Glossary
Browse the IADC Lexicon alphabetically or by category. Get comprehensive definitions of drilling industry terms.
PRD
Definition(s)
PRD
Pressure relieving device. Source: API 570, Piping Inspection Code: In-service Inspection, Rating, Repair, and Alteration of Piping Systems, Fourth Edition, February 2016, with Addendum May 2017. Global StandardsPRD
Pressure Relief Device. Source: API STD 521, Pressure-relieving and Depressuring Systems, Sixth Edition, January 2014. Global Standards Source: OGP Report No. 456, Process Safety – Recommended Practice on Key Performance Indicators, International Association of Oil & Gas Producers, November 2011. Global StandardsPressure relief device (PRD)
A device designed to open and relieve excess pressure (e.g. safety valve, thermal relief, rupture disk, rupture pin, deflagration vent, pressure/vacuum vents). Source: OGP Report No. 456, Process Safety – Recommended Practice on Key Performance Indicators, International Association of Oil & Gas Producers, November 2011. Global StandardsPRE
Definition(s)
PRE
Pitting-resistance equivalent. Source: API RP 17A, Design and Operation of Subsea Production Systems—General Requirements and Recommendations, Fourth Edition, Reaffirmed 2011. Global StandardsPRE
Pitting-resistance equivalent number. Source: API SPEC 5CRA, Specification for Corrosion Resistant Alloy Seamless Tubes for Use as Casing, Tubing and Coupling Stock, Upstream Segment, First Edition, February 2010 (Errata August 2011). Global StandardsPRE
Pitting resistance equivalent. Source: API SPEC 17E, Specification for Subsea Umbilicals, Upstream Segment, Fourth Edition, October 2010. Global StandardsPre-load Holding Load
Definition(s)
Pre-load Holding Load
The maximum design elevated weight of the hull, including pre-load ballast, to be held by the jacking unit during the pre-load operation. Source: Rules and Regulations for the Classification of Mobile Offshore Units, Part 5, Main and Auxiliary Machinery, June 2013, Lloyd’s Register, Global StandardsPre-load Jacking Load
Definition(s)
Pre-load Jacking Load
The maximum design elevated weight of the hull, including pre-load ballast load, to be lowered by the jacking unit in the event of sudden leg penetration during pre-load operation. Source: Rules and Regulations for the Classification of Mobile Offshore Units, Part 5, Main and Auxiliary Machinery, June 2013, Lloyd’s Register, Global StandardsPrecautionary Down-Manning
Definition(s)
Precautionary Down-Manning
A “Precautionary Down-Manning” may be required in a situation where there is no immediate threat to human life at the very moment, but there is a real possibility of the situation deteriorating and requiring an “Emergency Evacuation” in due time. In order to reduce the number of people having to be transferred during an “Emergency Evacuation”, a “Precautionary Down-Manning”, involving all non-essential personnel, is the first step. Such precautionary down-manning can be performed by both the commercial passenger helicopters and, if necessary, with the addition of the SAR helicopter. The SAR helicopter in this case will operate as a normal helicopter taking a maximum of 9 passengers, which relates to the number of seats available. Source: NOGEPA Industrial Guideline No. 20, Alerting Procedure SAR Helicopter for Drifting Vessel (NUC) Offshore, Netherlands, Version 0, January 2009. Global StandardsPrecharge
Definition(s)
Precharge
See accumulator precharge. 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 StandardsPrecision
Definition(s)
Precision
In this part of ISO 10426, calibrating an instrument refers to assuring the accuracy of the measurement. Accuracy is the degree of conformity of a measurement of a quantity to its actual or true value. Accuracy is related to precision, or reproducibility, of a measurement. Precision is the degree to which further measurements or calculations will show the same or similar results. Precision is characterized in terms of the standard deviation of the measurement. The results of calculations or a measurement can be accurate, but not precise, precise but not accurate, neither or both. A result is valid if it is both accurate and precise. Source: API SPEC 10A, Specification for Cements and Materials for Well Cementing, Twenty-fourth Edition, December 2010. Global StandardsPrecursor
Definition(s)
Precursor
An observable occurrence or sign that an attacker may be preparing to cause an incident. Adapted from: CNSSI 4009, NIST SP 800-61 Rev 2 (DRAFT). Source: NICCS™ Portal Cybersecurity Lexicon, National Initiative for Cybersecurity Careers and Studies (https://niccs.us-cert.gov/glossary) as of 11 November 2015, Global StandardsPredecommissioning Surveys/Data Gathering
Definition(s)
Predecommissioning Surveys/Data Gathering
Information-gathering phase required to gain knowledge about the existing platform and its condition. Source: API RP 2SIM, Structural Integrity Management of Fixed Offshore Structures, First Edition, November 2014. Global StandardsPredictive Model
Definition(s)
Predictive Model
Performs "what if" analyses by calculating the effects of transients introduced by scheduled or unscheduled line or vessel events, such as pump or compressor outages, valve closures, or supply variations. The operator typically enters these events into a "scenario".. Source: IADC UBO / MPD Glossary, December 2011. Global StandardsPreflush
Definition(s)
Preflush (Noun)
Fluid containing no insoluble weighting agents used to separate drilling fluids and cementing slurries. Source: API RP 10B-2, Recommended Practice for Testing Well Cements, First Edition, July 2005 (Reaffirmed: July 2010). Global StandardsPreload
Definition(s)
Preload
Compressive bearing load developed between box and pin members at their interface. This is accomplished by elastic deformation during makeup of the coupling. 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 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 StandardsPreload
