Volume 49

The kinetics of methane hydrate formation study in different sediments based on the “Haima” cold seep environment Xingyu Chen, Jingchun Feng, Yan Xie, Longhang Xu, Si Zhang, Zhifeng Yang

Abstract

The characteristics of hydrate transformation of deep-sea seepage methane in sediments affect the fate of methane and have a great impact on the global climate. However, there are many kinds of deep-sea sediments with complex compositions, as one of the main seafloor sediments, the mechanism of chlorite’s influence on hydrate formation is not clear. This study aims to investigate the effects of chlorite and quartz sand on the kinetics of methane hydrate formation. The experimental results show that when the sediment particle size is the same, the change of initial water saturation has a certain effect on the formation rate of hydrate and the final water conversion rate, however, when the initial water saturation of sediments is the same, the change of particle size has little effect on the final water conversion. Although the sediments with a high specific surface area can provide more nucleation sites for hydrate to promote the formation of hydrate, they can also absorb more water, leading to a decrease in water activity and slowing down the formation of hydrate. In addition, the results of this study provide a further understanding of the conversion characteristics of methane hydrate in sediments.

Keywords natural gas hydrate exploitation, kinetics, methane leakage, free gas, porous sediments