基于测井资料的经验模态分解法的沉积旋回界面划分

Demarcating Sedimentary Cycle Based on Empirical Mode Decomposition of Logging Data

沉积旋回是沉积事件的周期性重复,具有成因联系的地层序列是一定时间序列内各种沉积时间的物质记录。测井数据能够连续的反映所测地层的特征,由旋回导致的物质变化在测井频率域特征上表现较为明显。经验模态分解法(EMD)可以把测井信号分解在不同的频带内,得到不同频带的固有模态函数(IMF),通过各级IMF的频谱分析,建立不同级次的旋回周期与IMF阶数的关系,确定IMF阶数对应的不同级次的沉积旋回周期,将其与地质上划分的各级旋回界面建立对应关系。实例结果表明,通过各级IMF的频谱分析,较好地确定了不同级次旋回周期与IMF阶数的关系,并与不同级别的沉积旋回的界面相对应。

Sedimentary cycle was periodically repeated for sedimentary events,the stratigraphic sequence associated with genesis was the physical record of all kinds of sedimentary periods in a certain time sequence.Logging data could continuously reflect the characteristics of logging formation,the changes of the log characteristics in the frequency domain which came from the cycle of material was more obviously.By using the method of empirical mode decomposition(EMD),the log signal could be decomposed in different frequency bands,then intrinsic mode function of different frequency bands could be obtained.Through the spectrum analysis of IMF at different steps,the relationship and the corresponding method between the cycle period of different levels and the level of IMF were determined,then the corresponding relationship between geological cycle interface at different scales and IMF of different steps was established.Experiment results show that this method can effectively demarcate the interface of sedimentary cycle at different levels by spectrum analysis of IMF.