Critical Gel Strength Period (CGSP)

Critical Gel Strength Period (CGSP)

Definition(s)

Critical Gel Strength Period

Time required for the cement to progress from Critical Static Gel Strength to a static gel strength of 500 lb/100 ft2. Source: API RP 65, Cementing Shallow Water Flow Zones in Deepwater Wells, First Edition, September 2002 (August 2003). Global Standards

Critical Gel Strength Period (CGSP)

The time between the development of the critical static gel strength (CSGS) and a static gel strength of 500 lbf/100 ft2. Source: API STD 65 – Part 2, Isolating Potential Flow Zones During Well Construction, Upstream Segment, Second Edition, December 2010. Global Standards  
Conductor Casing

Conductor Casing

Definition(s)

Conductor Casing

Component that provides structural support for the well, wellhead and completion equipment, and often used for hole stability for initial drilling operations
  • Note: 1 to entry: This casing string is not designed for pressure containment, but upon completion of the well it might have a casing head; therefore, it can be capable of containing low annulus pressures. For subsea and hybrid wells, the low-pressure subsea wellhead is normally installed on this casing string.
[SOURCE: API RP 90, modified] Source: ISO 16530-1:2017, Petroleum and natural gas industries - Well integrity – Part 1: Life cycle governance, First Edition, March 2017. Global Standards  

Conductor Casing

“Conductor casing” means the casing that is installed in a well to facilitate drilling of the hole for the surface casing (tubage initial). Source: Canada Oil and Gas Drilling and Production Regulations, SOR/2009-315, February 2013. Regulations Source: Drilling and Production Guidelines, The Canada-Nova Scotia Offshore Petroleum Board and Canada-Newfoundland and Labrador Offshore Petroleum Board, Canada, March 31, 2011. Regulatory Guidance Source: Nova Scotia Offshore Petroleum Drilling and Production Regulations, SOR/2009-317, Canada, current to May 31, 2012. Regulations  

Conductor Casing

"Conductor casing" means a casing string which is often set and cemented at a shallow depth to support and protect the top of the borehole from erosion while circulating and drilling the surface casing hole. Source: Corporation Commission, Oil and Gas Conservation, Oklahoma Administrative Code 165:10, February 2013. Regulations  

Conductor Casing

  1. “Conductor casing” means one or more strings of casing set and cemented to provide a base for an air body for diversion of shallow naturally occurring natural gas including coalbed methane and to accomplish one or more of the following well construction objectives: (a) Stabilize unconsolidated sediments; (b) Isolate shallow aquifers that provide or are capable of providing groundwater for water wells and springs in the vicinity of the well; or (c) Isolate groundwater before penetrating the workings of an active underground mine.
Source: Division of Mineral Resources Management - Oil and Gas, Ohio Administrative Code, Chapter 1501:9, January 2012. Regulations

Conductor Casing

Provides structural support for the well, wellhead and completion equipment, and often provides hole stability for initial drilling operations. This casing string is typically not designed for pressure containment. However, in some cases, the conductor casing may serve to isolate shallow formations, similar to a surface casing. Source: API STD 65 – Part 2, Isolating Potential Flow Zones During Well Construction, Upstream Segment, Second Edition, December 2010. Global Standards  

Conductor Casing

"Conductor casing" means a casing string set before surface casing; depending on well configuration, "conductor casing" can be either the first or second string of casing set in a well and usually supports a diverter system. Source: Alaska Oil and Gas Conservation Commission, Definitions, Alaska Admin. Code tit. 20, § 25.990, December 7, 2012. Regulations

Conductor Casing or Conductor Pipe (onshore and bottom-supported offshore installations)

A relatively short string of large diameter pipe that is set to keep the top of the hole open and provide a means of returning the upward flowing drilling fluid from the well bore to the surface drilling fluid system until the first casing string is set in the well. Source: API RP 59, Recommended Practice for Well Control Operations, Second Edition, May 2006. Global Standards

Conductor Casing

Provides structural support for the well, wellhead and completion equipment, and often provides hole stability for initial drilling operations. This casing string is not designed for pressure containment, but upon completion of the well, it may have a casing head; therefore, it may be capable of containing low annular pressures. This casing is set prior to encountering any hydrocarbons at a depth where the fracture gradient will allow for an increase in mud density and is cemented to the surface or mudline. For subsea and hybrid wells, the low pressure subsea wellhead is normally installed on this casing string. Source: API RP 90, Annular Casing Pressure Management for Offshore Wells, Upstream Segment. First Edition, August 2006. Global Standards
Completion String

Completion String

Definition(s)

Completion String

String consisting primarily of production tubing, but also including additional components such as the surface-controlled subsurface safety valve (SCSSV), gas-lift mandrels, chemical injection and instrument ports, landing nipples, and packer or packer seal assemblies
  • Note: 1 to entry: The production string is run inside the production casing and is used to conduct production fluids to the surface.
[SOURCE: API RP 90, modified]. Source: ISO 16530-1:2017, Petroleum and natural gas industries — Well integrity – Part 1: Life cycle governance, First Edition, March 2017. Global Standards

Completion String

The completion string consists primarily of production tubing, but also includes additional components such as the surface controlled subsurface safety valve (SCSSV), gas lift mandrels, chemical injection and instrument ports, landing nipples, and packer or packer seal assemblies. The completion string is run inside the production casing and used to produce fluids to the surface. Source: API STD 65 – Part 2, Isolating Potential Flow Zones During Well Construction, Upstream Segment, Second Edition, December 2010. Global Standards 
CGSP

CGSP

Definition(s)

CGSP

Critical gel strength period. Source: API STD 65 – Part 2, Isolating Potential Flow Zones During Well Construction, Upstream Segment, Second Edition, December 2010. Global Standards 
Cased Hole

