Such challenges address the basic conceptual framework upon which theoretical and laboratory studies on the thermodynamics and flow properties of the GH sys­tems are based.

5.2.4 Development of Universal Standards for Hydrate Sample Creation

This is an important challenge for fundamental physico-chemical hydrate research, and it first involves the establishment of a protocol to fabricate artificial hydrate samples in sediment. The second part of this challenge is to ensure that the sample is a reasonable replicate of nature. Currently the method of Spangenberg et al. [181] appears to be dominant; however, months of sample preparation time are required, and there is an urgent need for a more time-effective techniques.

5.2.5 Thermodynamic Knowledge Gaps and Time-Dependence Issues

Gibbs energy minimization methods are currently the most effective tools in deter­mining the behavior of complex hydrates involving more than CH4 (a subject that needs to be tackled, as such hydrates are likely in GH systems), and form the basis of the statistical thermodynamics approach in the description of the properties and behavior of such systems. Because of serious experimental difficulties, the predic­tions of these methods currently cannot be verified in a large part of the P-T-X spectrum of composite hydrates, and especially in the presence of more than one inhibitors. Additionally, time-dependent measurements are required, to establish kinetic phenomena, which are currently confounded by the addition of heat and mass transfer.