US4898677A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for inhibiting scale formation and modifying the crystal structure of barium sulfate and other inorganic salts
Assignee: Ingredion Inc
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Filing: 1986-11-10
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Granted: 1990-02-06
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Expires: 2006-11-10
Abstract
Abstract The deposition of scale-imparting precipitates in aqueous media containing significant amounts of barium sulfate and other scale forming salts (e.g., calcium carbonate and calcium sulfate) is inhibited and controlled by adding a scale-inhibiting amount of a water-soluble acrylic acid copolymer with up to about 30% by weight of a vinyl sulfonate, with the copolymer having a weight average molecular weight of below about 90,000.
Inventors
- 👤 Ingrid E. Brase
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 17:04
CPC Classifications
C; C02; C02F; C02F5/00; C02F5/08; C02F5/10; Y; Y10; Y10S; Y10S507/00; Y10S507/927
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
88 words
A method of inhibiting the deposition of barium sulfate scale in a downhole aqueous system containing at least 50 ppm of barium sulfate, which consists of adding an effective scale-inhibiting amount of a water-soluble copolymer having a weight ratio of 70-95% acrylic acid and 5-30% of an alkali metal vinyl sulfonate, the copolymer having a weight average molecular weight of below about 90,000, wherein the solubility and/or the dispersibility of the barium sulfate is enhanced and the crystal structure of the barium sulfate is modified to produce fibers.
Claim 2
Independent Claim
88 words
A method of inhibiting the deposition of barium sulfate scale in a downhole aqueous system containing at least 50 ppm of barium sulfate, which consists of adding an effective scale-inhibiting amount of a water-soluble copolymer having a weight ratio of 70-95% acrylic acid and 5-30% of an alkali metal vinyl sulfonate, the copolymer having a weight average molecular weight of below about 90,000, wherein the solubility and/or the dispersibility of the barium sulfate is enhanced and the crystal structure of the barium sulfate is modified to produce fibers.
Claim 3
Dependent Claim
15 words
The method of claim 1, wherein the alkali metal vinyl sulfonate is sodium vinyl sulfonate.
Claim 4
Dependent Claim
30 words
The method of claim 2, wherein the polymer is the acrylic acid copolymer with about 5% sodium vinyl sulfonate and wherein the polymer has a molecular weight of about 6200-6300.
Claim 5
Dependent Claim
17 words
The method of claim 1, wherein the scale-forming aqueous system also contains calcium sulfate and calcium carbonate.
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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) | 1993-02-05 | 1993-08-07 | 1994-02-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-02-05 | 1997-08-07 | 1998-02-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-02-05 | 2001-08-07 | 2002-02-06 | $7700.00 | Window Closed / Lapsed |