Rock in which oil and gas are found in exploitable quantities that can produce a profit.
The property of a formation which quantifies the flow of a fluid through the pore spaces and into the well bore.
A generic name for hydrocarbons. This includes crude oil, natural gas liquids, natural gas and the products they produce.
An offshore structure that is permanently attached to the seabed.
The percentage of void in a porous rock compared to the solid formation.
Reserves which at present cannot be regarded as ‘probable’ but are estimated to have a significant but less than 50% chance of being technically and economically producible.
Recovery of oil or gas from a reservoir that uses only the natural pressure in the reservoir to force the oil or gas out of the ground.
Those reserves which are not yet proven to produce but are estimated to have a greater than 50% chance of being technically and economically producible.
An oil and/or gas field whose physical extent and estimated reserves have been determined.
The Reserves which on the available evidence and research are certain to be technically and economically producible (i.e. having a greater than 90% chance of being produced).