Phase transitions of water in gas-saturated grounds

We have experimentally studied the peculiarities of water-gas-hydrate and water-ice phase transitions under gas pressure in dispersed methane-saturated grounds on cyclic cooling-, heating. Data on the conditions of hydrate and ice formation in the ground pores have been obtained. It is shown that on cooling of dispersed rocks, only part of the pore water passes into hydrates; the rest (intimately bound with the particle surface) transforms into ice on further cooling. Hydrate formation in the studied grounds, compared with the system pure-water-gas, occurs at higher pressures and lower temperatures. It is demonstrated that the ground dispersion and cooling-heating cycles affect the PT-conditions of formation and decomposition of gas hydrates. Petrography of frozen artificially hydrate-saturated rocks is studied.