Experimental Investigation of Residence Time Effect on Formation of Asphaltene Deposition

Formation of asphaltene deposition in reservoirs during primary production and enhanced oil recovery techniques; such as, gas injection, especially carbon dioxide, is a devastating problem which occurs in many oil fields in the world. The experimental studies to predict the formation of asphaltene precipitation to be necessary to avoid possible irreparable problems resulting from its formation in the reservoir and eventually it will provide access to the best recovery efficiency. As a result of the technical and economic importance and the necessity of studying and understanding the operating conditions of the formation of asphaltene deposition in reservoirs is inevitable. In this paper, the thermodynamic behavior of fluids in oil processing unit has been studied at Sahand University of Oil and Gas Research Institute, which has the capability of testing high temperatures and pressures. The amount of asphaltene precipitation has initially been saturated by the injection of carbon dioxide into the porous media (sand pack), and then the amount of asphaltene precipitation pressurized with oil sample, at constant pressure and temperature, but various residence times. And then to investigate the effect of temperature and pressure and Oil composition at residence time, respectively, the test is repeated at lower temperature and higher pressure and oil change from Asmari reservoir oil to Paydarshrq oil reservoir. At a constant temperature and pressure with an increase in the residence time, more of asphaltene deposition has been formed on filter paper. At higher pressures and lower temperatures, and changing the oil samples also increased the amount of asphaltene with increasing residence time.