# Unveiling Accurate Seismic Imaging through the Advanced Target-Oriented Kirchhoff Migration Method
## 2 Methodology
### Validation of Redatumed Seismic Data as the Input for Seismic Migration  
Within this sub-section, we are presenting the validation process conducted on the redatumed data to confirm their dependability as a reliable input for the seismic migration  
Figure 3: Target-oriented migration strategies either by (**a**) migrating the whole area under the virtual depth or by (**b**) migrating several small areas of interest simultaneously depending on the aim of the migration. Either one still reduced the computational cost compared to full-scale imaging.  
process. Figure 4 indicates the concept of seismic redatuming, which involves separating the velocity model into segments above and below the datum level. The redatumed data, retrieved from the observed recorded data, basically represent reflections from the subsurface below datum level, as if the sources and receivers were located at datum level. It can be affirmed that the obtained redatumed shot gathers already encompass the effects of the overburden, resulting in an improved signal-to-noise ratio [35; 36; 43].  
Prior to that, we presented the validation process, which involved a comparison between the quality of the redatumed gather and the observed gather recorded at the surface, as illustrated in Figure 5. First, seismic redatuming was executed using the source and receiver configuration, as shown in Figure 4 at datum level. Then, the redatumed gather obtained for the area below datum was compared with the recorded data at the surface. As shown in Figure 5, it is evident that the primary reflections in the redatumed data exhibited greater visibility compared to those in the surface data. This discrepancy can be attributed to the distortion caused by the salt body in the overburden, affecting the transmission of waves deeper below the datum. Furthermore, it is noticeable that certain internal multiples associated with the intricate overburden have been mitigated. Hence, this serves as the primary purpose for conducting seismic redatuming in which to improve the quality of seismic data below the overburden.  
Furthermore, we conducted a modeling test to validate the accuracy of the obtained redatumed data. Using the identical source and receiver configuration at the datum level, we performed forward modeling to simulate data below the datum. Subsequently, these modeled data were compared to the previously obtained redatumed data, as shown in Figure 6. A strong correspondence is evident in most primary reflections between the two datasets. Equivalent results were published in [41], where a close agreement was observed between the redatumed data and the data simulated from the datum level. Hence, the reliability of redatumed data for seismic migration has been confirmed.  
Figure 4: An illustration shows the model is divided into segments above and below the datum. The original source locations (blue) and receivers (red) are positioned at the surface. These are subsequently virtually shifted to the datum level (indicated by the black dotted line), represented by black (source) and green (receivers) points.