US4190462A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Dissolving barium sulfate scale with aqueous solutions of salts of carboxymethyl monocyclic macrocyclic polyamines
Assignee: Shell USA Inc
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Filing: 1979-01-15
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Granted: 1980-02-26
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Expires: 1999-01-15
Abstract
Abstract Barium sulfate scale can be removed from remote locations such as those in or around the borehole of a well extending into a subterranean earth formation by contacting the scale with an aqueous solution consisting essentially of water,a monovalent cation salt of a monocyclic macrocyclic polyamine containing at least two nitrogen-linked carboxymethyl groups and enough monovalent basic compound to provide a solution pH of about 8.
Inventors
- 👤 Reike De Jong
- 👤 Gerridina J. Torny-Schutte
- 👤 David N. Reinhoudt
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 15:26
CPC Classifications
C; C09; C09K; C09K8/00; C09K8/60; C09K8/62; C09K8/72; C09K8/74; C09K8/78; C09K8/52; C09K8/528; Y; Y10; Y10S; Y10S507/00; Y10S507/927
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
109 words
A process for removing barium sulfate scale from fluid-contactable surfaces in a location into which fluid can be flowed which comprises; flowing into contact with said surfaces an aqueous solution consisting essentially of water, an effective complexing amount of a monovalent cation salt of a monocyclic macrocyclic polyamine containing at least two nitrogen-linked carboxymethyl groups and enough dissolved monovalent basic compound to provide a solution pH of at least about 8; said polyamine having an intra-molecular cavity or crypt which is selectively receitive to multivalent cations; and, said aqueous solution being both capable of relatively rapidly and extensively dissolving solid barium sulfate and free of any bicyclic macrocyclic polyether.
Claim 2
Dependent Claim
109 words
A process for removing barium sulfate scale from fluid-contactable surfaces in a location into which fluid can be flowed which comprises; flowing into contact with said surfaces an aqueous solution consisting essentially of water, an effective complexing amount of a monovalent cation salt of a monocyclic macrocyclic polyamine containing at least two nitrogen-linked carboxymethyl groups and enough dissolved monovalent basic compound to provide a solution pH of at least about 8; said polyamine having an intra-molecular cavity or crypt which is selectively receitive to multivalent cations; and, said aqueous solution being both capable of relatively rapidly and extensively dissolving solid barium sulfate and free of any bicyclic macrocyclic polyether.
Claim 3
Dependent Claim
155 words
The process of claim 1 in which said polyamine has the formula: ##STR4## wherein each A 1 represents a hydrocarbon radical having up to 12 carbon atoms and each D represents an oxygen or a sulphur atom or a hydrocarbon radical having up to 12 carbon atoms or a group of the formula ═N--R 2 (where R 2 represents a hydrogen atom or a hydrocarbon radical having up to 12 carbon atoms, a hydrocarbonsulfonyl radical having up to 12 carbon atoms, an alkoxycarbonyl radical having fewer than 5 carbon atoms, an alkoxycarbonyl-methylene radical having fewer than 5 carbon atoms or a carboxymethylene radical), at least two of the said D members being an oxygen or a sulphur atom or groups of the formula ═N--R 2 , and each R 1 represents an alkyl group having up to 6 carbon atoms or a hydrogen atom, and m and n are integers from 0 to 5 inclusive.
Claim 4
Dependent Claim
34 words
The process of claim 2 in which A 1 represents a hydrocarbon radical containing from about 2 to 8 carbon atoms and the integers m and n have values of from 1 to 3.
Claim 5
Dependent Claim
11 words
The process of claim 1 in which said polyamine is 1,10-di(carboxymethyl)-1,10-diaza-4,7,13,16-tetraoxocyclooctadecane.
Claim 6
Dependent Claim
26 words
The process of claim 4 in which said polyamine salt is mixed with a lesser proportion of a monovalent cation salt of a polyamino polyacetic acid.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1983-02-25 | 1983-08-27 | 1984-02-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-02-25 | 1987-08-27 | 1988-02-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-02-25 | 1991-08-27 | 1992-02-26 | $7700.00 | Window Closed / Lapsed |