渤海湾盆地渤中28-2南油田群鸟足状浅水三角洲识别与沉积演化

Identification and Sedimentary Evolution of the Shallow Water Delta of Bird-foot in Bozhong 28-2S Oilfield Group of Bohai Bay Basin

在区域沉积环境、岩心描述、岩心室内外分析化验资料、录井资料、测井资料分析基础上,结合渤海海域中南部晚第三纪沉积模式,通过河流相—曲流河和湖相—三角洲沉积、浅水三角洲沉积特点及相标志与渤中28-2南油田群的实际资料综合对比分析,认为渤中28-2南油田群明化镇组下段中部沉积了一套湖相浅水三角洲,浅水三角洲的形状主要以鸟足状浅水三角洲为主,它区别于曲流河沉积,也不同于典型的三角洲沉积。平面上是曲流河沉积向前伸入水下湖相的延伸,仍以河道沉积为主,表现出湖盆面积小、水体浅、能量弱、波浪及岸流作用小、无潮汐作用、湖水密度小等沉积特征。该认识对油田的滚动勘探开发具有重要指导意义。

Based on the regional sedimentary environment, core description, the analysis test data of in- side and outside o{ the core chamber, mud logging data and logging information, combined with the sed- imentary model of the Tertiary period of the central-southern part of the Bohai Sea, and the fluvial faci- es-meandering stream, limnetic facies-delta deposit and the characteristics of the shallow-water deltade- posit, as well as the facies markers and the practical information of the BZ28-2S oilfield group, it is be- lieved that a lake phase shallow water delta has been formed at the Lower Minghuazhen Formation of the BZ28-2S oilfield group, which is mainly shaped in bird foot delta, differing from meandering river depos- it and typical delta deposit. A meandering river deposit extends towards the underwater lake facies on the plane, mainly in the form of channel deposits featuring small lake basin, shallow water, low power, weak waves and shore current effects, no tide and small lake water density. This understanding has im- portant guiding significance for the roiling prospecting and development of oil fields.