I'm interested in any suggestion about the typical free-gas saturation beneath the gas hydrate stability zone in marine settings. Is this free-gas layer connected? What's the typical saturation to generate an effectively buoyant free-gas phase?
For free gas concentration you should check methane solubility curves. Free gas section and gas hydrate section might be connected or disconnected because in marine environment sediments alternating so if near intersection there is a impermeable layer such as clay or shale there will not be a connection