Glossary
Browse the IADC Lexicon alphabetically or by category. Get comprehensive definitions of drilling industry terms.
Barrier (Barrier Element)
Definition(s)
Barrier Element
Device that, alone, cannot prevent flow from one side to the other side of itself. Source: API RP 17G, Recommended Practice for Completion/Workover Risers, Second Edition, July 2006 (Reaffirmed April 2011). Global StandardsBarrier (Barrier Element)
A component or practice that contributes to the total system reliability by preventing liquid or gas flow if properly installed. Source: API STD 65 – Part 2, Isolating Potential Flow Zones During Well Construction, Upstream Segment, Second Edition, December 2010. Global StandardsAPB
Definition(s)
APB
Annular pressure buildup. Source: API STD 65 – Part 2, Isolating Potential Flow Zones During Well Construction, Upstream Segment, Second Edition, December 2010. Global StandardsWorking Temperature
Definition(s)
Working Temperature
The temperature to which a particular piece of equipment is subjected during normal 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 StandardsWorking Temperature
Temperature to which a particular piece of equipment is subjected during normal operation. Source: API SPEC 7-1, Specification for Rotary Drill Stem Elements, First Edition, March 2006 (Addendum April 2011). Global StandardsWorking Pressure (WP)
Definition(s)
Working Pressure
The pressure to which a particular piece of equipment is subjected during normal 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 StandardsWorking Pressure
Pressure to which a particular piece of equipment is subjected during normal operation. Source: API SPEC 7-1, Specification for Rotary Drill Stem Elements, First Edition, March 2006 (Addendum April 2011). Global StandardsWorking Pressure
SSSV internal pressure rating, including the differential rating with the valve closed. Source: API SPEC 14A, Specification for Subsurface Safety Valve Equipment, Eleventh Edition, October 2005 (Reaffirmed June 2012). Global StandardsWorking Pressure
The maximum pressure a component is subjected to during normal operations and applied to its design. Source: NOGEPA Industrial Guideline No. 43, Surface BOP Review, Best Practices Checklist, Netherlands, Version 0, December 2011. Global StandardsWorking Gauges
Definition(s)
Working Gauges
Gauges used for gauging product 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 StandardsUpper Kelly Cock
Definition(s)
Upper Kelly Cock
A valve immediately above the kelly that can be closed to confine pressures inside 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 StandardsUpper Kelly Cock
Valve immediately above the kelly that can be closed to confine pressure inside the drill stem. Source: API RP 7G-2, Recommended Practice for Inspection and Classification of Used Drill Stem Elements, First Edition, August 2009. Global StandardsTool Joint
Definition(s)
Tool Joint
A heavy coupling element for drill pipe having coarse, tapered threads and sealing shoulders designed to sustain the weight of the drill stem, withstand the strain of repeated make-up and break-out, resist fatigue, resist additional make-up during drilling, and provide a leak-proof seal. The male section (pin) is attached to one end of a length of drill pipe and the female section (box) is attached to the other end. Tool joints may be welded to the drill pipe, screwed onto the pipe, or a combination of screwed on and welded. Source: API RP 7G, Recommended Practice for Drill Stem Design and Operating Limits, Upstream Segment, Sixteenth Edition, August 1998 (Addendum 2: September 2009). Global StandardsTool Joint
Forged or rolled steel component for drill-pipe designed to be welded to the drill-pipe body and having a rotary shouldered connection. Source: API SPEC 5DP, Specification for Drill Pipe, First Edition, August 2009. Global StandardsTool Joint
Heavy coupling element for drill pipe having coarse, tapered threads and sealing shoulders. Source: API SPEC 7-1, Specification for Rotary Drill Stem Elements, First Edition, March 2006 (Addendum April 2011). Global StandardsTest Pressure
Definition(s)
Test Pressure
Internal pressure during field hydrostatic test of risers and/or riser components. NOTE Risers that are part of a pipeline may require field hydrostatic testing to a pressure greater than design pressure. Field hydrostatic testing of fabricated components may be to a lower pressure. Hydrostatic testing need not be required if other measures with an equivalent level of safety are employed and documented. Source: API Standard 2RD, Dynamic Risers for Floating Production Systems, Second Edition, September 2013. Global StandardsTest Pressure
