US3749174A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for selective plugging of wells
Assignee: Getty Oil Co
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Filing: 1971-06-11
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Granted: 1973-07-31
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Expires: 1991-06-11
Abstract
Abstract A composition is provided for use in selectively plugging waterrich strata of a subterranean formation so that the oil-to-water ratio of production will be increased, said composition including in preferred embodiments an aqueous solution of sodium carboxymethylcellulose, chromium potassium sulfate, and orthocresol. Methods for selective plugging are provided which include injection of a selective plugging composition into subterranean formations having water-rich and oil-rich strata whereupon the material, after a significant period of time, assumes a much greater viscosity in the water-rich strata. Pretreatment and post-treatment options are provided for improving results under certain conditions.
Inventors
- 👤 R Friedman
- 👤 J Krause
- 👤 W Bradford
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 17:36
CPC Classifications
C; C09; C09K; C09K8/00; C09K8/60; C09K8/84; C09K8/86; C09K8/88; C09K8/887; C09K8/90; E; E21; E21B; E21B43/00; E21B43/25; E21B43/26; E21B43/261
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
30 words
A method in accordance with claim 1, wherein said formation is first treated to neutralize the negatively charged sands thereof, by injecting into the formation a dilute aqueous cationic solution.
Claim 2
Dependent Claim
19 words
A method in accordance with claim 2, wherein said cationic solution is an aqueous solution of chromium potassium sulfate.
Claim 3
Dependent Claim
21 words
A method in accordance with claim 2, wherein fresh water is introduced after said cationic solution to form a buffer zone.
Claim 4
Dependent Claim
23 words
A method in accordance with claim 1, wherein said composition is continuously pumped into said formation to avoid premature gelling of the composition.
Claim 5
Independent Claim
168 words
A method for selectively plugging water-rich strata of a subterranean formation containing strata which are water-rich and other strata which are oil-rich, and said strata having a borehole therein, comprising: providing an aqueous composition of from about 0.20 to about 0.23 percent by weight sodium carboxymethylcellulose, from about 0.049 to about 0.075 percent by weight chromium potassium sulfate, and from about 0.05 to about 0.06 percent by weight ortho-cresol; passing said composition into said borehole; continuously pumping said composition into said formation at a pressure sufficient to overcome the natural formation pressure and at a temperature of less than about 120*F., whereupon said composition enters both oil-rich and water-rich strata of said formation, said composition not increasing in viscosity to any significant extent in said oil-rich strata, but greatly increasing in viscosity after about 7 to 10 days in said water-rich strata wherein the oil concentration is less than about 30 percent, and thereafter producing said well whereupon well fluids will be selectively produced from said oil-rich strata.
Claim 6
Independent Claim
196 words
A method for selectively plugging water-rich strata of a subterranean formation containing strata which are water-rich and other strata which are oil-rich, and said strata having a borehole therein, comprising: providing a dilute aqueous solution of a cationic material; injecting said solution into said borehole and thence into said formation so that the negatively charged formation sands are neutralized; providing an aqueous composition of from about 0.20 to about 0.23 percent by weight sodium carboxymethylcellulose, from about 0.049 to about 0.075 percent by weight chromium potassium sulfate, and from about 0.05 to about 0.06 percent by weight ortho-cresol; passing said composition into said borehole; injeCting said composition into said formation at a pressure sufficient to overcome the natural formation pressure and at a temperature of less than about 120* F, whereupon said composition enters both oil-rich and water-rich strata of formation, said composition not increasing in viscosity to any significant extent in said oil-rich strata, but greatly increasing in viscosity after about seven to ten days in the water-rich strata wherein the oil concentration is less than about 30 percent, and thereafter producing said well whereupon well fluids will be selectively produced from said oil-rich strata.
Claim 7
Independent Claim
184 words
A method for selectively plugging water-rich strata of a subterranean formation containing strata which are water-rich and other strata which are oil-rich, and said strata having a borehole therein, comprising: providing an aqueous composition of from about 0.20 to about 0.23 percent by weight sodium carboxymethylcellulose, from about 0.049 to about 0.075 percent by weight chromium potassium sulfate, and from about 0.05 to about 0.06 percent by weight ortho-cresol; passing said composition into said borehole; injecting said composition into said formation at a pressure sufficient to overcome the natural formation pressure and at a temperature of less than about 120*F, whereupon said composition enters both oil-rich and water-rich strata of said formation, said composition not increasing in viscosity to any significant extent in said oil-rich strata, but greatly increasing in viscosity after about 7 to 10 days in said water-rich strata wherein the oil concentration is less than about 30 percent, and reducing the permeability of mixed strata having an oil composition of from about 30 to about 45 percent; producing said well whereupon well fluids will be selectively produced from said oil-rich strata.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-07-30 | 1977-01-29 | 1977-07-31 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-07-30 | 1981-01-29 | 1981-07-31 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-07-30 | 1985-01-29 | 1985-07-31 | $7700.00 | Window Closed / Lapsed |