Several important problems in the research of gas hydrates

Three important aspects in the present researches on gas hydrate, their fossil fuel resource potential, their role as a submarine geohazard, and their effects on global climate change, have been summarized and future research targets have been presented in this paper. The total amount of methane in gas hydrates is likely to be up to 1019 g of methane carbon, which is 2 times larger than the carbon present in all known fuel deposits:coal, oil and natural gas. Therefore, gas hydrate is considered as the potential strategy resources with industry value during the 21st century. Because gas hydrates are metastable, changes of pressure and temperature may easily affect their stability. Breakdown of gas hydrates in gas hydrates-containing sediments may affect the physical/chemical properties of sediments such as shear strength and flow, geophysical properties such as acoustic velocity and resistivity, and geochemical properties such as pore fluid compositions, which may lead to geological hazards in the form of gravitational slid collapse or slumps on seafloor. Decomposition of gas hydrates may also release methane, a strong greenhouse gas, into the atmosphere, causing the change of global climate and environments.