Minerals Report - International Seabed Authority

natural gas is commonly formed in association with crude oil. However,
because of its lower viscosity, gas is often found separate from oil reservoirs.
Sedimentary sequences in excess of 1,000 m thick, in areas of high-heat flow,
and comprising organic-rich layers at depth overlain by porous rocks that are
in turn overlain by domed impermeable strata provide ideal environments for
hydrocarbon formation and retention.
4.6.3 Where marine hydrocarbon deposits are found
Table 4 (with references to Figure 21) shows the "proved" reserves of oil and gas (in
billions of barrels and trillions of cubic feet) in offshore fields around the world
(Klette, 1997).
Province
number
Oil
BB
Gas
TCF
NGL
BB
Total
BBOE
1 1.6 6.6 0 2.7
2