柿庄南区块排采15号煤层的煤层气井面临产出水量大、排水降压困难，水源判别不清的问题。通过常规离子和氢氧同位素测试，分析了煤层气井产出水及潜在来源水的水化学特征。结果显示，煤层气井产出水显示高矿化度特征，水质类型主要为Na-HCO3·Cl型和Na-HCO3型，个别为Na-Cl型；δD值为-85.5‰～-80.0‰，平均-83.2‰，δ18O值为-11.8‰～-10.2‰，平均-11.2‰，说明地下水的初始来源为大气降水。利用灰色关联度法及稳定同位素特征判别了煤层气井产出水的水源，得出与产出水关联度最高的为15号煤层水（0.72～0.87），其次为顶板灰岩水（0.5～0.89），最小为地表水（0.43～0.6）。其中，产出水中煤层水占73.3%～95.3%，顶板水占4.7%～26.7%。提出了应加强顶板灰岩裂缝展布的研究，阻止灰岩水对15号煤层的越流补给的建议。%The drainage of coal No.15 CBM well in the Shizhuang south block had faced issues of large amount of produced water, diffi⁃cult water drainage and depressurization, ill-defined water source. Through conventional ion and hydrogen, oxygen isotope tests, ana⁃lyzed CBM well produced water and potential sources water hydrochemical features. The result has shown that the CBM well produced water has high salinity features, water quality types mainly have Na-HCO3∙Cl and Na-HCO3, several Na-Cl type;δD value-85.5‰~-80.0‰, average-83.2‰;δ18O value-11.8‰~-10.2‰, average-11.2‰;thus illustrated the initial source of groundwater is from atmo⁃spheric precipitation. Using gray correlation method and stable isotope characteristics have identified CBM well produced water source;worked out the water from coal No.15 has highest correlation degree with CBM well produced water (0.72~0.87), roof limestone water the second (0.50~0.89), surface water the least (0.43~0.60). In which, in well produced water, coal seam water accounted for 73.3%~95.3%, roof water 4.7%~26.7%. Finally put forward suggestions including the research on roof limestone fissure distribution should be strengthened and leakage recharging from limestone water to coal No.15 prevented.
展开▼
