Gas hydrates in the data of thermodynamic research: Azerbaijan sector of the Southern Caspian

Geological structure and seafloor bathymetry in the deepwater part of the Southern Caspian are indicative of the possibility of generation of considerable gas hydrate amounts. Analysis of the materials related to gas hydrates of the Southern Caspian showed that all the activities aimed at determination of the zone of their possible accumulation are mainly based on the studies of Elm, Bozdag gas hydrate accumulations, and Apsheron area, and also on the thermodynamic factors of the region. As a part of the investigations, temperature and pressure distribution in the study area was examined in order to determine the depth of the formations occurrence at 24 °С, and also to analyse the range of pressure variations in near-surface. The temperature of gas hydrates formation is not the same for different components. As a result of the analysis, it was found that maximum depth of thermodynamic equilibrium at the time of gas hydrates formation from methane could reach 480 metres. On the basis of thermodynamic data and analysis of methodological bases of interpretation, the maximum depths of gas hydrates formation were determined. Finally, the amount of gas in gas hydrates was estimated within the identified zone of thermodynamic stability. Total amount of gas is 1.15 ∙ 1013 m3