Glossary
Browse the IADC Lexicon alphabetically or by category. Get comprehensive definitions of drilling industry terms.
Weld Preparation
Definition(s)
Weld Preparation
Geometry of surfaces for the purpose of welding. Source: API SPEC 6A, Specification for Wellhead and Christmas Tree Equipment, Twentieth Edition, October 2010 (Addendum November 2012). Global StandardsWeld Zone
Definition(s)
Weld Zone
Zone comprising the weld line and the heat-affected areas on either side of the weld line caused by the friction welding and subsequent heat-treatment processes. Source: API SPEC 5DP, Specification for Drill Pipe, First Edition, August 2009. Global StandardsWeld, Fabrication
Definition(s)
Weld, Fabrication
A weld joining two or more parts. Source: API SPEC 16C, Specification for Choke and Kill Systems, First Edition, January 1993 (Reaffirmed 2001). Global Standards Source: API SPEC 16RCD, Specification for Drill Through Equipment—Rotating Control Devices, Upstream Segment, First Edition, February 2005. Global StandardsWeld, Full Penetration
Definition(s)
Weld, Full Penetration
A weld which extends throughout the complete wall section of the parts joined. Source: API SPEC 16RCD, Specification for Drill Through Equipment—Rotating Control Devices, Upstream Segment, First Edition, February 2005. Global StandardsWeld, Major Repair
Definition(s)
Weld, Major Repair
Welds that are greater than 25% of the original wall thickness or 1 in., whichever is less. Source: API SPEC 16RCD, Specification for Drill Through Equipment—Rotating Control Devices, Upstream Segment, First Edition, February 2005. Global StandardsWeld, Non-Pressure Containing
Definition(s)
Weld, Non-Pressure Containing
A weld, the absence of which will not reduce the pressure containing integrity of the part. Source: API SPEC 16C, Specification for Choke and Kill Systems, First Edition, January 1993 (Reaffirmed 2001). Global StandardsWeld, Non-Pressure Containing
A weld the failure of which will not reduce the pressure-containing integrity of the component. Source: API SPEC 16RCD, Specification for Drill Through Equipment—Rotating Control Devices, Upstream Segment, First Edition, February 2005. Global StandardsWeld, Pressure Containing
Definition(s)
Weld, Pressure Containing
A weld, the absence of which will reduce the pressure containing integrity of the part. Source: API SPEC 16C, Specification for Choke and Kill Systems, First Edition, January 1993 (Reaffirmed 2001). Global StandardsWeld, Pressure Containing
A weld, the failure of which will reduce the pressure-containing integrity of the component. Source: API SPEC 16RCD, Specification for Drill Through Equipment—Rotating Control Devices, Upstream Segment, First Edition, February 2005. Global StandardsWeld, Verb
Definition(s)
Weld, Verb
Fuse materials, with or without the addition of filler materials. Source: API SPEC 6A, Specification for Wellhead and Christmas Tree Equipment, Twentieth Edition, October 2010 (Addendum November 2012). Global StandardsWeld, Verb
Act of fusing materials, with or without the addition of filler materials. 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 StandardsWelder
Definition(s)
Welder
The person operating gas or electric welding equipment; the person physically doing the welding. In some publications this person is referred to as a welding operator. API RP 2201, Safe Hot Tapping Practices in the Petroleum & Petrochemical Industries, Fifth Edition, July 2003 (Reaffirmed October 2010), Global Standards API RP 2009, Safe Welding, Cutting, and Hot Work Practices in the Petroleum and Petrochemical Industries, Seventh Edition, February 2002 (Reaffirmed, March 2012), Global StandardsWelding
Definition(s)
Welding
Application of any one of a group of welding processes that applies heat energy sufficient to melt and join one or more pieces of metal through localized fusion and coalescence. 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 StandardsWelding
Process of joining metal by bringing abutting surfaces to a molten state with or without the use of a filler material.
