US3953340A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Dissolving siliceous materials with self-acidifying liquid
Assignee: Shell USA Inc
•
Filing: 1974-05-03
•
Granted: 1976-04-27
•
Expires: 1994-05-03
Abstract
Abstract Siliceous materials in or around a well are dissolved by contacting them with a self-acidifying aqueous liquid system comprising an aqueous solution of at least one water-soluble fluoride salt mixed with a relatively slowly-reactive acid-yielding material that subsequently converts the salt solution to a hydrofluoric acid solution that has a relatively high pH but is capable of dissolving siliceous material.
Inventors
- 👤 Charles C. Templeton
- 👤 Evan H. Street, Jr
- 👤 Edwin A. Richardson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 22:42
CPC Classifications
C; C09; C09K; C09K8/00; C09K8/60; C09K8/62; C09K8/72; Y; Y10; Y10S; Y10S507/00; Y10S507/933
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
119 words
A self-acidifying liquid system which comprises a solution of at least one aqueous liquid, at least one water-soluble ammonium salt of hydrofluoric acid, and at least one relatively slowly reactive acid-yielding material that converts the solution of the fluoride salt to a water solution of hydrofluoric acid, with said solutes being present in proportions adapted to subsequently provide an aqueous solution having a hydrofluoric acid concentration of from about 0.2-5% by weight, a pH of at least about 2 and a capability of dissolving bentonite and with said acid-yielding material being a member of the group consisting of esters of aliphatic C 1-5 alcohols and fatty C 1-5 acids, hydrolyzable hydrocarbon chlorides, hydrolyzable acyl chlorides, and hydrolyzable acid anhydrides.
Claim 2
Dependent Claim
119 words
A self-acidifying liquid system which comprises a solution of at least one aqueous liquid, at least one water-soluble ammonium salt of hydrofluoric acid, and at least one relatively slowly reactive acid-yielding material that converts the solution of the fluoride salt to a water solution of hydrofluoric acid, with said solutes being present in proportions adapted to subsequently provide an aqueous solution having a hydrofluoric acid concentration of from about 0.2-5% by weight, a pH of at least about 2 and a capability of dissolving bentonite and with said acid-yielding material being a member of the group consisting of esters of aliphatic C 1-5 alcohols and fatty C 1-5 acids, hydrolyzable hydrocarbon chlorides, hydrolyzable acyl chlorides, and hydrolyzable acid anhydrides.
Claim 3
Dependent Claim
32 words
The composition of claim 1 in which the composition of said solution is adjusted so that the hydrofluoric acid solution is formed after a time and temperature exposure of a selected severity.
Claim 4
Dependent Claim
48 words
The composition of claim 2 in which the composition of said solution is adjusted so that said hydrofluoric acid solution contains less than about 5% by weight of hydrofluoric acid throughout a selected time period in which it is desired that the solution have a relatively high pH.
Claim 5
Dependent Claim
85 words
A self-acidifying aqueous liquid system, which comprises a solution of at least one aqueous liquid, at least one watersoluble ammonium salt of hydrofluoric acid and at least one water-reactive organic acid ester of an aliphatic C 1-5 alcohol and a fatty C 1-5 acid in proportions such that they interact to subsequently form an aqueous solution that contains from about 0.2-5% by weight hydrofluoric acid and at least one organic acid, has a pH of at least about 2 and is capable of dissolving bentonite.
Claim 6
Dependent Claim
85 words
A self-acidifying aqueous liquid system, which comprises a solution of at least one aqueous liquid, at least one watersoluble ammonium salt of hydrofluoric acid and at least one water-reactive organic acid ester of an aliphatic C 1-5 alcohol and a fatty C 1-5 acid in proportions such that they interact to subsequently form an aqueous solution that contains from about 0.2-5% by weight hydrofluoric acid and at least one organic acid, has a pH of at least about 2 and is capable of dissolving bentonite.
Claim 7
Dependent Claim
40 words
The composition of claim 4 in which the composition of said solution is adjusted relative to the temperature at which it is to be used so that said acids are formed after a time and temperature exposure of selected severity.
Claim 8
Dependent Claim
12 words
The composition of claim 4 in which said ester is methyl formate.
References Cited (Backward Citations)
US1990969A
Cited
US2059459A
Cited
US2094479A
Cited
US2238671A
Cited
US2652360A
Cited
US3122204A
Cited
US3215199A
Cited
US3630285A
Cited
US3826312A
Cited
US3794117A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1979-04-27 | 1979-10-27 | 1980-04-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-04-27 | 1983-10-27 | 1984-04-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-04-27 | 1987-10-27 | 1988-04-27 | $7700.00 | Window Closed / Lapsed |