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US4098337A
Expired / Lapsed
US
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Method of improving injectivity profiles and/or vertical conformance in heterogeneous formations
Assignee: Marathon Oil Co
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Filing: 1977-07-01
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Granted: 1978-07-04
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Expires: 1997-07-01
Abstract
Abstract Improved injectivity profiles and/or vertical conformance in flooding heterogeneous formations containing high permeability zones is obtained by injecting an aqueous polyacrylamide solution and an aqueous formaldehyde solution into the formation and allowing the polyacrylamide to react with the formaldehyde in the relatively high permeability zones to form a gel. Thereafter, improved sweep efficiency is realized in displacing hydrocarbon from the lesser permeability zones.
Inventors
- 👤 Perry A. Argabright
- 👤 John S. Rhudy
- 👤 Brian L. Phillips
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 16:39
CPC Classifications
C; C09; C09K; C09K8/00; C09K8/50; C09K8/504; C09K8/506; C09K8/508; C09K8/512; C09K8/58; C09K8/588
Claims Analysis
Total Claims: 21
Claim 1
Independent Claim
93 words
A process for improving the injectivity profile and/or vertical conformance of a hydrocarbon bearing subterranean formation having relatively high permeability zones and relatively lower permeability zones, the process comprising injecting an aqueous polyacrylamide solution into the formation, injecting an aqueous formaldehyde solution into the formation, displacing the aqueous solutions into the relatively high permeability zones, and allowing the polyacrylamide and the formaldehyde to react in the relatively high permeability zones to form a gel which reduces the permeability of the relatively high permeability zones to obtain the improved injectivity profile and/or vertical conformance.
Claim 2
Dependent Claim
93 words
A process for improving the injectivity profile and/or vertical conformance of a hydrocarbon bearing subterranean formation having relatively high permeability zones and relatively lower permeability zones, the process comprising injecting an aqueous polyacrylamide solution into the formation, injecting an aqueous formaldehyde solution into the formation, displacing the aqueous solutions into the relatively high permeability zones, and allowing the polyacrylamide and the formaldehyde to react in the relatively high permeability zones to form a gel which reduces the permeability of the relatively high permeability zones to obtain the improved injectivity profile and/or vertical conformance.
Claim 3
Dependent Claim
15 words
The process of claim 1 wherein the formaldehyde is incorporated into the aqueous polyacrylamide solution.
Claim 4
Dependent Claim
19 words
The process of claim 1 wherein the aqueous solutions of polyacrylamide and formaldehyde are separately injected into the formation.
Claim 5
Dependent Claim
22 words
The process of claim 3 wherein the aqueous solutions of polyacrylamide and formaldehyde are injected into the formation in alternating sequential slugs.
Claim 6
Dependent Claim
39 words
The process of claim 1 which further comprises reducing the pH of the aqueous polyacrylamide solution to about 3 to about 7 prior to injecting the aqueous polyacrylamide solution into the formation to retard the formation of the gel.
Claim 7
Dependent Claim
14 words
The process of claim 1 wherein the polyacrylamide is unhydrolyzed or partially hydrolyzed polyacrylamide.
Claim 8
Dependent Claim
25 words
The process of claim 1 wherein the polyacrylamide has a molecular weight in the range of about one hundred thousand to about one hundred million.
Claim 9
Dependent Claim
21 words
The process of claim 1 wherein the aqueous polyacrylamide solution comprises about 100 to about 2,000 ppm by weight of polyacrylamide.
Claim 10
Dependent Claim
27 words
The process of claim 2 wherein the aqueous polyacrylamide solution comprises about 0.1 to about 5.0 moles of formaldehyde per mole of amide groups within the polyacrylamide.
