Numerical Investigation of CO₂ Sequestration as Hydrates in Produced Natural Gas Hydrate Formation with Different Intrinsic Permeability and Water Saturation Conditions

The phase transition field model equations for hydrate-bearing formation are proposed to analyze the variations in pressure, temperature, hydrate growth rate and other parameters during CO₂ injection and storage as solid hydrates. The numerical algorithm results show that intrinsic permeability and water saturation has great influence on hydrate nucleation process. When the intrinsic permeability of sediment decreases from 100 mD to 10 mD and 1 mD, pressure distribution delays inside hydrate-bearing formation and indirectly it also suspends the hydrate growth process due to smaller hydrate growth rate. The slow hydrate nucleation speed affects other parameters variations like, temperature distribution, accumulative hydrate growth, CO₂ permeability and 1^st and 2^nd region boundaries movement. The hydrate growth termination effect is observed near the wellbore region at different absolute permeability conditions. The hydrate growth suspension is more prominent when the intrinsic permeability reduces from 100 mD to 10 mD and 1 mD. Therefore, CO₂ injection at low temperature and high pressure conditions may form hydrates but it seems challenging in lengthier formation. So, more than one injection facilities can solve this problem with less injection pressure.