Hydrate Formation Characteristics during Carbon Dioxide Flow Through Depleted Methane Hydrate Deposits

Abstract

AbstractDepleted methane hydrate (MH) reservoirs are potential sites for CO2 storage. Hydrate formation during the CO2 flow process in a dissociated MH sample was simulated to clarify the formation characteristics of CO2 hydrates and their effect on CO2 storage. Experiments included MH formation and dissociation, CO2 injection, water‐injection and CO2 hydrate dissociation, and liquid‐water distribution as monitored by magnetic resonance imaging (MRI). It was observed that the initial water saturation determined the hydrate saturation in the artificial sediment, and the depressurization range was the main factor influencing MH dissociation for the excess gas sample. Pressure is the key factor influencing hydrate formation during CO2 flow. An increase of the CO2 flow rate led to a decrease of both hydrate saturation and conversion of the injected CO2. The cumulative amount of injected water is not the key factor controlling CO2 hydrate formation, but it does determine the residual water saturation.