A nonlinear elastic constitutive model for artificial methane-hydrate-bearing sediment samples was presented. The triaxial compressive properties reported in an earlier work were analyzed to examine the applicability of Duncan-Chang model. The presented constitutive model considers the dependences of the mechanical properties of the samples on methane hydrate saturation and effective confining pressure.
Natural gas hydrate is anticipated to be a promising energy resource (Makogon, 1981, 1982; Kvenvolden, 1988; Kvenvolden et al., 1993). It is essential to consider the mechanical properties of a gas hydrate reservoir to ensure sustainable production (Collett and Dallimore, 2002; Bugge et al., 1988; Kleinberg, 2005; Sakamoto et al., 2009). There have been reports on laboratory studies concerning the triaxial compressive properties of artificial methane-hydrate-bearing sediment samples containing synthesized gas hydrates (Winters et al., 2005; Masui et al., 2005; Hyodo et al., 2005; Miyazaki et al., 2010a, 2010b, 2010c). In particular, Masui et al. (2005) developed a triaxial compression test method for artificial methane-hydrate-bearing sediment samples. Such laboratory studies are useful for determining the mechanical properties and/or constructing a mechanical model, or constitutive equation, for gas-hydrate-bearing sediments. Although there have been several studies of the triaxial compressive properties of such sediments, almost no constitutive model for gas-hydrate-bearing sediments has been published. A constitutive model for marine sediments containing gas hydrate is essential for the simulation of the geomechanical response to gas extraction from a gas-hydrate reservoir. An elastic constitutive model may be practically useful for the preliminary simulation of the mechanical behavior of a reservoir on the condition that we use it with particular attention to the applicable range. In this study, the application of a nonlinear elastic model (Duncan and Chang, 1970) to the analysis of the triaxial compressive properties of artificial methane-hydrate-bearing sediment samples was examined.
