A multi-orientation system for characterizing microstructure changes and mechanical responses of fine-grained gassy sediments associated with gas hydrates.

Fine-grained marine sediments containing veiny and nodular gas hydrates will evolve into fine-grained gassy sediments after hydrate dissociation due to climate-driven ocean warming. The mechanical properties of the fine-grained gassy sediments are basically acquired by ocean engineering design. However, they have not been fully understood, largely due to the lack of microstructure visualization.

Molecular Dynamics Simulation of the Three-Phase Equilibrium Line of CO Hydrate with OPC Water Model.

The three-phase coexistence line of the CO hydrate was determined using molecular dynamics (MD) simulations. By using the classical and modified Lorentz-Berthelot (LB) parameters, the simulations were carried out at 10 different pressures from 3 to 500 MPa. For the OPC water model, simulations with the classic and the modified LB parameters both showed negative deviations from the experimental values.

Integrating test device and method for creep failure and ultrasonic response of methane hydrate-bearing sediments.

Clarifying the creep behaviors of hydrate-bearing sediment (HBS) under long-term loading is crucial for evaluating reservoir stability during hydrate exploitation. Figuring out a way of characterizing deformation behaviors and their geophysical responses to HBS is the basis for modeling creep behaviors. In this study, we propose a novel device to test time-dependent deformation and the ultrasonic response of HBS under high-pressure and low-temperature.

Experimental apparatus for resistivity measurement of gas hydrate-bearing sediment combined with x-ray computed tomography.

Natural gas hydrate has sparked worldwide interest due to its enormous energy potential. Geophysical surveys are commonly used in gas hydrate exploration, and resistivity logging plays an important role in this field. Nevertheless, the electrical response mechanism as a result of the gas hydrate growth in sediment is not well understood.