Glossary
Browse the IADC Lexicon alphabetically or by category. Get comprehensive definitions of drilling industry terms.
Air Cushion
Definition(s)
Air Cushion
Air pumped into underbase compartments of the structure. NOTE Normally applied in order to reduce the draught and increase the freeboard and/or to alter the structural loading. [ISO 19903:2006, 3.10]. Source: API RP 2MOP, Marine Operations, Upstream Segment, First Edition, July 2010. Global Standards
Mean Time to Failure
Definition(s)
Mean Time to Failure
Expectation of the time to failure [2]. NOTE The MTTF of an item can be longer or shorter than the design life of the system. Source: ISO 20815:2008, Petroleum, petrochemical and natural gas industries – Production assurance and reliability management. Global StandardsMean Time to Failure
expectation of the down time
Source: ISO/TR 12489:2013(E) Reliability modelling and calculation of safety systems. Global Standardss
Mean Time Between Failures
Definition(s)
Mean Time Between Failures
Expectation of the time between failures. NOTE The MTBF of an item can be longer or shorter than the design life of the system. Source: ISO 20815:2008, Petroleum, petrochemical and natural gas industries – Production assurance and reliability management. Global StandardsMean Time Between Failures
MTBF expected time between successive failures of a repairable item Note 1 to entry: In the cases illustrated in Figure 4, the MTBF is linked with MTTF and MTTRes by the following relationship: MTBF = MTTF+MTTRes. More generally It is also linked to the MUT and MDT by MTBF = MUT+MDT. Note 2 to entry: The acronym MTBF is sometimes defined as the mean operating time between failures (e.g. in IEV191[14]). This is not at all the same and, in this case, the formula described in Note 1 to entry is no longer valid. This is very confusing, therefore the traditional definition of the MTBF is retained in this Technical Report.
Source: ISO/TR 12489:2013(E) Reliability modelling and calculation of safety systems. Global StandardsMaintenance Support Performance
Definition(s)
Maintenance Support Performance
Ability of a maintenance organization, under given conditions, to provide upon demand, the resources required to maintain an item, under a given maintenance policy. NOTE The given conditions are related to the item itself and to the conditions under which the item is used and maintained. Source: ISO 20815:2008, Petroleum, petrochemical and natural gas industries – Production assurance and reliability management. Global StandardsMaintenance Data
Definition(s)
Maintenance Data
Data characterizing the maintenance action planned or done. Source: ISO 20815:2008, Petroleum, petrochemical and natural gas industries – Production assurance and reliability management. Global StandardsLPG
Definition(s)
LPG
Liquefied Petroleum Gases. Source: API STD 521, Pressure-relieving and Depressuring Systems, Sixth Edition, January 2014. 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: ISO 20815:2008, Petroleum, petrochemical and natural gas industries – Production assurance and reliability management. Global StandardsCompression Chamber
Definition(s)
Compression Chamber
“Compression chamber” means a pressure vessel that is suitable for human occupancy at internal pressures greater than atmospheric pressure (caisson de compression ou compartiment de compression). Source: Canada Oil and Gas Drilling and Production Regulations, SOR/2009-315, February 2013. Regulations Source: Nova Scotia Offshore Area Petroleum Diving Regulations, SOR/95-189, Canada, current to May 31, 2012. RegulationsCategory III Diving Operation
Definition(s)
Category III Diving Operation
“Category III diving operation” means a diving operation in which a category III dive is made (opérations de plongée de catégorie III). Source: Canada Oil and Gas Diving Regulations, SOR/88-600, February 2013. Regulations Source: Nova Scotia Offshore Area Petroleum Diving Regulations, SOR/95-189, Canada, current to May 31, 2012. RegulationsLOSTREV
Definition(s)
LOSTREV
Lost revenue. Source: ISO 20815:2008, Petroleum, petrochemical and natural gas industries – Production assurance and reliability management. Global StandardsLost Revenue
Definition(s)
Lost Revenue
Total cost of lost or deferred production due to downtime. Source: ISO 20815:2008, Petroleum, petrochemical and natural gas industries – Production assurance and reliability management. Global StandardsLNG
Definition(s)
LNG
Liquefied Natural Gases. Source: API STD 521, Pressure-relieving and Depressuring Systems, Sixth Edition, January 2014. Global Standards Source: ISO 20815:2008, Petroleum, petrochemical and natural gas industries – Production assurance and reliability management. Global StandardsCategory III Dive
Definition(s)
Category III Dive
“Category III dive” means a saturation dive and any dive other than an ADS dive, a category I dive or a category II dive (plongée de catégorie III). Source: Canada Oil and Gas Diving Regulations, SOR/88-600, February 2013. Regulations Source: Nova Scotia Offshore Area Petroleum Diving Regulations, SOR/95-189, Canada, current to May 31, 2012. RegulationsGTL
Definition(s)
GLT
Gas to liquid. Source: ISO 20815:2008, Petroleum, petrochemical and natural gas industries – Production assurance and reliability management. Global StandardsFNA
Definition(s)
FNA
Flow-network analysis. Source: ISO 20815:2008, Petroleum, petrochemical and natural gas industries – Production assurance and reliability management. Global StandardsCategory II Diving Operation
Definition(s)
Category II Diving Operation
