Glossary
Browse the IADC Lexicon alphabetically or by category. Get comprehensive definitions of drilling industry terms.
Hard-Banding
Definition(s)
Hard-Banding (or Hard-Facing)
Sacrificial or wear-resistant material applied to component’s surface to prevent wear of the component. Source: API RP 7G-2, Recommended Practice for Inspection and Classification of Used Drill Stem Elements, First Edition, August 2009. Global StandardsHard-Banding (or Hard-Facing)
Application of material onto tool joints to reduce external wear of the tool joint. NOTE Also known as hard facing. Source: API SPEC 5DP, Specification for Drill Pipe, First Edition, August 2009. Global StandardsGouge
Definition(s)
Gouge
Elongated grooves or cavities caused by mechanical removal of metal. Source: API RP 7G-2, Recommended Practice for Inspection and Classification of Used Drill Stem Elements, First Edition, August 2009. Global StandardsGouge
Elongated groove or cavity caused by mechanical removal of metal. Source: API SPEC 5DP, Specification for Drill Pipe, First Edition, August 2009. Global StandardsGall
Definition(s)
Gall
Surface damage on threads and seals caused by localized friction. Source: API RP 7G-2, Recommended Practice for Inspection and Classification of Used Drill Stem Elements, First Edition, August 2009. Global StandardsFull-Depth Thread
Definition(s)
Full-Depth Thread
Thread for which the thread root lies on the minor cone of an external thread or lies on the major cone of an internal thread. Source: API RP 7G-2, Recommended Practice for Inspection and Classification of Used Drill Stem Elements, First Edition, August 2009. Global StandardsFull-Depth Thread
Thread in which the thread root lies on the minor cone of an external thread or on the major cone of an internal thread. Source: API SPEC 7-1, Specification for Rotary Drill Stem Elements, First Edition, March 2006 (Addendum April 2011). Global StandardsFish Neck
Definition(s)
Fish Neck
Region with a reduced diameter at or near the upper end of a drill string member which fishing tools can grab. Source: API RP 7G-2, Recommended Practice for Inspection and Classification of Used Drill Stem Elements, First Edition, August 2009. Global StandardsFiltered FWAC
Definition(s)
Filtered FWAC
Full-wave current rectified by passing it through a capacitor or other electrical device to remove the fluctuations associated with alternating current. Source: API RP 7G-2, Recommended Practice for Inspection and Classification of Used Drill Stem Elements, First Edition, August 2009. Global StandardsDrill-Pipe Body
Definition(s)
Drill-Pipe Body
Seamless steel pipe with upset ends. See Figure 1. Source: API RP 7G-2, Recommended Practice for Inspection and Classification of Used Drill Stem Elements, First Edition, August 2009. Global StandardsDent
Definition(s)
Dent
Local change in surface contour caused by mechanical impact, but not accompanied by loss of metal. Source: API RP 7G-2, Recommended Practice for Inspection and Classification of Used Drill Stem Elements, First Edition, August 2009. Global StandardsCritical Area
Definition(s)
Critical Area
Area from the base of the tapered shoulder of the tool joint to a plane located 660 mm (26.0 in) away, or the end of the slip marks, whichever distance is greater. See Figure 4. NOTE When applied to the work-string tubing area, it is from the end of the pipe to a plane located 508 mm (20 in) away, or the end of the slip marks, whichever distance is greater. Source: API RP 7G-2, Recommended Practice for Inspection and Classification of Used Drill Stem Elements, First Edition, August 2009. Global StandardsCritical Area
Highly stressed regions on a primary load-carrying component. Source: API SPEC 7K, Drilling and Well Servicing Equipment Upstream Segment, Fifth Edition, June 2010 (August 2010). Global Standards Source:API SPECIFICATION 7K, Drilling and Well Servicing Equipment, Sixth Edition, December 2015. Global StandardsCritical Area
Highly stressed region of a primary-load-carrying component as defined by the manufacturer. 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 StandardsCritical Area
A coastal wetland, an oyster reef, a hard substrate reef, submerged aquatic vegetation, or a tidal sand or mud flat as defined in Texas Natural Resources Code, §33.203. Source: Oil and Gas Division, Texas Administrative Code, Title 16, Chapter 3, February 2013. RegulationsCheck
Definition(s)
Check
Go/no-go determination that dimension is within tolerances. Source: API RP 7G-2, Recommended Practice for Inspection and Classification of Used Drill Stem Elements, First Edition, August 2009. Global StandardsClass 3
Definition(s)
Class 3
Third in the hierarchy of used drill pipe service classifications for used drill pipe that does not meet class 2 requirements. Source: API RP 7G-2, Recommended Practice for Inspection and Classification of Used Drill Stem Elements, First Edition, August 2009. Global StandardsLeak-Off Test (LOT)
Definition(s)
Leak-Off Test
Application of pressure by superimposing a surface pressure on a fluid column in order to determine the pressure at which the exposed formation accepts whole fluid. Source: ISO 16530-1:2017, Petroleum and natural gas industries — Well integrity – Part 1: Life cycle governance, First Edition, March 2017. Global Standards Source: API RP 59, Recommended Practice for Well Control Operations, Second Edition, May 2006. Global StandardsLeak-Off Test (LOT)
