水动力对煤层气成藏的差异性研究

水文地质条件是煤层气富集成藏的关键因素，一般认为地层总矿化度高值区的形成反映为闭塞的水动力环境，水体外泻条件差，封闭条件极好，因而，地层水的矿化度是反映煤层气运聚、保存和富集成藏的一个重要指标。通过研究发现，高煤阶煤层气符合上述规律，但是低煤阶煤层气却正好相反，低煤阶由于其生气量较小，其煤层气富集成藏的关键在于二次生物成因气，而活跃的、低矿化度的地层水有利于二次生物气的生成。研究结果对我国西北低煤阶煤层气勘探具有实际意义。

DIFFERENT EFFECTS OF HYDRODYNAMIC CONDITIONS ON COAL-BED GAS ACCUMULATION

Hydrogeological condition is a key factor of coal-bed gas enrichment and accumulation. It is generally believed that occurrence of high TDS (total dissolved solids) zone indicates a euxinic hydrodynamic environment with poor water drainage conditions but very well sealing conditions. Therefore, salinity of formation water is an important index reflecting migration, accumulation, preservation and accumulation of coal-bed gas. Study shows that this is true to high rank coal-bed gas, but just opposite to low rank coal-bed gas. As the amount of gas generated by low rank coal is small, secondary biogenetic gas plays a very important role in reservoiring of coal-bed gas, while active formation water with low salinity is favorable to generation of secondary biogenetic gas. This knowledge has practical significance to exploration of low rank coal-bed gas in Northwest China.