Mining technologies , Mining and underground construction machineries

[1308-15-06] Micro and macro-scale simulation of CO2 hydrate formation

○Toru Sato¹, Ayako Fukumoto¹, Kentaro Kamada¹, Hiroyuki Oyama¹, Georgios Fytianos¹ (1. Unievrsity of Tokyo)

司会：玉村修司（幌延地圏環境研究所）
Chairman: Shuji Tamamura (NOASTEC)

Keywords:CO2 hydrate , sub-seabecd CCS, CO2 leakage

One of the methods to produce CO2 gas from hydrates in such sub-seabed sediments is depressurization: pumping up water through a well in order to decrease the pressure in the sediment and cause hydrate dissociation. To make this procedure commercially viable, it is necessary to predict its productivity, thus an accurate simulation tool is required for the gas-water two-phase flow. The permeability of gas and water in hydrate bearing sediments is important for this purpose. In this study, we propose a numerical model for estimating the distribution of CO2 hydrate in porous media from the physical properties of the sediment. The formation of CO2 hydrate in microscopic porous media was numerically simulated using the classical nucleation theory and the phase-field model. Then, this method was applied to hydrate formation in simulated sand sediment on the pore scale, and it was elucidated how hydrate grows in volume from its nuclei, which are set at random locations considering the occurrence probability of hydrate nucleation.