ИСТИНА

Gas hydrates in permafrost can occur in subpermafrost layers under low positive temperatures and in permafrost horizons under low temperatures. During evolution of permafrost hydrate-saturated soils could be a subject of freezing and melting. This is reflected in a change of their composition and properties. To assess the impact of freezing and melting processes on thermal conductivity of hydrate-bearing sediments at pressures above the equilibrium special experimental investigations have been held. The experiments were performed on a special installation with integrated system for measuring the thermal conductivity of hydrate-saturated sediment samples under pressure of hydrate-forming gas. The experiments showed that for hydrate-bearing sediments freezing and melting under gas pressure above the equilibrium may be accompanied by a decreasing of thermal conductivity.