基于地震瞬时谱分析的三角洲砂体尖灭线识别技术

Pinch-out boundary recognition technology of delta sand body based on seismic instantaneous spectral analysis

岩性尖灭线的识别与刻画,一直是隐蔽圈闭描述的难题。文中以薄层调谐理论为依据,利用基于S变换的时频分析方法,分析了薄层调谐的瞬时谱特征及利用薄层调谐原理识别岩性尖灭线的可行性。研究发现可以通过不同频率的瞬时谱分量来表征不同厚度三角洲砂体的尖灭线。由于不同位置的三角洲砂体尖灭点处厚度不一致,将核主成分分析的思想引入到瞬时谱分量的处理中,利用核主成分分析技术,可以将原来分散到各瞬时谱分量中包含的所有尖灭线的有效信息,通过贡献值极高的第一主成分的形式综合表示出来,达到全面刻画三角洲砂体尖灭线的目的。该技术在JX1-2N工区东三层序低位域三角洲砂体尖灭线识别中取得了良好的应用效果。

The identification and characterization of lithologic pinch-out boundary is always a problem in the description of subtle traps. Based on the theory of thin layer tuning and S transform time-frequency analysis method, this paper analyzed the instantaneous spectral tuning characteristics of thin layer and the feasibility of using thin-layer tuning principle to identify lithologic pinch-out boundary. The study found that the pinch-out boundary in delta sand body with different thickness could be characterized through different frequency components of the instantaneous spectrum. Because different locations of the delta sand body, the thickness of pinch-out boundary was inconsistent. So the kernel principal component analysis method was introduced into the technology of instantaneous spectral component analysis. Using the kernel principal component analysis and through the first principal component that has high value contribution, all of the effective information of pinch-out boundary which were distributed to different components of the instantaneous spectrum could be represented. This technology was applied to the lithologic pinch-out boundary identification of delta sand body in JX1-2N work area with a good result.