洪泽凹陷沉积体系类型及分布明显受构造控制，东南部陡坡带发育近岸水下扇沉积体系。勘探实 践表明，近岸水下扇的不同部位其含油气性差异较大。为了落实近岸水下扇的主要勘探方向，该文对近岸 水下扇各亚相的成藏条件和成藏特征进行了分析。研究结果表明：近岸水下扇扇根亚相以砂砾岩沉积为 主，岩石致密，不易成藏；扇中和扇端亚相以砂、泥岩互层沉积为特征，砂岩上倾尖灭于成熟湖相泥质烃源 岩中，利于形成各类构造-岩性及岩性油气藏，是近岸水下扇勘探的主要方向。

The sedimentary system types and contribution are controlled by tectonic features in Hongze Sag. The steep slope zone in the southeast develops nearshore subaqueous fan sedimentary system. The exploration practice reveals that the difference among different parts of nearshore subaqueous fan is obvious. The accumulation conditions and characteristics of different subfacies are studied in order to clarify the main exploration direction of nearshore subaqueous fan. The result shows that fan foot is composed of compacted glutenite rocks and reservoir can not be easily accumulated. The midfan and fanhead are interbedded by sandstone and mudstone. The sandstone has good reservoir capacity and it is updip pinchouting in mature lacustrine source rocks, so it can form a variety of tectonic-lithologic and lithologic reservoirs. Therefore, the midfan and lower-fan are the main exploration target zones of nearshore subaqueous fan.