Zululand Basin - ZB Raw Data
These datasets were utilised for the evaluation of the potential of the onshore Cretaceous Zululand Basin for geological storage of CO2 as presented in the paper: L.V. Tibane, H. Pöllmann, F. Ndongani, B. Landman, W. Altermann, 2021. Evaluation of the lithofacies, petrography, mineralogy, and geochemistry of the onshore Cretaceous Zululand Basin in South Africa for geological CO2 storage. International Journal of Greenhouse Gas Control. 109, 103364. DOI:10.1016/j.ijggc.2021.103364. H2O-CO2-rock interactions experiments were performed over a period of 4 weeks under simulated in-situ conditions at the temperature of 100 °C and pressure of 100 bar. The data show that the sandstone and siltstone units investigated react with scCO2, causing a slight change in rock porosity and permeability. However, mineralogical, geochemical, geomechanical, and petrophysical characterisations require additional raw data from unweathered fresh drill cores to model the long-term effects of the trap mechanism.
Steps to reproduce
1. Generate spectral data using the mobile spectral imaging device, sisuRock (sisuMOBI). Use an IntelliCore software identify and quantify mineral phases. 2. Perform geological core logging to describe and identify the different types of lithology, their depth and thickness, sedimentary structures and fossils. 3. Sample at random intervals at lithological contacts ensuring that a representative sample is collected. The collected samples should typically be 10 cm to 15 cm in length. Split the drill cores into halves using a diamond saw blade. Place one half of the sample in a standard, named and numbered transparent plastic bags containing an identifying sample tag and utilise for further investigations. The remaining half of the sample should be returned to the core tray with a corresponding tag labelling placed at the bottom of the sample interval and stored back at the National Core Library in Donkerhoek. 4. Prepare thin sections by cutting the rock samples into thin slabs, mount the slabs on a glass slide using epoxy resin, before polishing to a standard thickness of 30 µm. 5. Examine the thin sections under transmitted light using Nikon Eclipse microscope for rock and mineral identification and description. Use a scanning electron microscope (SEM), JEOL JSM6300 version to perform textural examinations using SEM images. determine the chemical properties of the mineral phases by using energy dispersive spectroscopy analysis (EDS). 6. For XRD data, use crushed, milled and homogenised powder material and a McCrone micronising mill to reduce the particle size to 5-10 µm. Press a sub-sample into a shallow plastic sample holder against a rough filter paper ensuring random orientation. Use a 5 g powder pellet to generate X-ray diffraction (XRD) data using a Bruker D8 Advance XRD instrument equipped with a 2.2 kW Cu fine focus tube (CuKα, λ = 1.54060) and a 90-position sample changer. 7. Use part of the powder material to generate chemical composition data using X-ray fluorescence (XRF) technique. Examine the glass plates and wax pellets using a PANalytical Axios XRF spectrometer equipped with a 4 kW Rh tube. 8. Generate geochemical data using Enerpac P141, a single speed, hydraulic hand pump, 327 cm3 and 12.7 mm cylinder stroke, operated at the pressure of 700 bar. 9. Porosity and permeability estimation data are generated by using 2D and 3D image analysis, carried out under a transmitted light microscope and a scanning electron microscope. 10. Perform H2O-CO2-rock interaction experiments using a system of autoclaves placed in an oven at the temperature of 100 ºC and pressure of 100 bar over a period of 4 weeks.