东海丽水凹陷始新统温州组浪控三角洲-浊积扇沉积特征及沉积模式

东海陆架盆地丽水凹陷是重要的油气勘探区。为了加快浅层始新统温州组岩性圈闭勘探，利用新采集的三维地震、地质资料，运用层序地层学理论方法，对温州组进行层序地层划分，将其划分为SQ1、SQ2、SQ3共3个三级层序，其中，SQ1发育典型的低位、海侵和高位体系域，SQ2仅发育海侵和高位体系域。各体系域地震反射终止关系和地震相差异明显。本次研究重点是对SQ1低位域沉积平面展布特征进行刻画。SQ1低位域发育浪控三角洲-浊积扇沉积体系，沉积微相以三角洲前缘滨岸砂坝和薄层灰岩浅滩为主，垂向叠置样式以进积为主。根据浪控三角洲和浊积扇的沉积特征，建立了温州组SQ1低位域浪控三角洲-浊积扇沉积模式。本次研究厘清了低位域三角洲-浊积扇沉积体系的展布特征和形成机制，以期为在始新统温州组寻找岩性圈闭提供参考。

Sedimentary characteristics and facies model of wave-controlled delta-turbidity fan in the Eocene Wenzhou Formation in the Lishui Sag of the East China Sea Shelf Basin

Lishui Sag is an important oil and gas exploration area in the East China Sea Shelf Basin. To accelerate the exploration of lithologic traps in the shallow Eocene Wenzhou Formation, we analyzed new three-dimensional seismic and geological data in sequence stratigraphy theory, by which the sequence stratigraphy of the Wenzhou Formation was divided into three third-order sequences, i.e., SQ1, SQ2, and SQ3. Among them, SQ1 developed typical lowstand, transgressive, and highstand system tract, SQ2 developed transgressive system tract and highstand system tract. There are obvious differences between seismic reflection termination relations and seismic facies in each system tract. Moreover, the sedimentary plane distribution of the SQ1 tracts was anatomized. SQ1 lowstand domain system was a delta and turbidity fan featuring sedimentary microfacies indicative of delta front shore sandbars and thin limestone shoals, based on which the sedimentary model of wave-controlled delta turbidity fan was established. This study clarified the distribution characteristics and formation mechanism of the wave-controlled delta-turbidity fan sedimentary system in the Eocene Wenzhou Formation, in order to provide reference for searching lithological traps.