Trace-by-Trace Iterative VSP Wavefield Separation

The popular iterative vertical seismic profiling (VSP) wavefield separation method has higher precision wavefield separation results than the conventional VSP scalar wavefield separation method, but it still faces challenges in achieving desirable high-precision wavefield separation results due to the time-variant wavelet, the complex wavefield, and the precision of wavefield flattening. In this letter, in order to minimize the impact of the factors mentioned above, we propose a trace-by-trace iterative VSP wavefield separation method (TISM) based on the gradually changing characteristics of VSP data in adjacent traces, the cross correlation, and the iterative VSP wavefield separation method (ISM). TISM includes the flowchart of TISM, the target trace-guided sub-dataset automatic generation (TDG), the cross correlation-guided sub-dataset optimization (CDO), and the cross correlation-guided wavefield separation result optimization (CWO). TDG aims to automatically generate the sub-VSP dataset corresponding to the target trace and minimize the impact of the time-variant wavelet and complex wavefield. CDO aims to minimize the effect of wavefield flattening and form the high-precision wavefield flattened sub-dataset for scalar wavefield separation. CWO aims to obtain the high-precision wavefield separation result. Synthetic and actual VSP data applications demonstrate that TISM can minimize the impact of the time-variant wavelet, the complex wavefield, and the precision of wavefield flattening, thereby obtaining high-precision VSP wavefield separation results.