[HSC07-P08] Numerical study on leakage suppression of CO2 stored in sub-seabed strata by gas hydrate formation
Keywords:CO2 hydrate blocking, CCS, Leakage suppression, Reservoir-scale simulation
In the storage under the seafloor, it is conceivable the stable storage becomes possible by forming gas hydrate under the conditions of high pressure and low temperature.
Hydrate storage leads to further expansion of storage potential. This study aims to visualize the behavior of CO2 in the stratum, using numerical simulation.
As a previous study, Yu et al. (2016) proposed a new model of hydrate formation was developed depending on the microscopic position. The hydrate formation simulation on the reservoir scale was performed with coupling the hydrate formation model with GETFLOWS (General purpose Terrestrial fluid-FLOW Simulator). We carried out the simulations using the physical conditions of Sleipner, Snøhvit, and Tomakomai, which are typical seafloor storages, such as seafloor depth, seafloor temperature, geothermal gradient, injection rate, and permeability.
As a result, it was found that the diffusion of the hydrate formation heat made it difficult to form hydrate around the area where hydrate had already been formed, and that the hydrate might leak to the seafloor. Whether it is possible to classify cases that can be stored and cases that lead to leakage depends on the conditions.