Stability of asphaltenes is affected mainly by the change in pressure and temperature within the reservoir or in production lines. While there are numerous studies investigating the role of pressure and temperature on asphaltenes stability, the role of reservoir components on asphaltenes stability still remains unknown.<br/>This study investigates the effect of reservoir rock-asphaltenes interaction on asphaltenes stability. 11 different crude oil samples from all around the world and their asphaltenes were analyzed. Both n-pentane asphaltenes surfaces were visualized under scanning electron microscopy (SEM). Inorganic (mainly salts and clays) presence was observed on asphaltenes surfaces which might be the consequence of the reservoir rock-oil interaction. The inorganic content of separated asphaltenes were investigated by mixing asphaltenes and deionized water vigorously by a centrifuge to separate the inorganic content of asphaltenes from asphlatenes’ surfaces. The supernatant of these mixtures was subjected to total dissolved solids (TDS), pH, conductivity, and ion chromatography analyses.<br/>The TDS level was observed high which proves the physical interaction of asphaltenes with reservoir rock and this interaction is also found to generate high conductivity mainly due to sodium salts and colloids which were determined through ion chromatography. The electrostatic charges created in water due to inorganic content of asphaltenes were determined by zeta potential. Precipitation tendency of the colloids found very high for most of the asphaltenes samples and they are mainly because of the presence of the excessive amount of negatively charged particles. This study proves the presence of electrical charges on asphlatenes surface and highlights its importance on asphaltenes stability.

Reservoir rock-asphaltenes interaction impacts asphaltenes stability

253rd National Meeting (2017)

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