基于地震干涉法的可控震源黑三角噪声压制技术及应用

沙漠区可控震源资料通常存在严重的高能量黑三角噪声,应用常规的转换域滤波或基于Born近似的迭代反演预测-消除方法进行去噪时,效果不理想。利用新疆某工区可控震源资料,定性分析了黑三角噪声的形成机理,主要由散射面波和可控震源与地表之间的谐振形成。针对黑三角区内的散射面波消除问题,基于炮-检地震干涉及模式的匹配相减方法,研发了可控震源散射面波干涉预测与匹配相减技术,其特点是实测地震资料驱动,无需速度模型；同时,将该技术与用于压制如谐振等不规则强噪声的异常噪声压制技术相结合,形成了可控震源黑三角综合去噪方法技术。以新疆某工区可控震源地震资料为测试资料,对比了该综合去噪技术与某商业软件的应用结果,表明该综合去噪技术能有效消除黑三角区内的强能量噪声,尤其是有效压制了散射面波,显著改善了叠前时间偏移结果,进而恢复地层真实反射特征,断裂和断溶体成像效果优于某商业软件。

Vibroseis data acquired in desert areas are typically contaminated by high-energy “black triangle” noise.Conventional transform domain filtering or iterative inversion prediction-elimination techniques based on the Born approximation are not effective in suppressing this type of noise.This study qualitatively elucidated the mechanism through which the black triangle noise is generated.It was found that this noise is primarily due to the scattering of surface waves and the resonance between the vibroseis source and ground surface.To address this issue,a scattered surface wave elimination technique based on source-detection seismic interferometry and pattern-based matching and subtraction was developed.This technique is advantageous as it is driven by measured seismic data and does not require a velocity model.To suppress the black triangle noise,it was used in combination with the abnormal noise suppression technique (used to suppress irregular strong noises,such as resonances).The method was tested on field data from Xinjiang,and the results were compared with those obtained by a commercial software.Evidently,the high-energy black triangle noise (particularly that originating from the scattered surface waves) could be effectively eliminated by the proposed method.This significantly improved the pre-stack time migration results and characterized the true reflection characteristics of the formation under investigation.The imaging of fractures and dissolution areas was superior to that obtained by the commercial software.