04 NovPhD DissertationProbing Chemical Interactions of Asphaltene-like Compounds with Silica and Calcium Carbonate in the Context of Improved Oil
Probing Chemical Interactions of Asphaltene-like Compounds with Silica and Calcium Carbonate in the Context of Improved Oil
  • Ph.D. Candidate Saleh Hassan Supervised by Prof. Tadeusz W. Patzek
  • Wednesday, November 04, 2020
  • 06:00 PM - 07:30 PM
  • Zoom link: https://kaust.zoom.us/j/91014296683
2020-11-04T18:002020-11-04T19:30Asia/RiyadhProbing Chemical Interactions of Asphaltene-like Compounds with Silica and Calcium Carbonate in the Context of Improved OilZoom link: https://kaust.zoom.us/j/91014296683Saleh HassanSaleh.Hassan@kaust.edu.sa

Abstract: Recovery of crude oil is related to surface wettability, which is controlled by crude interactions with rock surfaces. Understanding these interactions is associated with studying the complex asphaltenes that (1) are irreversibly deposited from oil-brine interface onto reservoir mineral surfaces, (2) are bulky super-molecules and (3) incorporate several chemical groups by stacking aromatic rings together. This is a difficult task because of varying crude oil composition, asphaltene interfacial and chemical activity, and the potential of irreversibly contaminating analytical equipment by such substances.To overcome these challenges, we split the problem into parts by studying how different mono- and poly-functional groups mimic asphaltene interaction with mineral surfaces, like silica and calcium carbonate. The amine, carboxylate, and sulfate groups were identified as the highest potential functional groups responsible for asphaltene adsorption. Experiments included quartz crystal micro-balance with dissipation, bulk adsorption, and core samples. Adsorption tests for the studied mono-functional surfactants were fully reversible and, therefore, not representative of asphaltenes. Poly-functional compounds demonstrated irreversible adsorption, mimicking asphaltenes, through ion exchange and ion-bridging – depending on the type of functional group, chain length, mineral surface, and brine ionic composition. Poly-amines adsorb irreversibly onto silica and calcium carbonate surface regardless of the brine ionic composition or surface charge. However, irreversible adsorption of poly-sulfates and poly-carboxylates onto surface requires (1) sufficiently long chains and (2) abundant presence of calcium ions in solution to allow ion bringing mechanism. These findings suggest that crudes containing amine groups and long chains of carboxylates or sulfates have a higher tendency to be adsorbed onto surface and change wettability. This is important for designing efficient detachment of asphaltenic oil from rock surface, where no complete desorption or drastic wettability change is required. The weakening of asphaltene interactions may be sufficient to induce spontaneous imbibition and consequently increase efficiency of two-phase displacement.This work emphasizes the importance of understating crude-brine-rock interactions for the purpose of oil recovery.  In summary, evaluating potential candidates for deploying enhanced oil recovery, such as low salinity water, should consider rock and crude types — as successful implementation requires "specific" properties collaborating together to enable incremental oil production.  

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  • Saleh Hassan
  • Saleh.Hassan@kaust.edu.sa

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