In this work, the precipitation and re-dissolution of asphaltenes were studied for an Iranian relatively heavy crude oil. A series of experiments were designed and carried out to quantitatively examine the reversibility of asphaltenes precipitation upon the change in the solvent concentration along with the temperature. n-Heptane was used as the precipitant, and a temperature range of 30 to...

The molecular properties of asphaltenes have been the subject of uncertainty in the literature; in particular the molecular architecture is still a matter of debate. Some literature reports provide evidence that the contrast of petroleum asphaltenes versus coal-derived asphaltenes is useful for understanding the governing principles of asphaltene identity. Here, we employ fluorescence correlati...

We study chemical aging in "Cooee bitumen" using molecular dynamic simulations. This model bitumen is composed of four realistic molecule types: saturated hydrocarbon, resinous oil, resin, and asphaltene. The aging reaction is modelled by the chemical reaction: "2 resins → 1 asphaltene." Molecular dynamic simulations of four bitumen compositions, obtained by a repeated application of the aging ...

Asphaltene and smaller aromatic molecules tend to form linear nanoaggregates in bitumen. Over the years bitumen undergoes chemical aging and during this process, the size of the nanoaggregate increases. This increase is associated with an increase in viscosity and brittleness of the bitumen, eventually leading to road deterioration. This paper focuses on understanding the mechanisms behind nano...

A high content of asphaltene and wax in crude oil leads to difficulties the recovery transportation due precipitation asphaltenes deposition waxes. Comb-like polymers were found be capable inhibiting aggregation crystallization In this work, comb-like bipolymers α-olefins/ultra-long chain (C18, C22 C28) alkyl acrylate synthesized characterized by FT-IR 1H NMR spectra. The results show that, for...

Bridging the gap between laboratory-scale experiments and actual oilfield operations is a complex task that requires compromise real (authentic) fluids model systems. Commercial products (i.e., asphaltene inhibitors dispersants) are often designed to target wide range of operating conditions compositions crude oils, which means performance becomes almost case-specific. Through Atomic Force Micr...

this paper is concerned with asphaltene deposition in fluid flowing through pipelines. brownian diffusion and drag, gravitational, thermophoresis, buoyancy, and shear removal are considered as possible mechanisms in the asphaltene deposition process. the thermo-physical properties of the fluid were obtained from iranian oil fields. a model was used in the pipeline deposition modeling to predict...

Despite recent advances in spectroscopic techniques, there is uncertainty regarding the nature of the carbonyl groups in the asphaltene and resin fractions of crude oil, information necessary for an understanding of the physical properties and environmental fate of these materials. Carbonyl and hydroxyl group functionalities are not observed in natural abundance 13C nuclear magnetic resonance (...