Abstract:

Seismic method is one of the main and important tools to investigate the presence of gas hydrate, especially in case whenthere is no other geological or geophysical techniques that can provide quantitative information to study gas hydrate. In this paper, the authors analyse factors affecting the seismic velocities and select optimal method to generate velocity model for sediments containing GH in deep water areas offshore Vietnam. The modeling results points out that mineral structure affect velocities of GH sediment, even though GH located in sediment's pore but it is considered as a matrix during calculate elastic moduli. Moreover, porosity, Biot coefficient, depth of GH layer from seabed and depth of seabed, ratio between sand and shale affect velocities of sediments too. This research also confirms the ability of application of amplitude variation with offset (AVO) analysis to predict sediment containing GH.