Abstract
A high-speed X-ray computerized tomography (CT) system was developed for measuring the texture of methane hydrate sediment. The system enabled time dependent nondestructive observations of the hydrate sediment in a volume of φ100×100 mm3 within 40 s. The spatial variation of mass density and the volume fraction of an artificial methane hydrate sediment that is either ice or hydrate, hereafter referred to as the hydrate saturation ratio within methane hydrate sediments, were measured using the X-ray CT system. The three-dimensional (3D) distribution change of density and hydrate saturation caused by the hydrate dissociation were also visualized on the basis of the measured gray scale values of the CT images taken before and after their dissociation. The technique allows us observations of the dissociation process of methane hydrate sediment under experimental conditions which are the same as conditions in the natural environment, and will allow the simulation of methane gas production from wells in both oceanic and permafrost areas.