Patent US3630285A successfully refreshed from Google Patents.
US3630285A
Expired / Lapsed
US
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Acidizing high-temperature wells
Assignee: BP America Production Co
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Filing: 1970-05-22
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Granted: 1971-12-28
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Expires: 1990-05-22
Abstract
Abstract A high-temperature earth formation is acidized by injecting down a well and into the formation a water-soluble ester of an organic carboxylic acid which forms a calcium salt which is also watersoluble. The formation should be at a temperature of at least about 200* F., and preferably at least about 300* F. Water may be injected before, after, or with the ester. The well is preferably shut-in after injecting the ester to permit more complete hydrolysis of the ester before the well is returned to its usual operation. Various combinations of esters or combinations of esters and free acids can be used. The ester may be injected as a solution in aqueous or nonaqueous solvents. Preferred esters are methyl formate and ethyl acetate.
Inventors
- 👤 Edwin E Claytor Jr
- 👤 Loyd W Jones
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 05:59
CPC Classifications
C; C09; C09K; C09K8/00; C09K8/60; C09K8/62; C09K8/72
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
16 words
The method of claim 1 in which the formation temperature is at least about 300* F.
Claim 2
Dependent Claim
37 words
The method of claim 1 in which at least some of said water is injected from said well into said formation ahead of said ester and at least some of said water is injected behind said ester.
Claim 3
Dependent Claim
21 words
The method of claim 3 in which at least a part of said water following said ester contains a free acid.
Claim 4
Dependent Claim
31 words
The method of claim 3 in which at least some of said water injected into said formation includes a water-soluble alcohol to improve the solubility of said ester in said water.
Claim 5
Dependent Claim
21 words
The mEthod of claim 1 in which said ester is selected from the group consisting of methyl formate and ethyl acetate.
Claim 6
Dependent Claim
41 words
The method of claim 1 in which said well is shut-in for at least about an hour after injecting said ester into said formation, to permit hydrolysis of said ester in the formation, before returning said well to its usual operation.
Claim 7
Dependent Claim
29 words
The method of claim 1 in which the solvent in said hydrocarbon solution contains an aromatic hydrocarbon, whereby the ability of said solution to dissolve organic deposits is improved.
Claim 8
Dependent Claim
17 words
The method of claim 1 in which the solvent in said hydrocarbon solution is a petroleum fraction.
Claim 9
Independent Claim
133 words
A method for acidizing an earth formation penetrated by a well, the temperature of said formation being at least about 200* F., said method comprising injecting down said well and into said formation water and an ester of an organic carboxylic acid, said ester being soluble in water to the extent of at least about 5 grams in 100 milliliters of water at formation temperature, the calcium salt of which acid is water-soluble to the extent of at least about 2 grams in 100 milliliters of water at formation temperature, at least some of said water being injected from said well into said formation ahead of said ester and at least some of said water being injected behind said ester, at least a part of said water following said ester containing free acid.
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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) | 1974-12-27 | 1975-06-28 | 1975-12-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-12-27 | 1979-06-28 | 1979-12-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-12-27 | 1983-06-28 | 1983-12-28 | $7700.00 | Window Closed / Lapsed |