沙漠区可控震源采集资料“黑三角”强能量噪声压制技术

Technology for suppressing"black triangle"high-energy noise in vibroseis seismic data acquisition in a desert area

银额盆地拐子湖凹陷沙漠探区特殊的地形、地貌条件对地震资料的激发和接受产生不利的影响,其表层被巨厚且松散的沙土覆盖,沙丘厚度在50~100 m间。在该区开展可控震源采集时,受可控震源机械特征和近地表结构双重影响,在近道范围内,形成“黑三角”干扰,导致地震记录信噪比低。“黑三角”干扰具有能量强、频带宽、分布广、形态差异大等特征,在共炮点域、共检波点域等单一排列内,无法准确统计其振幅强度,导致压制“黑三角”噪声后残留噪声过多,为此提出先按照共炮—偏移距域进行数据重排,然后进行去噪处理的思路,基于银额盆地拐子湖地区的实际可控震源资料应用,验证了该方法在有效压制“黑三角”的同时,能有效保护近道反射信号,特别是深层弱反射信息,也验证了该方法在提高资料信噪比上的有效性。

The special topographic and geomorphic conditions in the desert exploration area of the Guaizihu sag in the Yin'e Basin produce adverse effects on the excitation and reception of seismic data.The surface of the area is covered by hugely thick loose sand,with the thickness of the sand dunes varying in the range of 50~100 m.In the process of vibroseis data acquisition in this area,"black triangle"noise is formed in the near-trace scope due to the dual effects of the mechanical characteristics of the vibroseis and the near-surface structure,resulting in a low signal-to-noise ratio of seismic records.Since the"black triangle"noise features high energy,wide frequency range,wide distribution,and great morphological difference,it is difficult to make accurate statistics of its amplitude(intensity)in a single arrangement of the common shot domain and the common receiver domain,thus resulting in too much residual noise after the suppression of the"black triangle"noise.Given this,this paper proposes a method,in which data rearrangement is firstly conducted based on the shot-offset domain and then denoising is performed.As verified by the application of actual vibroseis data of the Guaizihu area in the Yin'e Basin,this method can effectively protect the near-trace reflection signals(especially the deep weak reflection information)while effectively suppressing the"black triangle"noise and it is effective in improving the signal-to-noise ratio of seismic data.