Abstract

Most oceanic occurrences of gas hydrates in the sedimentary sequences are inferred, based mainly on the presence of an anomalous strong reflector on seismic profiles, termed as Bottom Simulating Reflector (BSR). Identification of BSR based on certain characteristics such as: reflection events with reversal polarity following the seafloor trend and crosscutting with the bedding planes. The amount of gas hydrates have been based mainly on the presence or absence of BSR and its relative amplitudes. The saturation of gas hydrates varies according to different physical properties like, porosity, velocity, bulk density and temperature etc. A model is developed to relate the seismic wave velocity with porosity and porosity with saturation. Three phase time-average equation is used to explain the velocities of compressional waves in various consolidated rocks measured at sub-zero temperature. Wood equation for the estimation of the compressional velocity is approximately valid for particles in suspension. These two above said equations comprises in a form of weighted equation, which applied to derive a relation between compressional wave velocity and porosity. The above theories predict that porosity decreases with increasing velocity. The saturation increases with increasing porosity and decreases velocity.