Effect of Resins on Asphaltene Deposition and the Changes of Surface Properties at Different Pressures: A Microstructure Study

Abstract

Asphaltene deposition has hindered oil production from asphaltenic oil reservoirs through deposition in reservoir rock and surface facilities. This paper investigates the effect of resin on asphaltene deposition at different pressures. To investigate the asphaltene deposition in the presence of resins at reservoir temperature and different pressures, a pressure, volume, and temperature (PVT) visual cell was designed. A high-resolution microscope and image processing software were used to detect and determine the amount of deposited asphaltene as well as its size distribution at different conditions. Two types of Iranian crude oils with different potential of deposition (low and high) were used in this work. In the first stage, the amount of asphaltene deposition and the changes of surface properties were recognized through the depressurizing process with and without the presence of resins in the fluid. The wettability changes as a sign of surface properties were studied by contact angle measurement, and also for further investigation, the atomic force microscopy (AFM) technique was used. The results verify that the amount of asphaltene deposition increases when the pressure increases and the quantity of asphaltene deposition decreases as the resin/asphaltene ratio in these samples increases. At high ratios of resin/asphaltene, the asphaltene was found to be more stable. However, the results showed that, as the pressure increases, the stability of asphaltene decreases more than expected. The surface property changes indicate that, in the presence of resins, the surfaces become more water-wet and their roughness decreases