## 4 Results  
### Dissolved Mineral Analysis Results  
The dissolved minerals are presented in Table 1. The produced water from CBM wells contains the highest concentrations of Na\({}^{+}\), Cl\({}^{-}\), and HCO\({}_{3}\)\({}^{-}\), while Ca\({}^{2+}\), Mg\({}^{2+}\), SO\({}_{4}\)\({}^{2-}\), and other ions are present in smaller amounts. Each ion exhibits varying degrees of change before and after the workover (Figures 3-6). Disturbance Stage Before and After Workover (15 Days Before and After): Ion concentrations increase significantly before and after the workover, particularly for Na\({}^{+}\), Ca\({}^{2+}\), and Mg\({}^{2+}\). Compared to 45 days before the workover, the ion concentration changes are smaller in the 15 days prior to the workover. Among the three wells (GC-06, GC-09, and GC-10), the largest increase in Na\({}^{+}\) was observed in well GC-06 (64 mg/L), and the largest increase in Mg\({}^{2+}\) was in well GC-09 (13 mg/L). However, the concentrations of Na\({}^{+}\) and Ca\({}^{2+}\) in well GC-10 decreased. In the 15 days following the workover, ion concentrations \begin{table}
\begin{tabular}{c c c c c c c c c c c} \hline \hline
**Well** & **Ions and** & **–135** & **–105** & **–75** & **–45** & **–15** & **+15** & **+45** & **+75** & **+105** & **+135** \\
**ID** & **Time** & **Days** & **Days** & **Days** & **Days** & **Days** & **Days** & **Days** & **Days** & **Days** & **Days** \\ \hline \multirow{6}{*}{GC-06} & Na\({}^{+}\) & 712.10 & 692.30 & 709.40 & 675.00 & 739.00 & 1056.90 & 802.30 & 730.20 & 605.90 & 542.60 \\  & Mg\({}^{2+}\) & 12.41 & 12.04 & 11.23 & 12.31 & 13.25 & 29.52 & 16.30 & 11.35 & 10.92 & 11.96 \\  & Ca\({}^{2+}\) & 14.63 & 13.21 & 14.32 & 13.24 & 21.50 & 42.45 & 32.61 & 19.32 & 13.46 & 13.85 \\  & Cl\({}^{-}\) & 705.30 & 706.20 & 685.70 & 678.90 & 782.10 & 1042.30 & 843.20 & 679.50 & 680.60 & 673.80 \\  & SO\({}_{4}\)\({}^{2-}\) & 22.67 & 21.36 & 25.41 & 25.39 & 31.63 & 51.31 & 29.30 & 24.39 & 21.36 & 20.97 \\  & HCO\({}_{3}\)\({}^{-}\) & 582.30 & 578.40 & 599.30 & 601.97 & 621.60 & 421.22 & 580.32 & 633.40 & 708.40 & 729.50 \\  & TDS & 1702.30 & 1681.50 & 1678.20 & 1772.00 & 1982.00 & 2563.40 & 2346.20 & 1682.50 & 1681.50 & 1692.10 \\ \hline \multirow{6}{*}{GC-09} & Na\({}^{+}\) & 1026.90 & 1037.20 & 1007.10 & 987.70 & 1045.30 & 1555.20 & 1042.99 & 975.26 & 977.67 & 935.98 \\  & Mg\({}^{2+}\) & 35.23 & 39.12 & 42.35 & 41.94 & 54.93 & 51.38 & 21.19 & 14.76 & 14.20 & 15.55 \\  & Ca\({}^{2+}\) & 29.34 & 27.66 & 28.53 & 30.96 & 41.23 & 55.21 & 35.89 & 18.62 & 17.50 & 18.21 \\  & Cl\({}^{-}\) & 392.40 & 370.60 & 372.50 & 351.20 & 373.00 & 854.99 & 766.16 & 583.35 & 404.78 & 375.94 \\  & SO\({}_{4}\)\({}^{2-}\) & 101.20 & 96.30 & 97.40 & 102.30 & 110.96 & 136.70 & 95.23 & 79.27 & 69.42 & 68.15 \\  & HCO\({}_{3}\)\({}^{-}\) & 1601.60 & 1642.90 & 1685.60 & 1633.50 & 1732.00 & 1406.85 & 1592.63 & 1665.16 & 1693.46 & 1703.05 \\  & TDS & 2674.50 & 2596.70 & 2545.70 & 2624.50 & 2822.00 & 3332.42 & 2631.20 & 2479.30 & 2496.70 & 2501.90 \\ \hline \multirow{6}{*}{GC-10} & Na\({}^{+}\) & 1152.86 & 839.67 & 752.96 & 648.51 & 616.08 & 1456.26 & 297.54 & 279.65 & 236.52 & 197.18 \\  & Mg\({}^{2+}\) & 9.06 & 7.82 & 6.75 & 6.48 & 6.61 & 10.41 & 6.43 & 6.02 & 5.96 & 5.94 \\  & Ca\({}^{2+}\) & 24.08 & 21.02 & 20.96 & 19.53 & 19.73 & 31.25 & 18.45 & 18.12 & 18.02 & 18.69 \\  & Cl\({}^{-}\) & 905.59 & 580.66 & 490.35 & 407.98 & 416.14 & 1186.56 & 264.48 & 175.34 & 198.36 & 210.78 \\  & SO\({}_{4}\)\({}^{2-}\) & 24.65 & 23.65 & 22.65 & 21.16 & 21.37 & 32.05 & 17.98 & 18.16 & 18.25 & 18.28 \\  & HCO\({}_{3}\)\({}^{-}\) & 1665.35 & 1635.69 & 1662.25 & 1690.05 & 1673.15 & 1342.75 & 1712.85 & 1721.30 & 1728.56 & 1736.60 \\  & TDS & 3011.50 & 2503.74 & 2102.45 & 1989.30 & 1991.29 & 3210.63 & 1492.45 & 1451.33 & 1406.96 & 1349.00 \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Analysis results of water samples at different time points before and after workover in CBM wells (unit in mg/L). Figure 3: The piper of chemical composition of water samples from three CBM wells before and after workover.