Make-Up Shoulder

Make-Up Shoulder

Definition(s)

Make-up Shoulder

The sealing shoulder on a rotary shouldered connection. Source: API RP 7G, Recommended Practice for Drill Stem Design and Operating Limits, Upstream Segment, Sixteenth Edition, August 1998 (Addendum 2: September 2009). Global Standards Source: API RP 7G-2, Recommended Practice for Inspection and Classification of Used Drill Stem Elements, First Edition, August 2009. Global Standards  

Make-up Shoulder

Sealing shoulder on a rotary shouldered connection. Source: API SPEC 7-1, Specification for Rotary Drill Stem Elements, First Edition, March 2006 (Addendum April 2011). Global Standards  
Last Engaged Thread

Last Engaged Thread

Definition(s)

Last Engaged Thread

The last thread on the pin engaged with the box or the box engaged with the pin. Source: API RP 7G, Recommended Practice for Drill Stem Design and Operating Limits, Upstream Segment, Sixteenth Edition, August 1998 (Addendum 2: September 2009). Global Standards  

Last Engaged Thread

Last thread on the pin engaged with the box or the box engaged with the pin. See Figure 2. Source: API RP 7G-2, Recommended Practice for Inspection and Classification of Used Drill Stem Elements, First Edition, August 2009. Global Standards  
Kelly Saver Sub

Kelly Saver Sub

Definition(s)

Kelly Saver Sub

A short substitute that is made up onto the bottom of the kelly to protect the pin end of the kelly from wear during make-up and break-out operations. Source: API RP 7G, Recommended Practice for Drill Stem Design and Operating Limits, Upstream Segment, Sixteenth Edition, August 1998 (Addendum 2: September 2009). Global Standards  

Kelly Saver Sub

Short rotary sub that is made up onto the bottom of the kelly to protect the pin end of the kelly from wear during make-up and break-out operations. Source: API SPEC 7-1, Specification for Rotary Drill Stem Elements, First Edition, March 2006 (Addendum April 2011). Global Standards  
Forging

Forging

Definition(s)

Forging

(1) Plastically deforming metal, usually hot, into desired shapes with compressive force, with or without dies. (2) A shaped metal part formed by the forging method. Source: API RP 7G, Recommended Practice for Drill Stem Design and Operating Limits, Upstream Segment, Sixteenth Edition, August 1998 (Addendum 2: September 2009). Global Standards  

Forging

(1) Plastically deforming metal, usually hot, into desired shapes with compressive force, with or without dies. (2) A shaped metal part formed by the forging method. Source: API SPEC 16C, Specification for Choke and Kill Systems, First Edition, January 1993 (Reaffirmed 2001). Global Standards  

Forging

(1) Plastically deforming metal, usually hot, into desired shapes with compressive force, with open or closed dies. (2) A shaped metal part formed by the forging method. Source: API SPEC 16RCD, Specification for Drill Through Equipment—Rotating Control Devices, Upstream Segment, First Edition, February 2005. Global Standards  
Fatigue Crack

Fatigue Crack

Definition(s)

Fatigue Crack

A crack resulting from fatigue. See fatigue. Source: API RP 7G, Recommended Practice for Drill Stem Design and Operating Limits, Upstream Segment, Sixteenth Edition, August 1998 (Addendum 2: September 2009). Global Standards  

Fatigue Crack

Crack resulting from fatigue. Source: API RP 7G-2, Recommended Practice for Inspection and Classification of Used Drill Stem Elements, First Edition, August 2009. Global Standards  
Fatigue Failure

Fatigue Failure

Definition(s)

Fatigue Failure

A failure which originates as a result of repeated or fluctuating stresses having maximum values less than the tensile strength of the material. Source: API RP 7G, Recommended Practice for Drill Stem Design and Operating Limits, Upstream Segment, Sixteenth Edition, August 1998 (Addendum 2: September 2009). Global Standards  

Fatigue Failure

Failure that originates as a result of repeated or fluctuating stresses having maximum values less than the tensile strength of the material. Source: API RP 7G-2, Recommended Practice for Inspection and Classification of Used Drill Stem Elements, First Edition, August 2009. Global Standards    
Fatigue

Fatigue

Definition(s)

Fatigue

The process of progressive localized permanent structural change occurring in a material subjected to conditions that produce fluctuating stresses and strains at some point or points and that may culminate in cracks or complete fracture after a sufficient number of fluctuations. Source: API RP 7G, Recommended Practice for Drill Stem Design and Operating Limits, Upstream Segment, Sixteenth Edition, August 1998 (Addendum 2: September 2009). Global Standards Source: API RP 7G-2, Recommended Practice for Inspection and Classification of Used Drill Stem Elements, First Edition, August 2009. Global Standards  