Source:API SPECIFICATION 19TT, Specification for Downhole Well Test Tools and Related Equipment, First Edition, October 2016. Global StandardsWelding
Welding means all activities connected with welding, including hot tapping and burning. Source: Oil and Gas and Sulphur Operations in the Outer Continental Shelf, 30 CFR 250 (2013). RegulationsWelding
The fusion of materials, with or without the addition of filler materials. Source: API SPEC 16C, Specification for Choke and Kill Systems, First Edition, January 1993 (Reaffirmed 2001). Global Standards Source: API SPEC 16RCD, Specification for Drill Through Equipment—Rotating Control Devices, Upstream Segment, First Edition, February 2005. Global StandardsWelding Machine And Welding Operator Performance Qualification (WPQ)
Definition(s)
Welding Machine And Welding Operator Performance Qualification (WPQ)
Written procedure used to demonstrate that a welding machine and welding operator combination has the capability to use the WPS to produce a weld meeting the requirements of this International Standard. NOTE It includes records from the qualification tests. Source: API SPEC 5DP, Specification for Drill Pipe, First Edition, August 2009. Global StandardsWelding Neck Flange
Definition(s)
Welding Neck Flange
Flange with a neck on the side opposite the sealing face, prepared with a bevel to weld to corresponding pipe or transition pieces. Source: API SPEC 6A, Specification for Wellhead and Christmas Tree Equipment, Twentieth Edition, October 2010 (Addendum November 2012). Global StandardsWelding Procedure Specification (WPS)
Definition(s)
Welding Procedure Specification (WPS)
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.
Welding Procedure Specification
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.
Welding Procedure Specification (WPS)
Written procedure that provides instructions to the welding operator for making production welds in accordance with the requirements of this International Standard.- NOTE: It includes all essential variables and non-essential variables for friction welding of tool joints to drill-pipe body. A WPS applies to all those welds, of which each element has the same specified dimensions and chemistry, that are grouped according to a documented procedure that ensures a predictable response to weld-zone treatment for a particular grade.
Weldment
Definition(s)
Weldment
Portion or area of a component on which welding has been performed.- NOTE: A weldment includes the weld metal, the heat-affected zone (HAZ), and the base metal unaffected by the heat of welding.
Well
Definition(s)
Well
"Well"- means a hole penetrating the earth, usually cased with steel pipe, and
- from which oil or gas, or both, or geothermal resources, is obtained or obtainable; or
- that is made for the purpose of finding or obtaining oil, gas, or geothermal resources, or of supporting oil, gas, or geothermal resources production; and
- includes a well with multiple well branches drilled to different bottom-hole locations.
Well
“Well” means any borehole, whether drilled or bored, for stratigraphic exploration or for the production, extraction or injection of any gas or liquid mineral, excluding potable water to be used as such, but including natural or artificial brines and oil field waters, sewage, and any liquid used in or resulting from any process of industry, manufacture, trade, business, or agriculture. Source: Division of Mineral Resources Management - Oil and Gas, Ohio Administrative Code, Chapter 1501:9, January 2012. RegulationsWell
“Well” means any borehole, whether drilled or bored, within the state, for production, extraction, or injection of any gas or liquid mineral, excluding potable water to be used as such, but including natural or artificial brines and oil field waters. Source: Division of Mineral Resources Management - Oil and Gas, Ohio Administrative Code, Chapter 1501:9, January 2012. RegulationsWell
“Well" means any opening in the ground (not being a seismic shot hole) that is made, is to be made or is in the process of being made, by drilling, boring or other method,- for the production of petroleum,
- for the purpose of searching for or obtaining petroleum,
- for the purpose of obtaining water to inject into an underground formation,
- for the purpose of injecting gas, air, water or other substance into an under ground formation,
- for any purpose, if made through sedimentary rocks to a depth of at least one hundred and fifty metres.
Well
Well―all wells drilled within the confines of any unit(s) sought to be terminated. Source: Natural Resources, Office of Conservation – General Operations, Louisiana Administrative Code, Title 43, Part XIX, March 2013. RegulationsWell
Well includes all equipment located downhole from a well. Examples:- Equipment leading to a blow-out preventer.
- Equipment leading to a well head.
- Equipment leading to a Christmas Tree.
