黔西龙场井田含煤岩系沉积环境及聚煤规律

Sedimentary Environment and Coal Accumulation Law of Coal Bearing Rock Series in Qianxi Longchang Well Field

在研究区野外实测剖面及钻孔岩芯资料分析的基础上,运用沉积相分析、沉积地球化学分析的基本理论及方法,对龙场井田晚二叠世含煤岩系的岩相类型、硫分特征、沉积特征进行了综合的探讨,得到了本区沉积环境及聚煤规律的相关认识。结果表明,东吴运动控制了含煤岩系沉积基底的演化,为含煤岩系的沉积提供了基本的沉积格架。成煤期构造活动相对较为稳定,基底的沉降速率与泥炭或煤层的堆积速率较为平衡,形成了一定厚度的含煤岩系。沉积环境依次经历了潮坪-潟湖、三角洲平原、潟湖-潮坪沉积体系,最有利的聚煤环境为位于三角洲平原上的分流间湾及分流河道,其次为受海水影响较为强烈的潟湖、潮坪环境。

Based on the analysis of field measured profiles and drilling hole rock core data in the research area,the basic theories and methods of sedimentary facies analysis and sedimentary geochemistry analysis are applied to comprehensively discuss the lithofacies types,sulfur content characteristics,and sedimentary characteristics of the Late Permian coal bearing rock series in Longchang well field.Relevant understanding of the sedimentary environment and coal accumulation laws in this area is obtained.The results indicate that the Dongwu Movement controls the evolution of the sedimentary basement of coal bearing rock series,providing a basic sedimentary framework for the sedimentation of coal bearing rock series.The tectonic activity during the coal formation period is relatively stable,and the subsidence rate of the basement is relatively balanced with the accumulation rate of peat or coal seams,forming a coal bearing rock series with a certain thickness.The sedimentary environment experiences tidal flat-lagoon,delta plain,and lagoon-tidal flat sedimentary systems in sequence.The most favorable coal accumulation environment is the distributary bay and distributary channel located on the delta plain,followed by the lagoon and tidal flat environments that are strongly influenced by seawater.