Compressive bearing load developed between box and pin members at their interface; this is accomplished by elastic deformation induced during makeup of the coupling. Source: API Specification 16Q, Design, Selection, Operation, and Maintenance of Marine Drilling Riser Systems, Second Edition, April 2017. Global Standards Source: API SPEC 16R, Specification for Marine Drilling Riser Couplings, Exploration and Production Department, First Edition, January 1997. Global StandardsPreload Reaction
Definition(s)
Preload Reaction
Maximum vertical reaction under a spudcan, VLo, supporting the in-water weight of the jack-up during the entire preloading operation. NOTE 1 The in-water weight is the full weight of the hull, variable load and preload ballast, plus the legs and spudcans and any contained water, reduced by the buoyancy in water of the legs and spudcans (calculated from their external dimensions). Soil buoyancy and the weight of any soil backfill above the spudcan are neglected. It is necessary to take care when accounting for water contained in the spudcan (in some cases this can be included in the quoted leg weight). NOTE 2 This is the maximum reaction on a spudcan, VLo, that would be obtained during preloading if the jack-up were installed on an infinitely rigid foundation. Source: ISO 19905-1:202, Petroleum and natural gas industries – Site-specific assessment of mobile offshore units – Part 1: Jack-ups. Global StandardsPreload Tool
Definition(s)
Preload Tool
Device used to engage and/or preload coupling members. 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 StandardsPreloading
Definition(s)
Preloading
Installation of the spudcans by vertical loading of the soil beneath a jack-up leg spudcan with the objective of ensuring sufficient foundation capacity under assessment situations through to the time when the maximum load is applied and held. NOTE Whilst three-legged jack-ups preload by taking water ballast on board, jack-ups with four or more legs typically achieve foundation preload by carrying the hull weight on pairs of legs in turn. This procedure is known as pre-driving and generally does not require the addition of water ballast. For the purposes of this part of ISO 19905, no distinction is made between preload and pre-drive. Source: ISO 19905-1:202, Petroleum and natural gas industries – Site-specific assessment of mobile offshore units – Part 1: Jack-ups. 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 StandardsPREN
Definition(s)
PREN
Pitting resistance equivalent number. Source: ISO 21457:2010, Petroleum and natural gas industries — Materials selection and corrosion control for oil and gas production systems, First Edition,September 2010. Global StandardsPREN (FPREN)
Number, developed to reflect and predict the pitting resistance of a stainless steel, based upon the proportions of Cr, Mo, W and N in the chemical composition of the alloy NOTE 1 For the purposes of this International Standard, FPREN is calculated from Equation (1): FPREN = wCr + 3,3(wMo + 0,5wW) + 16wN (1) where wCr is the percent (mass fraction) of chromium in the alloy; wMo is the percent (mass fraction) of molybdenum in the alloy; wW is the percent (mass fraction) of tungsten in the alloy; wN is the percent (mass fraction) of nitrogen in the alloy. NOTE 2 Adapted from ISO 15156-3:2009, definition 3.10, and ISO 15156-3:2009, 6.3. Source: ISO 21457:2010, Petroleum and natural gas industries — Materials selection and corrosion control for oil and gas production systems, First Edition,September 2010. Global StandardsPitting resistance equivalent number (PREN)
Number developed to reflect and predict the pitting resistance of a stainless steel, based on the proportions of Cr, Mo, W and N in the chemical composition of the alloy. NOTE This number is based on observed resistance to pitting of CRAs in the presence of chlorides and oxygen, e.g. seawater, and is not directly indicative of the resistance to produced oil and gas environments. FPREW = wCr + 3,3(wMo + 0,5wW) + 16wN where wCr is the mass fraction of chromium in the alloy, expressed as a percentage of the total composition; wMo is the mass fraction of molybdenum in the alloy, expressed as a percentage of the total composition; wW is the mass fraction of tungsten in the alloy, expressed as a percentage of the total composition; wN is the mass fraction of nitrogen in the alloy, expressed as a percentage of the total composition.1 Source: API RP 17A Addendum 1, Design and Operation of Subsea Production Systems—General Requirements and Recommendations, December 2010. Global StandardsPreparation
Definition(s)
Preparation
“Preparation” refers to surface preparation, joint preparation, fit-up and preheat. Source: API SPEC 6A, Specification for Wellhead and Christmas Tree Equipment, Twentieth Edition, October 2010 (Addendum November 2012). Global StandardsPreparation
“Preparation” means any commercial formulation containing one or more Active Substances including any additives. This term also includes any Active Substances generated onboard for purposes of ballast water management and any relevant chemicals formed in the ballast water management system that make use of Active Substances to comply with the Convention. Source: Resolution MEPC.169(57), revised Procedure for approval of ballast water management systems that make use of Active Substances (G9), 4 April 2008, International Maritime Organization. Regulatory GuidancePreparation
Preparation means a mixture or solution that consists of two or more substances. Source: Guidelines Regarding the Activities Regulations, Norway, updated December 2012. Regulatory GuidancePreparedness
Definition(s)
Preparedness
The activities to build, sustain, and improve readiness capabilities to prevent, protect against, respond to, and recover from natural or manmade incidents. Adapted from: NIPP. Source: NICCS™ Portal Cybersecurity Lexicon, National Initiative for Cybersecurity Careers and Studies (https://niccs.us-cert.gov/glossary) as of 11 November 2015, Global StandardsPrescribed Threaded Joint
Definition(s)
Prescribed Threaded Joint
Mechanical joint that complies with API 15 HR.- Note: 1 to entry: A prescribed threaded joint is a type of mechanical joint (3.2.76).
