Evaluation of carbon dioxide storage potential in wells of the Bredasdorp basin offshore South Africa
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Date
2024
Journal Title
Journal ISSN
Volume Title
Publisher
Taylor and Francis Ltd.
Abstract
This study focuses on determining how carbon dioxide (CO2) storage can be stored in the central Bredasdorp basin offshore South Africa. Logs, seismic lines, and reports of three exploration wells were used to build a 3D static model, and the compressibility method was used to estimate the CO2 static storage capacity of the reservoir. The wells displayed fair to good porosity and moderate permeability. The zone of interest had little to no faulting, and there is evidence of differential deposition of marine sandstones that overlie fluvial shales. The sandstones have good reservoir characteristics and are overlain by thick shales that serve as seals. The reservoir displayed thinning in the eastern direction and over structural highs. A static storage assessment of the reservoir showed 0.64 Mt of CO2, and the effect of changing pore volume and water saturation on overall CO2 storage volume was observed. The results revealed that an increase in pore volume would also increase the amount of CO2 stored in the reservoir. Conversely, increased water saturation leads to decreased CO2 that can be stored in the reservoir. This study has shown that the pre-existing reservoir fluid has an impact on CO2 storage volume; the greater the volume of water in the reservoir, the less the volume of CO2 that can be stored in the reservoir; this is because water is less compressible than rock, oil or gas.
Description
Keywords
Bredasdorp basin, Carbon dioxide storage, Petrophysical properties, Seismic, Static storage assessment
Citation
Ngcobo, L., Afolayan, B. and Opuwari, M., 2024. Evaluation of carbon dioxide storage potential in wells of the Bredasdorp Basin offshore South Africa. Marine Georesources & Geotechnology, pp.1-16.