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ORIGINAL RESEARCH article

Front. Chem.
Sec. Inorganic Chemistry
Volume 13 - 2025 | doi: 10.3389/fchem.2025.1540250

Impact of Geochemical Reactivity on Desulphation Requirements in a Sandstone Reservoir Containing Carbonate and Sulphate Minerals

Provisionally accepted
Ali Al-Behadili Ali Al-Behadili 1,2*Eric J Mackay Eric J Mackay 1,2
  • 1 Heriot Watt, Edinburgh, United Kingdom
  • 2 Institute of Geoenergy Engineering (IGE), Heriot-Watt University, EH14 4AS, Edinburgh, United Kingdom

The final, formatted version of the article will be published soon.

    This paper presents an investigation of the impact of in situ chemical and geochemical interactions on oil recovery efficiency and inorganic scale management. A common technique to support the reservoir pressure is water injection, scale problems are a major issue that develop during oil field production when there is water (especially seawater) injection. In such flooding scenarios, geochemical reactions occur between formation and injected water in terms of sulphate scales, such as Barite. However, the carbonate scales may form due to a variety of reasons: changes in temperature, pressure, pH and CO2 concentration in the aqueous or hydrocarbon phases. This paper investigates the impact of CO2 availability, and changes in pH, ionic concentrations and temperature on carbonate and sulphate scaling risk in waterflooded reservoirs where choices may be exerted over injection water composition. In this work, the injected water does not contain CO2, but CO2 is present in the oil phase, and may partition from there, or diffuse from the formation water. Also shows the relationship between brine composition and scale behaviour in the production wells. many factors affecting the system, such as injection and production flow rates and flow through the reservoir, and compositional effects due to use of Full Sulphate Seawater (FSSW) or Low Sulphate Seawater (LSSW), also variations in temperature and the concentration of CO2 in the oil phase. This study, we include geochemical reactions in a 1D model that has the field PVT properties, to test the impact of the various potential reactions in a simple system. This is necessary to fully understand the system before, in future work, moving on to the full field modelling. We have five mineral reactions (Anhydrite, Gypsum, Barite and Calcite) are in equilibrium, excepting for the magnesium rich carbonate mineral reaction, which is assumed to be kinetic. The results show there are major ions that have a very significant effect on the system, and impact on precipitation and dissolution of minerals. Dissolution of Anhydrite present is shown to have a significant impact in most scenarios, except FSSW has been heated up to reservoir temperature, where Anhydrite precipitation in situ occurs.

    Keywords: Carbonate mineral, Inorganic scale, pH, Aqueous phase, Geochemical reactions

    Received: 05 Dec 2024; Accepted: 15 Jan 2025.

    Copyright: © 2025 Al-Behadili and Mackay. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

    * Correspondence: Ali Al-Behadili, Heriot Watt, Edinburgh, United Kingdom

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