Well
Well means a hole in the seabed or subsoil made by drilling, boring or any other means in connection with:- exploration for petroleum; or
- petroleum recovery operations; or
- exploration for potential greenhouse gas storage formations; or
- exploration for potential greenhouse gas injection sites; or
- the injection of a greenhouse gas substance into an identified greenhouse gas storage formation; or
- the injection, on an appraisal basis, of a greenhouse gas substance into a part of a geological formation; or
- the injection, on an appraisal basis, of air, petroleum or water into a part of a geological formation;
Well
Well includes well-related equipment associated with a well. Source: Offshore Petroleum and Greenhouse Gas Storage Act 2006, Australia, amended 2012. LegislationWell
WELL when used alone in these Rules and Regulations, shall mean an oil or gas well, a hole drilled for the purpose of producing oil or gas, a well into which fluids are injected, a stratigraphic well, a gas storage well, or a well used for the purpose of monitoring or observing a reservoir. Source: Oil and Gas Conservation Commission, Practice and Procedure, Code of Colorado Regulations, 2 CCR 404-1, February 2013. RegulationsWell
“Well” means a well bore with single or multiple completions, including all horizons and producing formations from the surface to total depth. Source: Oil and Gas, New Mexico Administrative Code Title 19, Chapter 15, January 2013. RegulationsWell
A well drilled for any purpose related to exploration for or production or storage of oil or gas or geothermal resources, including a well drilled for injection of fluids to enhance hydrocarbon recovery, disposal of produced fluids, disposal of waste from exploration or production activity, or brine mining. Source: Oil and Gas Division, Texas Administrative Code, Title 16, Chapter 3, February 2013. RegulationsWell
A well as defined in Texas Natural Resources Code, Chapter 89. Source: Oil and Gas Division, Texas Administrative Code, Title 16, Chapter 3, February 2013. RegulationsWell
a well made by drilling; and a borehole drilled with a view to the extraction of minerals through it or another well Regulation 2, DCR. Source: Oil & Gas UK, Guidelines on subsea BOP systems, Issue 1, July 2012, Global StandardsWell
"Well" means a hole in the ground:- made, or being made, by drilling, boring, or in any other manner, and from which oil or gas is obtained, or is obtainable; or is for the purpose of attempting to obtain oil or gas;
- made, or being made, by drilling or boring for the purpose of obtaining water to inject to an underground formation;
- used, drilled, or being drilled for the purpose of injecting gas, air, water or other substance to an underground formation;
- which is a test-hole, excluding seismic drilling; or
- drilled or being drilled, for any other purpose than listed above using equipment and machinery normally used for oil and gas well drilling.
Well
“Well” includes any borehole associated with that well. Source: The Borehole Sites and Operations Regulations 1995, UK S.I. 1995/2038, 1995. RegulationsWell
Well. A well is any area on the deck exposed to the weather, where water may be entrapped. Wells are considered to be deck areas bounded on two or more sides by deck structures. <Chapter I, regulation 3>. Source: IMO Resolution MSC.143(77), amendments to Annex B to the 1988 Load Lines Protocol, 5 June 2003, International Maritime Organization. LegislationWell
Well: borehole taken into service following construction, fitting-out and completion. Source: Mining Regulation of the Netherlands, WJZ 02063603, Netherlands,16 December 2002. RegulationsWell
Well— (a) means a borehole drilled for the purpose of exploring for, appraising, or extracting petroleum; and (b) includes— (i) any borehole for injection or reinjection purposes; and (ii) any down-hole pressure containing equipment; and (iii) any pressure-containing equipment on top of the well well intervention operation means an operation in which a well is re-entered for a purpose other than to continue drilling or to maintain or repair it. Source: Health and Safety in Employment (Petroleum Exploration and Extraction) Regulations 2013, SR 2013/208, New Zealand, as of May 2013. RegulationsWell Abandonment
Definition(s)
Well Abandonment
Permanent subsurface isolation to prevent any undesired communication between any distinct zones and fluid movement out of a well using validated well barriers. Source: ISO 16530-1:2017, Petroleum and natural gas industries — Well integrity – Part 1: Life cycle governance, First Edition, March 2017. Global StandardsWell Barrier
Definition(s)
Well Barriers
System of one or several well barrier elements that contain fluids within a well to prevent uncontrolled flow of fluids within or out of the well.Source: ISO 16530-1:2017, Petroleum and natural gas industries — Well integrity – Part 1: Life cycle governance, First Edition, March 2017. Global Standards
Well Barriers
An envelope of one or more well barrier elements that prevents fluids from flowing unintentionally from the formation or well into another formation or to the surface.
Source:API SPECIFICATION 19TT, Specification for Downhole Well Test Tools and Related Equipment, First Edition, October 2016. Global StandardsWell Barrier
Envelope of one or several dependent barrier elements preventing fluids or gases from flowing unintentionally from the formation into another formation or to the surface. Source: API RP 90, Annular Casing Pressure Management for Offshore Wells, Upstream Segment. First Edition, August 2006. Global StandardsWell Barrier Elements
Definition(s)
Well Barrier Elements
One of several dependent components that are combined to form a well barrier. Source: ISO 16530-1:2017, Petroleum and natural gas industries — Well integrity – Part 1: Life cycle governance, First Edition, March 2017. Global StandardsWell Barrier Elements
A pressure and flow containing component that relies on other component(s) to create a well barrier.
