The variation of temperature and pressure may lead to decomposition of gas hydrate in a hydrate-bearing sediment (HBS); meanwhile

several coupling processes are induced

including phase transition

pore water and gas pressures dissipation

heat transfer and skeletal deformation. A mathematical model is developed to describe the decomposition process of gas hydrate-bearing sediments based on the theory of porous media. The model properly considers the coupling effect among pore water/gas flow

phase transition

the kinetic process of hydrate dissociation

heat transfer and the skeletal deformation. Based on the finite element method

a numerical model describing the process of gas hydrate decomposition is developed and a computer program is compiled. Through numerical simulation of both depressurization-based and heating-based production processes

variation of displacement

pore pressures

temperature and other parameters in gas hydrate bearing sediments reservoir are analyzed. The results indicate that reservoir deformation and excess pore pressure are induced by depressurization and heating method with varying degrees

meanwhile

the seepage and heat conduction are contained in the gas hydrate dissociation process.