余弦振幅加权定向地震波束形成方法

Seismic directional beam-forming with the Cosine amplitude distribution

可控震源进行地震勘探时,可以利用基于接收阵列的时域地震波束形成方法(TSBBRA)来提高信噪比。如果背景噪声很强,需要增大TSBBRA方法控制参数N来提高信噪比,但伴随的问题是波束会变窄,当主波束不能覆盖整个接收排列时,会造成单炮记录上有效波束范围较窄,仍难以满足数据处理过程要求。针对上述问题,提出一种基于接收阵列的余弦振幅加权定向地震波束形成方法(SDBCAD)。SDBCAD方法通过在接收端对各单炮记录进行余弦振幅加权,然后进行时域延时叠加形成定向地震波。论文合成了TSBBRA方法与SDBCAD方法下的地震数据,结果表明在TSBBRA方法的主波束无法覆盖整个观测系统时,合理利用SDBCAD方法可令地震波束展宽,更好覆盖接收排列。可见,SDBCAD方法在控制波束形态上具有适当展宽定向地震波束的能力,合理利用可改善数据质量。

We can use “time domain seismic beam-forming based on receiver array”（TSBBRA）to improve signal-to-noise ratio （SNR）when controlled source is used in seismic exploration.If the background-noise is very strong,SNR can be improved by enlarging the parameter N of TSBBRA.With the N increasing,the seismic beam will become narrower.When the beam does not cover the receiver array,the SNR of receiver array will not great enough to meet the requirements of seismic data processing.In order to improve the SNR of single shot record,we propose“Seismic Directional Beam-forming with the Cosine Amplitude Distribution”（SDBCAD）,which is also based on beam-forming theory.SDBCAD generates directional seismic records by introducing cosine amplitude distribution in beam-form-ing processing.We simulate the seismic data of TSBBRA and SDBCAD,and the results show that when the beam of TSBBRA can’t cov-er the receiver array,the beam of SDBCAD can be broadened to cover the receiver array.These demonstrate that SDBCAD is better on beam shape control than TSBBRA.Rational use of SDBCAD can improve the quality of seismic data.