Abstract: The present invention provides an oil and gas well treatment comprising (a) preparing a composition by mixing an epoxy-based resin, an alkylphenol-blocked isocyanate, and a polyamine, (b) introducing the composition into a wellbore, (c) reacting the composition to produce a solid product, wherein the solid product reduces or prevents ingress of formation water into the oil and gas well.

Abstract: The present invention provides methods and materials for treating an oil and gas well by introducing a polyurethane composition into the well to plug perforations and other non-productive zones of an oil and gas well to greatly reduce or prevent the ingress of formation water during production. These methods include: (a) preparing a polyurethane composition by mixing a polyol-containing component and a polyisocyanate-containing component; and (b) introducing the polyurethane composition into the well. The polyol-containing component includes a polymeric polyol having a viscosity at 25° C. of no more than 1000 mPa·s and the isocyanate-containing component includes an unblocked (cyclo)aliphatic polyisocyanate polymer, optionally including allophanate groups, and having a viscosity at 25° C. of no more than 1000 mPa·s and at least 99% solids content.