Phase field theory modeling of CH4/CO2 gas hydrates in gravity fields

Abstract

Natural gas hydrates in reservoirs are thermodynamically unstable due to the interactions with surrounding fluids (aqueous, gas) and mineral surfaces. Depending on the local flow hydrate will dissociate as well as reform. If the dissociation rate is faster than the capacity of the surrounding fluids to dissolve the released gas, the gas will form bubbles. Depending on the rate of released gas and possible fracture patterns this may lead to venting of gas. The proper implementation of hydrodynamics will provide a deeper insight of the hydrate kinetics involved during dissociation and formation processes which involve hydrate former phase as smaller or larger bubbles or even continuous gas phase. In this work the phase field theory coupled with hydrodynamics model is implemented with variable density using the relative composition, phase field parameter and flow, which is an extension of our previous work which considers a constant density.