US4569393A
Expired / Lapsed
US
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CO2 -Induced in-situ gelation of polymeric viscosifiers for permeability contrast correction
Assignee: Phillips Petroleum Co
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Filing: 1984-02-09
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Granted: 1986-02-11
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Expires: 2004-02-09
Abstract
Abstract A water permeability contrast correction process to improve the sweep efficiency of waterflooding which involves the sequential injection of (1) an optional aqueous preflush slug to adjust connate water salinity, (2) an aqueous thickened slug comprising a sequestered polyvalent metal cation such as aluminum citrate and a gelable polymeric viscosifier such as polyacrylamide, (3) carbon dioxide to decrease the pH of the polymer slug which triggers the delayed in-situ gelation of said thickened slug to preferentially decrease water permeability in highly permeable thief zones, and (4) an aqueous drive fluid.
Inventors
- 👤 Donald D. Bruning
- 👤 Donald R. Wier
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 16:39
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; C09K8/58; C09K8/594; E; E21; E21B; E21B43/00; E21B43/16; E21B43/164; Y; Y02; Y02P; Y02P90/00; Y02P90/70
Claims Analysis
Total Claims: 23
Claim 1
Independent Claim
67 words
A method for treating an underground formation which comprises: (A) injecting effective permeability control proportions of an in-situ gelable composition comprising effective ratios of: (a) water, (b) at least one polymer capable of gelling with a crosslinking agent within a gelation pH range, (c) at least one polyvalent metal cation, and (d) at least one sequestering anion; and thereafter (B) injecting carbon dioxide, thereby causing gelation in-situ.
Claim 2
Independent Claim
67 words
A method for treating an underground formation which comprises: (A) injecting effective permeability control proportions of an in-situ gelable composition comprising effective ratios of: (a) water, (b) at least one polymer capable of gelling with a crosslinking agent within a gelation pH range, (c) at least one polyvalent metal cation, and (d) at least one sequestering anion; and thereafter (B) injecting carbon dioxide, thereby causing gelation in-situ.
Claim 3
Dependent Claim
23 words
The method of claim 1 wherein said polymer is present in said gelable composition in an amount of about 500 to 10,000 ppm.
Claim 4
Dependent Claim
25 words
A method according to claim 2 wherein said polymer comprises polyacrylamide, the polyvalent metal cation comprises Al 3+ , and the chelating/sequestering anion comprises citrate.
Claim 5
Dependent Claim
44 words
The method of claim 2 employing in said in-situ gelable composition a range of about 10:1 to 1:10 molar ratio of polyvalent metal cation to crosslinkable side groups of said polymer; and a molar ratio of about 1:1 to 6:1 polyvalent metal cation:sequestering agent.
Claim 6
Dependent Claim
30 words
The method of claim 1 wherein said polymer is selected from the groups consisting of biopolysaccharides, cellulose ethers, acrylamide-based polymer, partially hydrolyzed polyacrylonitriles, polystyrene sulfonates, lignosulfonates, methylolated polyacrylamides, and mixtures.
Claim 7
Dependent Claim
68 words
The method of claim 5 wherein said polyvalent metal cation is selected from the group consisting of Fe 2+ , Fe 3+ , Al 3+ , Ti 4+ , Zn 2+ , Sn 4+ , Ca 2+ , Mg 2+ , Cr 3+ , and mixtures; and said chelating/sequestering agent is selected from the group consisting of acetate, nitrilotriacetate, tartrate, citrate, tripolyphosphate, metaphosphate, gluconate, phosphate, and mixtures thereof.
Claim 8
Dependent Claim
23 words
The process of claim 6 wherein said carbon dioxide is employed alone, in admixture with water, or diluted with nitrogen, steam, or mixture.
Claim 9
Dependent Claim
14 words
The process of claim 7 wherein said carbon dioxide is employed admixed with steam.
Claim 10
Dependent Claim
20 words
The process of claim 8 employing in said aqueous gelable composition about 500 ppm to 10,000 ppm of said polymer.
