Background Image
Table of Contents Table of Contents
Previous Page  26 / 78 Next Page
Information
Show Menu
Previous Page 26 / 78 Next Page
Page Background

FROZEN HEAT

26

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