Hydrogeochemical Characteristics and Water–Rock Interactions of Coalbed-Produced Water Derived from the Dafosi Biogenic Gas Field in the Southern Margin of Ordos Basin, China
Table 6
Saturation indices (SI) of minerals in the coalbed-produced water.
Minerals
Saturation index
DFS-05
DFS-09
DFS-45
DFS-69
DFS-128
DFS-131
DFS-133
DFS-148
DFS-M68
Chemical formula
Anhydrite
-1.33
-1.26
-0.53
-1.29
-1.22
-0.87
-0.08
0.40
-2.11
CaSO4
Aragonite
/
/
/
3.16
/
/
2.40
2.63
/
CaCO3
Calcite
/
/
/
3.3
/
/
2.54
2.77
/
CaCO3
Dolomite
/
/
/
6.67
/
/
5.32
5.61
/
CaMg(CO3)2
Gypsum
-1.18
-1.19
-0.43
-1.19
-1.14
-0.79
0.01
0.48
-1.92
CaSO4•2H2O
Halite
-0.37
0.18
-0.02
-0.01
0.13
0.07
-0.02
-0.01
-0.70
NaCl
Sylvite
-2.52
-2.13
-2.22
-2.65
-2.14
1.67
-2.40
-2.10
-2.80
KCl
Note: “/” indicates that the mineral does not occur in the water.
