CO2 influence on asphaltene precipitation

The energy industry has registered a considerable growth of petroleum production from reservoirs located in deep and ultra-deepwater, mainly in Brazil. The Brazilian Pre-Salt fields, specifically, have shown high carbon dioxide content which favors the precipitation of organic particles such as asphaltenes. This scenario has turned flow assurance into a major technical and economic challenge for the exploitation of those fields. In this work a variable-volume cell equipped with a near-infrared probe was used to study the onset of asphaltene precipitation induced by carbon dioxide, evaluating the effects of pressure, temperature, asphaltene concentration, and system composition. Furthermore, the Cubic Plus Association (CPA) was applied to model the asphaltene precipitation. The results show that temperature and the oil model system composition were the parameters that most influenced the asphaltene stability, and that the CPA adequately described the asphaltene precipitation.