Cased Hole

Definition(s)

Cased Hole

The wellbore intervals in a well that are cased with casing and/or liner pipe. The diameter of these hole sections is the inside diameter of the pipe contained therein. Source: API STD 65 – Part 2, Isolating Potential Flow Zones During Well Construction, Upstream Segment, Second Edition, December 2010. Global Standards 
Bottom Hole Assembly (BHA)

Bottom Hole Assembly (BHA)

Definition(s)

Bottom-Hole Assembly (BHA)

An assembly composed of the bit, stabilizers, reamers, drill collars, various types of subs, etc., that is connected to the bottom of a string of drillpipe. Source: API RP 16Q, Recommended Practice for Design, Selection, Operation and Maintenance of Marine Drilling Riser Systems, First Edition, November 1993 (Reaffirmed August 2001). Global Standards

Bottom Hole Assembly (BHA)

Bottom hole assembly is the collection of the bit, drill collars, stabilizers, reamers, hole openers, MWD/LWD/PWD, mud motor, directional steering system and other tools at the base of the drill string that serve special purposes associated with drilling. Source: API STD 65 – Part 2, Isolating Potential Flow Zones During Well Construction, Upstream Segment, Second Edition, December 2010. Global Standards  

Bottom-Hole Assembly

Assembly composed of the bit, stabilizers, reamers, drill collars, various types of subs, etc., that is connected to the bottom of a string of drillpipe. Source: ISO 13624-1:2009, Petroleum and natural gas industries – Drilling and production equipment – Part 1:Design and operation of marine drilling riser equipment. Global Standards
BHT

BHT

Definition(s)

BHT

Bottom hole temperature. Source: API STD 65 – Part 2, Isolating Potential Flow Zones During Well Construction, Upstream Segment, Second Edition, December 2010. Global Standards 
BHST

BHST

Definition(s)

BHST

Bottom hole static temperature Source: API STD 65 – Part 2, Isolating Potential Flow Zones During Well Construction, Upstream Segment, Second Edition, December 2010. Global Standards 
BHP

BHP

Definition(s)

BHP

Bottom hole pressure. 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 Guidelines Source: NORSOK D-010, Well integrity in drilling and well operations, Rev. 3, August 2004. Global Standards
BHCT

BHCT

Definition(s)

BHCT

Bottom hole circulating temperature. Source: API STD 65 – Part 2, Isolating Potential Flow Zones During Well Construction, Upstream Segment, Second Edition, December 2010. Global Standards 
BHA

BHA

Definition(s)

BHA

Bottomhole assembly Source: API Specification 16Q, Design, Selection, Operation, and Maintenance of Marine Drilling Riser Systems, Second Edition, April 2017. Global Standards

BHA

"BHA" means bottom-hole assembly. Source: Alaska Oil and Gas Conservation Commission, Definitions, Alaska Admin. Code tit. 20, § 25.990, December 7, 2012. Regulations

BHA

Bottom hole assembly. Source:API SPECIFICATION 19TT, Specification for Downhole Well Test Tools and Related Equipment, First Edition, October 2016. Global Standards Source: API STD 65 – Part 2, Isolating Potential Flow Zones During Well Construction, Upstream Segment, Second Edition, December 2010. Global Standards  Source: API RP 7G-2, Recommended Practice for Inspection and Classification of Used Drill Stem Elements, First Edition, August 2009. Global Standards Source: International Association of Drilling Contractors, Appendix 2 to Health, Safety and Environment Case Guidelines for Offshore Drilling Contractors, Issue 3.3.2, February 2010. IADC Guidelines Source: NOGEPA Industrial Guideline No. 44, Standards and Acceptance Guidelines, Enhance QA/QC for Critical Well Components, Netherlands, Version 0, July 2011. Global Standards Source: NORSOK D-010, Well integrity in drilling and well operations, Rev. 3, August 2004. Global Standards Source: NORSOK D-001, Drilling facilities, Rev. 3, December 2012. Global Standards Source: NORSOK D-002, Well intervention equipment, Rev. 2, June 2013. Global Standards  

BHA

Assembly composed of the bit, stabilizers, reamers, drill collars, various types of subs, etc., that is connected to the bottom of a string of drillpipe. Source: ISO 13624-1:2009, Petroleum and natural gas industries – Drilling and production equipment – Part 1:Design and operation of marine drilling riser equipment. Global Standards 
Barrier (Barrier Element)

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 Standards

Barrier (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 Standards    
APB

APB

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 Standards 
Working Temperature

Working 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 Standards  

Working 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 Standards
Working Pressure (WP)

Working 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 Standards  

Working 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 Standards  

Working 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 Standards  

Working 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 Standards  
Working Gauges

Working 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 Standards
Upper Kelly Cock

Upper 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 Standards  

Upper 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 Standards
Tool Joint

Tool 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 Standards  

Tool 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 Standards  

Tool 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 Standards
Test Pressure

Test 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 Standards  

Test 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 Standards  

Test 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 Standards  

Test 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 Standards  

Test 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 Standards
Tensile Strength

Tensile 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 Standards  

Tensile 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 Standards  

Tensile 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 Standards
Stress-Relief Feature

Stress-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 Standards
Slip Area

Slip 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 Standards  

Slip 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 Standards
Shear Strength

Shear 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 Standards
Rotary Shouldered Connection

Rotary 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 Standards  

Rotary 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 Standards  

Rotary 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 Standards  

Rotary 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 Standards  
Range

Range

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 Standards  
Quenched and Tempered

Quenched 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 Standards  
Premium Class

Premium 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 Standards  

Premium 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 Standards  
Oil Muds

Oil 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 Standards
Minimum OD

Minimum 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 Standards  
Minimum Make-Up Torque

Minimum 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 Standards