Prescriptive Preloading
Definition(s)
Prescriptive Preloading
During preloading, the hull is kept at, in or close to water level, with each individual leg preloaded by sequential filling and discharge of selected preload ballast tanks.
Source: ABS Guidance Notes on Geotechnical Performance of Spudcan Foundations, January 2017. Global StandardsPressure
Definition(s)
Pressure
Ratio of force to the area over which that force is distributed (i.e. pound force to an area (in2), measured in “psi”, etc.). Source: API Specification 16A, Specification for Drill-through Equipment, Fourth Edition, April 2017. Global StandardsPressure
"Pressure-test" means to demonstrate the pressure integrity of a system without actuating its components. Source: Alaska Oil and Gas Conservation Commission, Definitions, Alaska Admin. Code tit. 20, § 25.990, December 7, 2012. RegulationsPressure
Amount of force (F) exerted on a unit area (A) of a surface. Source: IADC UBO / MPD Glossary, December 2011. Global StandardsPressure Armour Layer
Definition(s)
Pressure Armour Layer
Structural layer with a lay angle close to 90°, that increases the resistance of the flexible pipe to internal and external pressure and mechanical crushing loads; structurally supports the internal-pressure sheath; and typically consists of an interlocked metallic construction, which may be backed up by a flat metallic spiral layer. Source: API SPEC 17J, Specification for Unbonded Flexible Pipe, Third Edition, July 2008. Global StandardsPressure Base
Definition(s)
Pressure base
The pressure at which gas volumes and quality are reported. The standard pressure base is 14.73 psia. Source: Oil and Gas and Sulphur Operations in the Outer Continental Shelf, 30 CFR 250 (2013). RegulationsPressure base
Assumed atmospheric pressure used in calculations requiring "absolute" pressure. (DATUM. Source: IADC UBO / MPD Glossary, December 2011. Global StandardsPressure Biased Control System
Definition(s)
Pressure Biased Control System
A discrete hydraulic control system utilizing a means to maintain an elevated pressure level (less than control valve actuation pressure) on pilot lines such that hydraulic signal transmission time is reduced. 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 StandardsPressure Boundary
Definition(s)
Pressure Boundary
The portion of the piping that contains the pressure retaining piping elements joined or assembled into pressure tight fluid-containing piping systems. Pressure boundary components include pipe, tubing, fittings, flanges, gaskets, bolting, valves, and other devices such as expansion joints and flexible joints.- NOTE: Also see non-pressure boundary definition.
Pressure Boundary
That portion of the pressure vessel that contains the pressure retaining elements joined or assembled into a pressure tight, fluid-containing vessel (e.g. typically the shell, heads, and nozzles but excluding items such as supports, skirts, clips, etc. that do not retain pressure). Source: API 510, Pressure Vessel Inspection Code: In-service Inspection, Rating, Repair, and Alteration, Tenth Edition, May 2014, with Addendum May 2017. Global StandardsPressure Boundary
The portion of the vessel that contains the pressure e.g. typically the shell, heads and nozzles. Source: API 510, Pressure Vessel Inspection Code: In-Service Inspection, Rating, Repair, and Alteration Downstream Segment, Ninth Edition, June 2006. Global StandardsPressure Containing Parts
Definition(s)
Post-Weld Heat Treatment
Those parts whose failure to function as intended would result in a release of retained fluid to the atmosphere. Examples are bodies, bonnets, and stems. Source: API SPEC 16C, Specification for Choke and Kill Systems, First Edition, January 1993 (Reaffirmed 2001). Global StandardsPressure Containment Barrier
Definition(s)
Pressure Containment Barrier
The well is defined in terms of its pressure containment boundary. Any equipment that is vital to controlling the pressure within the well is therefore covered. This would include downhole pressure-containing equipment and the pressure-containing equipment on top of the well such as blowout preventers or Christmas trees, but excludes well control equipment downstream that can be isolated from the well by valves. Examples of where the well ends are:- above the top blowout preventer (BOP) in the BOP stack and outside the choke and kill valves;
- downstream of the swab and production win valves of a Christmas tree;
- at the top of the wireline stuffing box of a wireline BOP.