Study of Pressure and Temperature Effects on Asphaltene Stability in Presence of CO2

In the prolific literature about asphaltenes, the effects of temperature and pressure on their stability are subjects of discussion. A new high-pressure cell, requiring a very small amount of sample and with wide working conditions, has been built in order to study the asphaltene phase behavior after injection of various gases and precipitants. A filtration technique is used to conclude on the effects of temperature, pressure, and composition. The precipitant used in this work is CO 2 . Two crude oils (from South America and the Middle East) were studied up to 383 K and 60 MPa. It was found for both oils that asphaltenes were more soluble when temperature was decreased and pressure was increased in the presence of a gas component. These effects were discussed with simple principles of thermodynamics.