Sequence Stratigraphy of the Post-jurassic in the Algoa and Gamtoos Basins: Implications for Hydrocarbon Potential in the Eastern Cape, South Africa

Abstract

Although a working petroleum system was proven in the Algoa and Gamtoos Basins of South Africa (Eastern Cape), seismic and well data acquired to date yielded limited exploration success. This limitation has prevented the development of contemporary basin development models for the Algoa and Gamtoos region. Based on vintage data by Soekor E&P (Pty.) Ltd. and preliminary sequence stratigraphic studies, New Age Global Energy Company reported ~620 million barrels of potential oil resources in offshore Algoa Canyon in 2010. Following this, the company undertook modern 3D seismic survey in 2013. This study is building a modern sequence stratigraphic framework for the Algoa and Gamtoos Basins by integrating all existing data to test the advantages and limitations of selected sequence stratigraphic models. The ultimate goal of this ongoing project is to understand the basin formation mechanisms and the hydrocarbon prospectivity in the Algoa and Gamtoos Basins. To achieve this, the following objectives are being addressed: 1. Analyse and interpret the geological record in the Algoa and Gamtoos Basins, firstly by using basic principles of stratigraphy and process sedimentology (i.e., independent of any sequence stratigraphic school of thought). 2. Understand the mechanisms (autocyclic and/or allocyclic) responsible for seismic reflector geometries and sequence generation in the Algoa and Gamtoos Basins. 3. Compare sequence boundaries and geometries observed in the Algoa and Gamtoos dataset to stratigraphic boundaries and geometries defined in different sequence stratigraphic models. 4. Use relevant sequence stratigraphic models to predict facies distribution in the basins, by testing the robustness of current models and highlighting their advantages and limitations for the Algoa and Gamtoos Basins. 5. Attempt to develop a robust predictive tool for facies distribution away from well control and hydrocarbon plays (i.e., build gross depositional environment) models) in the Algoa and Gamtoos Basins. 6. Provide recommendations on how sequence stratigraphy can be used in regions similar to Algoa and Gamtoos Basins.

AAPG Datapages/Search and Discovery Article #90332 © 2018 AAPG International Conference and Exhibition, Cape Town, South Africa, November 4-11, 2018