TGS and the Petroleum Directorate of Sierra Leone (PDSL) have commenced two major offshore seismic reprocessing projects aimed at enhancing the country's subsurface database and supporting future hydrocarbon exploration. The Sierra Leone 2D Vision and Mabesi 3D Vision projects represent one of the most significant recent investments in modernising Sierra Leone's regional seismic dataset.
The programme will apply advanced Pre-Stack Depth Migration (PSDM) workflows to approximately 24,000 kilometres of legacy 2D seismic data and 4,155 km² of 3D seismic data, using modern processing technologies including machine learning-based denoising and deghosting, adaptive demultiple techniques and Depth Model Enhanced Full Waveform Inversion (DM-eFWI). The objective is to deliver significantly improved depth-imaged seismic data that provides greater subsurface clarity and supports more reliable structural interpretation across Sierra Leone's offshore basin.
A key component of the programme is the integration of the reprocessed Mabesi 3D Vision dataset with the recently completed Fusion 3D Vision project, creating a unified regional 3D volume. The combined dataset is expected to improve understanding of depositional systems, structural and stratigraphic trapping styles, while preserving amplitude fidelity for advanced AVO analysis and reservoir characterisation of Upper Cretaceous plays.
The upgraded seismic data are intended to support efficient basin screening, prospect maturation and investment decisions across both shelf and deepwater areas. By applying modern imaging technologies to legacy datasets, the projects aim to reduce exploration uncertainty and provide companies with a stronger technical foundation for evaluating one of West Africa's underexplored Atlantic margin basins.
The projects are now underway, with early-out products expected during 2026 to support ongoing basin evaluation and licensing activities. Final products from Mabesi 3D Vision are scheduled for delivery in Q1 2027, followed by the Sierra Leone 2D Vision dataset in Q3 2027.
The programme highlights the continuing value of seismic reprocessing in unlocking new exploration potential from existing datasets. Advances in PSDM, full waveform inversion and machine learning are enabling legacy seismic surveys to reveal geological detail that was previously unresolved, helping operators reassess mature and frontier basins using today's imaging capabilities.
The initiative also reflects Sierra Leone's broader strategy to strengthen the quality of publicly available geological and geophysical data, providing explorers with modern, consistent datasets that can support responsible investment and future offshore licensing rounds.
