Patent US4474903A successfully refreshed from Google Patents.
US4474903A
Expired / Lapsed
US
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Hydrazide containing polymers
Assignee: BP PLC
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Filing: 1982-05-27
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Granted: 1984-10-02
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Expires: 2002-05-27
Abstract
Abstract 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 2 , C 3 or C 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.
Inventors
- 👤 Frank C. Robertson
- 👤 Douglas Wilson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 13:11
CPC Classifications
C; C09; C09K; C09K8/00; C09K8/50; C09K8/504; C09K8/506; C09K8/508; C09K8/512; C08; C08K; C08K5/00; C08K5/04; C08K5/07
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
86 words
A method for reducing formation permeability comprising mixing; (a) a homopolymer or a copolymer of methyl acrylate or hydroxy alkyl acrylate, where the alkyl group is C 2 , C 3 or C 4 , into which polymer hydrazide groups have been introduced, and (b) an aldehyde cross-linking agent, dispersing or dissolving the mixture in an aqueous medium and injecting the aqueous dispersion or solution into a formation, the amounts of polymer and aldehyde being such that they will form a gel in the aqueous medium.
Claim 2
Independent Claim
86 words
A method for reducing formation permeability comprising mixing; (a) a homopolymer or a copolymer of methyl acrylate or hydroxy alkyl acrylate, where the alkyl group is C 2 , C 3 or C 4 , into which polymer hydrazide groups have been introduced, and (b) an aldehyde cross-linking agent, dispersing or dissolving the mixture in an aqueous medium and injecting the aqueous dispersion or solution into a formation, the amounts of polymer and aldehyde being such that they will form a gel in the aqueous medium.
Claim 3
Dependent Claim
18 words
A method as claimed in claim 1 wherein the polymer has a molecular weight of at least 10,000.
Claim 4
Dependent Claim
43 words
A method as claimed in claim 1 or claim 2 wherein the polymer is a copolymer containing one or more monomer units selected from polymerisable unsaturated carboxylic acids, polymerisable amides of unsaturated carboxylic acids, polymerisable esters of unsaturated carboxylic acids or vinyl pyrolidone.
Claim 5
Dependent Claim
27 words
A method as claimed in claim 3 wherein the ratio of methyl acrylate or hydroxy alkyl acrylate monomer to co-monomer in the copolymer is greater than 1:20.
Claim 6
Dependent Claim
16 words
A method as claimed in claim 1 wherein the aldehyde has at least three carbon atoms.
Claim 7
Dependent Claim
20 words
A method as claimed in claim 1 wherein the ratio of aldehyde groups to hydrazide groups is 20:1 to 1:20.
Claim 8
Dependent Claim
20 words
A method as claimed in claim 6 wherein the ratio of aldehyde groups to hydrazide groups is 10:1 to 1:10.
Claim 9
Dependent Claim
26 words
A method as claimed in claim 1 wherein the concentration of polymer in the aqueous medium is from 1000 to 100,000 parts per million by weight.
Claim 10
Dependent Claim
24 words
A method as claimed in claim 1 wherein the aldehyde cross-linking agent is formaldehyde and is produced by the reacting hexamine with an acid.
Claim 11
Dependent Claim
16 words
A method as claimed in claim 9 wherein the acid is hydrochloric acid or acetic acid.
Claim 12
Dependent Claim
89 words
A composition suitable for use in the method of claim 1 comprising (a) a homopolymer or copolymer of methyl acrylate or hydroxy alkyl acrylate, where the alkyl group is C 2 , C 3 or C 4 , into which polymer hydrazide groups have been introduced, and (b) an aldehyde or cross-linking agent containing at least three carbon atoms, the composition being dispersed or dissolved in an aqueous medium and the amounts of the polymer and aldehyde being such that they will form a gel in the aqueous medium.
Claim 13
Dependent Claim
78 words
A composition suitable for use in the method of claim 1 comprising (a) a homopolymer or copolymer of hydroxy alkyl acrylate, where the alkyl group is C 2 , C 3 or C 4 , into which polymer hydrazide groups have been introduced, and (b) formaldehyde or glyoxal the compositions being dispersed or dissolved in an aqueous medium and the amounts of the polymer and aldehyde being such that they will form a gel in the aqueous medium.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1987-10-02 | 1988-04-02 | 1988-10-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-10-02 | 1992-04-02 | 1992-10-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-10-02 | 1996-04-02 | 1996-10-02 | $7700.00 | Window Closed / Lapsed |