Hydrate Surface Area Measurements During Dissociation Using Dynamic 3D Synchrotron Computed Tomography

Summary Availability of natural hydrates and ongoing rise in demand for energy, motivated researchers to consider hydrates as a potential energy source. Prior to gas production operations from hydrate-bearing sediments, hydrate dissociation is required to release gas into sediments. To reliably predict natural hydrate reservoir gas production potential, a better understanding of hydrate dissociation kinetics is needed. Hydrate dissociation models assume the relationship between hydrate surface area and (hydrate volume)2/3 to be linear due to hydrate sphericity assumptions. This paper investigates the validity of the spherical hydrate assumption using in-situ three-dimensional (3D) imaging of Xenon (Xe) hydrate dissociation in porous media with dynamic 3D synchrotron microcomputed tomography (SMT). Xe hydrate was formed inside a high-pressure, low-temperature cell and then dissociated by depressurization. During dissociation, full 3D SMT scans were acquired continuously and reconstructed into 3D volume images. A combination of cementing, pore-filling, and surface coating pore-habits were observed in the specimen. It was shown that hydrate surface area can be estimated using a linear relationship with (hydrate volume)2/3 during hydrate dissociation in porous media based on direct observations and measurements from 3D SMT images.