High Resolution X-ray Diffraction Studies of the Natural Minerals of Gas Hydrates and Occurrence of Mixed Phases

The types and concentrations of gas hydrates collected from four different geological sites were analyzed using high-resolution angular dispersive X-ray powder diffraction, with synchrotron radiation as the source. Measurements were taken across a temperature range of 80 to 300 K and a pressure range of 0.1 to 80 MPa. All four gas hydrate samples showed the presence of three mixed crystal structures: structures I, II, and H. Additionally, the ice Ih structure was inherently present in all the natural gas hydrate minerals. The variation in the types and concentrations of gas hydrates can be attributed to the diversity of natural gases at different geographic locations.