陆相断陷湖盆层序构型与砂体发育分布特征

Characterization of sequence architectures and sandbody distribution in continental rift basins

朱筱敏 陈贺贺 葛家旺 谈明轩 刘强虎 张自力 张亚雄

Xiaomin Zhu Hehe Chen Jiawang Ge Mingxuan Tan Qianghu Liu Zili Zhang Yaxiong Zhang

陆相断陷盆地蕴藏着极为丰富的油气资源，阐明这类盆地不同构造演化阶段的层序地层构型和砂体发育分布特征是油气资源勘探开发的重要基础。在综述层序地层学发展现状和陆相断陷湖盆地质特征的基础上，依据断陷盆地构造演化的4个阶段，表征层序构型及砂体成因分布特征：① 盆地初始断陷期，边界断裂开始活动，准层序垂向加积叠置，发育近源粗粒的冲积扇、分支河流和扇三角洲等沉积体系；② 盆地强烈断陷期，断层活动强烈，在不同构造带和体系域中，准层序发育多种叠置样式，沉积体系主要为河流、三角洲以及重力流；③ 盆地断-拗转换期，断层活动减弱，准层序进积、加积垂向叠置，发育长轴向河流和三角洲沉积体系；④ 盆地拗陷沉降期，断裂活动趋于停止，盆地沉积充填整体处于过补偿状态，以河流-浅水三角洲沉积体系为特征。结合上述分析，指出了陆相断陷湖盆层序地层学研究热点并展望未来发展趋势。

Efficient oil and gas exploration and development in petroliferous continental rift basins relies heavily on a profound understanding of sequence stratigraphic architectures and sandbody distribution characteristics in different tectonic evolution stages. Based on a review of the development status of sequence stratigraphy and geological characteristics of continental rift basins， this study characterizes the sequence stratigraphic architectures and sandbody distribution according to a four-stage tectonic evolution of the basins： ① During the early syn-rift stage， faulting at basin boundaries starts with parasequences being vertically aggraded and superposed， and with near-source coarse-grained depositional systems including alluvial fan， distributary channel， and fan delta being developed. ② During the main syn-rift stage， faulting intensifies with parasequences showing a variety of overlapping styles in different structural belts and systems tracts， and basins fill mainly with fluvial， delta and gravity flow. ③ During the transition stage from rifting to depression， faulting starts to wean with parasequences being overlapped and dominated by progradation and aggradation， and depositional systems dominated by axial fluvial and deltaic depositional systems being developed. ④ During the post-rift depression and subsidence stage， faulting nearly ends with basins in an overcompens and with the fluvial-shallow-water deltas being developed. Current hot topics and future development of sequence stratigraphy in continental rift basins are also discussed based on the above analyses.

10.11743/ogg20220402