Injection of CO2-saturated brine in geological reservoir : A way to enhanced storage safety

• Injection of free phase supercritical CO2 into deep geological reservoirs is associated with risk of considerable return flows towards the land surface due to the buoyancy of CO2, which is lighter than the resident brine in the reservoir. Such upward movements can be avoided if CO2 is injected in the dissolved phase (CO2aq). In this work, injection of CO2-saturated brine in a subsurface carbonate reservoir is modelled. Physical and geochemical interactions of injected low-pH CO2-saturated brine with the carbonate minerals (calcite, dolomite and siderite) are investigated in the reactive transport modelling. CO2-saturated brine, being low in pH, shows high reactivity with the reservoir minerals, resulting in a significant mineral dissolution and CO2 conversion in reactions. Over the injection period of 10 years, up to 16% of the injected CO2 is found consumed in geochemical reactions. Sorption included in the transport analysis resulted in additional quantities of CO2 mass stored. However, for the considered carbonate minerals, the consumption of injected CO2aq is found mainly in the form of ionic trapping.

Ämnesord

TEKNIK OCH TEKNOLOGIER  -- Naturresursteknik -- Mineral- och gruvteknik (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Environmental Engineering -- Mineral and Mine Engineering (hsv//eng)

Nyckelord

Injection of CO2-saturated brine

geological storage

carbonate reservoir

carbonate mineral reactions

ionic trapping

enhanced storage safety

Tillämpad matematik och beräkningsmatematik

Applied and Computational Mathematics

Chemical Engineering

Kemiteknik

Kemi

Chemistry

Byggvetenskap

Civil and Architectural Engineering

Land and Water Resources Engineering

Mark- och vattenteknik

Publikations- och innehållstyp

vet (ämneskategori)

ovr (ämneskategori)