Comprehensive analysis of fine particle migration and swelling: Impacts of salinity, pH, and temperature

Abstract

About 70% of the world's oil production comes from reservoirs with loose reservoir rock. The looseness of the reservoir rock causes fine particles to move during production. Additionally, there are different types of clays in the reservoir, which have the possibility of swelling in addition to migration. Migration and swelling of fine particles result in increased permeability reduction and formation damage. Identifying the migration and swelling mechanisms of fine particles can prevent the migration and swelling of fine particles in the porous media. As a result, it prevented production reduction and excess production costs and increased the EOR process's efficiency. Salinity, pH, and water temperature changes can significantly affect fine migration and swelling. This research investigates a laboratory's parameters affecting injection water, such as salinity, pH, and temperature. Due to the precision in analyzing the results and a better understanding of the mechanisms, synthetic cores containing fine particles and clays were used. The permeability, turbidity, electron microscope images, and pH data showed that the change in salinity, pH, and temperature disturbs the balance between the rock's surface and fine particles. With the decrease of salinity below the critical concentration of salt, permeability reduction and turbidity were observed. In this case, the dominant mechanism was the migration of fine and clay particles. When the pH of the injection fluid increased, the permeability reduction increased, the turbidity decreased, and the predominant mechanism was the swelling of fine particles. An increase in temperature also caused an increase in permeability reduction and turbidity. The mechanisms of migration and swelling were supposed to be simultaneous with the temperature rise.