The Effect of Water Chemistry on Thermochemical Sulfate Reduction: A Case Study from the Ordovician in the Tazhong Area, Northwest China
Table 1
Geochemical and sulfur isotopic composition of formation water, concentrations and sulfur isotopic composition of H2S in the gas, and concentrations of TAs in the oil in Tazhong area.
Well
Depth (m)
Strata
pH
(mg/l)
Cl− (mg/l)
(mg/l)
Ca2+ (mg/l)
Mg2+ (mg/l)
Na+ (mg/l)
TDS (g/L)
()
()
H2S (%)
TAs (μg/g)
TZ44
4873
7.0
781
50861
654
7333
92
—
84
—
—
0.1
32.96#
TZ82
5460
6.7▯
778▯
62400▯
341▯
10500▯
374▯
—
107▯
24.7▯
—
0.2
—
TZ83-1
5638
6.4&
99&
97900&
156&
8741&
684&
51530&
164&
—
—
0.7
—
ZG103
6191
6.3
371
54800
321
3122
341
31970
96
22.7
11.9
0.4
—
ZG11
6398
6.8
527
55340
224
3240
234
—
92
26.8▯
16.3
46.63#
ZG2
5880
7.1▯
239▯
58000▯
353▯
9840▯
395▯
24320▯
129▯
25.7▯
1.3
—
ZG433C
6133
8.0&
484&
120000&
73&
13500&
1070&
62400&
204&
—
13.2
—
ZG44
5647
7.2&
617&
100200&
450&
9635&
770&
53510&
170&
—
—
—
—
ZG44C
5647
5.5&
3080&
109000&
571&
14000&
698&
56900&
188&
—
—
—
—
ZG44-H2C
6056
6.8&
369&
95990&
343&
11150&
768&
46340&
159&
24.2
15.5※
—
ZG46
5148
7.0▯
6358▯
97300▯
330▯
1580▯
1050▯
—
166▯
24.2▯
13.4
—
ZG461
5560
6.0
1317
56990
891
19800
810
20140
104
—
13.4
0.1
ZG5
6406
6.3&
—
84900&
617&
43110&
474&
138&
27.8
15.5
104.19#
ZG511-2
5238
6.5&
88&
112000&
34&
10630&
1003&
52770&
182&
—
—
—
—
ZG6
6053
6.4&
127&
126000&
31&
13770&
918&
59260&
206&
29.8
147.20#
ZG7
5794
7.8▯
871▯
102000▯
53▯
8890▯
532▯
—
112▯
27.8▯
—
100.75#
ZS1C
6520
∈1
6.0
274
164000
182
41300
25500
248
1936.6#
Note that ※ is from Cai et al. [10], is from Cai et al. [21], # is Cai et al. [13], & is from Li and Cai [33], ▯ is from Zhang et al. [25], and “—” represents no data available.