API: American Petroleum Institute gravity, a measure of how heavy or light the oil is compared to water. If API degree is greater than 10, the oil is lighter and floats on water; if less than 10, it is heavier and sinks
Appraisal well: A well drilled as a part of an appraisal drilling programme to determine the physical extent, reserves and likely production rate of a discovery/field
bbl: Barrels of oil
Block: Also referred to as Concession(s) or Licence(s)
boe: Barrels of oil equivalent
bopd: Barrels of oil per day
Brent: A reference oil for the various types of oil in the North Sea, used as a basis for pricing
Concession: Also referred to as Block(s) or Licence(s)
DOC: Declaration of commerciality
EPSA: Exploration and Production Sharing Agreement
Exploration well: A well drilled to determine whether hydrocarbons are present in a particular area or structure
Farm out / farm in: The holder of shares in an oil licence may transfer shares (“farm out”) to another company in exchange for this company taking over (“farm-in”) some of the work commitments in the licence, such as paying for a drilling or a seismic investigation within a certain period
HSE: Health, Safety and Environment
Injection well: A well that is used for injection of fluids into the reservoir to enhance hydrocarbon recovery
Licence: Also referred to as Block or Concession
Onshore: Designation for operations on land
Offshore: Designation for operations at sea
Operator: The member that is leading the work on the block or field
Porosity: The porosity of a rock is determined by measuring the amount of cavities inside, and determining what percentage of the total volume that consists of cavities
Prospect: A geographical area which exploration has shown contains sedimentary rocks and structures that may be favourable for the presence of oil or gas
Reserves: Quantities of oil that may be commercially recoverable in future
Reservoir: An accumulation of oil or gas in a porous type of rock with good porosity, such as sandstone or limestone
Resources: Hydrocarbons that are viewed as potentially recoverable depending on either technical developments or a more favourable position
Seismic data: Seismic investigations are made to be able to describe geological structures in the bedrock. Such data is collected by shooting acoustic energy – sound pulses –into the ground and listening to the responding sounds
Spud: To start drilling
Stb/d: Stock tank barrels per day
