ABSTRACT

The pressure and temperature conditions were experimentally determined for methane hydrate dissociation in sodium chloride solutions, and an empirical equation of the conditions was obtained in the pressure range up to 18 MPa. The present results indicate that the maximum depth of oceanic sediments where methane hydrate is stable increases as water depth to seafloor increases, and that the maximum depth in saline water is smaller than that in pure water. The difference in the depth between saline and pure waters increases with decreasing the water depth, indicating that salinity of pore water affects significantly the amount of methane hydrate in oceanic sediments, in particular, beneath seafloor at relatively shallow depths.