“category II diving operation” means a diving operation in which a category II dive is made (opérations de plongée de catégorie II). Source: Canada Oil and Gas Diving Regulations, SOR/88-600, February 2013. Regulations Source: Nova Scotia Offshore Area Petroleum Diving Regulations, SOR/95-189, Canada, current to May 31, 2012. RegulationsFault Tolerance
Definition(s)
Fault Tolerance
Attribute of an item that makes it able to perform a required function in the presence of certain given sub-item faults. Source: ISO 20815:2008, Petroleum, petrochemical and natural gas industries – Production assurance and reliability management. Global StandardsCategory II Dive
Definition(s)
Category II Dive
“Category II dive” means a dive in which a diving bell or diving submersible is used for a lock-out dive to a depth of less than 50 m using a breathing mixture of air, or to a depth of 50 m or more using a breathing mixture of mixed gas other than air, but does not include a saturation dive (plongée de catégorie II). Source: Canada Oil and Gas Diving Regulations, SOR/88-600, February 2013. Regulations Source: Nova Scotia Offshore Area Petroleum Diving Regulations, SOR/95-189, Canada, current to May 31, 2012. RegulationsCategory I Diving Operation
Definition(s)
Category I Diving Operation
“Category I diving operation” means a diving operation in which a category I dive is made (opérations de plongée de catégorie I). Source: Canada Oil and Gas Diving Regulations, SOR/88-600, February 2013. Regulations Source: Nova Scotia Offshore Area Petroleum Diving Regulations, SOR/95-189, Canada, current to May 31, 2012. RegulationsBrine Pit
Definition(s)
Brine Pit
Pit used for storage of brine which is used to displace hydrocarbons from an underground hydrocarbon storage facility. Source: Oil and Gas Division, Texas Administrative Code, Title 16, Chapter 3, February 2013. RegulationsFailure Rate
Definition(s)
Failure Rate
Limit, if this exists, of the ratio of the conditional probability that the instant of time, T, of a failure of an item falls within a given time interval, [t, (t + Δt)] and the length of this interval, Δt, when Δt tends to zero, given that the item is in an up state at the beginning of the time interval. See ISO 14224:2006, Clause C.3 for further explanation of the failure rate. NOTE 1 In this definition, t may also denote the time to failure or the time to first failure. NOTE 2 A practical interpretation of failure rate is the number of failures relative to the corresponding operational time. In some cases, time can be replaced by units of use. In most cases, the reciprocal of MTTF (3.1.25) can be used as the predictor for the failure rate, i.e. the average number of failures per unit of time in the long run if the units are replaced by an identical unit at failure. NOTE 3 The failure rate can be based on operational time or calendar time. Source: ISO 20815:2008, Petroleum, petrochemical and natural gas industries – Production assurance and reliability management. Global StandardsFailure Rate
3.1.18
Source: ISO/TR 12489:2013(E) Reliability modelling and calculation of safety systems. Global Standards
Breathing Mixture
Definition(s)
Breathing Mixture
“Breathing mixture” means a mixture of gases used for human respiration and includes pure oxygen and any therapeutic mixture (mélange respiratoire). Source: Canada Oil and Gas Diving Regulations, SOR/88-600, February 2013. Regulations Source: Nova Scotia Offshore Area Petroleum Diving Regulations, SOR/95-189, Canada, current to May 31, 2012. RegulationsBell Bounce Diving Technique
Definition(s)
Bell Bounce Diving Technique
“Bell bounce diving technique” means a diving procedure whereby a diving bell or diving submersible is used to transport divers who are under atmospheric pressure or pressures greater than atmospheric pressure to a work site and subsequently to transport the divers under pressures greater than atmospheric pressure from an underwater work site, but does not include saturation diving techniques (technique de la plongée d’incursion). Source: Canada Oil and Gas Diving Regulations, SOR/88-600, February 2013. Regulations Source: Nova Scotia Offshore Area Petroleum Diving Regulations, SOR/95-189, Canada, current to May 31, 2012. RegulationsAttendant
Definition(s)
Attendant
“Attendant” means a person who has been trained in diving procedures and who is acting under the direction of a supervisor (adjoint). Source: Canada Oil and Gas Diving Regulations, SOR/88-600, February 2013. Regulations Source: Nova Scotia Offshore Area Petroleum Diving Regulations, SOR/95-189, Canada, current to May 31, 2012. RegulationsAttendant
Attendant means a person who is suitably trained within the safety management system, maintains a watch over those entering the enclosed space, maintains communications with those inside the space and initiates the emergency procedures in the event of an incident occurring. Source: IMO resolution A.1050(27), Revised recommendations for entering enclosed spaces aboard ships, 21 December 2011, International Maritime Organization. Regulatory GuidanceAction Effect
Definition(s)
Action Effect
Effect of actions on structural components. [ISO 19900:2002].- EXAMPLE Internal forces, moments, stresses, strains, rigid body motions or elastic deformations.
Action Effect
Effect of actions on structural components.- EXAMPLE Internal force, moment, stress or strain.
Action Effect
Effect of actions on structural components.- EXAMPLE Internal forces, moments, stresses, strains, rigid body motions or elastic deformations. [ISO 19904-1:2006, 3.5].