Key terms are defined as follows:
|
Term |
Definition |
|
Ultimate recovery |
Total recovery from a
field, i.e. reserves plus past production. |
|
Reserves |
Discovered, remaining
reserves which are recoverable and commercial. Can be proven, probable or
possible depending on confidence level (as described below). |
|
Potential additional
reserves |
Discovered reserves
that are not currently technically or economically producible. |
|
Undiscovered
resources |
Undiscovered
potentially recoverable resources in mapped leads. |
Reserves are categorised as being ‘proven’, ‘probable’ or ‘possible’ based on confidence levels, as follows:
|
Reserves
|
Description |
|
Proven
|
Reserves which on the
available evidence are virtually certain to be technically and commercially
producible, i.e. have a better than 90% chance of being produced. |
|
Probable
|
Reserves which are
not yet proven, but which are estimated to have a better than 50% chance of
being technically and commercially producible. |
|
Possible
|
Reserves which at
present cannot be regarded as probable, but which are estimated to have a
significant but less than 50% chance of being technically and commercially
producible. |
|
Oil (million tonnes) |
||
|
|
571 - 857 - 1267 |
Reserves |
|
|
95 - 247 -
496 |
Potential additional
reserves |
|
|
323 - 782 - 1826 |
Undiscovered
resource |
| Total |
989 - 1886 -
3589 |
|
|
Gas (billion
cubic metres) |
|
|
|
|
590 - 905 - 1241 |
Reserves |
|
|
74 - 153 -
276 |
Potential additional
reserves |
|
|
279 - 492 - 1259 |
Undiscovered
resource |
| Total |
943 - 1550 -
2776 |
|
The total UK reserves (including Potential additional reserves plus undiscovered resources) are estimated to lie in the range of some 989 - 1886 - 3,589 million tonnes of oil and 943 - 1550 - 2,776 bcm of gas.
Cumulative production to date is 2,910 million tonnes of oil and 1,828 billion cubic metres of gas.
In terms of barrels of oil equivalent (boe) the range of UK reserves (including Potential additional reserves plus undiscovered resources) is 13.1 - 23.6 - 43.8 billion boe and cumulative production is 33.0 billion boe to end 2003.
The approach used to calculate barrels of oil equivalent this year is based upon a slightly modified method compared with that used in previous years.
The reader should understand that the approaches for assessing probabilities are necessarily different for each of the three categories of reserves and resources listed in the table. Adding the ends of the ranges together, as done here, indicates only the broad scope for reserves. In particular, the upper limits of the ranges for the reserves of oil and gas are only indicative of the remaining potential.
This data was last updated on : July 2004 and is due to be updated on : June 2005
If any errors are found or if you have any comments or other queries please contact:
joy.gray@dti.gsi.gov.uk
Joy Gray
email: