Processing and joint interpretation of multi-resolution marine seismic datasets

Abstract

In contemporary marine seismic exploration, conventional 2D and 3D seismic surveys are fundamental methods for hydrocarbon prospecting. However, in marine geo-engineering studies, especially for geo-hazard analysis, single-channel and high-resolution seismic systems such as sparker or Chirp sub-bottom profiler surveys are employed. The complementary use of multi-resolution seismic systems provides extra information in the interpretation of seismic data especially from shallow waters.

While the processing of single and multi-channel multi-resolution seismic data is of similarities in various aspects (e.g., band-pass filtering, gain application, signal-to-noise (S/N) ratio enhancement, post-stack migration procedures, etc.), specific processes are also required due to certain characteristics of Chirp and sparker data. Among these is the inability to apply stacking to single-channel seismic data, leading to challenges in increasing the S/N ratio. Additionally, obtaining subsurface velocity distribution from single-channel seismic data is not possible, causing difficulties in processes requiring velocity information, such as migration. The first challenge has been addressed for Chirp and sparker data through the application of trimmed trace-mix and f-x deconvolution. The issue of unavailability of velocity information has been resolved by utilizing 2D velocity information obtained from multi-channel seismic data during the migration process.

In this study, multi-channel seismic (MCS), sparker, and Chirp sub-bottom profiler data have been collectively processed and interpreted. While MCS data reveals deep structural and stratigraphic architecture, the effects of these structures in shallow sub-surface have been investigated through the analysis of single-channel high-resolution seismic data. This approach has provided advantages, particularly in the analysis of small-scale anomalous structures in shallow sediments, such as gas chimneys and diapirs as well as in determining their connection with deep stratigraphy. Furthermore, the recent activity of faults observed in the MCS data, whether they extend to the seafloor, has been more accurately delineated through the joint analysis of MCS and single-channel high-resolution seismic data.