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Methane hydrate as a “new energy” 259
sample, equivalent to an experimental test. The controlling parameters are given in
Fig. 7.22.
The DEM simulations of thermal recovery are shown in Fig. 7.23, while the DEM
simulations of depressurization process are illustrated in Fig. 7.24. By comparing
Figs. 7.16 and 7.19 with Figs. 7.23 and 7.24, it is evident that the DEM simulations
of thermal recovery and depressurization process capture the sample responses as
observed in laboratory tests. The most important advantage of DEM simulation is that
it can visualize the micromechanism in a granular material. Some good examples are
given in the following section.
7.5.2 Micromechanism associated with MH dissociation
There are two types of contacts in MHBS, i.e., the bonded contact and the unbonded
contact. In order to study the effects of temperature and applied deviator stress during
thermal recovery, the distributions of the total, bonded, and unbonded contacts in
Fig. 7.22 Temperature and
confining pressure vs time in
laboratory test and DEM
simulation (A) thermal
recovery and
(B) depressurization [19].