Resumen del autor, extraido del trabajo. Excessive water production results in reduced well productivity, increased costs associated with produced water treatment and handling, and premature well abandonment. This paper discusses well treatments with relative permeability modifying (RPM) polymers-- polymers that are capable of selectively reducing the permeability to water of the rocks onto which they adsorb. The principal results of experimental and simulation studies, conducted with the goal of linking the basic physical mechanisms of the process to the development of operational rules for treatment design, are reported. The application of these understanding-based rules for candidate and chemical selection has led to a successful RPM application in an Italian gas field.