煤层群条件下的煤层气成藏特征

基于对我国煤层群发育特征的分析，在概述前人多煤层条件下煤层气成藏特征研究成果的基础上，发现煤层群成藏特征主要表现在垂向上存在“多层统一煤层气系统”或“多层叠置含气系统”， 陆相河流-三角洲-湖泊相的煤层群一般为“多层统一煤层气系统”，海陆过渡相的三角洲-潮坪-泻湖相煤层群一般为“多层叠置含气系统”。进一步解剖比德-三塘盆地实测钻孔资料显示，层序组合是煤层群独立含气系统发育的关键。依据该区抽水钻孔资料分析亦证明，至少存在4套独立含气系统。泻湖潮坪相发育的煤组存在超压的可能，但储层能势分布不均匀。另外，煤层群内部各煤层之间由于“烃浓度封闭效应”及煤层本身的低渗透性对流体流动存在“叠加封闭”作用，使煤层群储层存在“超压”可能性增大。这些结论深化了对煤层群成藏特征的认识。 

Coalbed methane (CBM) reservoir-forming character under conditions of coal seam groups

Based on development character of Chinese coal seam groups,research fruits of predecessors about CBM reservoir-forming character under conditions of coal seam groups were summarized.CBM reservoir-forming character of coal seam groups mainly exhibited multiple united CBM system or multiple superposed CBM system,coal seam groups of land river-delta-lake environments commonly showed multiple united CBM system,but coal seam groups of sea-land transition delta-tideflat-lagoon environments showed multiple superpo...