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FROZEN HEAT
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Gas Hydrate
Stability Boundary
Methane depleted zone
200 to 1000 meters
Sea Floor
~350 to 600 m water depth (depending on bottom-water temperature)
Hydrate-bearing
Marine Clays
Hydrate-bearing
sand
Water-bearing
sand
Hydrate-bearing
Deformed Clay
Free gas
Permafrost
“Chimney Structures”:
Dense fracture fills in muds
Sea Floor
Mounds
Deeply-buried, pore filling in sands
(resource targets, climate buffered)
“Strata-bound”
fractured muds
Disseminated,
pore-filling
Hydrate at upper edge of stability
(climate sensitive)
Relict Permafrost on
recently inundated
shelves (most climate sensitive?)
Pore-filling in sands at
high concentration
both within and below
permafrost (some pre-existing
free gas accumulations)
A
B
C
D
E
F
A,B
C
D
E
F
Minimal Gas Hydrate
(reduced gas supply)
far offshore
BIOGENIC GAS GENERATION
THERMOGENIC GAS GENERATION AND MIGRATION
R. Boswell - 2011
General schematic showing typical modes of gas hydrate
occurrence relative to the geologic environment
Figure 1.10:
General schematic showing typical modes of gas hydrate occurrence relative to the geologic environment. Thin (A) and thickly
veined (B) sediment-displacing gas hydrates (white) in fine-grained sediment (grey); (C) pore-filling gas hydrates in sand; (D) gas hydrate
mounds on the sea floor (hydrate has an orange coating from oil and is draped with grey sediment); (E) disseminated gas hydrates (white
specks) in fine-grained sediment (grey); (F) gas hydrates (white) in coarse sands (grey) (adapted from Boswell 2011).
A
B
C
D
E
F