力信号反褶积运算对于提高地震资料保真度的研究分析

Improving high-fidelity of seismic data based on deconvolution by force signals

提取可控震源单炮记录时,通常根据参考信号与母记录(原始地震记录)的互相关运算结果来压缩可控震源单炮记录长度。震源机械、液压系统以及平板和大地耦合的非线性特征导致可控震源单炮记录存在谐波畸变,虽然谐波能量相较于基波能量较弱,但仍对地震资料的保真度存在一定程度的影响。将提取的力信号作为反褶积算子与母记录进行反褶积运算,压缩地震子波,提高地震资料的信噪比和分辨率,以获取不含谐波干扰的地震记录。对比分析模型正演和实际地震数据处理中参考信号、震源力信号和近场力信号与母记录互相关和反褶积运算后的地震记录可知,将力信号作为地震子波与母记录进行反褶积运算,既可以避免谐波干扰,又可以提高深层地震资料的保真度,因此分离后的单炮记录能够更真实地反映地下地层反射系数序列的脉冲响应。

In the extraction process of vibroseis single shot records,the cross-correlation between the reference signal and the original record is usually used to compress the record length.The source output signal has harmonic distortion due to the nonlinear characteristics of vibroseis mechano-hydraulic and geodetic systems.Although the harmonic interference is relatively weak compared to the fundamental waves,it affects the fidelity of ultra-deep seismic data.In this study,by extracting force signals as a deconvolution operator,deconvolution was carried out with the original records by geophone,so as to compress the seismic wavelet,improve the signal-to-noise ratio and resolution of seismic data,and obtain seismic records without harmonic interference.Tests on model and real seismic data were implemented and cross-correlation and deconvolution of the reference signal,vibrator force signal,and near-field force signal were undertaken.The results demonstrated that when the force signal was used as a seismic wavelet to conduct deconvolution with the original record,harmonic interference in the cross-correlation was avoided and the fidelity of deep seismic data was improved.Consequently,the separated single shot record more closely characterized the impulse response of the reflection coefficient sequence of underground strata.