Source:API SPECIFICATION 19TT, Specification for Downhole Well Test Tools and Related Equipment, First Edition, October 2016. Global StandardsWell Barrier Elements
Well barrier elements include deep-set plugs under the production packer and plugs in the hanger assembly for the completion string. Source: Guidance Notes on Petroleum and Natural Gas (Safety in Offshore Operations) Rules, 2008, Oil Industry Safety Directorate (India), 2012. Regulatory GuidanceWell Barrier Plan
Definition(s)
Well Barrier Plan
Well operator’s specific programme for barrier placement and verification in a well to prevent unplanned flow during each stage of well construction, operation, abandonment or decommissioning. Source: ISO 16530-1:2017, Petroleum and natural gas industries — Well integrity – Part 1: Life cycle governance, First Edition, March 2017. Global StandardsWell Barrier System
Definition(s)
Well Barrier System
Well barrier system is one or more barriers that act in series to prevent flow. Well barriers that do not act in series are not considered part of a single well barrier system, as they do not act together to increase total system reliability. Source: API STD 65 Part 2, Isolating Potential Flow Zones During Well Construction, Upstream Segment, Second Edition, December 2010. Global StandardsWell Barriers
Definition(s)
Well Barriers
API STD 65-2, standard defines the requirements that must be met to maintain a safe well.
Source: API STD 65 – Part 2, Isolating Potential Flow Zones During Well Construction, Upstream Segment, Second Edition, December 2010. Global Standards
Well Competency Catalogue
Definition(s)
Well Competency Catalogue
A well competency catalogue is the hierarchical list of skills which are required to deliver well operations covered by the CMS. Figure 3 shows examples of skills, and their interrelationships, that are applicable throughout the well life cycle, including: — well design, planning and risk identification; — well control (primary and secondary); — project execution; — barrier identification, installation and testing. Source: ISO/TS 17969:2015, Petroleum, petrochemical and natural gas industries — Guidelines on competency for personnel, First Edition, June 2015. Global StandardsWell Completion
Definition(s)
Well Completion
Well operations including tubing installation, well perforation and test production. 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 StandardsWell Construction
Definition(s)
Well Construction
The construction features of inactive wells which provide the mechanical barriers to fluid migration include: i) surface casing installed below all fresh water aquifers with cement circulated to the surface; 2) any intermediate casing installed and cemented, 3) production casing installed and cemented into the lowermost confining zone; and 4) any tubing and packer set in the well above the completion interval. The Christmas-tree or stuffingbox assembly isolates the wellbore fluids from the surface and provides readily accessible gauges on all tubing, casing, and annuli outlets for ease of monitoring pressures. The mechanical integrity of these well construction components is the key factor in their ability to provide a barrier to fluid migration. There are inactive wells which provide adequate protection against fluid migration into a fresh water aquifer or to the surface, but they may not have all of the construction details discussed above. By tailoring the monitoring program to a well's construction, operators can increase monitoring frequency for inactive wells that have fewer barriers to fluid migration. 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 StandardsWell Construction
A set of operations to be directed by the lease operator employing the drilling contractor and third-party services equipment and personnel. Source: API Bulletin 97, Well Construction Interface Document Guidelines, First Edition, December 2013. Global StandardsWell Construction Interface Document – safety and Environmental Management System
Definition(s)
Well Construction Interface Document – safety and Environmental Management System
Bridging document between the lease operator's SEMS and the CSWP. Source: API Bulletin 97, Well Construction Interface Document Guidelines, First Edition, December 2013. Global StandardsWell Construction Interface Document – well Plan
Definition(s)
Well Construction Interface Document – well Plan
WCID-well plan Summary of the well plan from lease operator to drilling contractor. Source: API Bulletin 97, Well Construction Interface Document Guidelines, First Edition, December 2013. Global StandardsWell Control (Choke) Manifold
Definition(s)
Well Control (Choke) Manifold
Part of a specially-designed section of piping installed on a drilling rig for use during well control incidents and not for MPD. This manifold and any associated choke(s) are designed for lower flow rates and higher pressures than those used for drilling.
Source: ABS Guide for Classification and Certification of Managed Pressure Drilling Systems, September 2017. 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.