NUMERICAL MODELING OF GAS DISSOCIATION FROM GAS HYDRATE IN POROUS MEDIA

• Main Authors: N. R. Nanchary, S. L. Patil, R. B. Hunter
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Subjects: Methane hydrate; permafrost
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.430.3633; http://www.searchanddiscovery.com/documents/abstracts/2004hedberg_vancouver/extended/nanchary/images/nanchary.pdf

Gas hydrates may become an alternative future energy resource as large in-place volumes exist within and beneath permafrost and in offshore environments. However, gas production potential from gas hydrate reservoirs using different production mechanisms has not yet been fully investigated. This paper presents an axisymmetric model for simulating gas production from hydrate decomposition in porous media by a depressurization method. Several researchers have studied gas hydrate decomposition (Tsypkin, 1991; Ji et al., 2001; Moridis, 2002). Ullerich, Selim and Sloan (1987) described the decomposition of a synthetic core of methane hydrate as a moving boundary heat transfer problem. Most of the models assume equilibrium decomposition (Ji et al., 2001; Tsypkin, 1991). In the equilibrium models, the three-phase gas hydrate-gas-water interface is at equilibrium. Ahmadi, Ji (2003) developed an axisymmetric model for production of natural gas at a constant rate from gas hydrate-bearing reservoirs. The dissociation values of temperature, pressure and the position of the front enlisted in the table and figures displayed in the work of Ji et al. (2003) appear to be inconsistent for all different natural gas production rates. This work presents the acceptable values of dissociation temperature and pressure and location of the gas hydrate dissociation interface for different gas