A controlled-gelation aqueous solution is proposed. The solution contains
a hydrophobically-aggregating gelling agent, and an effective amount of
an inhibitor which suppresses hydrophobic aggregation of the gelling
agent. The inhibitor is soluble in water so that when the
controlled-gelation aqueous solution contacts aqueous media the inhibitor
disperses and gelation occurs. However, the inhibitor is substantially
insoluble in hydrocarbons so that when the controlled-gelation aqueous
solution contacts hydrocarbon media the inhibitor continues to suppress
said hydrophobic aggregation and gelation is suppressed. The solution may
be used to control the flow of water into oil wells, making it possible
to reduce the water cut.