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Table 1. Characteristic parameters of giant fields. Fields that have not yet reached their decline phase (as of 2005)
are excluded. In total the post-plateau behaviour of 261 giant oil fields, distributed all over the world, is summa-
rized here.
All giant fields
Mean
Median
Prod. weight
Std. dev.
Depletion-at-peak
8.1%
7.2%
7.2%
4.3%
Decline rate
-6.5%
-5.3%
-5.5%
4.9%
Cum. Prod./URR-at-peak
38.6%
38.3%
36.8%
16.9%
Discovery-to-First Oil
5.2 years
3.0 years
4.2 years
5.7 years
First Oil-to-Decline
17.7 years
13.0 years
18.7 years
16.1 years
An analysis of giant oil fields divided into onshore and offshore fields yields the results displayed in
Table 2. Both land and offshore fields enter the decline phase when about 40% of the URR have been
produced, but offshore fields tend to extract the oil at a higher rate than land-based fields. This also ex-
plains why the average lifetimes of offshore fields are shorter than for land-fields and why they decline
faster. Unsurprisingly, one can also, see that offshore fields require more time from discovery to the start
of commercial oil production. All this is logical due to the higher investments required for offshore instal-
lations.
Figure 8. Histogram of the depletion-at-peak of the 170 post-plateau giant fields located on land. A small spread
occurs, but the vast majority is centered in the 5-10% interval. Despite the fact that all the studied field are widely
different, in terms of reservoirs, production strategies and much more, the actual difference in behavior seems small.
Summary :
Prod./URR-at-peak 38.6% 38.3% 36.8% 16.9% Discovery-to-First Oil 5.2 years 3.0 years 4.2 years 5.7 years First Oil-to-Decline 17.7 years 13.0 years 18.7 years 16.1 years An analysis of giant oil fields divided into onshore and offshore fields yields the results displayed in Table 2.
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