Offshore reprocessing project to assess hydrocarbon potential

Targeting high potential basin to improve subsurface clarity

SIERRA LEONE: Reprocessing projects for offshore acreage have commenced to support efficient screening, early-stage evaluation and target prioritization across Sierra Leone’s high-potential basin.

TGS in partnership with the Petroleum Directorate of Sierra Leone (PDSL), confirmed the commencement of the Sierra Leone 2D and Mabesi 3D Vision reprocessing projects offshore Sierra Leone today.

“These projects represent another important milestone in Sierra Leone's strategy to continually enhance the quality of geological and geophysical information available to investors. By combining advanced imaging technologies with our existing seismic database, we are significantly improving the technical foundation upon which future exploration decisions will be made,” said Foday Mansaray, Director General of the Petroleum Directorate of Sierra Leone.

By delivering modern, depth-imaged seismic data with improved subsurface clarity, the projects will help operators better assess hydrocarbon plays and advance exploration opportunities from shelf to deepwater areas.

The program includes full reprocessing from field data of 24,000 kilometres from multiple input surveys of 2D seismic data and 4,155 square kilometres of Mabesi 3D seismic data through a comprehensive Pre-Stack Depth Migration sequence. The workflow will apply advanced machine learning-based denoise and deghosting, adaptive demultiple and advanced depth imaging, including DM-eFWI, to deliver clearer imaging of hydrocarbon plays in offshore Sierra Leone.

The Mabesi 3D Vision project will also be merged with the recently completed Fusion 3D Vision reprocessing, completed in December 2025, creating a unified 3D volume. This integrated dataset will provide improved insight into depositional systems and enhance understanding of structural and stratigraphic traps across Sierra Leone’s offshore basin.

The projects will also focus on balancing amplitudes and preservation of AVO fidelity throughout the processing sequence to support advanced reservoir characterization workflows and enable companies to better assess Upper Cretaceous AVO plays.

Interim early-out products from both projects are expected to be available in 2026. Final products from Mabesi 3D Vision are expected in Q1 2027, with final products from Sierra Leone 2D Vision expected in Q3 2027.

“Sierra Leone remains an underexplored basin with significant potential, as shown by recent new entrants to the offshore area. Through these PSDM reprocessing projects, TGS is applying advanced imaging technologies to deliver high-quality, modern seismic data that can support more efficient evaluation of exploration opportunities,” said David Hajovsky, Executive Vice President, Multi-Client at TGS.