扇三角洲沉积体系准层序频谱划分方法探讨——以胜坨油田坨76块为例

The subsequence division method by frequency spectrum in fan-delta sedimentary system-taking Block Tuo76 area in Shengtuo Oilfield as an example

地层的沉积旋回特征在地球物理资料中有一定的响应,通过频谱分析的方法能将这些特征有效地显示出来。利用这一原理,可以通过测井资料的频谱分析手段来识别不同沉积旋回,进而识别准层序旋回。以东营凹陷胜北断层下降盘坨76块沙四段上亚段的扇三角洲为研究对象,通过频谱分析方法划分出Cu—Fu,Cu—Cu和Fu—Fu型3种准层序模式并进行了研究,并建立了相应的频谱响应特征。研究表明,测井资料的频谱分析方法可以作为准层序划分的辅助手段。

The sedimentary cycle characters of strata have fixed responses in geophysical data and can be effectively showed by frequency spectrum analysis. According to this principle, we can identify different sedimentary cycles through the frequency spectrum analysis of logging data, and then identify the subsequence cycles. Taking the fan - delta which lies in upper Sha4 member in Block Tuo76 of the downthrow of the Shengbei fault in Dongying Sag as a target by the method of frequency spectrum analysis, three subsequence models such as Cu - Fu, Cu - Cu and Fu-Fu were studied, and the corresponding frequency spectrum response character was established. The study shows that the method of frequency spectrum analysis of logging data can serve as an assistant tool for subsequence division.