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Gas
Hydrates and Microbiological Processes
Gas hydrates are an energy resource composed of natural gas in a solid state, in which the gas molecules are surrounded by water molecules, in a relatively stable composition. One volume of gas hydrates is equivalent to approximately 164 volumes of methane. Gas hydrates may represent more than double the energy content of all other hydrocarbon resources. Gas hydrates are found in equilibrium under conditions of high pressures and low temperatures, and occur in arctic regions (permafrost) and in the continental shelf - in marine surface and subsurface deposits, above seismically observable BSR (bottom-simulating reflectors). The importance of gas hydrates is related to their potential for exploration and production as a source of natural gas; to the known problems they cause in drilling and production systems; to their climate change effects - negative (GHG) and positive (CO2 sequestration); to the clathrate gun hypothesis effect; and to their potential as a logistics solution for natural gas transportation. Various microbiological investigations of gas hydrates suggest the potential of biological applications for producing hydrates through destabilization. Among these are processes involving microbial conversion of CO2, biological in-situ methane production, and organisms which produce antifreeze proteins (AFPs), which inhibit the crystallization of hydrates and eliminate more rapid recrystallization or “memory effect”. These concepts require more research to explore techniques to uncover “green inhibitors” for hydrates. This represents a challenge to researchers involved in projects related to monetization of the very significant gas
hydrate accumulations worldwide: microbiological processes may be the key to their economical recovery. AAPG Search and Discover Article #90100©2009 AAPG International Conference and Exhibition 15-18 November 2009, Rio de Janeiro, Brazil