The Experimental Study of Temperature and Pressure Effects on Asphaltene Particles Size and Distribution Change, a Case Study on a Heavy Oil Sample

One of the challenges of the exploitation and production of oil from reservoirs is the deposition of asphaltene particles on the transfer surfaces; such as, porous media, wells and piplines. Knowing about the particle size of asphaltene, in the studies of solid mass transfer of fluid to the surface, is essential to estimate the location, amount and time of the scale. One of the questions wich has been studied less is «How do the sizes of asphaltene particles change at different thermodynamic conditions?» In this study, asphaltene instability in one of the iranian heavy oil was determined by SARA test, initially. Thermodynamic behavior of asphaltene was found through filtration tests in high pressure and temperature conditions. Then, using an optical microscope, the sizes and distributions of the asphaltene particles were measured at 12 temperature and pressure points. The experimental results showed that both particle sizes and distribution of particles are sensitive to temperature and pressure. The thermodynamic and microscopic results are matched appropriately. Finally, the obtained experimental results were modeled in the form of an empirical correlation. The results of this study could be as an integrated chain between thermodynamic behavior of the asphaltene and the transfer phenomena of the asphaltene deposition in the oil well column and reservoir porous media.