Abstract
Hypothesis:
Zeta-potential in the presence of brine has been studied for its application within hydrocarbon reservoirs. These studies have shown that sandstone’s zeta-potential remains negatively charged, non-zero, and levels-off at salinities > 0.4 mol.dm−3, thus becoming independent of salinity when ionic strength is increased further. However, research conducted to date has not yet considered clay-rich (i.e. clay ≥ 5 wt%) sandstones.
Experiments:
Firstly, streaming potential measurements were conducted on Bandera Gray sandstones (clay-rich and clay-poor) with 0.6 and 2 mol.dm−3 NaCl brine-saturated in pressurised environments (6.895 MPa overburden and 3.447 MPa back-pressure). Secondly, the streaming potential was determined at identical conditions for the effect of two surfactants, SDBS and CTAB, at concentrations of 0.01 and 0.1 wt% on the clay-poor sample in 0.6 mol.dm−3 NaCl. Thirdly, a comparison of zeta potentials determined via electrophoretic and streaming potential was conducted. Accordingly, this work analyses the effects of mineralogy and surfactants within this process.
Findings:
Clay-rich sandstone possessed lower zeta-potentials than clay-poor sandstone at the two tested salinities. SDBS reduced zeta-potential and yielded higher repulsive forces rendering the rock more hydrophilic. Additionally, electrophoretic zeta-potentials were higher when compared to streaming zeta-potentials. Mechanisms for the observed phenomena are also provided.
Keywords
Clay-rich sandstone, mineralogy, streaming potential, Zeta potential, Sodium Dodecylbenzene Sulfonate, Cetyl Trimethyl Ammonium Bromide, Electrophoretic potential
Document Type
Journal Article
Date of Publication
2022
Publication Title
Journal of Colloid and Interface Science
Publisher
Elsevier
School
School of Engineering / Centre for Sustainable Energy and Resources
RAS ID
45360
Funders
Edith Cowan University - Open Access Support Scheme 2021
Higher Education Commission (HEC) Pakistan / Edith Cowan University
Creative Commons License
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License.
Comments
Awan, F. U. R., Al-Yaseri, A., Akhondzadeh, H., Iglauer, S., & Keshavarz, A. (2022). Influence of mineralogy and surfactant concentration on zeta potential in intact sandstone at high pressure. Journal of Colloid and Interface Science, 607(Part 1), 401-411.
https://doi.org/10.1016/j.jcis.2021.08.015