Simulation of CO2 and steam injection to optimise the recovery of gas from hydrate formation

CO₂ and steam injection are currently recognised as two of the main methods for recovering gas from hydrates. Gas hydrates are vital components of the carbon cycle thought to hold more than fifty percent of all the hydrocarbon resources known world-wide. Such vast reserves are untapped because extraction is challenging. However, there is still a need to recover gas from hydrates to supplement the traditional sources with the increasing energy demand paired with depleting reserves. This research investigates methane recovery from a gas hydrate reservoir using CO₂ and steam injection while ensuring wellbore stability. Numerical simulation techniques were employed to evaluate extraction efficiency over injection periods of 1, 5, 15, 20, 30, and 365 days. The injection of both gases induced hydrate dissociation, leading to enhanced formation permeability, with steam injection leading to a more significant increase. Results showed 100 % hydrate dissociation and consequently a much higher gas production potential with steam, compared to 91 % dissociation and a lower gas production potential with CO₂ over one year. Based on these findings, this study recommends steam injection as the optimal method for methane recovery from hydrate formations due to its effectiveness in enhancing permeability while causing minimal formation perturbation.