Development of Environmental Reproduction and Visualization Systems for Deep Sea Methane 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. This study has two principal objectives. The first is to gain insight into the degradation characteristics of the membrane materials that will be employed in the methane hydrate environment in deep sea. A further objective is to gain insight into the behavior of methane bubbles with a hydrate film on their surface, which differ from normal methane bubbles in their interaction with membrane materials. This includes the process of bouncing, deformation, sliding, fixation, and aggregation occur. These knowledges will be employed in the design of membrane structures for the production of methane hydrate in the deep sea. Novel systems that reproduce the methane hydrate environment on the seafloor in a laboratory have been developed. They consist of an environmental test system and a visualization system. This paper describes the design of the systems and presents some results obtained using the developed systems.