【摘要】 煤层气井产出水的地球化学特征蕴含丰富的地质与生产信息，对揭示煤储层水化学演化规律、优化产层组合及预测产能潜力具有重要意义。为探究沁水盆地南部潘河区块煤层气井产出水的地球化学特征及其对产能的指示意义，采集研究区10口煤层气井产出水样品，测试常规离子浓度、氢氧同位素(δD、δ¹⁸O)、pH值和总溶解固体（TDS）等参数，结合Piper三线图、Stiff图解法、主成分分析（PCA）等手段，系统分析不同层位煤层气井产出水的地球化学特征差异及水化学形成机理，并探讨了关键水化学参数与单采井、合采井产能的关联性。结果表明：研究区产出水以Na-HCO₃型为主，呈弱碱性，矿化度中等，大气降水为产出水的主要初始来源；阳离子交换吸附作用和脱硫酸作用是控制产出水化学特征的关键水岩相互作用；潘河区块煤层气井产出水的地球化学特征受多种因素综合控制，其封闭性与产能密切相关；单采井以水平井为主，因封闭性好、降压效果显著，产能较高，但部分井可能沟通含水层（如5号井），需采取针对性堵水措施；合采井井型为直井，排采过程中易受外部水源越流补给影响，抑制降压效果，导致产能降低；封闭指数与产能呈非单调关系，拐点位于200附近，表明适度封闭条件有利于高产。更多还原

【Abstract】 The geochemical characteristics of produced water from coalbed methane(CBM) wells carry abundant geological and production information, which plays a significant role in revealing the hydro-chemical evolution of coal reservoirs, optimizing production zone combinations, and predicting productivity potential. To investigate the geochemical features of produced water and their implications for productivity in Panhe Block of southern Qinshui Basin, produced water samples were collected from 10 CBM wells in the study area. These samples were analyzed for conventional ion concentrations, hydrogen-oxygen isotopes(δD, δ18O), pH values, and total dissolved solids(TDS). Integrated analytical methods, including Piper trilinear diagrams, Stiff diagrams, and principal component analysis(PCA), were employed to systematically analyze the geochemical differences in produced water from different coal seams and the hydro-chemical formation mechanisms. Furthermore, the correlations between key hydro-chemical parameters and the productivity of single-zone production wells and commingled production wells were explored. The results indicate that the produced water in the study area is predominantly of the Na-HCO3 type, weakly alkaline and medium salinity, and atmospheric precipitation is the main initial source of produced water. The findings demonstrate that cation exchange adsorption and sulfate reduction are the key water-rock interactions controlling the hydro-chemical characteristics of the produced water. The geochemical characteristics of produced water in the coalbed methane wells in Panhe Block are controlled by a combination of factors,and its closure is closely related to the production capacity. The single-zone production wells(predominantly horizontal wells)demonstrate superior productivity due to effective reservoir confinement and significant pressure drawdown. However, some wells(e.g., Well 5) may connect with aquifers, necessitating targeted water shutoff measures. The commingled production wells(vertical wells) are prone to external water influx during drainage, which suppresses pressure depletion and consequently reduces productivity.The closure index(F) exhibits a non-monotonic relationship with the productivity, with an inflection point at approximately 200, indicating that moderate closure conditions are favorable for high production.更多还原