A
Acidise
To treat a well with acid, to dissolve limestone or other carbonate material in a producing zone. The object is to enlarge and reopen pores, vugs, and fractures in the zone to increase the flow of oil or gas into the well bore.
AGM
Annual General Meeting
Anticline
A subsurface geological structure in the form of a fold, with older rocks occupying the core.
In sedimentary rocks these are good prospects for drilling since, normally, oil & gas rises to the highest point in the structure
°API
Degrees API, a standard measure of oil specific gravity (related to density), defined by the American Petroleum Institute
B
Basin
A depression in the earth's crust in which sedimentary materials have accumulated over millions of years. Basins may contain oil or gas reservoirs.
bbl
Barrel
bcf
Billion cubic feet
boepd
Barrels of oil equivalent per day
bopd
Barrels of oil per day
Bottom hole pressure
The pressure at the bottom of a well, generally measured in pounds per square inch
C
Casing
Sections of steel pipe, which is lowered into the open well bore and cemented in place to isolate rock formations encountered during drilling. It prevents collapse of the borehole and stops formation fluids from different depths intermixing. Additionally, it provides pressure control by isolating strata with significantly different pressure gradients.
Completion
A term used to describe the assembly of downhole tubing and equipment to enable production from an oil or gas well, or hardware used to optimise production of hydrocarbons from a well
CSR
Corporate Social Responsibility
D
Development well
A well drilled within a proven productive area of a reservoir, with the objective of completing in that reservoir. The drilling of development wells involves a lower degree of risk than field extension or exploratory wells because they are reasonably expected to produce hydrocarbons at commercial rates.
Dip
The inclination or angle of slope of sedimentary rock strata, expressed in degrees from the horizontal.
E
Exploration well
A well drilled outside the boundaries of a known reservoir. It involves a higher degree of risk because it is drilled in a relatively unproven area or formation.
F
Fault
A fracture across which there is vertical or lateral displacement. Faults can be described as normal (extensional displacement), reverse (compressional), or strike-slip (lateral movement).
Frac
A term used to refer to the method used to increase the deliverability of a production or underground storage well by pumping a liquid or other substance into a well under pressure to crack (fracture) and prop open the created fracture with sand to provide a conduit for the hydrocarbons to easily travel from considerable distances out in the reservoir into the well bore.
Fracture
A break or joint in the rock which shows no significant signs of displacement. Fractures may be described as being open, closed (mineralised or 'healed'), or a mixture of both (part open).
Formation
Fundamental lithostratigraphic unit which can be mapped on a reasonable scale
FRS
Financial Reporting Standard
G
GBP
British Pound
Geophysics
Aspect of science which applies the principles of physics to the earth and the processes affecting it.
H
Heavy oil
Oil which has a low API <22°
Hydrocarbon
Solid, liquid, or gas composed of hydrogen and carbon only.
I
IAS
International Accounting Standard
IFRS
International Financial Reporting Standard
Impermeable
Not permeable. Incapable of transmission of fluids. Impermeable rocks form good hydrocarbon reservoir seals.
J
Joint
A fracture on which any displacement can not be discerned.
K
Kerogen
Found in source rocks, this insoluble organic matter generates hydrocarbons when subjected to specific ranges of temperature and pressure in the subsurface.
L
LIBOR
London Interbank Offered Rate
Light oil
Oil which has an API gravity >30°
LNG
Liquefied Natural Gas