A leak-off test is a procedure used to determine the wellbore pressure required to initiate a fracture in the open or exposed formations. Source: API STD 65 – Part 2, Isolating Potential Flow Zones During Well Construction, Upstream Segment, Second Edition, December 2010. Global StandardsBox Thread
Definition(s)
Box Thread
Internal (female) threads of a rotary shouldered connection. Source: API RP 7G-2, Recommended Practice for Inspection and Classification of Used Drill Stem Elements, First Edition, August 2009. Global StandardsLCM
Definition(s)
LCM
Life cycle management. Source: API STANDARD 18LCM, Product Life Cycle Management System Requirements for the Petroleum and Natural Gas Industries, First Edition, April 2017. Global StandardsLCM
Lost control material. Source:API SPECIFICATION 19TT, Specification for Downhole Well Test Tools and Related Equipment, First Edition, October 2016. Global StandardsLCM
Lost circulation material. Source: API STD 65 – Part 2, Isolating Potential Flow Zones During Well Construction, Upstream Segment, Second Edition, December 2010. Global Standards Source: Deepwater Well Control Guidelines. IADC GuidelinesBox End
Definition(s)
Box End
End of pipe with internal threads. Source: API RP 7G-2, Recommended Practice for Inspection and Classification of Used Drill Stem Elements, First Edition, August 2009. Global StandardsBottleneck Sub
Definition(s)
Bottleneck Sub
Sub with two distinct outside diameters. Source: API RP 7G-2, Recommended Practice for Inspection and Classification of Used Drill Stem Elements, First Edition, August 2009. Global StandardsHybrid Wells
Definition(s)
Hybrid Wells
Well drilled with a subsea wellhead and completed with a surface casing head, a surface tubing head, a surface tubing hanger and a surface tree.- Note: 1 to entry: A hybrid well can have either one (single-bore production riser) casing string or two (dual-bore production riser) casing strings brought up from the subsea wellhead and tied back to the surface equipment.
Hybrid Wells
Wells drilled with a subsea wellhead and completed with a surface casing head, a surface tubing head, a surface tubing hanger, and a surface christmas tree. A hybrid well may have either one (single bore production riser) casing string or two (dual bore production riser) casing strings brought up from the subsea wellhead and tied back to the surface equipment. These wells are typically located on floating production platforms such as spars or TLPs. Source: API RP 90, Annular Casing Pressure Management for Offshore Wells, Upstream Segment. First Edition, August 2006. Global StandardsHybrid Wells
Wells drilled with a subsea wellhead and completed with a surface casing head, a surface tubing head, a surface tubing hanger and a surface tree. Source: API STD 65 – Part 2, Isolating Potential Flow Zones During Well Construction, Upstream Segment, Second Edition, December 2010. Global StandardsFormation Fluids
Definition(s)
Formation Fluids
Fluids present within the pores, fractures, faults, vugs, caverns, or any other spaces of formations are called formation fluids whether or not they were naturally formed or injected therein. The physical state of formation fluids may be liquids or gases and include various types such as hydrocarbons, fresh or saline water, carbon dioxide, hydrogen sulfide, etc. Source: API STD 65 – Part 2, Isolating Potential Flow Zones During Well Construction, Upstream Segment, Second Edition, December 2010. Global StandardsFormation Fluids
Formation fluids as mentioned in the first subsection, also means hydrates and water under pressure. Source: Guidelines Regarding the Activities Regulations, Norway, updated December 2012. Regulatory GuidanceFixed Platform Wells
Definition(s)
Fixed Platform Wells
Wells completed with a surface wellhead and a surface tree on a fixed platform. All of the casing strings are tied back to the surface wellhead. Source: API STD 65 – Part 2, Isolating Potential Flow Zones During Well Construction, Upstream Segment, Second Edition, December 2010. Global Standards Source: API RP 90, Annular Casing Pressure Management for Offshore Wells, Upstream Segment. First Edition, August 2006. Global StandardsFIT
Definition(s)
FIT
Application of pressure by superimposing a surface pressure on a fluid column in order to determine ability of a subsurface zone to withstand a certain pressure. Source: ISO 16530-1:2017, Petroleum and natural gas industries — Well integrity – Part 1: Life cycle governance, First Edition, March 2017. Global StandardsFIT
Geometric relationship between parts. Source: API SPEC 6A, Specification for Wellhead and Christmas Tree Equipment, Twentieth Edition, October 2010 (Addendum November 2012). Global StandardsFIT
Fit, when defined as the geometric relationship between parts, includes the tolerance criteria used during the design of a part and its mating parts. Fit, when defined as the state of being adjusted to or shaped for, includes the tolerance criteria used during the design of a seal and its mating parts. Source: API SPEC 6A, Specification for Wellhead and Christmas Tree Equipment, Twentieth Edition, October 2010 (Addendum November 2012). 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 StandardsFIT
Geometric relationship between parts including the tolerance criteria used during the design of a part and its mating parts.
