渤海Z油田东二下亚段沉积特征及演化模式

采用Q型聚类的方法对辽西凹陷Z油田5口井的重矿物含量进行分析,同时结合岩心、录井、测井、测试等资料对目标区的层序地层格架、沉积微相类型以及沉积演化模式进行研究。结果表明,研究区存在东西两支物源,其中东侧物源来自中央凸起,而西侧物源来自燕山隆起;在层序地层学理论指导下,将东二下亚段四个油组划分为1个中期基准面旋回和5个短期基准面旋回,砂体主要位于基准面上升半旋回早期和下降半旋回中–晚期;主要的沉积微相类型有水下分流河道、河口坝、远砂坝–席状砂及水下分流间湾;研究区处于两个沉积体系的边部,中期基准面旋回的早期以东侧物源为主,中–晚期逐渐过渡为以西侧物源为主,两个沉积体系呈现出此消彼长的关系,研究成果可为Z油田后期的调整井挖潜提供地质参考。

Sedimentary characteristics and evolution model of the lower ED2 of Dongying formation in Bohai Z oilfield

The heavy mineral percentage data of 5 wells in Z oilfield of Liaoxi sag were analyzed by Q-type clustering method.At the same time,the sequence stratigraphic framework,sedimentary micro-facies types and sedimentary evolution model of the target area are studied combined with core,logging,logging and testing data.The results show there are two provenances in the research area,the east side is from the central uplift and west side is from the Yanshan uplift.Under the guidance of sequence stratigraphy,the four oil groups of the lower ED2 of Dongying formation are divided into one medium-term base level cycle and five short-term base level cycles.The sand bodies are mainly located in the early stage of base level rising half cycle and the middle late period of falling half cycle.The main sedimentary micro-facies include underwater distributary channel,mouth bar,distal bar sheet sand and underwater distributary bay.The study area is located at the edge of the two depositional systems.In the early stage of the medium-term base level cycle,the provenance is mainly from the east,and from the middle to the late stage,the provenance is mainly from the west.Besides,the two sedimentary systems present a reciprocal relationship.The research results can provide geological reference for potential tapping of adjustment wells in the later stage of Z oilfield.