition(s)
Well Control Equipment
Systems and subsystems (components, parts, or assemblies) that are used to control pressure within the wellbore. Source: API STD 53, Blowout Prevention Equipment Systems for Drilling Wells, Upstream Segment, Fourth Edition, November 2012. Global StandardsWell Control Equipment
Well control equipment includes all equipment used to:- detect unplanned influxes of formation fluids into the well;
- prevent, control or divert the flow of fluids from the well;
- purge formation fluids from the well;
- separate formation fluids from the drilling fluid.
Visual Position Indicator
Definition(s)
Visual Position Indicator
A visible means of determining the position of a valve, ram, connector, or annular activation to indicate the full open or close position. Source: API STD 53, Blowout Prevention Equipment Systems for Drilling Wells, Upstream Segment, Fourth Edition, November 2012. Global StandardsUmbilical
Definition(s)
Umbilical
Bundle of helically or sinusoidally wound small-diameter chemical, hydraulic, and electrical conductors for power and control systems. Source: API RP 17B, Recommended Practice for Flexible Pipe, Fourth Edition, July 2008. Global StandardsUmbilical
Flexible hose consisting of a group of electrical cables, optical fibre cables, hoses, pipes, either on their own or with combinations of each other, cabled together for flexibility and oversheathed and/or armoured for mechanical strength, used to transmit fluid/electrical signals to and from a power source to a remote station. Source: API RP 17G, Recommended Practice for Completion/Workover Risers, Second Edition, July 2006 (Reaffirmed April 2011). Global StandardsUmbilical
A control hose bundle or electrical cable used to control subsea functions. 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 StandardsUmbilical
Hose, tubing, piping, and/or electrical conductor that directs fluids and/or electrical current or signals to or from subsea trees. 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 StandardsUmbilical
Group of functional components, such as electric cables, optical fibre cables, hoses, and tubes, laid up or bundled together or in combination with each other, that generally provides hydraulics, fluid injection, power and/or communication services. NOTE Other elements or armouring may be included for strength, protection, or weight considerations. Source: API SPEC 17E, Specification for Subsea Umbilicals, Upstream Segment, Fourth Edition, October 2010. Global StandardsUmbilical
Combination of electric cables, hoses or steel tubes, either on their own or in combination (or with fibre optic cables), cabled together for flexibility and over-sheathed and/or armoured for mechanical strength and typically supplying power and hydraulics, communication and chemicals to a subsea system. Source: API SPEC 17F, Specification for Subsea Production Control Systems, Second Edition, December 2006 (Reaffirmed April 2011). Global StandardsUmbilical
A control hose bundle or electrical cable that runs from the reel on the surface to the subsea control pod on the LMRP. Source: API STD 53, Blowout Prevention Equipment Systems for Drilling Wells, Upstream Segment, Fourth Edition, November 2012. Global StandardsUmbilical
“Umbilical” means a composite hose or cable or number of separate hoses or cables capable of supplying a breathing mixture, power, heat, communications and other services, as required for a diving operation (ombilical). Source: Canada Oil and Gas Diving Regulations, SOR/88-600, February 2013. Regulations Source: Nova Scotia Offshore Area Petroleum Diving Regulations, SOR/95-189, Canada, current to May 31, 2012. RegulationsSurface Base Pressure
Definition(s)
Surface Base Pressure
Minimum operating pressure of the hydraulic circuit for supplying power to the function(s). NOTE 1: This is usually a regulated 1500 psig. NOTE 2: Exceptions are to special functions that have a specific pressure requirement, such as shear rams used to cut a specific drill pipe or tubing. NOTE 3: This value is used in Method C accumulator calculations as defined in API 16D and referenced in Annex C. Source: API STD 53, Blowout Prevention Equipment Systems for Drilling Wells, Upstream Segment, Fourth Edition, November 2012. Global StandardsSurface Base Pressure
Minimum operating pressure of the hydraulic circuit for supplying power to the function(s). NOTE 1: This is usually a regulated 1500 psig (10.47 MPa). NOTE 2: Exceptions are to special functions that have a specific pressure requirement, such as shear rams used to cut a specific tubular. Source: API STD 53, Blowout Prevention Equipment Systems for Drilling Wells, Upstream Segment, Fourth Edition, November 2012. Global StandardsSurface Base Precharge Pressure
Definition(s)
Surface Base Precharge Pressure
Precharge value that is appropriate for surface testing. NOTE 1: This value should be available within the manufacturer’s operations and maintenance manual. NOTE 2: This value is used in Methods A and B accumulator calculations as defined in API 16D and referenced in Annex C. Source: API STD 53, Blowout Prevention Equipment Systems for Drilling Wells, Upstream Segment, Fourth Edition, November 2012. Global StandardsSurface Base Precharge Pressure
