Abstract: Method for selectively treating wells using a low viscosity epoxy resin-forming composition containing a single curing agent. The composition comprises a liquid bisphenol A-based epoxy material and a polyamide hardener for ambient temperature curing of the liquid epoxy material. The epoxy material has a very low viscosity at well surface temperatures and is immiscible with well fluids. The polyamide curing agent used is an amber-colored mobile liquid having a low viscosity at ambient temperature and is further characterized as having long pot life and low exotherm. The method is applicable to plugging permeable zones in a gravel-packed well and may be used to repair leaks in well casing or production tubing and in cementing to prevent communication between subterranean regions.