同步挤压改进短时傅里叶变换分频相干技术在断裂识别中的应用

Fault identification with short-time Fourier transform frequency-decomposed coherence improved by synchronous extrusion

受地震资料分辨率低以及地层产状所造成的背景噪声影响,难以准确识别小断裂及裂缝发育区,因此,利用同步挤压改进短时傅里叶变换的高时频分辨率技术,将地震数据体谱分解得到不同频率的单频数据体,再结合多道倾角导向相干技术对单频数据体进行相干计算。结果表明:同步挤压改进短时傅里叶变换分频多道倾角导向相干技术能够有效削弱因地震资料分辨率以及地层产状所造成的背景噪声影响,不仅具同步挤压改进短时傅里叶变换的高时频分辨率的优势,而且还有多道倾角导向相干技术对断裂准确刻画的优点。应用该方法在南海某工区断裂识别中取得了很好的效果。

Limited by low resolution seismic data and background noise caused by stratigraphic occurrence,minor faults and fractures are very difficult to be accurately identified.To solve this issue,an approach is proposed in the paper.The high-frequency multi-resolution of short-time Fourier transform improved by synchronous extrusion decomposes seismic data volume spectrum into single-frequency data of different frequencies,and the multi-trace tilt-oriented coherence is used to coherently calculate the single-frequency data volume.The proposed approach can effectively eliminate the background noise and improve seismic data resolution.The multi-trace tilt-oriented coherence can accurately characterize minor faults and fractures.This proposed approach is successfully applied to the fault identification in some work areas in the South China Sea and rather good results are achieved.