US4980393A
Expired / Lapsed
US
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Polymers for oil reservoir permeability control
Assignee: Mobil Oil AS
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Filing: 1989-03-10
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Granted: 1990-12-25
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Expires: 2009-03-10
Abstract
Abstract Improved polymer gels for oil reservoir permeability control have a continuous, cross-linked polymer phase having a relatively low density of cross-linking with domains of clustered, high density cross-linking. The clustered high density cross-linkings contribute to the gel's shear stability and gel strength while the continuous, low density phase contributes to good injectivity. Gels of this kind are produced by cross-linking a base polymer with a relatively low density of cross-linking sites with a reinforcing polymer having a higher cross-linking site density. Suitable polymers have ligand groups which are capable of forming coordination cross-linkages with polyvalent metals, especially chromium and include polyacrylamides as base polymers and polyacrylic acids as reinforcing polymers.
Inventors
- 👤 Paul Shu
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 22:50
CPC Classifications
C; C09; C09K; C09K8/00; C09K8/50; C09K8/504; C09K8/506; C09K8/508; C09K8/512
Claims Analysis
Total Claims: 47
Claim 1
Independent Claim
116 words
A heterogeneous gel-forming polymer of improved rheological properties exhibiting good gel strength, shear stability and good injectivity, which comprises a continuous, cross-linked polymer phase of a base polymer having a density of cross-linked sites of 1 to 10 percent of the functional groups and a suspended phase of domains of a reinforcing polymer, present in the amount of 0.1 to 20 weight percent of the base polymer, having a density of cross-linking sites of at least 20 percent of the functional groups, the molecular weight (number) ratio of the base to the reinforcing polymer being 10,000:1 to 5.1, the base polymer and the reinforcing polymer being cross-linked with each other by a polyvalent metal cross-linking agent.
Claim 2
Dependent Claim
116 words
A heterogeneous gel-forming polymer of improved rheological properties exhibiting good gel strength, shear stability and good injectivity, which comprises a continuous, cross-linked polymer phase of a base polymer having a density of cross-linked sites of 1 to 10 percent of the functional groups and a suspended phase of domains of a reinforcing polymer, present in the amount of 0.1 to 20 weight percent of the base polymer, having a density of cross-linking sites of at least 20 percent of the functional groups, the molecular weight (number) ratio of the base to the reinforcing polymer being 10,000:1 to 5.1, the base polymer and the reinforcing polymer being cross-linked with each other by a polyvalent metal cross-linking agent.
Claim 3
Dependent Claim
23 words
A polymer according to claim 1 in which the base polymer comprises a polyacrylamide having a relatively low proportion of carboxylate functional groups.
Claim 4
Dependent Claim
25 words
A polymer according to claim 1 in which the reinforcing polymer comprises polyacrylic acid, a partly hydrolyzed polyacrylamide or a partly hydrolyzed polyacrylic acid ester.
Claim 5
Dependent Claim
118 words
A heterogeneous aqueous polymer gel having improved gel structure and rheological properties exhibiting good gel strength, shear stability and good injectivity, comprising a cross-linked base polymer having regions of density of cross-linking sites of 1 to 10 percent of the functional groups and a reinforcing polymer having regions of density of cross-linking sites of at least 20 percent of the functional groups, said reinforcing polymer being present in the gel in the amount of 0.1 to 20 weight percent of said base polymer, the molecular weight (number) ratio of said base polymer to said reinforcing polymer being 10,000:1 to 5:1, said base polymer and said reinforcing polymer being cross-linked with each other by a polyvalent metal cross-linking agent.
Claim 6
Dependent Claim
118 words
A heterogeneous aqueous polymer gel having improved gel structure and rheological properties exhibiting good gel strength, shear stability and good injectivity, comprising a cross-linked base polymer having regions of density of cross-linking sites of 1 to 10 percent of the functional groups and a reinforcing polymer having regions of density of cross-linking sites of at least 20 percent of the functional groups, said reinforcing polymer being present in the gel in the amount of 0.1 to 20 weight percent of said base polymer, the molecular weight (number) ratio of said base polymer to said reinforcing polymer being 10,000:1 to 5:1, said base polymer and said reinforcing polymer being cross-linked with each other by a polyvalent metal cross-linking agent.
