Clathrate hydrates (CHs) are ice structures in which water molecules (host) form cages through hydrogen bonds. The cages can accommodate various types of molecules (guests), e.g. gases such as hydrogen and methane, and CHs with hydrocarbons exist naturally in large quantities in the deep sea floor sediments. We here explore the changes in structure when the crystalline ice host structure becomes amorphous (disordered) when pressure increases to 10 000 times atmospheric pressure at temperatures below -140 C, and also further changes as the amorphous state is heated. One objective is to determine if the guests remain in an ordered array in the amorphous ice structure. Another is to observe the changes in structure when the water molecules start to move on heating. In particular, if the state transforms into an ultraviscous liquid with the guest molecules in an initially ordered array