Triaxial Compression Test of Artificial Sediments Containing CO₂ for Enhanced Methane Hydrate Recovery Available to Purchase

Methane hydrate (CH₄ hydrate) consists of cagelike crystal structures made up of hydrogen-bonded water molecules surrounding guest molecules of CH₄. CH₄ hydrate existing in marine sediments is anticipated to be a promising source of natural gas. Depressurization method is considered the most effective procedure for CH₄ -hydrate production. CH₄ -hydrate dissociation into CH₄ gas and water takes heat energy from the neighboring strata. CO₂ injection into marine sediments is thought to be a potential method to enhance CH₄ -hydrate recovery, because heat energy is generated by CO₂ -hydrate formation. It is essential to consider the geomechanical characteristics of CO₂ -hydrate-bearing sediments to ensure sustainable CH₄ -hydrate production using CO₂ injection. However, the mechanical properties of CO₂ -hydrate-bearing marine sediments have not been clarified, although they are essentially required to simulate the geomechanical response to CO₂ injection. It has recently been revealed that gas-hydrate-bearing sediments have rocklike mechanical properties due to the cementation effect of the hydrate between soil particles. In this study, the experimental methods of drained triaxial compression test for artificial CO₂ -hydrate-bearing sandy sediment were developed. The mechanical properties of CO₂ -hydrate-bearing specimen were compared to those of CH₄ -hydrate-bearing specimen.