川南地区石宝矿段龙潭组层序地层研究

针对川南地区上二叠统龙潭组煤系地层埋深和厚度变化大的特点,以沉积岩石学、层序地层学的理论方法为指导,综合前人研究成果,通过对石宝矿段内上二叠统龙潭组野外露头、钻井岩芯和物探测井资料的研究,识别出区域不整合面、河流冲刷侵蚀面、岩性、岩相转换面和最大海泛面4种层序界面及其物质表现形式,并将其划分为3个长期基准面旋回层序(LSC1-LSC3)和若干中期基准面旋回层序。运用等时对比法,进行连井层序地层对比,建立了等时地层格架。根据基准面旋回升降趋势对各长期旋回层序内物质变化规律和成煤机制进行了系统的描述。认为对石宝矿段的煤层气勘探开发工作具有重要意义。

sequence stratigraphy of the Longtan Formation in the Shibao ore block of South Sichuan

Upper Permian Longtan Formation coal-bearing strata in southern Sichuan region is characterized by the depth and thickness variation. Guided by the theories and methods of the Sedimentary petrology and sequence stratigraphy, through consolidated results of previous studies, the authors divided the Upper Permian Longtan Formation in the Shibao ore block of South Sichuan into 3 long-term sequence(LSC1-LSC3) and many medium-term sequences through comprehensive study of outcrops, coring, logging and seismic data. According to the identified four kinds of sequence boundary and its manifestations substances, including regional unconformity, fluvial erosion surface, lithology, lithofacies conversion surface and maximum flooding surface, the long-term base-level cycles in each cycle of the material change and mechanism of coal accumulation has been described . By multi-well sequence stratigraphy contrast, isochronous stratigraphic framework has been established that has important implications for coalbed methane exploration and mine development work Shibao ore block .