利用广义S变换提取地震旋回的方法

Seismic cycles extraction using generalized S-transform.

1. 中国海洋大学海洋地球科学学览,山东青岛266003;2. 中国石油天然气股份有限公司石油勘探开发科学研究院,北京100083

School of Marine Geo-Science, Ocean University of China, Qingdao 266003, China

在地震地层学中,可以采用时频分析方法刻画地层厚度的变化和地质特征的不连续性,研究特定沉积环境和岩性组合的变化。目前,通常采用短时Fourier变换或连续小波变换求取地震道的主能量和主极值频率,进行地震旋回研究,但由于小波变换的尺度与频率的关系并不确定,因此主要用于求取能量谱。介于短时Fourier变换和小波变换之间的S变换是一种非平稳信号分析和处理的方法,具有良好的时频特性,因此将S变换引入到地震地层学的研究中,用广义S变换代替短时Fourier变换或连续小波变换提取地震道的主能量和主极值频率, 进行地震旋回特征分析。对S变换、短时Fourier变换和连续小波变换的时频特性进行了分析对比,阐述了广义 S变换的高分辨率性质。在广义S变换时频域,利用实际资料求取了地震道的主能量和主极值频率,分析了主能量和主极值频率的纵向变化规律。数值模拟和实际资料试算表明,广义S变换可以更好地反映地震旋回特征。

In order to study sedimentary cycles, the main energy and main frequency of the seismic signals is usually calculated by STFT and CWT. In this paper, S transform is introduced to study seismic stratigraphy due to its better time-frequency characteristics. By analyzing the time-frequency characteristics of generalized S transform (GST) , STFT and CWT, it is recognized that GST has higher resolution. The main energy and main frequency is estimated by GST in time-frequency domain. The calculating results are consistent with real 2-D seismic data, which show that GST has more advantage in reflecting sedimentary cycles cycles.