  The paper is dedicated to the mechanics of the methane bubbles in the gas
hydrate stability zone of the basin. Transformation of deep-water methane
bubbles into solid hydrate was investigated in Lake Baikal in situ. Released
from the bottom methane bubbles were caught by different traps with transparent
walls. It was observed that when bubbles entered into internal space of the
trap, the bubbles could be transformed into two different solid hydrate
structures depending on ambient conditions. The first structure is hydrate
granular matter consisted of solid fragments with sizes of order of 1 mm. The
second structure is high porous solid foam consisted of solid bubbles with
sizes of order of 5 mm. The formed granular matter did not change during trap
lifting up to top border of gas hydrate stability zone, whereas free methane
intensively released from solid foam sample during it lifting. It was concluded
that the decrease of the depth of bubble sampling and the decrease of the
bubble flux rate assist to formation of hydrate granular matter, whereas
increase of the depth of bubble sampling and growth of bubble flux rate assist
to conversation of bubbles into high porous solid hydrate foam.
