CGG’s newly re-imaged dataset in the region opens the door for a fundamental re-assessment of the prospective Pre-Salt system.
Imaging the deep, Pre-Salt reservoirs of the Outer Kwanza Basin, while traditionally a challenge, is significantly improved by applying advanced proprietary imaging techniques that have already proven their ability to uplift existing seismic data in other Pre-Salt basins. CGG’s newly re-imaged dataset in the region opens the door for a fundamental re-assessment of the prospective Pre-Salt system.
Read the full article, originally published in GEOExPro Vol. 19, No. 6 – 2022, by Madhurima Bhattacharya and Harrison Moore, CGG, here.
A fully ticked prospectivity check list for the Kwanza Basin Pre-Salt play
All key elements of a working petroleum system are present within the Pre-Salt play of the Kwanza Basin, including:
-Barremian type I oil-prone source rocks of the Bucomazi Formation
-Excellent carbonate reservoirs, proven in both the Cameia and Mavinga discoveries as well as a secondary Pre-Salt reservoir in the Cuvo Formation
-The regional Loeme salt along with tight carbonate layers deposited over the Pre-Salt unit acting as a vertical regional seal
CGG’s Block 21 and 22 Surveys in the Outer Kwanza Basin
CGG’s broadband 3D multi-client surveys were acquired with a total data coverage of over 7,000 km2 and are currently being re-imaged to enable interpreters to explore for new targets in the Pre-Salt. The first phase has now been completed with re-imaging of a sub-set of Block 21 survey. The next phase will begin in Q1 2024 and will focus on re-imaging of 4,300 sq. km of Block 22 3D survey.
Advanced imaging techniques, fully described in the Geo Expro article, include:
Machine learning algorithms used a trained deep neural network (DNN) to de-noise and remove seismic interference
Robust interpretation of complex faulting by a machine-learning fault extraction algorithm
Time-lag full-waveform inversion (TLFWI) produced a more accurate velocity model for final imaging in a geological setting with strong fault-bounded velocity contrasts from layered carbonates and salt
Angola, Kwanza Basin: This depth slice at 4,160 m, overlaid by a 8 Hz TLFWI velocity model, shows compartmentalization of carbonates (red concentric body) by bounding faults and rafting associated with salt diapir (purple concentric body) halokinesis. For a closer look, come to the CGG booth (image courtesy of CGG Earth Data).
Find out more at Africa Oil Week
Madhurima Bhattacharya, lead author of the original GEOExPro article ‘Angolan Kwanza Basin – Expanding Proven Opportunities’, will present further insights at Africa Oil Week:
Wednesday 11th October | 15:30 | PROSPECT FORUM – Stage B| Deepwater Zambezi Delta – Exploring a frontier basin using high-end imaging
Join Madhurima and fellow CGG experts at the CGG booth, #C20 where the team will showcase exceptional images for deep pre-salt prospecting and high-definition interpretation of shallow targets using cutting-edge broadband data.
For more information, go to: cgg.com/AOW2023