**7.3 Mineral dissolution and precipitation**

Significant geochemical reactions are expected to occur during the shut-in period when fracturing fluid is in contact with formation. Wang et al. [111] studied rock-fluid interactions during the shut-in period to assess the water chemistry over the period using 15% HCL and water. They also assessed the possibility of scale formation in the reservoir based on these reactions. Their results showed ability of fracturing fluid to react with and dissolve formation minerals to increase permeability. However, these reactions also lead to release of ions into solution which may cause precipitation of scale-forming and permeability reduction minerals. Wang et al. [111] proposed their study as a way of understanding the long-term implications of rock-fluid interactions. Future research to expand the frontiers of this work should consider using different fracturing fluid compositions.

Furthermore, the impact of microstructural and geochemical interactions between fracturing fluids and fracture face in organic rich carbonates was studied by Liang et al. [112]. They concluded that 2% Potassium Chloride, though used to inhibit adverse reactions between fluids and clays minerals, may in fact increase the dissolution rates of carbonates thus increasing absolute permeability. This increase was observed to be more pronounced for slickwater relative to synthetic sea water. Their study is evidence that water-based fracturing fluids could be beneficial when used in some formation types such as organic-rich carbonates. Future research in this area should therefore be focused on understanding the mechanisms that cause faster dissolution in presence of Potassium Chloride.
