Quantitative Identification of Water Sources of Coalbed Methane Wells, Based on the Hydrogen and Oxygen Isotopes of Produced Water—A Case of the Zhijin Block, South China

The quantitative identification of water sources is an important prerequisite for objectively evaluating the degree aquifer interference and predicting production potential coalbed methane (CBM) wells. However, this issue has not been solved yet, are far from being completely understood. Stable isotopes carriers source information, which can be used to identify CBM Taking Zhijin block in Western Guizhou Province as example, produced samples were collected relationships between stable isotopic compositions data quantitatively analyzed. following main conclusions obtained. (1) δD δ18O values −73.37‰ −27.56‰ (average −56.30‰) −11.04‰ −5.93‰ −9.23‰), respectively. have D-drift characteristics, showing dual properties atmospheric precipitation genesis water–rock interaction modification water. An index d was constructed enable characterization (2) showed control on productivity. probability susceptible increased with increasing span producing seam combination, reflected lowering decreasing gas (3) Three types water, namely, static dynamic mixed identified. characteristic determined. Accordingly, a method constructed, based their compositions. results clear correlation production, output contributes efficient production. proposed study, help improve development efficiency optimize drainage technology.