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oa Simulation of Geochemical Effects of SO2 Impurities in CO2 streams Near the Wellbore
- Publisher: European Association of Geoscientists & Engineers
- Source: Conference Proceedings, World CCUS Conference 2025, Sep 2025, Volume 2025, p.1 - 5
Abstract
This study employs CMG-GEM reactive transport modeling to investigate geochemical interactions of SO2-contaminated CO2 streams with near-wellbore rock-fluid systems in a Danish depleted reservoir. Building on prior research highlighting injectivity risks during pure CO2 injection, we specifically evaluate SO2’s additional impacts on mineral dissolution/precipitation and pH evolution. Our 2D model, incorporating SO2-specific chemistry and a horizontal well configuration, reveals: Pure CO2 injection dissolves calcite and glauconite while precipitating K-feldspar, siderite, and quartz, yielding a net 1.2% porosity increase. SO2 co-injection intensifies this mineral reactions, enhancing porosity to 3.7% through amplified dissolution-precipitation dynamics. Critically, SO2 induces extreme near-wellbore acidification (pH ∼2.0). Siderite exhibits dual behavior—precipitating under pure CO2 conditions via Fe2+ and HCO3 − combination but partially dissolving under SO2-driven acidity, with spatial dissolution patterns correlating to pH gradients.
As the first implementation of SO2-incorporated reactive transport in CMG, this work demonstrates SO2’s unique influence through its elevated density and reactivity, providing new insights into near-wellbore formation alterations during contaminated CO2 storage.
