A review of the geochemistry of methane in natural gas hydrate

doi:10.1016/0146-6380(96)00002-2

Organic Geochemistry

Volume 23, Issues 11–12, November–December 1995, Pages 997-1008

https://doi.org/10.1016/0146-6380(96)00002-2 Get rights and content

Abstract

The largest accumulations on Earth of natural gas are in the form of gas hydrate, found mainly offshore in outer continental margin sediment and, to a lesser extent, in polar regions commonly associated with permafrost. Measurements of hydrocarbon gas compositions and of carbon-isotopic compositions of methane from natural gas hydrate samples, collected in subaquatic settings from around the world, suggest that methane guest molecules in the water clathrate structures are mainly derived by the microbial reduction of CO₂ from sedimentary organic matter. Typically, these hydrocarbon gases are composed of > 99% methane, with carbon-isotopic compositions (δ¹³C_PDB) ranging from − 57 to − 73‰. In only two regions, the Gulf of Mexico and the Caspian Sea, has mainly thermogenic methane been found in gas hydrate. There, hydrocarbon gases have methane contents ranging from 21 to 97%, with δ¹³C values ranging from − 29 to − 57‰. At a few locations, where the gas hydrate contains a mixture of microbial and thermal methane, microbial methane is always dominant. Continental gas hydrate, identified in Alaska and Russia, also has hydrocarbon gases composed of > 99% methane, with carbon-isotopic compositions ranging from − 41 to − 49‰. These gas hydrate deposits also contain a mixture of microbial and thermal methane, with thermal methane likely to be dominant. Published by Elsevier Science Ltd

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Review paperA review of the geochemistry of methane in natural gas hydrate

Abstract

Earth Planet. Sci. Lett.

Org. Geochem.

Marine Geol.

Appl. Geochem.

Geochim. Cosmochim. Acta

Appl. Geochem.

Marine Petrol. Geol.

Chem. Geol.

Org. Geochem.

Org. Geochem.

Geochim. Cosmochim. Acta

Molecular and isotopic compositions of hydrocarbons at Site 533, Deep Sea Drilling Project Leg 76

Geochemistry of hydrate gas and water from Site 570, Deep Sea Drilling Project Leg 84

Thermogenic gas hydrates in the Gulf of Mexico

Science

Isotopic composition of interstitial fluids and origin of gases in sediments of the Middle America Trench, DSDP Leg 84

Potential of gas hydrates outlined

Oil Gas J.

Natural gas hydrates of the Prudhoe Bay and Kuparuk River area, North Slope, Alaska

Am. Assoc. Petrol. Geol. Bull.

Natural gas production from Arctic gas hydrates

Clathrate hydrates

Natural gas hydrates in northern Canada

Regional aspects of deep sea drilling in the western North Atlantic

Concentrations and carbon isotopic compositions of CH4 and CO2 in gas from sediments of the Blake Outer Ridge, Deep Sea Drilling Project Leg 76

Filtrogenic gas hydrates in the Black Sea (Twenty-first voyage of the research vessel Evpatoriya)

Geologiya i Geofizika

Gas hydrates of the southern Caspian

Int. Geol. Rev.

Gas hydrates from the continental slope, offshore Sakhalin Island, Okhotsk Sea

Geo-Marine Lett.

Gas hydrates in sediments of holes 497 and 498A, Deep Sea Drilling Project Leg 67

Review paper
A review of the geochemistry of methane in natural gas hydrate

Concentrations and carbon isotopic compositions of CH₄ and CO₂ in gas from sediments of the Blake Outer Ridge, Deep Sea Drilling Project Leg 76