Abstract: The Subei Basin is a half-graben which was developed in Late Cretaceous. The Upper Cretaceous Taizhou Formation(K₂t)is dominated by a set of clastic rocks which were deposited in the early stage of the sag evolution and constituted an upward fining sedimentary cycle. Based on the comprehensive analyses of the logging and core data of 52 wells，three facies types including braided fluvial delta，meandering fluvial delta and lacustrine facies were identified in the Taizhou Formation，which can be sub-divided into 7 types of sedimentary subfacies and 12 types of sedimentary microfacies. During the early-middle depositional period of the Member 1 of Taizhou Formation，braided fluvial delta was mainly developed.During the late period，the depositional environment was dominated by the（meandering fluvial）delta. During the early depositional period of the Member 2 of Taizhou Formation，semi-deep-deep lacustrine facies was developed and shallow lacustrine was developed during the middle-late period.With the lake level rising and falling，it was characterized by an obvious multi-cycle.The Member 1 of Taizhou Formation was characterized by an obvious retrograding delta.On the basis of the analyses of the planar distribution and evolution of sedimentary facies of the Member 1 of Taizhou Formation，it is concluded that sandbodies are developed along the Liangduo-Anfeng-Libu area，which is the favorable area for the development of petroleum reservoir.

Key words: Subei Basin, Dongbu Sag, Upper Cretaceous, Taizhou Formation, sedimentary facies

摘要： 苏北盆地是在晚白垩世发育起来的箕状断陷盆地。上白垩统泰州组（K₂t）为东部凹陷发育初期形成的一套碎屑岩沉积地层，自下而上总体构成由粗到细的沉积旋回。通过对区内52口探井的录井、测井和岩心资料综合分析，认为泰州组主要发育辫状河三角洲、曲流河三角洲及湖泊相3种沉积相类型，在此基础上又进一步识别出7种亚相和12种微相。泰州组分为两段，泰州组一段沉积早、中期为辫状河三角洲沉积，晚期转变为(曲流河)三角洲沉积；泰州组二段早期为深湖—半深湖沉积，中晚期为浅湖亚相。伴随湖平面的反复升降，表现出明显的多旋回性。研究区泰州组一段表现为典型的退积型三角洲沉积。通过进一步研究泰州组一段各沉积时期沉积相的平面分布及演变特征，指出在梁垛—安丰—李堡一带沉积砂体发育，是油气储集层发育的有利地区。

关键词: 苏北盆地, 东部凹陷, 上白垩统, 泰州组, 沉积相

CLC Number: 

• P512.2