Fatigue

Degradation of the material caused by cyclic loading. Source: Offshore Standard DNV-OS-C101, Design of Offshore Steel Structures, General (LRFD Method, Det Norske Veritas, April 2011. Global Standards  
Drill Collar

Drill Collar

Definition(s)

Drill Collar

Thick-walled pipe or tube designed to provide stiffness and concentration of weight at the bit. Source: API RP 7G, Recommended Practice for Drill Stem Design and Operating Limits, Upstream Segment, Sixteenth Edition, August 1998 (Addendum 2: September 2009). Global Standards  

Drill Collar

Thick-walled pipe or tube designed to provide stiffness and concentration of mass at or near the bit. Source: API RP 7G-2, Recommended Practice for Inspection and Classification of Used Drill Stem Elements, First Edition, August 2009. Global Standards  

Drill Collar

Thick-walled pipe used to provide stiffness and concentration of mass at or near the bit. Source: API SPEC 7-1, Specification for Rotary Drill Stem Elements, First Edition, March 2006 (Addendum April 2011). Global Standards  
Drift

Drift

Definition(s)

Drift

Bar utilized to verify the passage of a specified diameter and length through a well test tool.

Source:API SPECIFICATION 19TT, Specification for Downhole Well Test Tools and Related Equipment, First Edition, October 2016. Global Standards

Drift

A drift is a gauge used to check minimum ID of loops, flowlines, nipples, tubing, casing, drill pipe, and drill collars. Source: API RP 7G, Recommended Practice for Drill Stem Design and Operating Limits, Upstream Segment, Sixteenth Edition, August 1998 (Addendum 2: September 2009). Global Standards  

Drift

Cylindrical gauge used to check the minimum inside diameter. Source: API RP 7G-2, Recommended Practice for Inspection and Classification of Used Drill Stem Elements, First Edition, August 2009. Global Standards  

Drift

Cylindrical mandrel for verifying drift diameter of individual and assembled equipment. 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 Standards  

Drift

Gauge used to check minimum internal diameter of drill stem components. Source: API SPEC 7-1, Specification for Rotary Drill Stem Elements, First Edition, March 2006 (Addendum April 2011). Global Standards  

Drift (times)

Variation in the apparatus indication with time at any fixed gas volume fraction (including clean air) under constant ambient conditions. Source: IEC 60079-29-1, Explosive atmospheres – Part 29-1: Gas detectors – Performance requirements of detectors for flammable gases. Global Standards
Dogleg Severity

Dogleg Severity

Definition(s)

Dogleg Severity

A measure of the amount of change in the inclination and/or direction of a borehole, usually expressed in degrees per 100 feet of course length. Source: API RP 7G, Recommended Practice for Drill Stem Design and Operating Limits, Upstream Segment, Sixteenth Edition, August 1998 (Addendum 2: September 2009). Global Standards  
Dogleg

Dogleg

Definition(s)

Dogleg

A term applied to a sharp change of direction in a wellbore or ditch. Applied also to the permanent bending of wire rope or pipe. Source: API RP 7G, Recommended Practice for Drill Stem Design and Operating Limits, Upstream Segment, Sixteenth Edition, August 1998 (Addendum 2: September 2009). Global Standards  
Dedendum

Dedendum

Definition(s)

Dedendum

The distance between the pitch line and root of thread. Source: API RP 7G, Recommended Practice for Drill Stem Design and Operating Limits, Upstream Segment, Sixteenth Edition, August 1998 (Addendum 2: September 2009). Global Standards  
Decarburization

Decarburization

Definition(s)

Decarburization

The loss of carbon from the surface of a ferrous alloy as a result of heating in a medium that reacts with the carbon at the surface. Source: API RP 7G, Recommended Practice for Drill Stem Design and Operating Limits, Upstream Segment, Sixteenth Edition, August 1998 (Addendum 2: September 2009). Global Standards  

Decarburization

Loss of carbon from the surface of a ferrous alloy as a result of heating in a medium that reacts with the carbon at the surface. Source: API SPEC 7-1, Specification for Rotary Drill Stem Elements, First Edition, March 2006 (Addendum April 2011). Global Standards  
Annuli

Annuli

Definition(s)

Annuli

Plural of annulus. A well may contain several annuli formed by multiple casing and liner pipe strings. Source: API STD 65 – Part 2, Isolating Potential Flow Zones During Well Construction, Upstream Segment, Second Edition, December 2010. Global Standards 
Critical Rotary Speed

Critical Rotary Speed

Definition(s)