Claim 11
Dependent Claim
16 words
The process of claim 1 preceded by an aqueous preflush slug to adjust connate water salinity.
Claim 12
Dependent Claim
81 words
A process of controlling sweep efficiency in a subterranean formation which comprises the sequential injection of effective quantities of: (1) an aqueous preflush slug to adjust connate water salinity, (2) an in-situ gelable aqueous thickened slug comprising a sequestered polyvalent metal cation and a gelable polymeric viscosifier, (3) carbon dioxide in amounts sufficient to effectuate gelation of said aqueous thickened slug; and (4) an aqueous drive fluid; thus effecting preferential decrease in water permeability of the otherwise highly permeable thief zones.
Claim 13
Dependent Claim
81 words
A process of controlling sweep efficiency in a subterranean formation which comprises the sequential injection of effective quantities of: (1) an aqueous preflush slug to adjust connate water salinity, (2) an in-situ gelable aqueous thickened slug comprising a sequestered polyvalent metal cation and a gelable polymeric viscosifier, (3) carbon dioxide in amounts sufficient to effectuate gelation of said aqueous thickened slug; and (4) an aqueous drive fluid; thus effecting preferential decrease in water permeability of the otherwise highly permeable thief zones.
Claim 14
Dependent Claim
14 words
The process of claim 11 wherein said aqueous preflush comprises a sodium chloride brine.
Claim 15
Dependent Claim
96 words
The process of claim 12 wherein said in-situ gelable slug comprising effective ratios of: (a) water, (b) a polymer capable of gelling with a crosslinking agent at a pH in the gelation range, (c) a crosslinking agent comprised of sequestered polyvalent metal cations, selected from the group consisting of Fe 2+ , Fe 3+ , Al 3+ , Ti 4+ , Zn 2+ , Sn 4+, Ca 2+ , Mg 2+ , Mg 2+ , (d) chelating anions selected from the group consisting of acetate, nitrilotriacetate, tartrate, citrate, and tripolyphosphate, metaphosphate, gluconate, phosphate, and mixtures thereof.
Claim 16
Dependent Claim
23 words
The method of claim 13 wherein the polymer is present in said gelable composition in an amount of about 500 to 10,000 ppm.
Claim 17
Dependent Claim
25 words
A method according to claim 14 wherein the polymer comprises partially hydrolyzed polyacrylamide, said multivalent metal is Al 3+ and said chelating anion is citrate.
Claim 18
Dependent Claim
53 words
The method of claim 14 wherein said multivalent metal cation is present in said aqueous gelable solution in a molar ratio of about 10:1 to 1:10 polyvalent metal cation:crosslinkable groups of said polymer, and said polyvalent metal cation is present in a molar ratio of about 1:1 to 6:1 polyvalent metal cation:sequestering anion.
Claim 19
Dependent Claim
30 words
The process of claim 16 wherein said polymer is selected from the groups consisting of biopolysaccharides, cellulose ethers, acrylamide-based polymers, partially hydrolyzed polyacrylonitriles, polystyrene sulfonates, lignosulfonates, methylolated polyacrylamides, and mixtures.
Claim 20
Dependent Claim
27 words
The process of claim 17 wherein said carbon dioxide employed as such, or in admixture with at least one of air, nitrogen, steam, water, or mixtures thereof.
Claim 21
Dependent Claim
15 words
The process of claim 18 wherein said carbon dioxide is employed in admixture with steam.
Claim 22
Dependent Claim
20 words
The process of claim 19 employing in said aqueous gelable composition about 500 ppm to 10,000 ppm of said polymer.
Claim 23
Dependent Claim
24 words
The process of claim 20 wherein said polymer comprises polyacrylamide, said polyvalent metal cation comprises Al 3+ , and said chelating/sequestering anion comprises citrate.
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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) | 1989-02-10 | 1989-08-12 | 1990-02-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-02-10 | 1993-08-12 | 1994-02-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-02-10 | 1997-08-12 | 1998-02-11 | $7700.00 | Window Closed / Lapsed |