Glossary
Browse the IADC Lexicon alphabetically or by category. Get comprehensive definitions of drilling industry terms.
Well Branch
Definition(s)
Well Branch
"Well branch" means that portion of a well drilled below the structural or conductor casing to access a given objective in a well with more than one bottom-hole location or whose bottom-hole location is being or has been changed by plugging back and redrilling. Source: Alaska Oil and Gas Conservation Commission, Definitions, Alaska Admin. Code tit. 20, § 25.990, December 7, 2012. RegulationsUnderbalanced Drilling
Definition(s)
Underbalanced Drilling
"Underbalanced drilling" means drilling under conditions where the hydrostatic head of the drilling fluid column is intentionally designed to be lower than the pressure of the formation being drilled. Source: Alaska Oil and Gas Conservation Commission, Definitions, Alaska Admin. Code tit. 20, § 25.990, December 7, 2012. RegulationsUnderbalanced Drilling (UBD)
A drilling activity employing appropriate equipment and controls where the pressure exerted in the wellbore is intentionally less than the pore pressure in any part of the exposed formations with the intention of bringing formation fluids to the surface. Source: IADC UBO / MPD Glossary, December 2011. Global StandarSuspend
Definition(s)
Suspend
"Suspend" means to plug a well in accordance with 20 AAC 25.110 and to reserve the option later to re-enter and- redrill the well; or
- complete the well as an oil, gas, or service well.
Suspend
Suspend, in relation to a well, means to render the well temporarily inoperative, and suspension has a corresponding meaning verification scheme has the meaning set out in regulation 54. Source: Health and Safety in Employment (Petroleum Exploration and Extraction) Regulations 2013, SR 2013/208, New Zealand, as of May 2013. RegulationsStratigraphic Test Well
Definition(s)
Stratigraphic Test Well
"Stratigraphic test well" means a hole drilled for the sole purpose of gaining structural or stratigraphic information to aid in exploring for oil and gas. Source: Alaska Oil and Gas Conservation Commission, Definitions, Alaska Admin. Code tit. 20, § 25.990, December 7, 2012. RegulationsStratigraphic Test Well
"Stratigraphic test well" means any well or hole, except a seismograph shot hole, drilled for the purpose of gathering information in connection with the oil and gas industry with no intent to produce oil or gas from such well. Source: Oil and gas Conservation, North Dakota Administrative Code, Chapter 43-02-03, April 2012. RegulationsStock Tank Barrel
Definition(s)
Stock Tank Barrel
"Stock tank barrel" means 42 U.S. gallons, measured at 60ø F and 14.65 psia. Source: Alaska Oil and Gas Conservation Commission, Definitions, Alaska Admin. Code tit. 20, § 25.990, December 7, 2012. RegulationsSTB
Definition(s)
STB
"Stb" means stock tank barrel. Source: Alaska Oil and Gas Conservation Commission, Definitions, Alaska Admin. Code tit. 20, § 25.990, December 7, 2012. RegulationsStandard Cubic Foot
Definition(s)
Standard Cubic Foot
"Standard cubic foot" has the meaning given to "cubic foot" in AS 31.05.170. Source: Alaska Oil and Gas Conservation Commission, Definitions, Alaska Admin. Code tit. 20, § 25.990, December 7, 2012. RegulationsSidetrack Operation
Definition(s)
Sidetrack Operation
"Sidetrack operation" means a drilling operation conducted for the purpose of straightening the original hole, bypassing junk, or correcting mechanical difficulties in the original hole. Source: Alaska Oil and Gas Conservation Commission, Definitions, Alaska Admin. Code tit. 20, § 25.990, December 7, 2012. RegulationsShut In
Definition(s)
Shut In
"Shut in" means to close a well's surface, wellhead, or subsurface valves to halt flow from or into the well, with the completion interval remaining open to the tubing below the closed valves. Source: Alaska Oil and Gas Conservation Commission, Definitions, Alaska Admin. Code tit. 20, § 25.990, December 7, 2012. RegulationsShut In
“Shut-in” means the status of a production well or an injection well that is temporarily closed down, whether by closing a valve or disconnection or other physical means. Source: Oil and Gas, New Mexico Administrative Code Title 19, Chapter 15, January 2013. RegulationsService Well
Definition(s)
Service Well
"Service well" means a well used for injecting water, gas, or other fluids into a reservoir or producing formation in pressure maintenance, enhanced recovery, or storage operations, for disposing of oil field wastes, or for conducting other operations in support of oil or gas production. Source: Alaska Oil and Gas Conservation Commission, Definitions, Alaska Admin. Code tit. 20, § 25.990, December 7, 2012. RegulationsService Well
"Service well" means a well that, as part of a multi-well system, is used for drilling laterals, stimulation, or maintenance, or functions in any capacity other than as a conduit to the surface for the production of oil and gas. Source: Corporation Commission, Oil and Gas Conservation, Oklahoma Administrative Code 165:10, February 2013. RegulationsReservoir
Definition(s)
Reservoir
