The problem of cold gas injection into the reservoir saturated with snow and gas, accompanied by hydrate formation process

In this paper, the problem of cold gas injection into the reservoir initially saturated with snow and gas with simultaneous formation of hydrate is considered. The mathematical model assumes gas injection in the equilibrium state. The self-similar solutions describing the distribution of the basic parameters (pressure fields, temperature, hydrate saturation, snow and gas saturation) in the reservoir are constructed. It is found that, depending on the initial state of the system «snow + gas» and the intensity of gas injection, different zones in the filtering area, such as «gas + hydrate», «gas + hydrate + snow», and «gas + snow», can be generated. The existence condition of maximum heating of «gas + snow + hydrate» system which provides a complete transition of snow in the hydration state is obtained. It is shown that initial state of the reservoir and parameters of gas injection define the conditions of full or partial hydrate formation in a volume region and at the front surface. It is revealed that the hydrate formation is more intensive and the length of the heated area decreases with increasing initial snow saturation in the reservoir.

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