A high carrying capacity temperature-stable breakable gel of selectable viscosity with exceptional lubricity and high-temperature stability for varied use as a carrier of solids and particulate matter, as well as semi-solids and liquids in water and petroleum well drilling, completion and production such as gravel pack fluid, drilling fluid, fracturing fluid, pigging fluid, sweep for coiled tubing, and other uses. A preferred formulation comprises a formulated “Base Concentrate” which is added to water or drilling fluids to be viscosified and an “Activator” which is added in amounts to develop the desired gel consistency. When breaking of the gel is desired a “Breaker” composition containing multivalent ions collapses the gel into a free-flowing liquid.