利用可控震源的力信号压制谐波干扰

Harmonic interference suppressing by force signal of vibroseis

(CNPC东方地球物理勘探有限责任公司采集技术支持部,河北涿州072751)

Cao Wuxiang，Acquisition Technical Support Department,BGP,CNPC,ZhuoZhou 072751,China

谐波是可控震源采集中的一种特殊干扰,压制谐波一直是可控震源资料处理中的任务之一。迄今为止，大部分压制谐波的方法都是基于理论扫描信号与实际震动记录相关的技术特点提出的,易受表层介质特点的影响,很难取得明显的效果。事实上,可控震源的力信号才是真正的下传信号,其包含扫描基波和谐波分量,因此震源记录可近似看成力信号与反射系数系列的褶积体。提出了用力信号代替理论扫描信号,用反褶积算法代替传统的相关算法实现震动记录的反褶积处理。该方法的直接输出资料是褶积记录,与可控震源的相关记录相比,谐波成分得到消除,信噪比明显提高。

Harmonic wave is a special interference in vibroseis acquisition,and suppressing harmonic interference is an important task in vibroseis data processing.Up to now most methods for suppressing harmonic interference is based on the technical characteristics of correlating method between theoretical sweeping signal and actual vibrating record,which is easily impacted by the surface media so suppressing effect isn’t good.In fact,the force signal of vibroseis is real downgoing signal,which contains sweeping fundamental signal and harmonic component.So vibroseis record can be regarded as the convolution volume of force signal and reflectivity series.After research,we proposed force signal replacing theoretical sweeping signal and deconvolution algorithm replacing traditional correlating method to complete the deconvolution of vibrating record.The direct data of the method is convolution record.Compared to the correlation method of vibroseis,the harmonic interference is attenuated,and the SNR is largely improved.