NaCl solid particles that have a specified minimum and maximum range of particle sizes and may also have a specified distribution of sizes. Sized salt is used as a bridging agent in saturated saltwater systems used as drill-in, workover and completion fluids. Sized salt can positively seal permeable zones by plugging pores at the wellbore face. It is a preferred bridging agent because it can be dissolved by low-salinity water treatment to clean up the zone afterwards.