Seismoacoustic Study of the Shallow Gas Transport and ... - E-LIB

Chapter 1
numerous countries such as the United States, Japan, India, and South Korea are showing
substantial interest in exploiting this resource over the long term.
Figure 14 Gas hydrate production options (from Geir, 2010)
In order to produce natural gas from hydrates, it is necessary to dissociate the hydrate.
Based on the dissociation techniques involved, the exploitation methods are divided into
three major potential gas production methods, which are illustrated by Geir (2010) (Fig.
14) as follows: (1) the thermal stimulation method involves dissociating hydrates by
increasing the in situ temperature above the gas hydrate equilibrium point - as illustrated,
hydrate reservoirs are heated by injecting hot water, steam, or hot salt water; (2) the
depressurization technique is the method of discharging part of the gas from the gas
hydrate reservoir to reduce pressure below the hydrate equilibrium value, making hydrate
become unstable and decompose; (3) the chemical injection method utilizes some kind of
thermodynamic inhibitor, such as salts and alcohols, which cause a shift in the P-T
equilibrium. Beside the traditional methods, some new exploitation methods have also
been proposed, such as CO 2 replacement, electromagnetic heating, and microwave
heating (Geir, 2010; Liu, 2012).
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