Aqueous gels and uses thereof
AssigneePhillips Petroleum Company
InventorsRichard L. Clampitt, James E. Hessert
Life of this patent
Estimating the term…
Abstract
Improvements in secondary recovery operations for the recovery of oil, and other oil field operations wherein subterranean formations are contacted with a fluid medium, are accomplished through the use of aqueous mediums comprising new aqueous gels prepared from water and biopolysaccharides.
Claims15
An aqueous gel, suitable for use in secondary recovery operations for the recovery of oil and in other oil field operations wherein subterranean formations are contacted with a fluid medium, said gel comprising water having incorporated therein:
- a water-thickening amount of a biopolysaccharide produced by the action of bacteria of the genus Xanthomonas on a carbohydrate;
- a water-soluble compound of chromium, wherein the valence of the chromium therein is +6 and is capable of being reduced to +3, in an amount which is sufficient to cause gelation of said water when the valence of at least a portion of said +6 chromium is reduced to +3;
- and
- a water-soluble reducing agent in an amount which is effective to reduce at least a portion of said +6 chromium to +3 chromium and cause said gelation with the formation of said gel, said reducing agent being selected from the group consisting of hydroquinone, sodium sulfide, hydrogen sulfide, sodium hydrosulfite, potassium hydrosulfite, potassium sulfite, sodium bisulfite, potassium bisulfite, sodium metabisulfite, potassium metabisulfite, sodium sulfite, sodium thiosulfate, potassium thiosulfate, thioacetamide, p-hydrazinobenzoic acid, hydrazine phosphite, hydrazine dihydrochloride, and mixtures thereof.
An aqueous gel according to claim 3 wherein said water contains:
- from 0.025 to 1 weight percent of said polysaccharide, based upon the weight of said water;
- from 0.5 to 30 weight percent of said +6 chromium compound, based upon the weight of said polysaccharide;
- and
- from 0.1 to at least about 150 weight percent of the stoichiometric amount of said reducing agent required to reduce said +6 chromium to said lower valence state.
A method for producing an aqueous gel, which method comprises:
- thickening water by adding thereto a thickening amount of a biopoly-saccharide produced by the action of bacteria of the genus Xanthomonas on a carbohydrate;
- and
- causing gelation of the so-thickened water by adding thereto an amount of a water-soluble compound of chromium wherein the valence of the chromium therein is +6 and is capable of being reduced to +3 and which amount is within the range of from 0.1 to 60 weight percent based on the weight of said polysaccharide and is sufficient to cause gelation of said water when the valence of at least a portion of said +6 chromium is reduced to +3, and an amount of a water-soluble reducing agent which is effective to reduce at least a portion of said +6 chromium to +3 chromium and cause said gelation with the formation of said gel, said reducing agent being selected from the group consisting of hydroquinone, sodium sulfide, hydrogen sulfide, sodium hydrosulfite, potassium hydrosulfite, potassium sulfite, sodium bisulfite, potassium bisulfite, sodium metabisulfite, potassium metabisulfite, sodium sulfite, sodium thiosulfate, potassium thiosulfate, thioacetamide, p-hydrazinobenzoic acid, hydrazine phosphite, hydrazine dihydrochloride, and mixtures thereof.
Dependencies are inferred from the claim text.