Research on the anisotropy of gas hydrate reservoirs in South China Sea

Abstract

The leakage-type hydrate is filled in the fractures, with steep and directional dips characteristics and the reservoir is basically anisotropic. The fractures characteristics are the key factors for reserve estimation and making of the production plan, and it is also the challenge and difficulty of the seismic exploration. Here we use the existing data recorded from ocean-bottom seismometers in the northeastern slope of South China Sea to carry out the research on whether the hydrate reservoir has the seismic anisotropy characteristics, and the results show that the seismic anisotropy characteristics is very obvious. The thickness and position of HTI medium lies between the time of 1550 ms and 1600 ms. On the basis of HTI anisotropy, combined with the geological situation of the region, it is assumed that vertical fractures exist in the region and the leakage-type hydrate exists. Also the research on parameters extracted from the fracture strike is carried out. The symmetry axis and the fracture directions of fractures are estimated. The results show that 60° and 240° correspond to the fractures symmetry axis, and 150° and 300° are the fractures trend. The recognition is very important for the estimation of the gas hydrate’s saturation.