Claim 11
Dependent Claim
117 words
A process for recovering hydrocarbon from a hydrocarbon bearing subterranean formation having at least one injection means in fluid communication with at least one production means and further having relatively high permeability zones and relatively lower permeability zones, comprising injecting an aqueous solution of unhydrolyzed or partially hydrolyzed polyacrylamide into the formation, injecting an aqueous solution of formaldehyde into the formation, displacing the aqueous solutions into the relatively high permeability zones, allowing the polyacrylamide and formaldehyde to react in the relatively high permeability zones to form a gel which reduces the permeability of the high permeability zones, and then injecting a displacing fluid into the formation to displace hydrocarbon toward the production means to recover hydrocarbon therethrough.
Claim 12
Dependent Claim
117 words
A process for recovering hydrocarbon from a hydrocarbon bearing subterranean formation having at least one injection means in fluid communication with at least one production means and further having relatively high permeability zones and relatively lower permeability zones, comprising injecting an aqueous solution of unhydrolyzed or partially hydrolyzed polyacrylamide into the formation, injecting an aqueous solution of formaldehyde into the formation, displacing the aqueous solutions into the relatively high permeability zones, allowing the polyacrylamide and formaldehyde to react in the relatively high permeability zones to form a gel which reduces the permeability of the high permeability zones, and then injecting a displacing fluid into the formation to displace hydrocarbon toward the production means to recover hydrocarbon therethrough.
Claim 13
Dependent Claim
15 words
The process of claim 10 wherein the formaldehyde is incorporated into the aqueous polyacrylamide solution.
Claim 14
Dependent Claim
19 words
The process of claim 10 wherein the aqueous solutions of polyacrylamide and formaldehyde are separately injected into the formation.
Claim 15
Dependent Claim
22 words
The process of claim 12 wherein the aqueous solutions of polyacrylamide and formaldehyde are injected into the formation in alternating sequential slugs.
Claim 16
Dependent Claim
40 words
The process of claim 10 which further comprises reducing the pH of the aqueous polyacrylamide solution to about 3 to about 7 prior to injecting the aqueous solution of polyacrylamide into the formation to retard the formation of the gel.
Claim 17
Dependent Claim
24 words
The process of claim 10 wherein the polyacrylamide has a molecular weight in the range of about one million to about seventy five million.
Claim 18
Dependent Claim
21 words
The process of claim 10 wherein the aqueous polyacrylamide solution comprises about 100 to about 2,000 ppm by weight of polyacrylamide.
Claim 19
Dependent Claim
27 words
The process of claim 10 wherein the aqueous polyacrylamide solution comprises about 0.1 to about 5.0 moles of formaldehyde per mole of amide groups within the polyacrylamide.
Claim 20
Dependent Claim
125 words
A process for improving the injectivity profile and/or vertical conformance of a heterogeneous subterranean formation having at least one injection means in fluid communication with at least one production means and having at least one relatively high permeability zone, the method comprising injecting an aqueous solution of unhydrolyzed or partially hydrolyzed polyacrylamide into the formation through the injection means, injecting an aqueous solution of formaldehyde into the formation through the injection means, displacing the aqueous solutions into the at least one relatively high permeability zone in the formation and allowing the polyacrylamide and the formaldehyde to react in the relatively high permeability zone to form a gel which reduces the permeability of the high permeability zone to obtain the improved injectivity profile and/or vertical conformance.
Claim 21
Dependent Claim
125 words
A process for improving the injectivity profile and/or vertical conformance of a heterogeneous subterranean formation having at least one injection means in fluid communication with at least one production means and having at least one relatively high permeability zone, the method comprising injecting an aqueous solution of unhydrolyzed or partially hydrolyzed polyacrylamide into the formation through the injection means, injecting an aqueous solution of formaldehyde into the formation through the injection means, displacing the aqueous solutions into the at least one relatively high permeability zone in the formation and allowing the polyacrylamide and the formaldehyde to react in the relatively high permeability zone to form a gel which reduces the permeability of the high permeability zone to obtain the improved injectivity profile and/or vertical conformance.
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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) | 1981-07-03 | 1982-01-02 | 1982-07-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-07-03 | 1986-01-02 | 1986-07-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-07-03 | 1990-01-02 | 1990-07-04 | $7700.00 | Window Closed / Lapsed |