Gulf Keystone Petroleum - Glossary

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Glossary

A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | R | S | T | U | V | W

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		Liquid Natural Gas

M
Migration		The movement of hydrocarbons from source to reservoir. Primary migration refers to expulsion from the source itself, secondary migration describes its passage through the reservoir to the trap.
mmbbl		Million barrels
mmboe		Millions of barrels of oil equivalent
mmscfd		Millions of standard cubic feet per day

N
Nitrogen lift		Nitrogen injection into the fluid column to stimulate flow into the well bore.

O
Outcrop		An area of rocks occurring at surface

P
Perforation		Holes in casing and cement (if present) to allow formation fluid to enter the well bore. One common method of perforating is by shooting holes through the casing by means of a 'gun' lowered into the hole. Others use shaped charges to penetrate the casing and up to 36" into the surrounding formation.
Permeability		A measure of the ability of a rock to transmit fluids. It is measured in darcies or milledarcies.
Porosity		Expressed in bulk percentage, it is a measure of the ratio of void space to total rock volume. Fluids occupying porosity in a reservoir may include hydrocarbons.
PSC		Production Sharing Contract

R
Reserves		That portion of the identified resource (oil or gas), from which a usable mineral and energy commodity can be economically and legally extracted at time of determination.
Reservoir		Used to describe subsurface rocks with sufficient porosity and permeability to allow the storage and transmission of fluids (primarily hydrocarbons).

S
Seismic survey		Controlled transmission and recording of energy (vibration) into the ground to delineate subsurface structures and potentially identify hydrocarbon traps
Spud		This term refers to the point in time at which the drill bit begins to turn into the earth and drilling actually starts.
sq km		Square kilometres
Strike		A horizontal straight line on a planar surface perpendicular to the true dip direction. Usually expressed as a azimuth.

T
tcf		Trillion cubic feet
Total Depth		This is the point at which the drilling operation has reached the total intended depth. Once this depth is reached, the operator must analyze the results of the drilling and determine whether the well is to be completed.
Trap		A subsurface feature which can contain hydrocarbon accumulations. Structural traps are a result of deformation of the earth such as folding and faulting. Stratigraphic traps are a result of lateral and vertical variations in rock properties such as permeability and porosity, and may be caused by facies changes.

U
Unconformity		A break in the stratigraphic record. They can be the result of a hiatus in sediment deposition, or a period of uplift and erosion. These may be recognised in the subsurface using stratigraphic correlation between wells or seismic interpretation (angular or landscape unconformities).
$		US Dollar

V
Vug		A large pore or cavity, frequently found in carbonate rocks, which is often lined with minerals

W
Wells		Types of Wells:
		Wildcat - a well drilled far from known production in a setting which has no conventional prospectivity.
		Exploratory - A well drilled outside the boundaries of a known reservoir.
		Development - A well drilled within the boundaries of a known producing reservoir to increase the production in the field.
		Offset Well - This is a type of development well that is drilled near a well that is producing or had previously been productive.