Critical Rotary Speed

A rotary speed at which harmonic vibrations occur. These vibrations may cause fatigue failures, excessive wear, or bending. Source: API RP 7G, Recommended Practice for Drill Stem Design and Operating Limits, Upstream Segment, Sixteenth Edition, August 1998 (Addendum 2: September 2009). Global Standards  
Corrosion

Corrosion

Definition(s)

Corrosion

Degradation of a component or components due to corrosion. Corrosion may be categorized as either general or local and may cause pitting, holes, or crevices. Source: API RP 2SIM, Structural Integrity Management of Fixed Offshore Structures, First Edition, November 2014. Global Standards  

Corrosion

The alteration and degradation of material by its environment. Source: API RP 7G, Recommended Practice for Drill Stem Design and Operating Limits, Upstream Segment, Sixteenth Edition, August 1998 (Addendum 2: September 2009). Global Standards Source: API RP 7G-2, Recommended Practice for Inspection and Classification of Used Drill Stem Elements, First Edition, August 2009. Global Standards  

Corrosion

Corrosion as mentioned in this sub rule means both external and internal corrosion. Source: Guidance Notes on Petroleum and Natural Gas (Safety in Offshore Operations) Rules, 2008, Oil Industry Safety Directorate (India), 2012. Regulatory Guidance
Cold Working

Cold Working

Definition(s)

Cold Working

Plastic deformation of metal at a temperature low enough to insure or cause permanent strain. Source: API RP 7G, Recommended Practice for Drill Stem Design and Operating Limits, Upstream Segment, Sixteenth Edition, August 1998 (Addendum 2: September 2009). Global Standards  

Cold Working

Plastic deformation of the thread roots of a rotary shouldered connection, of radii and of cylindrical sections at a temperature low enough to ensure or cause permanent strain of the metal. Source: API SPEC 7-1, Specification for Rotary Drill Stem Elements, First Edition, March 2006 (Addendum April 2011). Global Standards  
Class 2

Class 2

Definition(s)

Class 2

An API service classification for used drill pipe and tubing work strings. Source: API RP 7G, Recommended Practice for Drill Stem Design and Operating Limits, Upstream Segment, Sixteenth Edition, August 1998 (Addendum 2: September 2009). Global Standards  

Class 2

Second in the hierarchy of used drill pipe service classifications for used drill pipe that does not meet premium class requirements. Source: API RP 7G-2, Recommended Practice for Inspection and Classification of Used Drill Stem Elements, First Edition, August 2009. Global Standards  
Box Connection

Box Connection

Definition(s)

Box Connection

A threaded connection on Oil Country Tubular Goods (OCTG) that has internal (female) threads. Source: API RP 7G, Recommended Practice for Drill Stem Design and Operating Limits, Upstream Segment, Sixteenth Edition, August 1998 (Addendum 2: September 2009). Global Standards  

Box Connection

Threaded connection on oilfield tubular goods (OCTG) that has internal (female) threads. Source: API SPEC 7-1, Specification for Rotary Drill Stem Elements, First Edition, March 2006 (Addendum April 2011). Global Standards  
Bit Sub

Bit Sub

Definition(s)

Bit Sub

A sub, usually with 2 box connections, that is used to connect the bit to the drill string. Source: API RP 7G, Recommended Practice for Drill Stem Design and Operating Limits, Upstream Segment, Sixteenth Edition, August 1998 (Addendum 2: September 2009). Global Standards  

Bit Sub

Sub, usually with two box connections, that is used to connect the bit to the drill stem. Source: API RP 7G-2, Recommended Practice for Inspection and Classification of Used Drill Stem Elements, First Edition, August 2009. Global Standards Source: API SPEC 7-1, Specification for Rotary Drill Stem Elements, First Edition, March 2006 (Addendum April 2011). Global Standards    
Bevel Diameter

Bevel Diameter

Definition(s)

Bevel Diameter

The outer diameter of the contact face of the rotary shouldered connection. Source: API RP 7G, Recommended Practice for Drill Stem Design and Operating Limits, Upstream Segment, Sixteenth Edition, August 1998 (Addendum 2: September 2009). Global Standards Source: API RP 7G-2, Recommended Practice for Inspection and Classification of Used Drill Stem Elements, First Edition, August 2009. Global Standards  

Bevel Diameter

Outer diameter of the sealing shoulder of a rotary shouldered connection. Source: API SPEC 5DP, Specification for Drill Pipe, First Edition, August 2009. Global Standards  

Bevel Diameter

Outer diameter of the contact face of the rotary shouldered connection. Source: API SPEC 7-1, Specification for Rotary Drill Stem Elements, First Edition, March 2006 (Addendum April 2011). Global Standards  
Annular Pressure Buildup (APB)

Annular Pressure Buildup (APB)

Definition(s)

