Patent US5225090A successfully refreshed from Google Patents.
US5225090A
Expired / Lapsed
US
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Visible gels prepared using stainless steel as a crosslinking agent
Assignee: Union Oil Company of California
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Filing: 1992-04-14
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Granted: 1993-07-06
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Expires: 2012-04-14
Abstract
Abstract Visible gels are formed by mixing an inorganic crosslinking agent with a low viscosity aqueous solution having a low polyacrylamide content. The visible gels are employed to reduce the water/hydrocarbon permeability ratio of subterranean formations.
Inventors
- 👤 Richard D. Hutchins
- 👤 Hoai T. Dovan
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 17:08
CPC Classifications
C; C09; C09K; C09K8/00; C09K8/60; C09K8/84; C09K8/86; C09K8/88; C09K8/887; C09K8/50; C09K8/504; C09K8/506; C09K8/508; C09K8/512; E; E21; E21B; E21B43/00; E21B43/25; E21B43/26; E21B43/261; Y; Y10; Y10S; Y10S507/00; Y10S507/903
Claims Analysis
Total Claims: 22
Claim 1
Independent Claim
94 words
A visible gel prepared by the step of contacting an inorganic crosslinking agent with an aqueous solution comprising at least some cationic polyacrylamide, the concentration of the cationic polyacrylamide in the solution being less than about 4,000 ppm by weight, wherein a 2 weight percent KCl solution having the same cationic polyacrylamide concentration has a viscosity of less than about 30 cp when measured at about 70° F. and at a rotational speed of about 6 rpm with a Brookfield LVT viscometer fitted with a UL adapter, wherein the crosslinking agent comprises stainless steel.
Claim 2
Dependent Claim
94 words
A visible gel prepared by the step of contacting an inorganic crosslinking agent with an aqueous solution comprising at least some cationic polyacrylamide, the concentration of the cationic polyacrylamide in the solution being less than about 4,000 ppm by weight, wherein a 2 weight percent KCl solution having the same cationic polyacrylamide concentration has a viscosity of less than about 30 cp when measured at about 70° F. and at a rotational speed of about 6 rpm with a Brookfield LVT viscometer fitted with a UL adapter, wherein the crosslinking agent comprises stainless steel.
Claim 3
Dependent Claim
46 words
The gel of claim 1 wherein the contacting step includes the step of mixing a supplemental inorganic crosslinking agent with the aqueous cationic polyacrylamide-containing solution, the supplemental inorganic crosslinking agent being selected from the group consisting of cobalt-, chromium-, aluminum-, and molybdenum-containing compounds and mixtures thereof.
Claim 4
Dependent Claim
60 words
The gel of claim 1 wherein the contacting step includes the step of mixing a supplemental inorganic crosslinking agent with the aqueous cationic polyacrylamide-containing solution, the supplemental inorganic crosslinking agent being selected from the group consisting of cobalt salts, chromium salts, aluminum salts, aluminates, molybdates, gallates, dichromates, titanium chelates, aluminum citrate, chromium citrate, chromium acetate, chromium propionate, and mixtures thereof.
Claim 5
Dependent Claim
28 words
The gel of claim 1 wherein the contacting step includes the step of mixing a compound capable of yielding a polyvalent metal with the aqueous cationic polyacrylamide-containing solution.
Claim 6
Dependent Claim
24 words
The gel of claim 1 wherein the contacting step includes the step of mixing a chelated polyvalent metal with the aqueous cationic polyacrylamide-containing solution.
Claim 7
Dependent Claim
23 words
The gel of claim 1 wherein the aqueous solution has a cationic polyacrylamide concentration of about 1,000 to about 4,000 ppm by weight.
Claim 8
Dependent Claim
53 words
The gel of claim 1 wherein the 2 weight percent KCl solution having the same cationic polyacrylamide concentration has a viscosity of about 1 to about 25 cp when measured at about 70° F. and at a rotational speed of about 6 rpm with the Brookfield LVT viscometer fitted with the UL adapter.
Claim 9
Dependent Claim
53 words
The gel of claim 1 wherein the 2 weight percent KCl solution having the same cationic polyacrylamide concentration has a viscosity of about 1 to about 20 cp when measured at about 70° F. and at a rotational speed of about 6 rpm with the Brookfield LVT viscometer fitted with the UL adapter.
Claim 10
Dependent Claim
53 words
The gel of claim 1 wherein the 2 weight percent KCl solution having the same cationic polyacrylamide concentration has a viscosity of about 3 to about 15 cp when measured at about 70° F. and at a rotational speed of about 6 rpm with the brookfield LVT viscometer fitted with the UL adapter.
Claim 11
Dependent Claim
20 words
The gel of claim 1 wherein the cationic polyacrylamide has a viscosity average molecular weight of less than about 10,000,000.
Claim 12
Dependent Claim
23 words
The gel of claim 1 wherein the contacting step includes the step of mixing a polyvalent metal with the aqueous cationic polyacrylamide-containing solution.
Claim 13
Dependent Claim
39 words
The gel of claim 1 wherein the cationic polyacrylamide is selected from the group consisting of copolymers containing acrylamide and copolymers containing modified acrylamide monomers, the modified acrylamide monomers being selected from the group consisting of methacrylamide and ethylacrylamide.
Claim 14
Dependent Claim
21 words
The gel of claim 1 wherein the cationic polyacrylamide has a viscosity average molecular weight of about 1,000,000 to about 10,000,000.
Claim 15
Dependent Claim
23 words
The gel of claim 1 wherein the contacting step includes the step of mixing a boron-containing compound with the aqueous cationic polyacrylamide-containing solution.
Claim 16
Dependent Claim
21 words
The gel of claim 1 wherein the cationic polyacrylamide has a cationic charge density of less than about 40 weight percent.
Claim 17
Dependent Claim
22 words
The gel of claim 1 wherein the cationic polyacrylamide has a cationic charge density of about 25 to about 35 weight percent.
Claim 18
Dependent Claim
24 words
The gel of claim 1 wherein the contacting step includes the step of mixing an organic crosslinking agent with the aqueous cationic polyacrylamide-containing solution.
Claim 19
Dependent Claim
26 words
The gel of claim 17 wherein the organic crosslinking agent is selected from the group consisting of aldehydes, dialdehydes, phenols, substituted phenols, ethers, and mixtures thereof.
Claim 20
Dependent Claim
49 words
The gel of claim 1 wherein the contacting step includes the step of mixing a supplemental inorganic crosslinking agent with the aqueous cationic polyacrylamide-containing solution, wherein the supplemental crosslinking agent is selected from the group consisting of boron, polyvalent metals, compounds capable of yielding polyvalent metals, and mixtures thereof.
Claim 21
Dependent Claim
33 words
The gel of claim 19 wherein the contacting step includes the step of mixing less than about 200 ppm by weight of the supplemental inorganic crosslinking agent with the aqueous cationic polyacrylamide-containing solution.
Claim 22
Dependent Claim
34 words
The gel of claim 19 wherein the contacting step includes the step of mixing about 10 to about 100 ppm by weight of the supplemental inorganic crosslinking agent with the aqueous cationic polyacrylamide-containing solution.
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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) | 1996-07-05 | 1997-01-04 | 1997-07-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2000-07-05 | 2001-01-04 | 2001-07-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2004-07-05 | 2005-01-04 | 2005-07-06 | $7700.00 | Window Closed / Lapsed |