The British Petroleum Company, P.l.c.

Douglas Wilson

Frank C Robertson

Sidney G Fogg

A hardenable epoxy resin comprising a curable epoxy resin, a hardener for the epoxy resin and a polymer of epihalohydrin which composition is characterized in that the amount of the polymer of epihalohydrin in the composition is from 1 to 6 parts per one hundred parts by weight of the epoxy resin and in that the composition also comprises from 2 to 25 parts by weight per hundred parts by weight of the epoxy resin, of a polycarbonate having the general formula: ##STR1## where R.sub.1 and R.sub.2 are the same or different and are phenyl or cyclohexyl groups, R.sub.3 and R.sub.4 are the same or different and are hydrogen, methyl or cyclohexyl groups and n is from 60 to 400 and represents the average number of monomer units in the polymer chain.

Epoxy resin compositions

A method for reducing formation permeability comprising mixing (a) a homopolymer or copolymer of methyl acrylate or hydroxy alkyl acrylate, where the alkyl group is C.sub.2, C.sub.3 or C.sub.4, into which polymer hydrazide groups have been introduced, and (b) an aldehyde cross-linking agent, dispersing the mixture in an aqueous medium and injecting the aqueous dispersion into a formation, the amounts of the polymer and aldehyde being such that they will form a gel in the aqueous medium. The invention includes compositions for use in the method.

Hydrazide containing polymers

A method of treating salt water-in-oil dispersions comprises mixing with the dispersion a latex of a rubber having a high wet gel strength. The incorporation of the latex into the dispersion causes exudation of water from the dispersion with resulting thickening. If sufficient latex is used the dispersion may be transformed into a solid. Suitable rubbers include natural rubber, polychloroprene rubber, butadiene acrylonitrile rubber, styrene butadiene rubber and poly (methyl methacrylate) graft natural rubber. The tackiness of solids formed using for example a natural rubber latex can be reduced by using in addition to the natural rubber latex, a latex of a low or zero wet gel strength polymer e.g. PVC, poly (vinyl acetate) or polystyrene. The effectiveness of the method of treatment may be improved by the use of a suitable compatible solvent e.g. toluene or a filler such as a clay filler.

Method of treating water-in-oil dispersions

Delayed action setting of a composition comprising an amonic latex of a film forming polymer is effected by the addition of a delayed action setting agent which is a mixture of:

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Godalming, United Kingdom

Douglas Wilson