小波变换在饶阳凹陷层序地层格架建立中的应用

小波变换提供了一种研究层序地层格架的新方法,它将测井信号从一维深度域转换到二维深度—尺度域,从多尺度识别不同级次的地层旋回界面。根据小波变换的原理,确定了测井数据小波变换在层序地层划分中的地质意义,建立了四种小波变换中的地层旋回模型。在饶阳凹陷的实际应用中,选取自然伽马曲线进行小波变换,应用时频色谱图分析和快速傅里叶变换多种方法选取尺度因子。通过对时频色谱图和不同尺度下小波系数曲线的综合分析,对饶阳凹陷古近系G104井层序地层进行了划分,并以2 198.625m位置为突变界面,划分出两个较大尺度旋回,以2142.375m、2 163.875m、2 198.625m、2 238.625m位置为界面,划分出5个较小尺度旋回。实际结果应用表明,小波多尺度变换划分层序地层的结果和传统方法划分基本一致。

Application of Wavelet Transform in Building of Sequence Stratigraphic Framework in Raoyang Sag

The wavelet transform providing a new method to study the sequence stratigraphic framework, makes logging signals converting from one dimensional depth domain to two dimensional depth-scale domain and identifies the stratigraphic cycle interfaces of different orders by using multi-scale. This thesis introduces the principle of wavelet transform and its geological significance in sequence division and establishes four wavelet transform models of stratigraphic cycles. In the practical application in Raoyang sag, natural gamma-ray trace is selected to carry out wavelet transform, and time-frequency ehromatograms analysis, fast Fourier transform and many other ways are applied to select the scale factors. Through comprehensive analysis of time-frequency chromatograms and the wavelet coefficient curves at different scales, quantitative division of sequence stratigraphy is eventually realized. According to actual results, it is proved that the results from wavelet transform of multi-scale divided sequences are almost the same as those from traditional methods.