Claim 7
Dependent Claim
23 words
A gel according to claim 4 in which the base polymer comprises a polyacrylamide having a relatively low proportion of carboxylate functional groups.
Claim 8
Dependent Claim
25 words
A gel according to claim 4 in which the reinforcing polymer comprises polyacrylic acid, a partly hydrolyzed polyacrylamide or a partly hydrolyzed polyacrylic acid ester.
Claim 9
Dependent Claim
23 words
A gel according to claim 4 in which the cross-linkages are coordinate cross-linkages extending between ligand polymers and polyvalent metals as cross-linking agents.
Claim 10
Dependent Claim
14 words
A gel according to claim 7 in which the polyvalent metal is chromium (III).
Claim 11
Dependent Claim
14 words
A gel according to claim 7 in which the polyvalent metal is zirconium (IV).
Claim 12
Dependent Claim
17 words
A gel according to claim 4 which has a total polymer content of 500 to 10,000 ppm.
Claim 13
Dependent Claim
38 words
A polymer gel according to claim 4 which has a cross-linked polymeric structure having isolated regions of relatively high density cross-linking of the reinforcing polymer in a continuous phase of relatively low density cross-linking of the base polymer.
Claim 14
Dependent Claim
17 words
A gel according to claim 11 which contains 500 to 10,000 ppm by weight of the polymer.
Claim 15
Dependent Claim
17 words
A gel according to claim 12 which contains 1,000 to 5,000 ppm by weight of the polymer.
Claim 16
Dependent Claim
39 words
A gel according to claim 4 in which the concentration of the base polymer is from 500 to 10,000 ppm and the amount of the reinforcing polymer is from 0.1 to 10 percent by weight of the base polymer.
Claim 17
Dependent Claim
26 words
A gel according to claim 14 in which the amount of the reinforcing polymer is from 1 to 5 percent by weight of the base polymer.
Claim 18
Dependent Claim
25 words
A gel according to claim 15 in which the reinforcing polymer has a cross-linking site density of 30 to 50 percent of the functional groups.
Claim 19
Dependent Claim
21 words
A gel according to claim 16 in which the base polymer has a molecular weight of at least 1×10 6 .
Claim 20
Dependent Claim
22 words
A gel according to claim 17 in which the base polymer has a molecular weight of 5×10 6 to 20×10 6 .
Claim 21
Dependent Claim
22 words
A gel according to claim 18 in which the reinforcing polymer has a molecular weight of 1×10 3 to 10×10 6 .
Claim 22
Dependent Claim
27 words
A gel according to claim 19 in which the reinforcing polymer has a molecular weight of at least 2×10 3 and not greater than 0.1×10 6 .
Claim 23
Dependent Claim
26 words
A gel according to claim 20 in which the molecular weight (number) ratio of the base polymer to the reinforcing polymer is 5,000:1 to 10:1 .
Claim 24
Independent Claim
106 words
A method of forming a polymer gel of improved structure and rheological properties, exhibiting good gel strength, shear stability and good injectivity, which comprises cross-linking a base polymer having a density of cross-linking sites of 1 to 10% of the functional groups with a reinforcing polymer, present in the amount of 0.1 to 20% wt. of the base polymer having a density of cross-linking sites of at least 20% of the functional groups, the molecular weight (number) of the base polymer to the reinforcing polymer being 10,000:1 to 5:1, the base polymer and the reinforcing polymer being cross-linked with each other by a polyvalent cross-linking agent.
Claim 25
Independent Claim
106 words
A method of forming a polymer gel of improved structure and rheological properties, exhibiting good gel strength, shear stability and good injectivity, which comprises cross-linking a base polymer having a density of cross-linking sites of 1 to 10% of the functional groups with a reinforcing polymer, present in the amount of 0.1 to 20% wt. of the base polymer having a density of cross-linking sites of at least 20% of the functional groups, the molecular weight (number) of the base polymer to the reinforcing polymer being 10,000:1 to 5:1, the base polymer and the reinforcing polymer being cross-linked with each other by a polyvalent cross-linking agent.
Claim 26
Dependent Claim
18 words
A method according to claim 22 in which the base and reinforcing polymers are polymers having ligand groups.
