Multiphase flow in porous media has wide range of engineering applications, most notably in the oil and gas extraction in hydrocarbon reservoirs. More often, the multiphase flow also involves coupled processes such as heat transfer, solute transport, phase change etc. In the previous part of this work, the changes in fluid properties and phases during surfactant-polymer flooding leading to viscous instabilities among those phases of different viscosities were studied. The effects of various miscible and immiscible viscous fingering on the oil recovery from water and oil wet reservoir were analyzed. In the present work, the methane flow, hydrate saturation change and the deformation behaviour of a hydrate reservoir during gas recovery by depressurization are studied. A thermo-hydro-mechanical-chemical (THMC) solver to simulate the non-linear coupled processes which include hydrate phase change kinetics, non-isothermal multiphase flow in porous media, alteration of porosity, permeability, bearing capacity and reservoir deformation has been developed. The deformation behaviour of the hydrate bearing media depends on its elastic moduli which not only depends on the host sediment and hydrate morphology but also on the spatio-temporal variation of effective porosity, hydrate saturation and pore pressure due to depressurization. These effects have been taken into account in our calculation of bulk and shear modulus of the media using a modified effective medium model for gas hydrates. A parametric study is performed to understand the deformation behaviour when intrinsic porosity changes in relation to critical porosity and also when the fraction of matrix supporting hydrate changes. It is observed that the deformation is 55% more when the intrinsic porosity (ф=0.45) is greater than critical porosity (фc=0.38) than when it is less (фc=0.5) because of the change in soil behaviour from fluid supported suspension to consolidated media. It is also observed that the deformation is about 20% less when the fraction of matrix supporting hydrate increases from 0.1 to 0.4 because of increased bonding of the soil.