Precharge value that is appropriate for surface testing. NOTE 1: This value should be available within the manufacturer’s operations and maintenance manual. NOTE 2: This value is used in Methods A and B accumulator calculations as defined in API 16D and referenced in Annex C. Source: API STD 53, Blowout Prevention Equipment Systems for Drilling Wells, Upstream Segment, Fourth Edition, November 2012. Global StandardsSubsea Blowout Preventer
Definition(s)
Subsea BOP
Blowout preventer stack designed for use on subsea wellhead and wellhead assemblies, complete with redundant controls. Source: API STD 53, Blowout Prevention Equipment Systems for Drilling Wells, Upstream Segment, Fourth Edition, November 2012. Global StandardsSubsea Blowout Preventer
A series of ram blowout preventers and annular blowout preventers designed to be installed as a unit on a subsea wellhead, tubing head, or subsea tree. Source: API RP 96, Deepwater Well Design and Construction, First Edition, March 2013. Global StandardsStored Hydraulic Fluid
Definition(s)
Stored Hydraulic Fluid
The fluid volume recoverable from the accumulator system between the maximum designed accumulator operating pressure and the precharge pressure. Source: API STD 53, Blowout Prevention Equipment Systems for Drilling Wells, Upstream Segment, Fourth Edition, November 2012. Global StandardsStable
Definition(s)
Stable (Stabilized)
A state in which the pressure change rate has decreased to within acceptable limits before beginning the hold period during a pressure test. NOTE: Pressure changes can be caused by such things as variations in temperature, setting of elastomer seals, or compression of air or fluids, etc. Source: API STD 53, Blowout Prevention Equipment Systems for Drilling Wells, Upstream Segment, Fourth Edition, November 2012. Global StandardsSR
Definition(s)
SR
Shearing ratio. Source: API STD 53, Blowout Prevention Equipment Systems for Drilling Wells, Upstream Segment, Fourth Edition, November 2012. Global StandardsSR
Supplementary requirement. Source: API Specification 16A, Specification for Drill-through Equipment, Fourth Edition, April 2017. Global Standards Source: API SPEC 5CT, Specification for Casing and Tubing, Upstream Segment, Ninth Edition, July 2011 (Errata September 2012). Global StandardsSpacer Spool
Definition(s)
Spacer Spool
Pressure-containing piece of equipment having end connections, used below or between drill-through equipment.- NOTE: A spool is used to provide separation between two components with equal-sized end connections.
Spacer Spool
A spool used to provide separation between two components with equal sized end connections. Source: API STD 53, Blowout Prevention Equipment Systems for Drilling Wells, Upstream Segment, Fourth Edition, November 2012. Global StandardsSpacer Spool
Used in underbalance operations to adjust height of stack and components on assembly, and to raise or lower height of flow line. Source: IADC UBO / MPD Glossary, December 2011. Global StandardsSOP
Definition(s)
SOP
Standard operating procedure(s). Source: API STD 53, Blowout Prevention Equipment Systems for Drilling Wells, Upstream Segment, Fourth Edition, November 2012. Global Standards Source: Oil & Gas UK, Guidelines on subsea BOP systems, Issue 1, July 2012, Global StandardsSOP
Abbreviation for Standard Operating Procedures. Source: API RP 5A5, Field Inspection of New Casing, Tubing, and Plain-end Drill Pipe, Reaffirmed August 2010. Global StandardsShuttle Valve
Definition(s)
Shuttle Valve
A checking type valve that shifts between two or more inlets allowing the movement of control fluid to and from multiple sources. Source: API STD 53, Blowout Prevention Equipment Systems for Drilling Wells, Upstream Segment, Fourth Edition, November 2012. Global StandardsShuttle Valve
A valve with two or more supply ports and only one outlet port. Note: When fluid is flowing through one of the supply ports the internal shuttle seals off the other inlet port(s) and allows flow to the outlet port only. 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 StandardsShearing Ratio
Definition(s)
Shearing Ratio (SR)
The higher value of the closing ratios provided by the manufacturer. NOTE: The shearing ratio is dependent on piston size and/or booster addition. Source: API STD 53, Blowout Prevention Equipment Systems for Drilling Wells, Upstream Segment, Fourth Edition, November 2012. Global StandardsRWP
Definition(s)
RWP
Rated working pressure. Source: API Technical Report 17TR7, Verification and Validation of Subsea Connectors, First Edition, April 2017. Global Standards Source: API STD 53, Blowout Prevention Equipment Systems for Drilling Wells, Upstream Segment, Fourth Edition, November 2012. Global Standards Source: NORSOK D-001, Drilling facilities, Rev. 3, December 2012. Global Standards Source: Oil & Gas UK, Guidelines on subsea BOP systems, Issue 1, July 2012, Global StandardsRWP
Maximum internal pressure that the equipment is designed to contain and/or control.
