Volume 54

Effect of Ca-MMT with different water content on methane hydrate kinetics in sandy environments Zhen Zhang, Jing-chun Feng, Bin Wang, Yan Xie, Si Zhang, Zhifeng Yang

Abstract

The kinetic characteristics of methane conversion to hydrates in deep-sea cold seep sediments have a significant impact on hydrate accumulation and resource distribution. Consequently, they have important implications for the assessment of carbon sequestration and hydrate extraction potential. Nevertheless, the impact of clay minerals in cold seep sediments on the kinetics of methane hydrate formation in sandy environments remains uncertain. To investigate this, quartz sand was employed to simulate a sandy environment, allowing the effect of varying levels of calcium-based montmorillonite on the kinetics of methane hydrate formation in porous media to be studied. The results demonstrated that the initial rate of hydrate formation increased, while the final methane consumption decreased as the mass fraction of calcium-based montmorillonite (MMT) increased in comparison to the pure quartz sand system. The observed effects were mainly attributed to the high specific surface area of MMT and its capacity for adsorbing water. This work contributes to our understanding of the mechanism by which calcium-based montmorillonite affects the transformation of hydrates at varying water contents. Furthermore, it provides scientific support for the estimation of marine carbon sink capacity and carbon sequestration.

Keywords South China Sea cold seep, Methane leakage, Formation kinetics, Calcium-based montmorillonite