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.

A self curing aqueous solution/dispersion comprising about 50-70 wt. % water, about 25-35 wt. % of a novel N-polymethylene substituted polyoxypropylene polyamine and about 3-9 wt. % of a curable polymer-forming component such as an epoxy-resin is described. The solution is useful for injection into permeable earth formations such as unconsolidated sands to reduce their permeability and consolidate the formation. Novel N-substituted polyamines of the formula [NaO.sub.3 S--R.sub.1 ].sub.m A wherein R.sub.1 is a C.sub.2 to C.sub.6 polymethylene group and A is a polyoxyalkylene polyamine are employed in the solution to render the epoxy-resin component adequately soluble or dispersible in the aqueous solution and to act as the curing agent for the resin.

An aqueous based slurry is disclosed containing an aqueous carrier fluid, a chelating agent, an epoxy resin, a curing agent for the resin, a solvent for said resin and curing agent, a finely divided particulate material, a quaternary ammonium halide, and a coupling agent to promote bonding of the resin to the particulate. Optionally, the slurry may contain a thickening or gelling agent for the water to enhance its solids carrying capacity and an agent to break the gel after its purpose has been served. The slurry, suitable for use in placing a permeable, consolidated gravel pack adjacent an incompetent subterranean formation, is characterized in that it does not require an oil-based carrier and also in that it can easily be prepared in the field by adding the particulate directly to the aqueous carrier without precoating the particulate with the resin.

Sand control in an incompetent formation is effected by squeezing a thickened composition [comprising a hydrocarbon oil carrier, particulate matter (e.g. sand) a base-settable thermosetting resin, a neutralizing agent (e.g., lauryl amine), a miscible polar solvent (e.g. ethanol), and a carboxy vinyl polymer (e.g. CARBOPOL 934)] in contact with the incompetent formation and curing with a basic catalyst.

The invention relates to a process for stabilizing an aqueous gel-forming system comprising one or more water-soluble acrylic monomer as gellifying agent, methylenebis-acrylamide co-monomer and/or one or more mono- or bivalent aldehyde as cross-linking agent, a redox catalyst system containing an alkali metal and/or ammonium persulfate as oxidizing component along with one or more amine compound as reducing component, furthermore optionally one or more water-soluble polymer for adjusting the viscosity of the solution and/or modifying the gel structure. According to the invention said gel-forming system is stabilized by saturating it with molecular oxygen. The invention relates further to a process for improving the strength and impermeability of particulate materials and/or solid articles. According to the invention an aqueous gel-forming system, stabilized as discussed above, is applied into or onto the article to be treated or into the surroundings thereof, and oxygen saturation of the gel-forming system is suspended at an appropriate time.