A subterranean formation having at least one borehole is treated with an aqueous gel wherein crude oil and water were produced from the subterranean formation through the borehole until the production of crude oil was reduced due to the presence of sandy material restricting the borehole, and the production of crude oil is increased as a result of said treatment as, for example, by producing crude oil and water from the formation at a lower water-oil ratio as compared to the water-oil ratio prior to treatment with the aqueous gel.
A gellable aqueous compositions able to reduce the permeability of high-permeability zones in an oil reservoir is a aqueous solution containing metered quantities of: a) a water-soluble organic polymer cross-linkable by the effect of a polyvalent metal ion cross-linking agent; b) a Cr(III) ion cross-linking agent; and c) a ligand for the cross-linking agent chosen from water-soluble organic alpha-hydroxy acids and alpha-amino acids.
An abandoned well penetrating a subterranean formation is plugged using a gel comprising a high molecular weight, water-soluble carboxylate-containing polymer and a chromic carboxylate complex crosslinking agent. The gel components are combined at the surface and injected into the wellbore to form a continuous single-phase gel therein.
A process of profile modifying permeable soils with an environmentally safe composition of a non-toxic water-soluble polymer, a redox couple of a water-soluble ferrous salt and a non-toxic, oxidizing agent which are mixed in water and pumped into a subterranean formation wherein ferrous ion is oxidized to ferric ion to gel the polymer making the subterranean formation impermeable.
Water-soluble polysaccharides, including cellulose ethers, containing pendent vicinal dihydroxy structure capable of cis geometry, which upon crosslinking with a polyvalent metal, have shear-thermal stability characteristics of at least about 30 at 250.degree. F., are useful in oilfield applications.
Methods and compositions for altering the water permeability of subterranean formations are provided. The compositions are comprised of water, at least one polymer capable of being gelled when contacted with a crosslinking agent, at least one crosslinking agent comprised of polyvalent metal cation, and a cation reactivity retarding chelating agent which provides anion for chelating the polyvalent metal cation selected from substantially water soluble dicarboxylic acids, hydroxy carboxylic acids, ketocarboxylic acids and the corresponding salts thereof.
