EGU22-13060
https://doi.org/10.5194/egusphere-egu22-13060
EGU General Assembly 2022
© Author(s) 2022. This work is distributed under
the Creative Commons Attribution 4.0 License.

Zeta Potential of Intact Carbonate Core Samples Saturated with Natural Aqueous Solutions with Varying Concentration of Negative Potential Determining Ions

Nacha Atiwurcha1, Jos Derksen2, David Vega-Maza3, and Jan Vinogradov4
Nacha Atiwurcha et al.
  • 1University of Aberdeen, School of Engineering, Elphinstone Road, AB24 3UE Aberdeen, United Kingdom (n.atiwurcha.18@abdn.ac.uk)
  • 2University of Aberdeen, School of Engineering, Elphinstone Road, AB24 3UE Aberdeen, United Kingdom (jderksen@abdn.ac.uk)
  • 3University of Aberdeen, School of Engineering, Elphinstone Road, AB24 3UE Aberdeen, United Kingdom, Now at the University of Valladolid, School of Engineering, TermoCal, BioEcoUva, Valladolid, Spain (d.vega-maza@abdn.ac.uk)
  • 4University of Aberdeen, School of Engineering, Elphinstone Road, AB24 3UE Aberdeen, United Kingdom (jan.vinogradov@abdn.ac.uk)

Zeta potential is an important petrophysical property that controls electrostatic interactions between mineral, water, and non-aqueous phase fluids. These interactions play an important role in defining the wetting state of reservoir rocks. The zeta potential can be interpreted from the streaming potential measurements, which are shown to be an efficient means for a broad range of applications including monitoring of single- and multi-phase flows in subsurface settings, characterization of fracture networks, efficiency of CO2 sequestration, hydrogen underground storage and enhanced oil recovery. It is widely agreed that the zeta potential in carbonate rocks is controlled by the concentration of potential determining ions (PDI), but the understanding of this is still poor and there are very limited experimental data on quantitative characterization of the dependence of the zeta potential on concentration of negative potential determining ions (PDI) such as SO42-, CO32-, HCO3-, especially when their concentration is high and exceeds that of the positive PDIs.

In this study, the streaming potential method is used to investigate the zeta potential of natural carbonate rock samples in contact with natural aqueous solutions of low-to-high ionic strength and with varying concentration of sulphate (SO42-) and carbon (C4) related (HCO3-, CO32-) ions. In each set of experiments the total ionic strength was kept constant to eliminate the impact of concentration on the zeta potential. The study probed the concentration of negative PDIs that has never been reported before, with their respective lowest concentration consistent with previously reported values, and the highest concentration equal to the maximum achievable by stripping the tested solutions of Cl-.

Our results demonstrate that zeta potentials strongly depend on concentration of the negative PDIs, thus providing explicit empiric relationship between the zeta potential and a broad range of PDI concentration. Our findings improve the current understanding of the complex physicochemical processes that take place at calcite-water interface and provide important experimental data for surface complexation modelling of carbonate-brine systems.

How to cite: Atiwurcha, N., Derksen, J., Vega-Maza, D., and Vinogradov, J.: Zeta Potential of Intact Carbonate Core Samples Saturated with Natural Aqueous Solutions with Varying Concentration of Negative Potential Determining Ions, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-13060, https://doi.org/10.5194/egusphere-egu22-13060, 2022.