Hybrid Method Carbon Dioxide Flooding with Solvent and Temperature for Asphaltene Precipitation

Asphaltene precipitation and deposition are well-known problems in the transportation and processing of oil recovery. The cause of asphaltene is triggered by various factors such as changes in pressure, temperature (T), and gas (carbon dioxide) flooding (CO<sub>2</sub>). The study aimed to investigate the best economical method that can best enhance oil recovery (EOR). Two hybrid methods carbon dioxide flooding/ solvent (C<sub>5</sub>) and carbon dioxide flooding/ solvent (C<sub>5</sub>) /temperature were considered for the study. Firstly, the study was explored by singly utilizing pentane, hexane and heptane alkane solvents at different volumes to each of the three dead crude oils A, B and C. The study proves that the lower molecular weight and boiling point (C<sub>5</sub>) managed to deasphaltene 24.0 g/mL from solvent/oil ratio 20:1/2; 100 mL into 2.5 g. This was due to the higher repulsive force between the solvent and the asphaltene. The study was further extended using the hybrid method and proven carbon dioxide/solvent (C<sub>5</sub>)/temperature (90°) in precipitating higher asphaltene. The selection of pentane was based on its ability to meet the saturation point of the oil reservoir and EOR. The weaker London dispersion and the intermolecular forces between asphaltene and crude oil were the mechanisms responsible for the asphaltene precipitation.