Claim 27
Dependent Claim
38 words
A method according to claim 23 in which the cross-linkages are formed by the use of a polyvalent metal cross-linking agent which forms coordinate bonds with the ligand groups on the polymers to form the cross-linkages between them.
Claim 28
Dependent Claim
29 words
A method according to claim 24 in which the polyvalent metal cross-linking agent comprises a compound of aluminum, zirconium or a metal of the first series of transition metals.
Claim 29
Independent Claim
18 words
A method according to claim, 25 in which the polyvalent metal cross-linking agent comprises a chromium (III) compound.
Claim 30
Dependent Claim
14 words
A method according to claim 24 in which the base polymer comprises a polyacrylamide.
Claim 31
Dependent Claim
28 words
A method according to claim 27 in which the base polymer comprises a partly hydrolyzed polyacrylamide having a relatively low proportion of hydrolyzed amide groups as cross-linking sites.
Claim 32
Dependent Claim
25 words
A method according to claim 24 in which the reinforcing polymer comprises a polymer having a relatively high proportion of carboxylate groups as cross-linking sites.
Claim 33
Dependent Claim
25 words
A method according to claim 24 in which the reinforcing polymer comprises polyacrylic acid, a partly hydrolyzed polyacrylamide or a partly hydrolyzed polyacrylic acid ester.
Claim 34
Dependent Claim
22 words
A method according to claim 22 in which the base polymer is first cross-linked to itself and then to the reinforcing polymer.
Claim 35
Dependent Claim
19 words
A method according to claim 22 in which the base and reinforcing polymers are simultaneously cross-linked to each other.
Claim 36
Dependent Claim
87 words
A method according to claim 22 which comprises: (i) forming an aqueous solution of a partly hydrolyzed polyacrylamide base polymer having a relatively low density of hydrolyzed amide groups as cross-linking sites, (ii) incorporating a reinforcing polymer comprising a polymer having a relatively high density of carboxylate groups as cross-linking sites into the solution, (iii) forming cross linkages between the polymers with a compound of a polyvalent metal as a cross-linking agent to form regions of relatively low density cross-linking and regions of clustered, high density cross-linking.
Claim 37
Dependent Claim
14 words
A method according to claim 33 in which the polyvalent metal is chromium (III).
Claim 38
Dependent Claim
42 words
A method according to claim 33 in which the concentration of the base polymer in the solution is from 500 to 10,000 ppm and the amount of the reinforcing polymer is from 0.1 to 10 percent by weight of the base polymer.
Claim 39
Dependent Claim
26 words
A method according to claim 35 in which the amount of the reinforcing polymer is from 1 to 5 percent by weight of the base polymer.
Claim 40
Dependent Claim
25 words
A method according to claim 36 in which the base polymer has a cross-linking site density of 1 to 10 percent of the functional groups.
Claim 41
Dependent Claim
25 words
A method according to claim 37 in which the reinforcing polymer has a crosslinking site density of 30 to 50 percent of the functional groups.
Claim 42
Dependent Claim
25 words
A method according to claim 34 in which the base polymer has a cross-linking site density of 1 to 5 percent of the functional groups.
Claim 43
Dependent Claim
20 words
A method of claim 39 in whIch the base polymer has a molecular weight of at least 1×10 6 .
Claim 44
Dependent Claim
21 words
A method of claim 40 in which the base polymer has a molecular weight of 5×10 6 to 20×10 6 .
Claim 45
Dependent Claim
22 words
A method oF claim 41 in which the reinforcing polymer has a molecular weight of 1×10 3 to 10 ×10 6 .
Claim 46
Dependent Claim
26 words
A method of claim 42 in which the reinforcing polymer has a molecular weight of at least 2×10 3 and not greater than 0.1×10 6 .
Claim 47
Dependent Claim
24 words
A method of claim 43 in which the molecular weight (number) ratio of the base polymer to the reinforcing polymer is 10,000:1 to 5:1.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1993-12-24 | 1994-06-25 | 1994-12-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-12-24 | 1998-06-25 | 1998-12-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-12-24 | 2002-06-25 | 2002-12-25 | $7700.00 | Window Closed / Lapsed |