Experimental study for the impacts of flow rate and concentration of asphaltene precipitant on dynamic asphaltene deposition in microcapillary medium

Abstract

Asphaltenes have been referred to ‘cholesterol of petroleum’ and the heaviest and the most complex components in crude oil. Asphaltene aggregation and deposition have always been a challenging issue on fluid transport in porous media for oil recovery and production processes in industries. Many experimental efforts have been done to study asphaltene aggregation and deposition from crude oil. Most of these works were carried out by coreflood tests or in bulk solution. Only several macroscopic parameters, such as pressure variation and permeability reduction caused by asphlatene deposition, were studied. Few experimental studies have been done to make the direct pore-scale visualization of dynamic asphaltene deposition behavior in capillary flow. In this study, we developed a new experimental approach to directly visualize and measure the dynamic asphaltene deposition process in capillary flow. Effects of concentration of asphaltene precipitant and flowrate were examined. The results indicate that the concentration of precipitant has a significant effect on the dynamic asphaltene deposition in capillary flow. The size of asphaltene deposit increases significantly with elapsed time and size distribution becomes wider at higher precipitant concentration. Higher concentration of asphaltene precipitant could lead to higher deposition rate. The results also indicate that higher flowrate causes faster growth of asphaltene deposits in capillary flow. Larger sizes of asphaltene deposits are formed and number of asphaltene deposits decreases with the elapsed time at higher flowrate. The results produced provide new sights into the dynamic asphaltene deposition in capillary flow at a pore scale. They could contribute to predict the growth rate of arterial asphaltene deposition in porous media and develop accurate numerical simulator for enhanced oil recovery purpose in industries.