Mineral Interfaces and Oil Recovery: A Microscopic View on Surface Reconstruction, Organic Modification, and Wettability Alteration of Carbonates

Ashit Rao*, Saravana Kumar, Carla Annink, Duy Le-Anh, Subhash C. Ayirala, Mohammed B. Alotaibi, Igor Siretanu, Michel H. G. Duits, Ali A. Yousef, Frieder Mugele*

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

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While it is generally known that aging protocols have an important impact on the interaction between crude oil (CRO), brines, and mineral surfaces, the microscopic consequences of the various steps of aging have hardly been described. In this study, we characterize the properties of fluids and carbonate mineral surfaces throughout a series of equilibration steps at 95 °C and correlate these microscopic observations with macroscopic contact angle measurements. Chemical equilibration of CRO (eqCRO) and FW (eqFW) leads to transfer of organic molecules from the former to the latter, causing also a pH change in the eqFW. Confocal Raman microscopy, atomic force microscopy, and infrared spectroscopy are used to reveal how consecutive aging of calcite in eqFW and eqCRO induces: first, in eqFW, considerable surface reconstruction and precipitation of mineral particles with colocalized organic species, and second, upon exposure to eqCRO, the formation of a second adlayer primarily composed of polyaromatic hydrocarbon-rich particles. Our results show how these interconnected microscopic chemical and topographical surface modifications give rise to more “oil wetting” contact angles after the two-step aging procedure.
Original languageEnglish
Pages (from-to)5611-5622
Number of pages12
JournalEnergy & fuels
Issue number5
Early online date6 Apr 2020
Publication statusPublished - 21 May 2020


  • UT-Hybrid-D

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