Dynamic Evaluation Method of Caprock Microscopic Sealing in CO₂ Sequestration Project

Table 2

Initial mineral and hydrochemical composition of X oilfield formation.

Initial mineral content of reservoir (%)
Quartz	Feldspar		Carbonatite			Clay
	K-feldspar	Plagioclase	Dolomite	Calcite	Dawsonite	Kaolinite	Illite	Montmorillonite
30.18	7.65	37.35	9.46	7.16	4.73	1.73	0.57	1.17
Initial mineral content of caprock (%)
Quartz	Feldspar		Carbonatite			Clay
	K- feldspar	Plagioclase	Dolomite	Calcite	Dawsonite	Kaolinite	Illite	Montmorillonite
19.67	4.85	28.93	9.55	12.37	3.5	4.64	8.16	8.33
Initial composition of formation water (mol·kg^-1 H2O)
H^+	^-8	Al^3+	^-7	Fe^2+	^-3	K^+		0.5100
SiO2	^-4	OH^-	^-5	Ca^2+	0.161	Mg^2+		0.0344
Reaction equation [35–37]						Reaction rate constant
					-2.762	-15.63-
					4.3024	11.52
^-					1.235	-10.03
					2.2247	-9.744
					-0.481	-12.13