Understanding of Long-Term CO₂-Brine-Rock Geochemical Reactions Using Numerical Modeling and Natural Analogue Study

Table 3

Initial mineral volume fractions in the sandstone and possible secondary mineral phases in the simulation.

Mineral	Chemical formula	Volume fraction (%)
Primary
Quartz	SiO2	55.11
Illite	K0.6Mg0.25Al1.8(Si3.5Al0.5O10)(OH)2	18.02
Kaolinite	Al2Si2O5(OH)4	0.39
Chlorite	Mg2.5Fe2.5Al2Si3O10(OH)8	1.45
Smectite-Na	Na0.29Mg0.26Al1.77Si3.97O10(OH)2	0.725
Smectite-Ca	Ca0.145Mg0.26Al1.77Si3.97O10(OH)2	0.725
Albite	NaAlSi3O8	5.725
Anorthite	CaAl2Si2O8	5.725
K-feldspar	KAlSi3O8	0.32
Calcite	CaCO3	2.58
Ankerite	CaMg0.3Fe0.7(CO3)2	0.71
Siderite	FeCO3	4.37
Barite	BaSO4	4.15
Secondary
Dawsonite	NaAlCO3(OH)2
Dolomite	CaMg(CO3)2
Magnesite	MgCO3