Source:API SPECIFICATION 19TT, Specification for Downhole Well Test Tools and Related Equipment, First Edition, October 2016. Global StandardsFIT
Geometric relationship between parts. NOTE This includes the tolerance criteria used during the design of a part and its mating parts, including seals. Source: API SPEC 14A, Specification for Subsurface Safety Valve Equipment, Eleventh Edition, October 2005 (Reaffirmed June 2012). Global StandardsFIT
1. The geometric relationship between parts. This would include the tolerance criteria used during the design of a part and its mating parts. 2. The state of being adjusted to or shaped for, this would include the tolerance criteria used during the design of a seal and its mating parts. Source: API SPEC 16C, Specification for Choke and Kill Systems, First Edition, January 1993 (Reaffirmed 2001). Global StandardsFIT
Formation integrity test. Source: ISO 16530-1:2017, Petroleum and natural gas industries — Well integrity – Part 1: Life cycle governance, First Edition, March 2017. Global Standards Source: API Bulletin 97, Well Construction Interface Document Guidelines, First Edition, December 2013. Global Standards Source: API STD 65 – Part 2, Isolating Potential Flow Zones During Well Construction, Upstream Segment, Second Edition, December 2010. Global Standards Source: Deep Water Well Control Guidlines. IADC GuidelinesFG
Definition(s)
FG
Frac gradient. Source: API STD 65 – Part 2, Isolating Potential Flow Zones During Well Construction, Upstream Segment, Second Edition, December 2010. Global StandardsExternal Casing Packer (ECP)
Definition(s)
External Casing Packer (ECP)
An external casing packer is a mechanical annular barrier that has elastomeric elements that seal the annulus when inflated. Also see the definition in this section for annular packers and the description of an ECP in 4.4. Source: API STD 65 – Part 2, Isolating Potential Flow Zones During Well Construction, Upstream Segment, Second Edition, December 2010. Global StandardsEquivalent Circulating Density (ECD)
Definition(s)
Equivalent Circulating Density
The effective density of the circulating fluid in the wellbore resulting from the sum of the pressure imposed by the static fluid column, friction pressure and surface back-pressure.
Source: ABS Guide for Classification and Certification of Managed Pressure Drilling Systems, September 2017. Global StandardsEquivalent Circulating Density (ECD)
Equivalent circulating density is the effective density of the circulating fluid in the wellbore resulting from the sum of the hydrostatic pressure imposed by the static fluid column and the friction pressure. Source: API STD 65 – Part 2, Isolating Potential Flow Zones During Well Construction, Upstream Segment, Second Edition, December 2010. Global StandardsEquivalent Circulating Density (ECD)
The sum of pressure exerted by hydrostatic head of fluid, drilled solids, and friction pressure losses in the annulus divided by depth of interest and by 0.052, if ECD is to be expressed in pounds per gallon (lb/gal). Source: API RP 59, Recommended Practice for Well Control Operations, Second Edition, May 2006. Global StandardsEMW
Definition(s)
EMW
Equivalent mud weight. Source: API STD 65 – Part 2, Isolating Potential Flow Zones During Well Construction, Upstream Segment, Second Edition, December 2010. Global StandardsECP
Definition(s)
ECP
External casing packer. Source: API STD 65 – Part 2, Isolating Potential Flow Zones During Well Construction, Upstream Segment, Second Edition, December 2010. Global StandardsECD
Definition(s)
ECD
Equivalent circulating density. Source: ABS Guide for Classification and Certification of Managed Pressure Drilling Systems, September 2017. Global Standards Source: ISO 16530-1:2017, Petroleum and natural gas industries — Well integrity – Part 1: Life cycle governance, First Edition, March 2017. Global Standards Source: API STD 65 – Part 2, Isolating Potential Flow Zones During Well Construction, Upstream Segment, Second Edition, December 2010. Global Standards Source: NORSOK D-010, Well integrity in drilling and well operations, Rev. 3, August 2004. Global StandardsECD
The effective density of the circulating fluid in the wellbore resulting from the sum of the pressure imposed by the static fluid column, friction pressure and surface back-pressure.
Source: ABS Guide for Classification and Certification of Managed Pressure Drilling Systems, September 2017. Global StandardsDrive/Jet Pipe
Definition(s)
Drive/Jet Pipe
Supports unconsolidated deposits and provides hole stability for initial drilling operations. This is normally the first string set and provides no pressure containment. This string can also provide structural support to the well system. Source: API RP 90, Annular Casing Pressure Management for Offshore Wells, Upstream Segment. First Edition, August 2006. Global StandardsDrive/Jet Pipe
Casing which supports unconsolidated sediments providing hole stability for initial drilling operations. This is normally the first string set and provides no pressure containment. This string can also provide structural support to the well system. See also definition for structural pipe (or casing). Source: API STD 65 – Part 2, Isolating Potential Flow Zones During Well Construction, Upstream Segment, Second Edition, December 2010. Global StandardsDiverter
Definition(s)
Diverter
Device attached to the marine riser or wellhead to close the vertical flow path and direct the flow in a predetermined direction.
Source: API Specification 16Q, Design, Selection, Operation, and Maintenance of Marine Drilling Riser Systems, Second Edition, April 2017. Global Standards