Investigation of formation damage by Deep Eutectic Solvents as new EOR agents

Permeability measurements by core flooding tests showed that the water shock phenomenon caused severe damage (65% reduction in absolute permeability) when distilled water was injected after brine flooding. Both DESs showed positive effect on reducing the water shock damages at different temperatures, where DES2 was much more effective when compared with DES1. Core weight measurements confirmed that whenever permeability damages were higher, the amount of core weight increase was also high. Moreover, results of SEM and quantitative XRD showed that precipitation and deposition inside pores are the main sources of formation damage. In addition, CT-scanning images provided good comparisons between fresh and damaged cores. We observed that using DESs showed that despite the DES׳s solutions role in preventing severe water shock damage and stabilizing the clays, there was still some formation damage caused by re-crystallization and precipitation processes reducing the permeability of the core samples.