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Kinetics of asphaltene aggregation phenomena in live oils

Mohammadi, S ; Sharif University of Technology

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  1. Type of Document: Article
  2. DOI: 10.1016/j.molliq.2016.07.062
  3. Publisher: Elsevier
  4. Abstract:
  5. The thorough knowledge of the asphaltene aggregation phenomena and pressure/temperature related kinetics is helpful for accurate prediction/control of the asphaltene issues in all facets of petroleum production/processing. However, characterizing the asphaltene aggregation phenomena in live oils at high pressure-high temperature conditions is not well discussed in the available literature. In this work, the asphaltene aggregation phenomena as well as the kinetics of aggregation at different levels of pressure and temperature are investigated in light and heavy live oils using high pressure microscope. The results are presented and discussed in terms of asphaltene onset pressure, aggregates size-growth, particle size distribution, and fractal dimension of the aggregates. For the samples studied, it was discovered that the de-pressurization process at higher temperatures results in higher asphaltene onset pressure. The oil viscosity reduction with temperature rise is the dominant driving force in earlier asphaltene precipitation rather than the solubility effect of oil/asphaltene. The effect of temperature on asphaltene aggregates growth is much more pronounced in light oil than in heavy oil. In light oil, as the temperature of the de-pressurization process increases the kinetics of asphaltene aggregation changes gradually from diffusion limited aggregation to reaction limited aggregation. In heavy oil, the kinetics of aggregation is mainly governed by slow aggregation or reaction limited control of the aggregation. The observed differences in the mechanisms of asphaltene aggregation may be attributed to the stability/nature of the oil rather than the asphaltene content of oil. The findings of this research reveal that accurate prediction/control of the asphaltene related issues seek to kinetics behavior of the asphaltene aggregation at reservoir conditions of pressure and temperature
  6. Keywords:
  7. Aggregation ; Light/heavy oils ; Aggregates ; Asphaltenes ; Crude oil ; Enzyme kinetics ; Fractal dimension ; Heavy oil production ; Kinetics ; Particle size ; Particle size analysis ; Pressurization ; Reaction kinetics ; Asphaltene aggregation ; Asphaltene onset pressures ; Asphaltene precipitation ; Diffusion limited aggregation ; Experimental ; High pressure high temperature ; Pressure and temperature ; Reaction limited aggregations ; Agglomeration
  8. Source: Journal of Molecular Liquids ; Volume 222 , 2016 , Pages 359-369 ; 01677322 (ISSN)
  9. URL: http://www.sciencedirect.com/science/article/pii/S0167732216318529