Minerals Report - International Seabed Authority

At present, the technical and economic limit for permanent
offshore platforms is a water depth of 300 metres in the North Atlantic
(North and Norwegian seas) and 450 metres, in regions with less harsh
environments. In future, the depth limit for permanent offshore platforms
may be extended by means of new, stronger and more elastic materials.
Exploratory drilling in water depths up to 400 metres dates back to
the 1960s. Field development in water depths more than 200 metres began
in the 1980s, when deepwater petroleum exploration rapidly expanded. In
the 1990s, hydrocarbon exploration and development extended into new
areas at even greater water depths.
L. Weeks, an American scientist presented the first estimate of
offshore hydrocarbon resources in 1971 at the 8th Petroleum Congress in
Moscow. He estimated the offshore recoverable hydrocarbon resources of
the World’s Oceans as 320 Gtoe (1 toe = 100 m 3 gas), consisting of 230 Gt 1
oil and 90 Tm 3 2 gas. In the following 20 years, new recoverable
hydrocarbon resource estimates were regularly published. They varied
from 100–150 Gtoe 3 to 1.5-2 Ttoe, primarily due to poor geologic
knowledge of the World’s Oceans, the use of different sets of data, and
assumptions of different geologic or economic allowances and limits. In
all cases, however, the petroleum potential of deepwater areas (deeper
than 500 metres of water) was never discussed independently.
The Research institute VNIIZarubezhgeologia (Moscow, Russia)
has repeatedly estimated deepwater oil and gas resources of the World’s
Oceans within the framework of the quantitative estimation of world
petroleum potential. The latest estimate that it made was in 1996, and was
based on the available geologic and economic data.
2. Sedimentary Basins As The Main Object Of Hydrocarbon
Resource Estimation
Sedimentary basins of various sizes, structure and geologic history
are considered the main object of hydrocarbon resource exploration.
These basins are morphologically expressed in the modern crustal
1 Gt. Gigatonnes equal to one billion metric tons (tonnes) = 1000 million tonnes.
2 Tm3 - Tera cubic metres = 1012 cubic metres
3 Gtoe – Gigatonnes of oil equivalent
INTERNATIONAL SEABED AUTHORITY 485