Shallow gas hydrate within the areas of subaquatic seepage
- Institute for Geology and Mineral Resource of the Ocean, St. Peterburg (Russian Federation)
Sedimentary framework of worldwide hydrate-bearing areas and structures of sediments containing hydrates suggest that fluid filtration is the major process responsible for its generation. A study of seepage-associated hydrate accumulations that are accessible without drilling is useful for gaining an understanding of subaquatic gas hydrate formation general. Localities of shallow hydrate are indicative of oil and gas content. They also may be hazardous for oil and gas field development. The paper presents the results of exploration of gas hydrate accumulations that associate with diapirs, mud volcanoes, faults, subaquatic canyons, and pockmarks in the Caspian, Black, Okhotsk, and Barents seas. Data acquisition included echo sounding, seismic survey, ground sampling geothermic measurements, chemical and isotopic analyses of gas and water, definition of water content, and measurement of equilibrium pressures and temperatures. Hydrate content in sediments of discovered accumulations was up to 30-40% by volume. Somewhere, hydrate rests immediately on the bottom. Hydrate accumulation requires not only gas but also water input. It may be filtering either water bringing dissolved gas or pore/sea water migrating to meet gas diffusing bottomward. The models of gas hydrate formation have been developed for both gas-saturated water and free gas. Isotopic composition of water oxygen mainly results from exchange with carbonate inclusions rather than from the effect of hydrate fractionation. It is possible to evaluate hydrate content in sediments from the amount and composition of water.
- OSTI ID:
- 6916382
- Report Number(s):
- CONF-9310237--
- Journal Information:
- AAPG Bulletin (American Association of Petroleum Geologists); (United States), Journal Name: AAPG Bulletin (American Association of Petroleum Geologists); (United States) Vol. 77:9; ISSN 0149-1423; ISSN AABUD2
- Country of Publication:
- United States
- Language:
- English
Similar Records
Role of naturally occurring gas hydrates in sediment transport
Seabed features caused by shallow gas in North Sea
Related Subjects
020200* -- Petroleum-- Reserves
Geology
& Exploration
03 NATURAL GAS
030200 -- Natural Gas-- Reserves
Geology
& Exploration
BUILDUP
ENERGY SOURCES
EVALUATION
EXPLORATION
FLUID FLOW
FLUIDS
FOSSIL FUELS
FUEL GAS
FUELS
GAS FUELS
GAS HYDRATES
GASES
GEOLOGIC DEPOSITS
GEOLOGIC FAULTS
GEOLOGIC FRACTURES
GEOLOGIC MODELS
GEOLOGIC STRUCTURES
GEOPHYSICAL SURVEYS
HAZARDS
HYDRATES
MINERAL RESOURCES
NATURAL GAS
NATURAL GAS DEPOSITS
NATURAL GAS FIELDS
OIL FIELDS
PETROLEUM
PETROLEUM DEPOSITS
RESOURCE DEVELOPMENT
RESOURCES
SEEPS
SEISMIC SURVEYS
SURVEYS