频谱分解技术在准噶尔盆地油气勘探中的应用

地震数据振幅谱可以识别地层的时间厚度变化，相位谱可以检测地质体横向上的不连续性。常规频谱地层检测技术分辨力有限，采用频谱分解技术，可以获得更精细的地质图像。准噶尔盆地腹部侏罗系为一套曲流河或辫状河三角洲沉积，地震资料主频较低，用常规方法难以描述岩性圈闭和地层圈闭，将频谱分解技术应用到准噶尔盆地中的多个三维工区，识别出了河道、岩性边界、断层及地层剥蚀线，取得了良好的地质效果。

APPLICATION OF FREQUENCY SPECTRUM DECOMPOSITION TECHNIQUE IN EXPLORATION IN THE JUNGGAR BASIN

Frequency spectrum decomposition technique is a frequency-based reservoir interpretation method. As an advanced high-definition imaging technique of discrete geologic bodies, it can be used to detect the discreteness of thin layers and geologic bodies in the 3D survey areas by using seismic data. Seismic data in time domain can be converted into frequency domain through Discrete Fourier Transform (DFT). The converted amplitude spectrum can be used to detect the variability of temporal bed thickness, while the phase spectrum can be used to indicate the lateral discontinuity of geologic bodies. Jurassic in the central Junggar Basin is a sequence of meandering river or braided river delta deposits, but the dominant frequency of the seismic data is relatively low, so it is difficult to describe the lithologic and stratigraphic traps by using conventional methods. It has been successfully used to identify channels, lithologic boundaries, faults and stratigraphic denudation line in several 3D survey areas in Junggar Basin.