Asphaltene transformation and agglomeration in compressed light oil systems under carbon dioxide injection in a porous structure: A molecular dynamics study
The rising depletion of light fossil fuels is leading to an increasing global dependence on heavy oil production. Asphaltene deposition poses a significant challenge in the application of improved oil recovery by CO2 injection, adversely affecting reservoir permeability and extraction efficiency. De...
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| Main Authors: | , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Elsevier
2025-10-01
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| Series: | Case Studies in Thermal Engineering |
| Subjects: | |
| Online Access: | http://www.sciencedirect.com/science/article/pii/S2214157X25010299 |
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| Summary: | The rising depletion of light fossil fuels is leading to an increasing global dependence on heavy oil production. Asphaltene deposition poses a significant challenge in the application of improved oil recovery by CO2 injection, adversely affecting reservoir permeability and extraction efficiency. Despite previous research highlighting the importance of this problem, there was a critical deficiency of knowledge on the impacts of pressure changes on asphaltene agglomeration and structural transformation at the atomic level in compressed light oil reservoirs. This research addressed the information gap using molecular dynamics simulations to elucidate the intricate processes of asphaltene aggregation under CO2 injection. The findings demonstrate that the model structure reached stability after 10 ns, with total and potential energies converging at 52.39 and 51.53 kcal/mol, respectively. The maximum density increases markedly from 0.3789 to 0.3889 atm/Å3 as pressure increases from 0.5 to 2 bar. Furthermore, the gyration radius of asphaltene molecules increases from 30.02 to 33.95 Å owing to elevated pressure, signifying enhanced molecular dispersion, whereas viscosity had a little reduction from 21.09 to 20.64 Pa s. Conversely, when the concentration of asphaltene molecules increases from 11 to 44, the profile increases from 0.3656 to 0.4138 atm/Å3. The radius of gyration decreased from 30.66 to 29.07 Å, whilst the viscosity increases markedly from 23.16 to 28.50 Pa s. These results expand understanding of asphaltene molecular dynamics during CO2 injection, providing essential information for optimizing enhanced oil recovery and preventing reservoir impairment. |
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| ISSN: | 2214-157X |