Fahdi Maula, Marsha Sakina, Haryo Trihutomo

The Vertical Seismic Profile (VSP) is a widely used technique for extracting velocity information and seismic well tie purposes. However, the full potential of VSP data remains underutilized. This study explores the broader applicability of VSP data beyond its conventional usage by investigating its benefits for seismic data processing and interpretation. Advanced VSP products, incorporating features such as formation attenuation and multiple generator identification, play a crucial role in optimizing seismic data processing workflows.

In this paper, we present an extended workflow for zero-offset VSP processing that leverages the value of the downgoing wavefield. By utilizing a robust industry method, we estimate formation attenuation by analyzing the spectral ratio of the downgoing wavefield. The multispectral method is employed to compute the attenuation ratio, considering all receiver pair combinations. This results in the extraction of a 1-D attenuation profile along the well based on statistical coherence. To identify the multiple generators, we apply a separate deconvolution process involving trace-by-trace analysis and reference trace comparison. The adaptive subtraction method is utilized to compute the difference, outputting a wavefield exclusively containing multiple reflections. Additionally, we incorporate the available sonic and density logs from the well to calculate seismic multiples reflectivity modeling, which is then compared with the wavefields.

We demonstrate the effectiveness of our proposed workflow by applying it to Zero Offset VSP datasets from two wells in the Browse Basin, Australia. The integration of VSP datasets into the subsurface model highlights their value and contributes to subsurface interpretation and processing. The obtained results are can upscaled to a 3D field scale using property modeling, yielding valuable insights. Moreover, this study emphasizes the critical role of VSP data as an essential input for subsurface imaging and reservoir characterization.