Hydrate is Part of the Fluid

In this first model (Figure A), the hydrate is treated as part of the pore fluid, thus having no effect on the sediment properties. This is equivalent to a fluid substitution in purely brine-saturated sediments: instead of being 100% brine-saturated, the pore fluid consists of a mixture of brine and hydrate. The bulk modulus of the fluid can therefore be calculated as an average of the water and hydrate moduli:

$$\rm K_{\rm f} \:=\: {[\rm S_{\rm w}\: / \: \rm K_{\rm w} \: + \: (1-\rm S_{\rm w})\:/\:\rm K_{\rm h}]}^{-1},$$ (16)

where $\rm K_{\rm h}$ is the bulk modulus of the hydrate, $\rm K_{\rm w}$ the bulk modulus of water and $\rm S_{\rm w}$ the water saturation. The required dry and saturated rock properties are then calculated using equations through .