准噶尔盆地乌-夏地区二叠系夏子街组层序格架

Sequence framework in Xiazijie formation of Permian in Wu-xia area of Junggar Basin

准噶尔盆地乌-夏地区巨厚的夏子街组为隐蔽性圈闭,其地震反射特征在地震资料上表现不明显,层序界面识别起来较困难。应用经典的层序地层学原理和方法,综合运用乌-夏地区地震、钻井和测井资料,借助地震时频分析技术和测井小波旋回理论来确定层序界面的位置,在各层序井-震联合标定的基础上,分析研究了夏子街组不同层序的展布特征和体系域构成,从而建立了夏子街组层序地层格架。研究表明:地震时频分析和测井连续小波变换技术用来进行层序旋回划分较为可靠,应用此技术确定出准噶尔盆地乌-夏地区二叠系夏子街组共发育有4个具有等时意义的层序界面,并将其划分为3个三级层序;应用地震时频分析手段来分析地层中的信息,会大大提高沉积旋回研究的定量化水平;小波变化具有尺度可大可小的优点,这对于提取单井的沉积旋回、识别同一套沉积体具有重要作用,它的放大显微功能有助于识别不同级别的层序体。

Thick Xiazijie formation is characterized by concealed trap in Wu-xia area of Junggar Basin. The seismic reflection characteristic of seismic data shows indistinctly, and identification of sequence boundary is difficult. By using the principle and the method of classic sequence stratigraphy and the data of seismic, drilling and well logging, sequence boundary was confirmed in virtue of seismic time-frequency analysis and logging continuous wavelet cycle theory. On the basis of log and seismic combined calibration, spreading feature and system tract composition of different sequences were analyzed, and the sequence framework in Xiazijie formation of Permian in Wu-xia area of Junggar Basin was established. The results show that seismic time-frequency analysis and logging continuous wavelet transformation are relatively credible to division of sequence cycle. Xiazijie formation in Permian develops four isochronous sequence boundaries and is divided into three third class sequences by the technology. Analyzing the information in stratum by the instrument of seismic time-frequency analysis can improve the quantificational level of sedimentary cycle. Wavelet transformation has the virtue of transformable scale, which has the important function of distilling well＇s sedimentary cycle and identifing the same sediment, and its function of magnifying and dwindling lends itself to identify different class sequence body.