Development of a Deep Sea Remote Experiment System for Visualizing Methane Bubbles Behavior in Hydrate Environment

As part of the research and development of shallow methane hydrate recovery and production technologies for deep-sea environments, the potential use of membrane structures for capturing methane seeps while mining and for pollution prevention to reduce environmental impact of mining has been investigated. In our previous study, we developed a visualization system that replicates the methane hydrate environment on the seafloor in a laboratory setting. This system has been utilized to conduct numerous laboratory experiments, providing insights into the behavior of methane bubbles with a hydrate film on their surface. These bubbles differ from conventional methane bubbles in their interaction with various membrane materials. The pure water is utilized in these experiments to eliminate the impact of complex variables present in sea water, such as dissolved gases, ions, and particles. To validate the applicability of the obtained characteristics to the actual sea environment, comparison tests should be conducted in the deep sea, where methane hydrate exists. In this study, we have developed a deep sea remote experiment system that has capabilities to execute analogous tests in situ within a deep sea environment. The design of the system and some results obtained at depths of approximately 1000 meters are presented in this paper.