A pressure above working pressure used to demonstrate structural integrity of a pressure vessel. 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 SPEC 7-1, Specification for Rotary Drill Stem Elements, First Edition, March 2006 (Addendum April 2011). Global StandardsTest Pressure
Pressure at which the equipment is tested based upon all relevant design criteria. Source: API SPEC 14A, Specification for Subsurface Safety Valve Equipment, Eleventh Edition, October 2005 (Reaffirmed June 2012). Global StandardsTest Pressure
The pressure at which the component or system is tested to verify structural and pressure integrity. 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 StandardsTest Pressure
The test pressure shall be determined by the working pressure. This shall be a minimum 1.5 x maximum working pressure if not otherwise specified in applied codes and standards. Source: NOGEPA Industrial Guideline No. 43, Surface BOP Review, Best Practices Checklist, Netherlands, Version 0, December 2011. Global StandardsTensile Strength
Definition(s)
Tensile Strength
The maximum tensile stress which a material is capable of sustaining. Tensile strength is calculated from the maximum load during a tension test carried to rupture and the original cross-sectional area of the specimen. Source: API RP 7G, Recommended Practice for Drill Stem Design and Operating Limits, Upstream Segment, Sixteenth Edition, August 1998 (Addendum 2: September 2009). Global StandardsTensile Strength
Maximum tensile stress that a material is capable of sustaining that is calculated from the maximum load during a tensile test carried to rupture and the original cross-sectional area of the specimen. Source: API SPEC 7-1, Specification for Rotary Drill Stem Elements, First Edition, March 2006 (Addendum April 2011). Global StandardsTensile Strength
Minimum stress level where strain hardening is at maximum or at rupture. Source: Offshore Standard DNV-OS-C101, Design of Offshore Steel Structures, General (LRFD Method, Det Norske Veritas, April 2011. Global StandardsStress-Relief Feature
Definition(s)
Stress-Relief Feature
A modification performed on rotary shouldered connections which removes the unengaged threads of the pin or box. This process makes the joint more flexible and reduces the likelihood of fatigue cracking in this highly stressed area. Source: API RP 7G, Recommended Practice for Drill Stem Design and Operating Limits, Upstream Segment, Sixteenth Edition, August 1998 (Addendum 2: September 2009). Global StandardsSlip Area
Definition(s)
Slip Area
The slip area is contained within a distance of 48 inches along the pipe body from the juncture of the tool joint OD and the elevator shoulder. Source: API RP 7G, Recommended Practice for Drill Stem Design and Operating Limits, Upstream Segment, Sixteenth Edition, August 1998 (Addendum 2: September 2009). Global StandardsSlip Area
That part of the pipe body where there is visible evidence of the trip slips having been repeatedly set numerous times in the same area. See Figure 4. NOTE At the upper end, it is typically located approximately 560 mm (22 in) from the box-tool joint elevator shoulder, and extends from that point approximately 660 mm (26 in) toward the pin end. It can be located elsewhere depending on rig design and positioning of handling equipment. It does not include occasional setting of slips in other areas as a result of fishing operations, drill stem tests and similar applications. Source: API RP 7G-2, Recommended Practice for Inspection and Classification of Used Drill Stem Elements, First Edition, August 2009. Global StandardsShear Strength
Definition(s)
Shear Strength
The stress required to produce fracture in the plane of cross section, the conditions of loading being such that the directions of force and of resistance are parallel and opposite although their paths are offset a specified minimum amount. The maximum load divided by the original cross-sectional area of a section separated by shear. Source: API RP 7G, Recommended Practice for Drill Stem Design and Operating Limits, Upstream Segment, Sixteenth Edition, August 1998 (Addendum 2: September 2009). Global StandardsRotary Shouldered Connection
Definition(s)
Rotary Shouldered Connection
A connection used on drill string elements which has coarse, tapered threads and sealing shoulders. Source: API RP 7G, Recommended Practice for Drill Stem Design and Operating Limits, Upstream Segment, Sixteenth Edition, August 1998 (Addendum 2: September 2009). Global StandardsRotary Shouldered Connection
Connection used on drill stem elements that have coarse, tapered threads and sealing shoulders. Source: API RP 7G-2, Recommended Practice for Inspection and Classification of Used Drill Stem Elements, First Edition, August 2009. Global StandardsRotary Shouldered Connection
