Post-fracturing flowback fluids constitute a diagnostic tracer for investigating geochemical processes during hydraulic fracturing. However, analyses of flowback fluids from field trials are limited in their ability to characterize post-fracturing mineralogical changes and microstructures of tight sandstones, as many geochemical processes are masked by the mixing of fracturing fluids with formation water. Laboratory water–rock experiments thus compensate for these shortcomings and serve as a valuable supplement to field-scale investigations.