Full Wavefield Redatuming: Accurate Velocity Modelling for Imaging Beneath Complex Overburden

Abstract
Salt is known for having a generally low density and higher velocity compared with the surrounding rock layers which causes the energy to scatter once the seismic wavefield hits the salt body and relatively less energy is transmitted through the salt to the deeper subsurface. As a result, most of imaging approaches are unable to image the base of the salt and the reservoir below the salt. Even the velocity model building such as FWI often fails to illuminate the deeper parts of salt area. In this paper, we show that Full Wavefield Redatuming (FWR) is used to retrieved and enhance the seismic data below the salt area, leading to a better seismic image quality and allowing us to focus on updating the velocity in target area below the salt. However, this redatuming approach requires a good overburden velocity model to retrieved good redatumed data. Thus, by using synthetic SEAM model, our objective is to study on the accuracy of the overburden velocity model required for imaging beneath complex overburden. The results show that the kinematic components of wave propagation are preserved through redatuming even with heavily smoothed overburden velocity model.

Citation
Dzulkefli, F. S., Xin, K., Ghazali, A. R., Qiang, G., & Alkhalifah, T. (2021). Full Wavefield Redatuming: Accurate Velocity Modelling for Imaging Beneath Complex Overburden. Day 4 Fri, March 26, 2021. doi:10.2523/iptc-21771-ms

Acknowledgements
We would like to thank PETRONAS management for giving permission to publish this work and to KAUST for the successful collaboration and to our colleagues for their unconditional support. Bakulin, A., & Calvert, R. (2004). Virtual source: new method for imaging and 4D below complex overburden. In SEG Technical Program Expanded Abstracts2004 (pp. 2477–2480). Society of Exploration Geophysicists.

Publisher
Society of Petroleum Engineers (SPE)

Conference/Event Name
The International Petroleum Technology Conference

DOI
10.2523/iptc-21771-ms

Additional Links
https://onepetro.org/IPTCONF/proceedings/21IPTC/4-21IPTC/Virtual/460722

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