基于沉积相反演的砂砾岩体沉积期次精细划分与对比——以东营凹陷盐家地区古近系沙四段上亚段为例

Fine Division and Correlation of Glutenite Sedimentary Periods Based on Sedimentary Facies Inversion——A Case Study from the Paleogene Strata of Upper Es^4 in the Yanjia Area,Dongying Depression

砂砾岩体一般为多期发育、多次沉积的复合体,其内部结构非常复杂,对砂砾岩体沉积期次的精细划分与对比问题,国内外尚无很好的解决先例。本文提出了基于沉积相反演的砂砾岩体沉积期次精细划分方法。文章在岩芯观察和描述的基础上,用岩芯对成像测井资料进行刻度,建立研究区成像测井模式,并精确地识别出鲍马层序、高密度浊流序列和中扇辫状水道、外扇泥岩等微相层序,建立了东营凹陷北坡盐家地区沙四段上亚段全层位的成像测井的单井相层序。通过成像测井单井相层序进行层序界面识别及旋回特征分析,从而实现砂砾岩体沉积期次精细划分。用成像测井单井相层序标定常规测井曲线,将岩芯、成像测井与常规测井的层序界面识别标志有机结合并以相带展布规律作为约束,在由上升半旋回控制的长期旋回内采取由上而下的"递推对比法"和从高级到低级的"层次对比法"进行连井旋回对比,在一定程度上解决了平面相变问题,建立了研究区的高分辨率层序地层格架。

Glutenite sedimentary system is a complex characterized with multiple developments and depositions.At present,there have been no practicable methods available for the fine division and contrast of glutenite sedimentary cycles at home and abroad.This study,based on sedimentary facies inversion,put forward a new method for fine division of glutenite sedimentary cycles.Based on the core observation and description,an FMI logging model was established for the study area using calibrating FMI logging data with the cores,and then four kinds of sedimentary sequences was identified precisely：Bouma cycle,high density turbidity flow,middle fan channel and outer fan mudstone.In addition,an FMI sequence of single well was set up for the whole Upper Es4 in the Yanjia area of the northern slope of the Dongying depression.Sequence interface and cyclic features were analyzed using FMI single-well sequence,which helped achieving the fine division of glutenite sedimentary periods.Through calibrating conventional curve with FMI single-well sequence,and employing the recognition indicators of the cores,FMI logging and conventional logging and constraint of the distribution rule of the facies belts,this study compared the cycles of running wells using the recurrence method for the long-term ascent-dominating cycle and sequence antithesis for high-grade to low-grade.This to some extent solved the areal facies change and then set up a high-resolution sequence framework.