川西坳陷上侏罗统遂宁组洪水-漫湖沉积特征

利用岩芯、薄片鉴定、粒度分析、录井及测井解释等资料和手段，对四川盆地川西坳陷上侏罗统遂宁组沉积特征进行研究。结果表明，川西坳陷在遂宁组沉积时期处于稳定坳陷阶段，沉积作用明显受周期性洪水注入影响，形成“洪水-漫湖”沉积体系。“洪水-漫湖”沉积主要发育冲积扇、曲流河、曲流河三角洲和湖泊4个沉积相和若干个沉积微相，其沉积具有以下特征:①频繁的湖平面升降，形成砂泥互层的地层叠加样式；②缺乏大面积分布的半深湖-深湖沉积；③河流相为主要的沉积类型；④湖盆具有多物源、多期漫湖、满盆含砂的沉积特点。“洪水-漫湖”是川西坳陷遂宁组一种沉积充填新模式，对指导油气勘探具有重要的理论和实践意义。

Flood-overlake Sedimentary Characteristics of the Suining Formation (Lower Jurassic) in Western Sichuan Depression

The sedimentary characteristics of the Suining Formation in Western Sichuan Depression have been studied based on core observation, electron microscope observation, grain size analysis and logging data. It is obvious that the lake was in a stable depression stage, the weather was dry-half dry and the sedimentation was significantly controlled by inflow of periodic flood; a flooded lacustrine sedimentary system formed in the Western Sichuan Depression. Alluvial fan, meandering river, meandering river delta and lacustrine facies formed flood-overlake sediments which have the following features:①lake level changed frequently and sand and mud interbed stratigraphic stacking patterns was formed; ② lacking of widely distributed semi-deep lake to deep lake sediment; ③ fluvial facies is the dominant type of the basin filling; ④the lacustrine basin beared multiple provinces and overlakes, and sandstone was deposited everywhere in the basin. As a new type of depositional model of the Suining Formation in Western Sichuan Depression, flood-overlake has important theoretical and practical significance.