2C - best estimate
2D - two dimensional
2P - proven and probable
ACQ - Annual contract quarterly
Appraisal well - Well drilled after the discovery of oil or gas to establish the limits of the reservoir, the productivity of wells in it and the properties of the oil or gas. See also development well
Barrel - (bbl: barrel; mmbbls: million barrels) a unit of measure for oil and petroleum products equal to 42 US gallons or 35 imperial gallons
Bbtud - Billion British thermal units per day
Block - Subdivision of sea area for the purpose of licensing to a company or companies for exploration/production rights. A UK block is 1/30 of a quadrant and is approximately 200-250 sq. km (a quadrant is one degree by one degree.)
Blow-out - Accidental escape of oil or gas from a well during the drilling stage
BOP - Blow out preventer - a high pressure valve fitted to the top of the casing to prevent blow-outs
Boepd - Barrels of oil equivalent per day
Bopd - Barrels of oil per day
bcf - billion cubic feet
Compressor - An engine used to increase the pressure of natural gas so that it will flow more quickly through a pipeline
Condensate - Liquid hydrocarbons separated and recovered from a condensate gas reservoir
Decommissioning - Removal of production equipment and facilities from depleted oil fields
Development well - A well drilled within the proved area of an oil or gas reservoir to the depth of a stratigraphic horizon known to be productive
Directional drilling - Also known as deviated drilling; technique used in production drilling whereby wells are drilled at an angle from a central point so that a number of development wells can be drilled from a single drilling facility
Downhole - A term used to describe tools, equipment, and instruments used in the wellbore, or conditions or techniques applying to the wellbore
Downstream - Refining of crude oil and the marketing and distribution of oil products that occur after refining, as opposed to upstream
Downtime - The time during which offshore operations cannot be continued owing to adverse weather conditions, mechanical or other factors
Drill-bit - The cutting head attached to the drill-pipe
Drilling muds or fluid - Fluid, containing barytes, which is pumped through the drill-string to the bottom of the well, whence it rises to the surface through the space between drill-string and bore-hole wall. It acts as a lubricant and is used to control flow
Dry hole - Any exploratory or development well that does not find commercial quantities of hydrocarbons
E&P - Exploration and production; the "upstream" sector of the oil and gas industry
EOR - Enhanced oil recovery
Equity - Share or interest in an oil or gas licence or field
Exploratory well - A hole drilled: a) to find oil or gas in an area previously considered unproductive; b) to find a new reservoir in a known field, i.e., one previously producing oil and gas from another reservoir, or c) to extend the limit of a known oil or gas reservoir
Farm in - Where a company joins a joint venture in return for paying disproportionately for future joint venture operations
Field - An area consisting of a single reservoir or multiple reservoirs all grouped on, or related to, the same individual geological structural feature or stratigraphic condition. The field name refers to the surface area, although it may refer to both the surface and the underground productive formations
Floater - An offshore drilling platform without a fixed base, usually held in position by anchor chains
FPSO - Floating production storage and offloading vessel
GSA - Gas sales agreement
GSPA - Gas sales and purchase agreement
HSEQ - Health, safety, environment and quality
HSFO - High sulphur fuel oil
IFRS - International financial reporting standards
Integrated - When applied to an oil company, it indicates a firm that operates in both the upstream and downstream sectors (from exploration through to refining and marketing)
Jacket - Supporting structure for an offshore platform
Jack-up - Mobile offshore drilling platform with retractable legs, on which the platform rests on the seabed when operational
Joint venture - Oil and gas companies generally participate projects through their equity share in a joint venture; the relationship between the companies is governed by a joint venture agreement
Kboepd - Thousand barrels of oil equivalent per day
Lease - A legal document conveying the right to drill for oil and gas, or the tract of land on which a lease has been obtained where the producing wells and production equipment may be located
Licence - An exploration licence permits only geological and geophysical surveying and the drilling of shallow wells; a production licence confers exclusive rights on the licensee to search and bore for and get petroleum
Log - The results of a survey which gathers information about the subsurface formations. Logs typically consist of several curves on a long grid that describe properties within the wellbore or surrounding formations that can be interpreted to provide information about the location of oil, gas, and water. Also called well logs
M&A - Mergers and acquisitions
Mmbbls - Million barrels
Mmboe - Million barrels of oil equivalent
MMBtu - Million British thermal units per day
Mmcf - Million cubic feet
Mmcfd - Million cubic feet per day
Mmscfd - Million standard cubic feet per day
Midstream - A term sometimes used to refer to those industry activities that fall between exploration and production (upstream) and refining and marketing (downstream). The term is most often applied to pipeline transportation of crude oil and natural gas
NCS - Norwegian Continental Shelf
NUI - Normally unmanned installation
OPEC - Organisation of petroleum exporting countries, founded in 1960
Operator - One member of a joint venture is appointed operator and has the responsibility of carrying out operations on behalf of the joint venture
P&A - Plugging and abandonment - a depleted well or dry hole that has been (typically) filled with cement with all surface equipment removed
Plateau level - The level of peak production reached by an oil or gas field
Platform - A fixed structure resting on the seabed or piled into it from which development wells are drilled, using directional drilling, to exploit an oil or gas field
PSC - Production sharing contract
Reservoir - A subsurface, porous, permeable rock formation in which oil and gas are found
Seismic - Data that is acquired by reflecting sound from underground strata and is processed to yield a picture of the sub-surface geology of an area
Semi-submersible - Mobile offshore drilling platform with floats or pontoons submerged to give stability while operating, kept in position by anchors or dynamic positioning
Spud - To commence drilling operations
Tbtu - Trillion British thermal units
Topsides - The top part of a platform positioned on the jacket
USV - Un-crewed surface vessel
UKCS - United Kingdom Continental Shelf
Upstream - Upstream covers the exploration, production and transport prior to refining
Wellhead - The equipment at the surface of a well-used to control the pressure and flow of fluids; the point at which the hydrocarbons and water exit the ground or seabed
Wildcat - Speculative exploration well drilled in search of a new oil or gas accumulation