The proposed models for brine, gas and hydrate-saturated sediments require knowledge of the mineralogy of the sediments. Mineralogy information can be obtained either from geological interpretations of an area or from well-logs. The seismic data from the Blake Outer Ridge that are the basis of this analysis do not have direct well control. However, well information is available from several kilometers distance (see Figure 2.1). Since the drilling has shown that the sediments at the Blake Outer Ridge are very uniform and lithology does not change significantly Holbrook et al. (1996); Matsumoto et al. (1996), I feel confident about relating mineralogy information obtainable from the well-logs to the seismic data at hand. Because of the absence of quantitative core values of the exact sediment mineralogy, the actual mineralogy was inferred by fitting the well-velocities, excluding areas of hydrate and gas saturation Dvorkin et al. (1997).
The so-inferred mineralogy
model used in this study consists of 60% clay, 35% calcite and 5% quartz.
These three mineralogy components and the high amount of clay is
consistent with the drilling description of the sediments. The elastic
properties of this mineralogy and the water, gas and pure hydrate properties
needed to calculate the saturated rock properties are summarized
in Table ![[*]](http://sepwww.stanford.edu/latex2html/cross_ref_motif.gif)
.