Abstract: A water shut-off is provided in a hydrocarbon well by injecting a first chemical composition, effective as a relative permeability modifier polymer, into the hydrocarbon and a water zone of the well followed immediately by the injection of a second chemical composition, which forms a flow blocking polymer composition, into the zones and, after a shut-in period for reaction of the relative permeability modifier polymer, back producing the polymer compositions from they hydrocarbon zones to provide a path for the hydrocarbons from the zones while allowing the flow blocking polymer compositions to form the water shut-off in the water zones.

Abstract: A pipe repair clamp comprises a two-piece type split-collar, the collar being formed by joining the two pieces together about the surface of the pipe to be repaired. The pieces are shaped to form scarf-type joints and are provided with, affixed to their internal surfaces, portions of a gasket for sealing the surface of the pipe to be repaired from the external surface of the collar.