Patent US4710303A successfully refreshed from Google Patents.
US4710303A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Low molecular weight polyvinyl sulfonate for low pH barium sulfate scale control
Assignee: Nalco Energy Services LP
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Filing: 1986-08-14
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Granted: 1987-12-01
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Expires: 2006-08-14
Abstract
Abstract A method of preventing the formation of barium sulfate scale deposited by aqueous produced or injection fluids having a pH below 7.5 which are recovered with or are used to recover petroleum from underground formations which comprises treating these aqueous fluids with a low molecular weight polyvinyl sulfonate which has a molecular weight within the range of between 500-10,000.
Inventors
- 👤 Daniel H. Emmons
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 14:31
CPC Classifications
C; C02; C02F; C02F5/00; C02F5/08; C02F5/10; Y; Y10; Y10S; Y10S507/00; Y10S507/927
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
78 words
A method of preventing the formation of barium sulfate scale deposited by aqueous produced or injection fluids having a pH below 7.5 which are recovered with or are used to recover petroleum from underground formations which comprises treating these aqueous fluids with from 1-25 ppm by weight of a low molecular weight water-soluble polyvinyl sulfonate which has a molecular weight within the range of between 500-10,000 and containing a minimum of 90 mole percent of vinyl sulfonate monomer.
Claim 2
Independent Claim
78 words
A method of preventing the formation of barium sulfate scale deposited by aqueous produced or injection fluids having a pH below 7.5 which are recovered with or are used to recover petroleum from underground formations which comprises treating these aqueous fluids with from 1-25 ppm by weight of a low molecular weight water-soluble polyvinyl sulfonate which has a molecular weight within the range of between 500-10,000 and containing a minimum of 90 mole percent of vinyl sulfonate monomer.
Claim 3
Dependent Claim
29 words
The method of claim 1 wherein the pH of the aqueous fluid is below 4 and the molecular weight of the polyvinyl sulfonate is within the range of 1,000-5,000.
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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) | 1990-11-30 | 1991-06-01 | 1991-12-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-11-30 | 1995-06-01 | 1995-12-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-11-30 | 1999-06-01 | 1999-12-01 | $7700.00 | Window Closed / Lapsed |