Natural gas hydrates with locally different cage occupancies and hydration numbers in Lake Baikal

M. Kida , Akihiro Hachikubo (1) , Hirotoshi Sakagami (1) , Hirotsugu Minami (1) , Alexey Krylov (2) , S. Yamashita , N. Takahashi , H. Shoji (3) , Oleg Khlystov (4) , Jeffrey Poort (5, 6) , H. Narita

1 Kitami Institute
2 I.S. Gramberg All-Russia Research
3 New Energy Resources Research Center
4 Limnologial Institute of the Siberian Division of the Russina
5 IPGP - Institut de Physique du Globe de Paris
6 iSTeP - Institut des Sciences de la Terre de Paris

[1] Knowledge of cage occupancies and hydration numbers (n) of naturally occurring gas hydrate in a local environment is important for the improvement in global estimates of hydrate-bound natural gas. We report on local differences in cage occupancies and hydration number of gas hydrates from Lake Baikal. Natural gas hydrates of both structures I and II (sI and sII) and ranging in composition from pure CH 4 to mixed gas hydrate containing up to 15% C 2 H 6 are compared. The average hydration numbers are n = 6.1 for the sI CH 4 hydrates recovered from the Malenky and Bolshoy mud volcanoes, n = 6.2 for the sI hydrates, containing 3-4% C 2 H 6 recovered from the K-2 mud volcano, and n = 6.9 for the sII hydrate containing about 15% C 2 H 6 recovered from the K-2 mud volcano. The differences in hydration number are due to the differences in the small cage occupancy of CH 4 among the samples studied.

Mots clés: cage occupancy; hydration number; methane; ethane; natural gas hydrate; Lake Baikal

Domaines: Minéralogie

M. Kida, Akihiro Hachikubo, Hirotoshi Sakagami, Hirotsugu Minami, Alexey Krylov, et al.. Natural gas hydrates with locally different cage occupancies and hydration numbers in Lake Baikal. Geochemistry, Geophysics, Geosystems, 2009, 10 (Q05003), pp.8 P. ⟨10.1029/2009GC002473⟩. ⟨hal-00688072⟩