Impact of hydrate and ice formation on gas permeability of sandy soils
Permeability and porosity of dispersive rocks in the permafrost well depends on a phase of a pore mosture, which subject to thermobaric and geochemical conditions can take the forms of ice, unfrozen water, gas hydrates (relict and stable). In the lower horizons of the cryolitozone (under the permafrost) a phase composition of pore moisture is usually represented by liquid water, and a gas hydrate in case of either gas-saturated rocks, or a zone of gas hydrates stability occur. In that context to analyze gas permeability of dispersive rocks of the criolitozone it is necessary to carry over filtration tests using soil samples with different phases of a pore moisture: water-ice, water-ice-hydrate, water-hydrate.In this paper presents the experimental results related to studying gas permeability of modelling unconsolidated reservoirs wet (sandy soils) in conditions when ice and methane hydrate form in voids. Test procedure included schedules for sample preparation, building-up of necessary moisture phases in pores of the soil samples by keeping given thermobaric provisions for hydrate and ice generation, determination of gas permeability, and controle of physical parameters of the samples. Tests were performed using an original experimental apparatus enabling provisions for freezing and/or hydrate saturation of rock samples.The named tests gave experimental data about gas permeability of sandy soils for various phases of moisture in their pores (water, ice, hydrate). Also, a fact that the sandy soils’ gas permeability in different thermobaric