Multi-scale modeling of CO_2 dispersion leaked from seafloor off the Japanese coast

摘要

A numerical simulation was conducted to predict the change of pCO_2 in the ocean caused by CO_2 leaked from an underground aquifer, in which CO_2 is purposefully stored. The target space of the present model was the ocean above the seafloor. The behavior of CO_2 bubbles, their dissolution, and the advection-dif-fusion of dissolved CO_2 were numerically simulated. Here, two cases for the leakage rate were studied: an extreme case, 94,600 t/y, which assumed that a large fault accidentally connects the CO_2 reservoir and the seafloor; and a reasonable case, 3800 t/y, based on the seepage rate of an existing EOR site. In the extreme case, the calculated increase in ΔpCO_2 experienced by floating organisms was less than 300 ppm, while that for immobile organisms directly over the fault surface periodically exceeded 1000 ppm, if momentarily. In the reasonable case, the calculated ΔpCO_2 and pH were within the range of natural fluctuation.