IN-SITU RAMAN SPECTROSCOPIC STUDY OF THE DISSOLUTION AND REACTION PROCESS DURING CO-INJECTION SO2 WITH CO2 INTO PORE SPACE AT CONDITIONS RELEVANT TO CARBON CAPTURE AND STORAGE

Co-injection SO₂ with CO₂ can reduce the total capture cost, but result to highly reactive water-rock interactions and increase risk of leakage from the storage site. We used Raman spectroscopic imaging method to monitor the multiphase reactive transport processes of co-injection of SO₂ together with CO₂ in optical cell and micro-model at conditions relevant to carbon capture and storage (CCS). Based on a large number of calibration experiments, we established the quantitative relationship between the Raman spectral parameters and the concentration of SO₂-CO₂, determined the phase equilibria of the ternary mixture of SO₂−CO₂−H₂O, and observed the dynamic partitioning of the gases between the CO₂ rich phase and aqueous phase. Additional, in order to understand the interaction among acid gas, water, and rocks, we observed the reaction of CO₂-SO₂ mixtures with water saturated silicate particles, we found that SO₂ can accelerate the dissolution of silicate and results of precipitation of sulfates, when SO₂ is consumed, carbonate precipitation will be produced. Such reaction definitely affects the pore structure and permeability of rocks at some injection sites.