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 1

Geochemical parameters and water types of coalbed-produced water.

Parameters	Sample ID
	DFS-05	DFS-09	DFS-45	DFS-69	DFS-128	DFS-131	DFS-133	DFS-148	DFS-M68
pH	8.2	7.9	8.1	9.0	7.7	8.0	8.3	8.3	7.2
TDS	9828.0	14199.0	12545.7	14886.1	13819.2	13318.7	15076.0	16505.6	7601.9
Na^+	3824.2	5395.5	4826.4	6052.0	5275.4	5045.2	5933	6367.6	2968.0
K^+	13.0	18.8	18.4	8.1	19.3	59.1	14.5	30.8	9.4
Mg^2+	15.0	59.5	40.2	5.2	50.1	47.9	8.7	10.8	11.5
Ca^2+	52.0	109.8	60.5	7.7	81.3	79.9	7.6	12.8	30.3
NH4^+	11.3	16.9	23.2	0.0	21.8	15.4	9.2	0.0	9.7
Cl^-	5457.7	8441.8	7238	6229.8	8118.7	7840.3	6462.1	6347.4	4096.6
SO4^2-	4.3	2.2	22.6	126.9	3.3	7.5	1142.4	2385.7	1.2
HCO3^-	885.6	285.5	613.7	4092.2	477.0	427.1	2747.0	2426.1	936.5
CO3^2-	0.0	0.0	0.0	371.0	0.0	0.0	114.9	123.0	0.0
Water type	Na–Cl	Na–Cl	Na–Cl	Na–Cl–HCO3	Na–Cl	Na–Cl	Na–Cl	Na–Cl	Na–Cl

Note: the unit of ions and TDS are mg/L.