Raman spectroscopic and calorimetric observations on natural gas hydrates with cubic structures I and II obtained from Lake Baikal

Akihiro Hachikubo (1) , Oleg Khlystov (2) , Masato Kida (3) , Hirotoshi Sakagami (1) , Hirotsugu Minami (1) , Satoshi Yamashita (1) , Nobuo Takahashi (1) , Hitoshi Shoji (1) , Gennadiy Kalmychkov (4) , Jeffrey Poort (5)

1 Kitami Institute
2 Limnologial Institute of the Siberian Division of the Russina
3 Methane Hydrate Research Center, National Institute of Advanced
4 A.P. Vinogradov Institute of Geochemistry
5 iSTeP - Institut des Sciences de la Terre de Paris

This study reports measurements of the Raman spectra of Lake Baikal gas hydrates and estimations of the hydration number of methane-rich samples. The hydration number of gas hydrates retrieved from the southern Baikal Basin (crystallographic structure I) was approx. 6.1. Con- sistent with previous results, the Raman spectra of gas hydrates retrieved from the Kukuy K-2 mud volcano in the central Baikal Basin indicated the existence of crystallo- graphic structures I and II. Measurements of the dissociation heat of Lake Baikal gas hydrates by calorimetry (from the decomposition of gas hydrates to gas and water), employing the hydration number, revealed values of 53.7-55.5 kJ mol- 1 for the southern basin samples (structure I), and of 54.3- 55.5 kJ mol-1 for the structure I hydrates and 62.8-64.2 kJ mol-1 for the structure II hydrates from the Kukuy K-2 mud volcano.

Domaines: Sciences de la Terre

Akihiro Hachikubo, Oleg Khlystov, Masato Kida, Hirotoshi Sakagami, Hirotsugu Minami, et al.. Raman spectroscopic and calorimetric observations on natural gas hydrates with cubic structures I and II obtained from Lake Baikal. Geo-Marine Letters, 2012, pp.1-8. ⟨10.1007/s00367-012-0285-z⟩. ⟨hal-00732969⟩