Abstract
In the surface methane hydrate (MH) mining project, MH and mud drilled together with seawater will be pumped on board a ship, and only methane gas will be recovered in a gasification facility on board the ship. In this process, understanding the impact of turbidity on the surrounding environment and efficient discharge methods into the depression are important issues.
In this study, in order to understand the turbidity of unwanted mud when it is discharged to the seafloor, we conducted a mud injection test using simulated deep-sea mud to understand the sedimentation characteristics of the mud when it is discharged. As a result, it was found that although the initial stage of the mud discharge is density flow-like, advection-diffusion behavior is dominant, and that the turbidity spreading is caused by the horizontal movement of the mud after it hits the seafloor and the upward turbulence after it strikes the tank wall. Numerical analysis using a three-dimensional flow model was used to qualitatively describe the behavior of the dumping mud.
