Objective of this Thesis

Three ultimate goals arise with respect to the importance of hydrate structures as a potential future energy resource and influence on the global climate: (1) the delineation of hydrate location, (2) the mechanism for the formation of hydrate deposits, and (3) the estimation of the amount of hydrate actually present in the hydrate structures. My objective is to use an integrated study of seismic AVO analysis and modeling and rock physics analysis to estimate the hydrate and BSR properties directly from surface seismic. The reflection amplitude variation with offset can be an important indicator of free gas at an interface Ostrander (1984); Shuey (1985), and should help to discriminate clearly between the two proposed BSR models and to estimate possible velocity structures around the BSR. A subsequent relation of the inferred hydrate properties with physical rock models should considerably limit the possible explanations of the physical origin of the BSR and the hydrate structures.

In the course of this study I intend to address the following key questions related to the BSR and hydrate properties:

• What causes the bottom simulating reflector?
• What are the elastic properties, i.e., P- and S-wave velocity, of hydrate-bearing sediments?
• Which rock physics models support these properties?
• How can we tell from these models how much hydrate is contained within the hydrate structures?

This dissertation will thus provide a tool for characterizing hydrate properties and estimating the amount of hydrate present from surface seismic. Even though the study is applied to data from the Blake Outer Ridge region, it is by no means restricted to this area.