Earth Science Frontiers ›› 2009, Vol. 16 ›› Issue (6): 359-371.

• Article • Previous Articles     Next Articles

 A thermodynamic model based on ab initio intermolecular potential to predict the equilibrium condition of methane hydrate under the influence of temperature, pressure, salinity and capillary force.

 CHEN Ya-Li, DUAN Zhen-??, SUN Rui, MAO Shi-De, ZHANG Chi   

  1. 1Faculty of Earth Science and Resources, China University of Geosciences(Beijing), Beijing 100083, China
    2
    3Institute of Geology and Geophysics, Chinese Academy of Sciences, Key Laboratory of the Earths Deep Interior,  Beijing 100029, China
    4Faculty of Sciences, University of Henri Poincare,  BP23, 54501 Vandoeuvre, Nancy, France
  • Received:2008-10-12 Revised:2009-06-18 Online:2009-12-16 Published:2009-12-10

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Abstract:

 A thermodynamic model is presented for predicting the multiphase equilibria of methane hydrate, liquid and vapor phases under conditions of different temperature, pressure, salinity and pore sizes. The model is based  on Van der WaalsPlatteeuw model, angledependent ab initio intermolecular potentials, DMW92 equation of state and Pitzer theory. Comparison with the experimental data shows that this model can  predict the equilibrium pT condition of CH4 hydrate in seawater and porous media with high accuracy. Online calculations of the pT condition for the formation of methane hydrate at a given salinity and pore sizes of sediments is available on: www.geochemmodel.org/models.htm.

Key words: methane hydrate; quantum simulation; ab initio potential; salinity; porous sediment; forming conditions; phase equilibria