Source: API Technical Report 17TR7, Verification and Validation of Subsea Connectors, First Edition, April 2017. Global StandardsRemanufacture
Definition(s)
Remanufacture
Activity involving disassembly, reassembly and testing of equipment where machining, welding, heat treating, or other manufacturing operations are employed. Source: API STD 53, Blowout Prevention Equipment Systems for Drilling Wells, Upstream Segment, Fourth Edition, November 2012. Global StandardsRemanufacture
Action performed on equipment that involves a special process or re-machining. 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 StandardsRemanufacture
Activity involving disassembly, reassembly and testing of wellhead and christmas tree equipment, with or without the replacement of parts other than bodies, where machining, welding, heat treating or other manufacturing operations are employed. NOTE Remanufacture does not include the replacement of bodies. Source: API SPEC 6A, Specification for Wellhead and Christmas Tree Equipment, Twentieth Edition, October 2010 (Addendum November 2012). Global StandardsRemanufacture
Process of disassembly, reassembly and testing of drill-through equipment, with or without the replacement of parts, in which machining, welding, heat treatment or other manufacturing operation is employed. 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 16A, Specification for Drill-through Equipment, Third Edition, June 2004 (Errata/Supplement November 2004). Global StandardsPressure Test
Definition(s)
Pressure Test
A test performed on pressure vessels that have been in service and that have undergone an alteration or repair to the pressure boundary(s) to indicate that the integrity of the pressure components are still compliant with the original construction code. The pressure test can be hydrostatic, pneumatic, or a combination thereof. Pressure tests at less than those specified by the construction code to determine if there may be leaks in the system are generally referred to as tightness tests.
Source: API 510, Pressure Vessel Inspection Code: In-service Inspection, Rating, Repair, and Alteration, Tenth Edition, May 2014, with Addendum May 2017. Global StandardsPressure Test
Application of pressure to a piece of equipment or a system to verify the pressure containment capability for the equipment or system. Source: ISO 16530-1:2017, Petroleum and natural gas industries — Well integrity – Part 1: Life cycle governance, First Edition, March 2017. Global StandardsPressure Test
The periodic application of pressure to a piece of equipment or a system to verify the pressure containment capability for the equipment or system. Source: API STD 53, Blowout Prevention Equipment Systems for Drilling Wells, Upstream Segment, Fourth Edition, November 2012. Global StandardsPressure-Controlling
Definition(s)
Pressure-Controlling
Product or part intended to control or regulate the movement of pressurized fluids.
Source: API STANDARD 18LCM, Product Life Cycle Management System Requirements for the Petroleum and Natural Gas Industries, First Edition, April 2017. Global StandardsPressure-Controlling
The control of the movement of pressurized fluids. Source: API STD 53, Blowout Prevention Equipment Systems for Drilling Wells, Upstream Segment, Fourth Edition, November 2012. Global StandardsPressure-Controlling
Part intended to control or regulate the movement of pressurized fluids (API 6A). Source: API TR 1PER15K-1, Protocol for Verification and Validation of High-pressure High-temperature Equipment, First Edition, March 2013. Global StandardsPressure-Containing Equipment
Definition(s)
Pressure-Containing Equipment
Equipment (parts or members) whose failure to function as intended can result in a release of fluids to the environment.
Source: API Specification 16Q, Design, Selection, Operation, and Maintenance of Marine Drilling Riser Systems, Second Edition, April 2017. Global Standards