Coring and direct evidence

Infrared (IR) sensing of the cores gave reduced temperatures (AT) as a result of endothermic heats of hydrate dissociation. These temperature indications were taken as linearly related to the amounts of hydrate present. 

Hydrated-methane evolution from the pressure core sampler (PCS) was far beyond the normal gas solubility in the core waters, and provided an estimate of hydrate amounts. 

Reduction in chlorinity resulted from hydrate dissociation upon retrieval, and the amount of the reduction can be used to estimate hydrate amount (Torres et al., 2004). It should be noted that an accurate method was determined for the chlorinity baseline decrease, due to the deposit of ions within the shale, and the expulsion of fresh water from the shale, due to overpressure. 

Trehu et al. (2004b) distinguish between the GHSZ defined as the region from the BSR to the mudline, and the GHOZ, a thinner zone, defined as the region 

Hydrate Amount Estimates (% Pore Volume) Via Four Techniques 

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