Glossary

Best estimate

Two dimensional

Proven and probable

Annual contract quarterly

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

(bbl: barrel; mmbbls: million barrels) A unit of measure for oil and petroleum products equal to 42 US gallons or 35 imperial gallons

Billion British thermal units per day

billion cubic feet

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)

Accidental escape of oil or gas from a well during the drilling stage

Blow-out preventer – a high pressure valve fitted to the top of the casing to prevent blow-outs

Barrels of oil equivalent per day

An engine used to increase the pressure of natural gas so that it will flow more quickly through a pipeline

Liquid hydrocarbons separated and recovered from a condensate gas reservoir

Removal of production equipment and facilities from depleted oil fields

A well drilled within the proved area of an oil or gas reservoir to the depth of a stratigraphic horizon known to be productive

Also known as deviated drilling.

A 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

A term used to describe tools, equipment, and instruments used in the wellbore, or conditions or techniques applying to the wellbore

Refining of crude oil and the marketing and distribution of oil products that occur after refining, as opposed to upstream

The time during which offshore operations cannot be continued owing to adverse weather conditions, mechanical or other factors

The cutting head attached to the drill-pipe

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

Any exploratory or development well that does not find commercial quantities of hydrocarbons

Exploration and production.

The "upstream" sector of the oil and gas industry

Enhanced Oil Recovery

Share or interest in an oil or gas licence or field

A hole drilled to

• find oil or gas in an area previously considered unproductive; 
• find a new reservoir in a known field, i.e., one previously producing oil and gas from another reservoir; or 
• extend the limit of a known oil or gas reservoir

Where a company joins a joint venture in return for paying disproportionately for future joint venture operations

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

An offshore drilling platform without a fixed base, usually held in position by anchor chains

Floating Production Storage and Offloading vessel

Gas Sales Agreement

Gas Sales and Purchase Agreement

Health, Safety, Environment and Quality

High Sulphur Fuel Oil

International Financial Reporting Standards

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)

Supporting structure for an offshore platform

Mobile offshore drilling platform with retractable legs, on which the platform rests on the seabed when operational

Oil and gas companies generally participate in projects through their equity share in a joint venture; the relationship between the companies is governed by a joint venture agreement

Thousand barrels of oil equivalent per day

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

• 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

Also called well logs.

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 

Mergers and acquisitions

Million barrels

Million barrels of oil equivalent

Million British thermal units per day

Million cubic feet

Million cubic feet per day

Million standard cubic feet per day

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

Norwegian Continental Shelf

Normally unmanned installation

Organisation of Petroleum Exporting Countries, founded in 1960

One member of a joint venture is appointed operator and has the responsibility of carrying out operations on behalf of the joint venture

Plugging and abandonment.

A depleted well or dry hole that has been (typically) filled with cement with all surface equipment removed

The level of peak production reached by an oil or gas field

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

Production sharing contract

A subsurface, porous, permeable rock formation in which oil and gas are found

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

Mobile offshore drilling platform with floats or pontoons submerged to give stability while operating, kept in position by anchors or dynamic positioning

To commence drilling operations

Trillion British thermal units

The top part of a platform positioned on the jacket

Un-crewed surface vessel

United Kingdom Continental Shelf

Upstream covers the exploration, production and transport prior to refining

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

Speculative exploration well drilled in search of a new oil or gas accumulation