Annular pressure buildup (APB)

Pressure generated within an annulus by thermal expansion of wellbore fluids, typically during production. NOTE APB can also occur during drilling operations when trapped annular fluids at cool shallow depths are exposed to high temperatures induced by fluids circulating from deep, hot hole sections. This thermally induced pressure is defined and listed in API 90 as thermal casing pressure. NOTE 2 Can also occur from migration of formation fluids, as defined in API 90. Source: API RP 96, Deepwater Well Design and Construction, First Edition, March 2013. Global Standards

Annular Pressure Buildup (APB)

Pressure generated within a sealed annulus by thermal expansion of trapped wellbore fluids typically during production. May also occur during drilling operations when trapped annular fluids at cool shallow depths are exposed to high temperatures from fluids circulating in deep, hot hole sections. This thermally induced pressure is defined and listed in API RP 90 as thermal casing pressure. APB is also referred to as annular fluid expansion (AFE). Source: API STD 65 – Part 2, Isolating Potential Flow Zones During Well Construction, Upstream Segment, Second Edition, December 2010. Global Standards    
Annular Packers and Seal Rings

Annular Packers and Seal Rings

Definition(s)

Annular Packers and Seal Rings

Mechanical barrier devices with flexible, elastomeric sealing elements that can be run into a well on casing or liners for application as: a) annular element installed between an inner and outer pipe or between a casing and openhole formation to seal the annulus, b) annular seal rings installed on the inner pipe string to seal the micro-annulus and voids formed between the cement sheath and the inner pipe string. Source: API STD 65 – Part 2, Isolating Potential Flow Zones During Well Construction, Upstream Segment, Second Edition, December 2010. Global Standards 
VME

VME

Definition(s)

VME

Von Mises equivalent stress. Source: API RP 5C5, Recommended Practice on Procedures for Testing Casing and Tubing Connections, Third Edition, July 2003 (Reaffirmed August 2010). Global Standards
TSC

TSC

Definition(s)

TSC

Thread sealing connection. Source: API RP 5C5, Recommended Practice on Procedures for Testing Casing and Tubing Connections, Third Edition, July 2003 (Reaffirmed August 2010). Global Standards
TLE

TLE

Definition(s)

TLE

Test load envelope. Source: API RP 5C5, Recommended Practice on Procedures for Testing Casing and Tubing Connections, Third Edition, July 2003 (Reaffirmed August 2010). Global Standards
TC

TC

Definition(s)

TC

Thermal cycle. Source: API RP 5C5, Recommended Practice on Procedures for Testing Casing and Tubing Connections, Third Edition, July 2003 (Reaffirmed August 2010). Global Standards  

T&C

Threaded and coupled. Source: API SPEC 5CT, Specification for Casing and Tubing, Upstream Segment, Ninth Edition, July 2011 (Errata September 2012). Global Standards  

TC

Test coupon. Source: API SPEC 6A, Specification for Wellhead and Christmas Tree Equipment, Twentieth Edition, October 2010 (Addendum November 2012). Global Standards  

TC

To contain. Source: API SPEC 13A, Specification for Drilling Fluids Materials, Eighteenth Edition, February 2010. Global Standards  

TC

Transport Canada. Source:  Offshore Physical Environmental Guidelines, The Canada-Newfoundland and Labrador Offshore Petroleum Board, Canada-Nova Scotia Offshore Petroleum Board, and National Energy Board, Canada, September 2008. Regulatory Guidance
Std

Std

Definition(s)

Std

Standard. Source: API RP 5C5, Recommended Practice on Procedures for Testing Casing and Tubing Connections, Third Edition, July 2003 (Reaffirmed August 2010). Global Standards Source: API RP 14G, Recommended Practice for Fire Prevention and Control on Fixed Open-type Offshore Production Platforms: Upstream Segment, Fourth Edition, April 2007. Global Standards  
Annular Flow

Annular Flow

Definition(s)

Annular Flow

The flow of formation fluids (liquids and/or gases) from the formation into a space or pathway in an annulus within a well. The annular flow may follow various flow paths inside the annulus to other points including those at shallower or deeper depths. Source: API STD 65 – Part 2, Isolating Potential Flow Zones During Well Construction, Upstream Segment, Second Edition, December 2010. Global Standards 
SRG

SRG

Definition(s)

SRG

Seal ring groove. Source: API RP 5C5, Recommended Practice on Procedures for Testing Casing and Tubing Connections, Third Edition, July 2003 (Reaffirmed August 2010). Global Standards  

SRG

Stress-relief groove. Source: API RP 7G-2, Recommended Practice for Inspection and Classification of Used Drill Stem Elements, First Edition, August 2009. Global Standards