基于层序地层学和地震沉积学的高精度三维沉积体系:以渤中凹陷西斜坡BZ3-1区块东营组为例

High Resolution Three-Dimensional Facies Architecture Delineation Using Sequence Stratigraphy,Seismic Sedimentology: Example from Dongying Formation in BZ3-1 Block of Western Slope of Bozhong Sag,Bohai Bay Basin

基于层序地层学、地震沉积学理论及三维可视化技术,结合3D高分辨率地震资料,对渤中凹陷西斜坡BZ3-1区块东营组层序进行高精度三维沉积体系分析.研究将东营组古沟谷分为V型、U型、W型及复合型4种类型,并详细刻画不同类型、不同期次的古沟谷从上游-下游的分叉、汇合的充填特征及其从发育-消亡的不同时期演化特征.研究区地震多属性异常区域在平面上多紧靠断层的下降盘,呈规模不一的扇状展布.结合测井曲线、岩心、地震相、地震多属性特征等分析可知,东营组层序沉积相类型分为扇三角洲、辫状河三角洲、滨浅湖,同时对不同相带边界进行了定量厘定.高精度三维沉积体系分析结果表明,由于三级层序发育于二级层序的不同体系域,会导致三级层序的体系域沉积体发育特征产生不同.SQd3层序发育于二级层序的低位体系域,其低位体系域的扇体规模要远远大于高位体系域的扇体;SQd2L层序发育于二级层序的水进体系域,其低位体系域三角洲朵体规模与高位体系域的三角洲朵体相当;SQd2u层序发育于二级层序的高位体系域,其高位体系域三角洲朵体规模远远大于低位体系域的三角洲朵体.

Based on sequence stratigraphy,seismic sedimentology theory and 3D visualization technology,High resolution three-dimensional facies architecture was described in detail using the recent 3D seismic data of Dongying Formation of BZ3-1 Block,western slope of Bozhong sag.The paleo-channels of Dongying formation could be subdivided into four types including type V,U,W and Compound,and were delineated the branching and converging infilling characteristics from up-stream to down-stream and the evolution stage from occurrence to extinction.Normally,Fan-shaped abnormal areas of seismic multi-attributes were located in the footwall of faults.On the basis of an integrated analysis of well log and core data,seismic facies,seismic multi-attribute,the sedimentary facies of sequences of Dongying formation were found to include fan-delta,braided river delta and coast-shallow lake,and the boundaries of these facies were crystallized quantitatively.The results of high resolution three-dimensional sedimentary systems analysis show that the third-order sequence located in different system tracts of second-order sequence could be lead to their system tracts with the different sedimentary types and scale.Because sequence SQd3 belong to the lowstand system tracts of second-order sequence,and the fan scale of lowstand system tracts of sequence SQd3 was larger than that of its highstand system tracts＇;Sequence SQdL2 is located in the transgressve system tracts of second-order sequence,and the delta scale of lowstand system tracts of sequence SQdL2 was equal to that of its highstand system tracts＇;Sequence SQdu2 developed in the highstand system tracts of second-order sequence,and the delta scale of lowstand system tracts of sequence SQdL2 was less than that its highstand system tracts＇.