可控震源高保真采集数值模拟及炮集分离

Numerical simulation and source separation for high fidelity vibroseis seismic data acquisition

可控震源高保真采集(HFVS)方法利用多震源在多位置同时激发,大大提高了地震数据采集效率。但多震源同步激发,增加了记录的相邻干扰,降低了资料信噪比,原始记录需要进行炮集分离后才能应用。采用可控震源激发的线性扫描信号模拟高保真采集(HFVS)技术进行的二维地震数据采集,对震源信号进行相位编码,正演模拟多张混叠记录。利用震源检测信号以及地震记录获得震源与各检波点之间对应物理路径各频率点处的传输函数,并将传输函数作用于各震源检测信号,即可得到分离后的单炮地震记录。对比炮集分离结果与单炮正演模拟结果可以看出,远炮点道和近炮点道的分离效果都较好,且远炮点道的分离效果好于近炮点道。

High Fidelity Vibroseis Seismic Data Acquisition(HFVS) is to simultaneously shoot at multi-positions with multi-sources,which greatly improves the acquisition efficiency.Simultaneous shooting leads to the increase of adjacent interference on record and the decrease of the S/N ratio of seismic data,so raw record requires source separation before application.The linear sweep signals shoot by vibroseis was used to simulate 2D seismic data acquisition with HFVS method.Then,phase encoding was carried out on source signals and several aliasing records were obtained by forward modeling.Source detection signal and seismic record were adopted to gain the transfer function of every frequency points of the physical path between shot point and every receiving point.Then transfer function was taken as source detection signal,by this means,the single-shot seismic record after separation can be obtained.By comparing separated result with single-shot forward modeling result,we can see that the separation results of far-shotpoint traces and near-shotpoint traces are both good;moreover,the former one is better than the later.