Connection used on drill string elements which has tapered threads and sealing shoulders. Source: API SPEC 5DP, Specification for Drill Pipe, First Edition, August 2009. Global StandardsRotary Shouldered Connection
Connection used on drill stem elements, which has coarse, tapered threads and sealing shoulders. Source: API SPEC 7-1, Specification for Rotary Drill Stem Elements, First Edition, March 2006 (Addendum April 2011). Global StandardsRange
Definition(s)
Range
A length classification for API Oil Country Tubular Goods. Source: API RP 7G, Recommended Practice for Drill Stem Design and Operating Limits, Upstream Segment, Sixteenth Edition, August 1998 (Addendum 2: September 2009). Global StandardsQuenched and Tempered
Definition(s)
Quenched and Tempered
Quench hardening - Hardening a ferrous alloy by austenitizing and then cooling rapidly enough so that some or all of the austenite transforms to martensite. Tempering - Reheating a quenched-hardened or normalized ferrous alloy to a temperature below the transformation range and then cooling at any rate desired. Source: API RP 7G, Recommended Practice for Drill Stem Design and Operating Limits, Upstream Segment, Sixteenth Edition, August 1998 (Addendum 2: September 2009). Global StandardsPremium Class
Definition(s)
Premium Class
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 StandardsPremium Class
Highest in the hierarchy of used drill pipe service classifications, better than class 2 and class 3. Source: API RP 7G-2, Recommended Practice for Inspection and Classification of Used Drill Stem Elements, First Edition, August 2009. Global StandardsOil Muds
Definition(s)
Oil Muds
The term “oil-base drilling fluid” is applied to a special type drilling fluid where oil is the continuous phase and water the dispersed phase. Such fluids contain blown asphalt and usually 1 to 5 percent water emulsified into the system with caustic soda or quick lime and an organic acid. Silicate, salt, and phosphate may also be present. Oilbase drilling fluids are differentiated from invert-emulsion drilling fluids (both water-in-oil emulsions) by the amounts of water used, method of controlling viscosity and thixotropic properties, wall-building materials, and fluid loss. Source: API RP 7G, Recommended Practice for Drill Stem Design and Operating Limits, Upstream Segment, Sixteenth Edition, August 1998 (Addendum 2: September 2009). Global StandardsMinimum OD
Definition(s)
Minimum OD
For tool joints on drill pipe with rotary shouldered connections, the minimum OD is the minimum box OD that will allow the connection to remain as strong as a specified percentage of the drill pipe tube in torsion. Source: API RP 7G, Recommended Practice for Drill Stem Design and Operating Limits, Upstream Segment, Sixteenth Edition, August 1998 (Addendum 2: September 2009). Global StandardsMinimum Make-Up Torque
Definition(s)
Minimum Make-Up Torque
The minimum makeup torque is the minimum amount of torque necessary to develop an arbitrarily derived tensile stress in the pin or compressive stress in the box. This arbitrarily derived stress level is perceived as being sufficient in most drilling conditions to prevent downhole make-up and to prevent shoulder separation from bending loads. Source: API RP 7G, Recommended Practice for Drill Stem Design and Operating Limits, Upstream Segment, Sixteenth Edition, August 1998 (Addendum 2: September 2009). Global StandardsMake-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 StandardsMake-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 StandardsLast 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 StandardsLast 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 StandardsKelly 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 StandardsKelly 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 StandardsForging
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 StandardsForging
(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 StandardsForging
(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 StandardsFatigue 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 StandardsFatigue 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 StandardsFatigue 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 StandardsFatigue 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 StandardsFatigue
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 StandardsFatigue
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 StandardsDrill 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 StandardsDrill 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 StandardsDrill 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 StandardsDrift
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