徐则林等-中国科学院广州能源研究所-Pore-scale characteristics of methane-hydrate bearing porous media

Session 3 - Oral 16

Pore-scale characteristics of methane-hydrate bearing porous media

Zelin Xua, b, Chungang Xua, b, Hao Chena, b, Gang Lia, b, Qiunan Lva, b, Xiaosen Lia, b

(a. Guangzhou Institute of Energy Conversion, Chinese Academy of Sciences, Guanghzou 510640, P. R. China;

b. University of Chinese Academy of Sciences, Beijing 100049, P. R. China)

Abstract: The occurrence modes of natural gas hydrate in porous media are concerned by hydrate academic community. In this study, the methane hydrate-bearing fine quartz sands were synthesized in the hydrate-bearing sediments apparatus, and the Scanning Electron Microscopy and the Energy Dispersive Spectrometry were combined to analyze the morphology and the dissociation characteristics of methane hydrate and ice in fine quartz sands. Results showed the methane hydrates covered the whole surface of the fine quartz sands and were cemented with obvious lines, and the particle size of simple methane hydrate was 5.00~20.00 µm. The percentage of methane clathrate hydrate and the empty clathrate hydrate were 85.70% and 14.30%, respectively. In the process of dissociation of methane hydrate, The spongy micro-pores (about 0.20 µm) occurred on the surface, which were rarely interconnected. The distance between each spongy micro-pore was 0.30~2.00 µm, and the porosity of the hydrate surface was about 25%. Ice showed mainly spherical, hexagonal, cubic and cluster shapes in fine quartz sands, and the particle size of ice varied between 0.50~10.00 µm, which were intrinsic different from that of methane hydrate. The micro-morphology and the decomposition spatial variation of methane hydrate in fine quartz sands were investigated in this work, which were important for further understanding of natural gas hydrate exploitation mechanism.

Keywords：methane hydrate; porous media; morphology; dissociation; ice