When water cluster begins at the Point A, CO2 and CH4 are gradually increased, adsorbed into the empty space of pore as show by snapshots in Figure 9 . Further pressure increases to Point B the sharp condensation of water is formed where water clusters merge together as shown by snapshot, resulting the empty space in the pore is smaller that CO2 and CH4 can be condensed. During the packing process at Points D and E, the amount adsorptions of CO2 and CH4 are extremely decrease as we have described in the last section. Upon the desorption, when water is gradually evaporated at Point F, CO2 and CH4 uptakes is slightly increased than the previous higher pressures. Due to there is an empty space for CO2 and CH4 to adsorb at this state. The hysteresis loop of CO2 and CH4 in the present water in 3 nm width slit-pore at 300 K have been observed which cannot be found in the case of without water. In the case for adsorption-desorption of CO2/CH4/H2O mixture (65:20:15) in 3nm width slit-pore at 300K which according to the real composition in nature is provided in the Appendix which we found is tendency similar to that of 1:1.