Study of Pressure and Temperature Effects on Asphaltene Stability in Presence of CO_2

摘要

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.