Non-aqueous carrier fluids containing nano-sized particles in high concentration are effective for zone isolation and flow control in water shutoff applications for subterranean formations. The nanoparticles interact with water and solidify it to inhibit its flow, but do not have the same effect on hydrocarbons and thus selectively assist the production of hydrocarbons while suppressing water. Suitable nanoparticles include alkaline earth metal oxides, alkaline earth metal hydroxides, alkali metal oxides, alkali metal hydroxides, transition metal oxides, transition metal hydroxides, post-transition metal oxides, post-transition metal hydroxides, piezoelectric crystals, and / or pyroelectric crystals.