In view of the differential productivity of coalbed methane (CBM) wells in the Linfen block on the southeastern margin of the Ordos basin, geochemical analysis is performed to determine the hydrodynamic condition of coal reservoirs, identify the water and gas source of commingled wells, reveal different pressure drop mechanisms, and finally clarify the geological and engineering controls on the production performance. The positive correlations between average daily gas production and the concentrations of Na⁺, Cl¯, TDS, Sr, and Ba imply that strong hydraulic closure is the premise of high productivity. There is no obvious relationship between water and gas production. Commingled (5 + 8#) wells tend to produce more water than single-layered (5#) wells, because the No. 8 coal seam has more active hydrodynamic condition, which is proven by the lighter δ²H and δ¹⁸O and smaller Sr/Ba ratio of waters from commingled wells. The difficulty in pressure drop funnel expansion is the primary constrains for the single-layered wells, which is only resolved by the horizontal wells located in low structural positions at present characterized by increasing trends of TDS, Na⁺ and Cl¯ contents during drainage. The faster the ion concentration rises, the faster the pressure drop funnel expands and a high peak daily gas production can be quickly achieved. The L-shaped horizontal well is thought to be the most suitable well type due to its high gas yield, low time investment and engineering cost. Due to hydrodynamic heterogeneity, commingled wells often show strong interlayer interference and a change in the water-producing horizon from 5# to 8# coal, which is manifested in the tendency of Cl¯, Na⁺, and TDS to increase first and then decrease. By selecting superior lithologic assemblages and avoiding strong aquifers, relatively continuous and stable production of commingled wells can also be achieved. This study provides a basis for the further development of CBM in the Linfen block and enriches engineering geochemistry theory.

针对鄂尔多斯盆地东南缘临汾区块煤层气（CBM）井产能差异性，开展地球化学分析，确定煤储层水动力条件，识别混井水源和气源，揭示不同的压降机制，最终明确生产性能的地质和工程控制。日均产气量与Na ^{+浓度呈正相关}, Cl¯, TDS, Sr, 和 Ba 暗示强水力闭合是高生产率的前提。产水量和产气量之间没有明显的关系。混井（5+8#）比单层（5#）井产水多，因为 8 号煤层的水动力条件更活跃，δ ² H 和 δ ¹⁸ O较轻，证明了这一点。混合井水的 Sr/Ba 比值较小。压降漏斗扩容困难是单层井的主要制约因素，目前仅通过位于低构造位置的水平井来解决，TDS、Na ^{+呈上升趋势}和引流过程中的 Cl¯ 含量。离子浓度上升得越快，压降漏斗膨胀得越快，日产气量可以快速达到高峰。L形水平井由于产气率高、时间投资少、工程成本低，被认为是最合适的井型。由于水动力非均质性，混井经常表现出强烈的层间干扰，5#煤到8#煤的产水层位发生变化，表现为Cl¯、Na ^{+的倾向。}, TDS 先增大后减小。通过选择优越的岩性组合，避开强含水层，还可以实现混井的相对连续稳定生产。该研究为临汾区块煤层气的进一步开发提供了依据，丰富了工程地球化学理论。