Patent US3633672A successfully refreshed from Google Patents.
US3633672A
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Inhibition of deposition of scale
Assignee: Schlumberger Technology Corp
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Filing: 1970-05-11
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Granted: 1972-01-11
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Expires: 1990-05-11
Abstract
Abstract Long term inhibition of the deposition or accumulation of inorganic scale in operations concerned with working or treating, or producing from, an underground reservoir is attained by employing an organic phosphorus-type scale inhibitor then precipitating its salt within said underground reservoir by a polyvalent inorganic metal salt in an aqueous acidic carrier.
Inventors
- 👤 Charles F Smith
- 👤 Thomas J Nolan
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 13:08
CPC Classifications
C; C02; C02F; C02F5/00; C02F5/08; C02F5/10; C02F5/14; C02F5/145; Y; Y10; Y10S; Y10S507/00; Y10S507/927
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
71 words
The method according to claim 1 wherein the salt of said composition consists essentially of between about 1 and about 5 percent of a salt selected from the class consisting of at least one of a halide, nitrate, sulfate, phosphate, and acetate of at least one metal selected from the class consisting of Fe , Fe , Ni , Ni , Cr , Cr 6, Mg , Ba and Al .
Claim 2
Dependent Claim
17 words
The method according to claim 2 wherein said salt is a ferric salt of a mineral acid.
Claim 3
Dependent Claim
54 words
The method according to claim 1 wherein the aqueous composition containing said salt and organic phosphorus-containing compound is injected down the well and forced back into the formation sufficiently to become at least temporarily lodged in the outer recesses of a fluid-bearing zone thereof when the pH of the aqueous solution exceeds about 2.
Claim 4
Dependent Claim
39 words
The method according to claim 3 wherein the formation being treated contains available iron ions and an iron salt is obtained by contacting iron-containing components of the formation with a low pH aqueous liquid containing the organic phosphorus-containing compound.
Claim 5
Dependent Claim
32 words
The method according to claim 1 wherein the organic phosphorus-containing compound employed is nitrilotrimethylene phosphonic acid in an amount of between about 0.5 and 5.0 percent by weight of said aqueous composition.
Claim 6
Dependent Claim
18 words
The method according to claim 1 wherein the well is closed in for at least about 3 hours.
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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) | 1975-01-10 | 1975-07-12 | 1976-01-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-01-10 | 1979-07-12 | 1980-01-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-01-10 | 1983-07-12 | 1984-01-11 | $7700.00 | Window Closed / Lapsed |