Minerals Report - International Seabed Authority

In the 1960's scientists discovered that hydrates could also form in
natural environments. In 1972, the first pressurized specimen of naturally
occurring gas hydrate was recovered from the wildcat well on the north
slope of Alaska in the Prudhoe oil field8 . In the 1970's geophysicists of
Lamont-Doherty Earth Observatory of Columbia University found the
earliest indication of methane hydrates beneath the seafloor from the
seismic data collected over the Blake Ridge, along the southeast US coast9, 10 . Since then, the presence of gas hydrates has been inferred in many
places around the world. In 1997, the first drilling campaign specifically
designed for hydrate and related issues such as methane generation and
flux was carried out by the international scientific Ocean Drilling Program
(ODP) on the Blake Plateau. This effort greatly increased the
understanding of the deposits. Recognition of their widespread occurrence
on a global scale has recently spurred more focused programmes.
2. Global Occurrences and Resource Estimate
Gas hydrate occurrences are mostly concentrated at the
depocenters of the continental margins where both organic detritus (from
which bacteria generate methane) and sediments (which protect detritus
from oxidation) accumulate rapidly.
2.1. Occurrences
The first worldwide data set summary (published in 1980), on the
occurrences of sub- marine gas hydrates listed only nine regions with gas
hydrate indications. Subsequently, due to numerous marine geo-scientific
investigations and revelations by deep sea drilling (DSDP and ODP), the
findings increased continuously and the list now number 48 regions. Out
of these, hydrates were directly observed in 16 1ocations 11 and some of the
sites are given in Table 1.
INTERNATIONAL SEABED AUTHORITY 520