"Reservoir" means the same as "pool" in AS 31.05.170. Source: Alaska Oil and Gas Conservation Commission, Definitions, Alaska Admin. Code tit. 20, § 25.990, December 7, 2012. RegulationsReservoir
An economic hydrocarbon-bearing zone. Source: IADC UBO / MPD Glossary, December 2011. Global StandardsReservoir
A roofed excavation for the storage of petroleum liquids. Source: Petroleum Safety Orders--Drilling and Production, Definitions, California Code of Regulations, 8 CCR § 6505, December 2012. RegulationsReservoir
"Reservoir" means pool or common source of supply. Source: Oil and gas Conservation, North Dakota Administrative Code, Chapter 43-02-03, April 2012. RegulationsReservoir
A storage tank for BOP control system fluid. 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 StandardsPublic Water System
Definition(s)
Public Water System
"Public water system" has the meaning given in 18 AAC 80.1990, as amended as of October 1, 1999, and as amended from time to time; 18 AAC 80.1990 is adopted by reference. Source: Alaska Oil and Gas Conservation Commission, Definitions, Alaska Admin. Code tit. 20, § 25.990, December 7, 2012. RegulationsPublic Water System
PUBLIC WATER SYSTEM shall mean those systems listed in Appendix VI to these Rules. These systems provide to the public water for human consumption through pipes or other constructed conveyances, if such systems have at least fifteen (15) service connections or regularly serve an average of at least twenty-five (25) individuals daily at least sixty (60) days out of the year. Such definition includes:- Any collection, treatment, storage, and distribution facilities under control of the operator of such system and used primarily in connection with such system.
- Any collection or pretreatment storage facilities not under such control, which are used primarily in connection with such system.
PSIG
Definition(s)
PSIG
"Psig" means pounds per square inch gauge. Source: Alaska Oil and Gas Conservation Commission, Definitions, Alaska Admin. Code tit. 20, § 25.990, December 7, 2012. RegulationsPSIG
Pounds per square in. gauge. Source: API RP 64, Recommended Practice for Diverter Systems Equipment and Operations, Second Edition, November 2001 (March 1, 2007). Global StandardsPSI/FT
Definition(s)
PSI/FT
"Psi/ft" means pounds per square inch per foot, as a measure of pressure change with depth. Source: Alaska Oil and Gas Conservation Commission, Definitions, Alaska Admin. Code tit. 20, § 25.990, December 7, 2012. RegulationsPSIA
Definition(s)
PSIA
"Psia" means pounds per square inch absolute. Source: Alaska Oil and Gas Conservation Commission, Definitions, Alaska Admin. Code tit. 20, § 25.990, December 7, 2012. RegulationsPSIA
Pounds per square in. absolute. Source: API RP 64, Recommended Practice for Diverter Systems Equipment and Operations, Second Edition, November 2001 (March 1, 2007). Global StandardsProperty
Definition(s)
Property
"Property" means a legally described tract of land, submerged or otherwise, to which a person has the right to drill, extract, remove, clean, process, and dispose of oil, gas, and associated substances. Source: Alaska Oil and Gas Conservation Commission, Definitions, Alaska Admin. Code tit. 20, § 25.990, December 7, 2012. RegulationsPressure
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 StandardsPilot Gas
Definition(s)
Pilot Gas
"Pilot gas" means gas routed to a safety flare system to maintain an ignition source. Source: Alaska Oil and Gas Conservation Commission, Definitions, Alaska Admin. Code tit. 20, § 25.990, December 7, 2012. RegulationsMultiple Completion
Definition(s)
Multiple Completion
"Multiple completion" means the completion of a well so as to permit production from more than one pool, with the production from each pool completely segregated. Source: Alaska Oil and Gas Conservation Commission, Definitions, Alaska Admin. Code tit. 20, § 25.990, December 7, 2012. RegulationsMultiple Completion
Multiple Completion―the completion of any well so as to permit simultaneous production from two or more pools while maintaining segregation of each such pool through the single wellbore to the surface. Segregation and simultaneous production of separate intervals within a recognized pool through a single wellbore to the surface shall not be considered a multiple completion. Source: Natural Resources, Office of Conservation – General Operations, Louisiana Administrative Code, Title 43, Part XIX, March 2013. RegulationsMultiple Completion
"Multiple completion" means the completion of any well so as to permit the production from more than one common source of supply. Source: Oil and gas Conservation, North Dakota Administrative Code, Chapter 43-02-03, April 2012. RegulationsMudline Datum
Definition(s)
Mudline Datum
"Mudline datum" means- for a beach location, the plane of mean low water depth extended beneath the well site;
- for a location on a shifting natural island, the depth at which a horizontal plane through the toe of the island intersects the wellbore;
- for a location on an artificial island, the depth of the mudline as it existed before construction of the island; or
- for other offshore locations, the mudline.