Abstract: As the continental faulted lacustrine basin is characterized by complex evolution, intense tectonic activity and diverse source-sink systems, the traditional method that predicts the transportation path of the paleo-drainage system through the description of gully system or the change of sediment grain size cannot effectively restore the paleo-drainage system, especially its evolution process in the deep sag area with a low degree of exploration. To improve the accuracy of restoration results for the ancient water system, guided by the theory of seismic sedimentology and comprehensively using the core, logging and 3D seismic data, the spatial distribution characteristics of the paleo-drainage system in different tectonic evolution stages during the sendimentary period for Member 3 of Shahejie Formation in Panshan subsag, Western sag of Liaohe depression were reconstructed by using stratigraphic slice and well-seismic calibration, classifying the levels of the paleo-drainage system, and semi-quantitatively characterizing the development degree of the ancient water system (i.e. water system length and distribution area). The research shows that the terrain of Panshan subsag was very rugged during the sedimentary period of the Lower Submember of Member 3 of Shahejie Formation (SQ1), and the distribution of main water systems was also limited by fault activities; during the sedimentary period of the Middle Submember of Member 3 of Shahejie Formation (SQ2), syndepositional faults were continuously active. Affected by subsidence and western provenance supply, the paleo-drainage system of the fan delta front in the southwest of Panshan subsag is gradually developed, and its distribution area reached a peak in the sedimentary period of SQ2²; during the sedimentary period of the Upper Submember of Member 3 of Shahejie Formation (SQ3), the study area basically inherited the tectonic framework of the SQ2 sedimentary period; however, the rift activity of Panshan subsag was weakened and the terrain drop was decreased during this period, which hindered the development of the water system of the fan delta front in the southwest of Panshan subsag; at the end of SQ3 sendimentary period, the basement structure in the north of the Western sag uplifted, and the provenance supply increased in this area; the water system of the fan delta front in the north of Panshan subsag was gradually developed, and the water system of sedimentary gravity flow was extensively developed in the east and south; the main water system in the southwest of Panshan subsag shrank rapidly and shifted to the southern low-lying area. Based on seismic sedimentology, the restoration of the paleo-drainage system in faulted lacustrine basin and its evolution process can provide certain technical reference and theoretical support for detecting favorable reservoirs and carrying out refined oil and gas exploration.

Key words: paleo-geomorphology, paleo-drainage system, provenance system, tectonic evolution, Member 3 of Shahejie Formation, Panshan subsag, Western sag of Liaohe depression

摘要： 陆相断陷湖盆演化复杂、构造活动强烈、源-汇系统多样，利用沟谷体系刻画或沉积物粒度变化来推测古水系搬运路径等传统方法无法有效恢复其古水系，特别是勘探程度较低的深洼区的古水系演化过程的恢复难度更大。为提升古水系恢复结果的准确度，以地震沉积学理论为指导，综合岩心、测井、录井和三维地震资料，通过地层切片和井震标定，划分古水系级次，半定量化表征古水系的发育程度（水系长度和展布面积），重建了辽河坳陷西部凹陷盘山洼陷沙河街组三段（沙三段）沉积期不同构造演化阶段的古水系空间展布特征。研究表明，沙三段下亚段（SQ1）沉积期，盘山洼陷地形起伏较大，受断裂活动影响，其主水系分布局限；沙三段中亚段（SQ2）沉积期，同沉积断裂持续活动，受沉降作用和西部物源供给影响，盘山洼陷西南部扇三角洲前缘水系逐渐发育，并于SQ2²沉积期展布面积达到最大；沙三段上亚段（SQ3）沉积期，研究区基本继承了SQ2沉积期的构造格局，但该阶段盘山洼陷裂陷活动减弱、地势落差减小，导致西南部扇三角洲前缘水系发育受阻；SQ3沉积末期，西部凹陷北部基底构造隆升，北部物源供给量增加，该阶段盘山洼陷北部扇三角洲前缘水系逐渐发育，东部和南部地区广泛发育重力流沉积水系，而西南部主水系快速萎缩，并向南部低洼区偏移。基于地震沉积学恢复断陷湖盆古水系及其演化可以为寻找有利储集体、开展精细油气勘探提供一定技术借鉴和理论支撑。

关键词: 古地貌, 古水系, 物源体系, 构造演化, 沙河街组三段, 盘山洼陷, 辽河坳陷西部凹陷