Influence of aggregation of asphaltenes on the rheological properties of oil

Experimental and Theoretical Study on Supramolecular Ionic Liquid (IL)–Asphaltene Complex Interactions and Their Effects on the Flow Properties of Heavy Crude Oils

“…Asphaltenes have no specific molecular structure but are a solubility class that is present in higher proportion in the heavy crude oils (HCOs), according to the oil formation characteristics and its origin. The modification of initial thermodynamic conditions of petroleum fluids may cause precipitation of asphaltenes with deleterious effects of industrial installations along the production chain, − i.e., plugging of pipelines, valves fouling in oil fields, refractory effects for processing in refineries, etc., which provoke large operation cuts and enormous economic losses, a lower recovery factor, and lower benefit/production ratios overall. − From a molecular viewpoint, asphaltenes are complex polyaromatic hydrocarbons (PAHs) with about 5–10 fused rings having lateral alkyl type chains attached to the molecule outskirts and have high aromaticity, high polarity, and a marked tendency to form asphaltene–asphaltene supramolecular aggregates by a mechanism of π–π orbital type association . Another solubility class of molecules associated with asphaltenes is resins, which are aromatic type molecules with a molecular weight smaller than asphaltenes, having only three to six fused rings and short lateral chains.…”