Patent US4502965A successfully refreshed from Google Patents.
US4502965A
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Terpolymers for use as high temperature fluid loss additive and rheology stabilizer for high pressure, high temperature oil well drilling fluids
Assignee: Nalco Exxon Energy Chemicals LP
•
Filing: 1983-09-09
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Granted: 1985-03-05
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Expires: 2003-09-09
Abstract
Abstract Novel water-soluble terpolymers comprising: ______________________________________ Ingredients Mole % ______________________________________ 2-acrylamido-2-methylpropane- 58-77 sulfonic acid, sodium salt (AMPS) N--vinylpyrrolidone 2-20 acrylonitrile 4-36 ______________________________________ These terpolymers provide high temperature fluid loss additives and rheology stabilizers for high calcium-containing brine clay drilling fluids.
Inventors
- 👤 David M. Giddings
- 👤 Donald G. Ries
- 👤 Allen R. Syrinek
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 15:14
CPC Classifications
C; C09; C09K; C09K8/00; C09K8/02; C09K8/04; C09K8/14; C09K8/18; C09K8/22; C09K8/24; C08; C08F; C08F220/00; C08F220/02; C08F220/52; C08F220/54; C08F220/58; C08F220/585
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
61 words
A method of improving high temperature fluid loss and rheology stabilization of high calcium brine clay-containing oil well drilling fluids which comprises adding thereto a stabilizing amount of a water-soluble terpolymer comprising: ______________________________________
Ingredients Mole %
______________________________________
2-acrylamido-2-methylpropane-
58-77
sulfonic acid, sodium salt
N--vinylpyrrolidone 2-20
acrylonitrile 4-36
______________________________________ and said terpolymer being further characterized as having a molecular weight below 1,000,000.
Claim 2
Independent Claim
61 words
A method of improving high temperature fluid loss and rheology stabilization of high calcium brine clay-containing oil well drilling fluids which comprises adding thereto a stabilizing amount of a water-soluble terpolymer comprising: ______________________________________
Ingredients Mole %
______________________________________
2-acrylamido-2-methylpropane-
58-77
sulfonic acid, sodium salt
N--vinylpyrrolidone 2-20
acrylonitrile 4-36
______________________________________ and said terpolymer being further characterized as having a molecular weight below 1,000,000.
Claim 3
Independent Claim
61 words
A method of improving high temperature fluid loss and rheology stabilization of high calcium brine clay-containing oil well drilling fluids which comprises adding thereto a stabilizing amount of a water-soluble terpolymer comprising: ______________________________________
Ingredients Mole %
______________________________________
2-acrylamido-2-methylpropane-
58.9
sulfonic acid, sodium salt
N--vinylpyrrolidone 08.3
acrylonitrile 32.8
______________________________________ and said terpolymer being further characterized as having a molecular weight below 1,000,000.
Claim 4
Independent Claim
61 words
A method of improving high temperature fluid loss and rheology stabilization of high calcium brine clay-containing oil well drilling fluids which comprises adding thereto a stabilizing amount of a water-soluble terpolymer comprising: ______________________________________
Ingredients Mole %
______________________________________
2-acrylamido-2-methylpropane-
58.9
sulfonic acid, sodium salt
N--vinylpyrrolidone 08.3
acrylonitrile 32.8
______________________________________ and said terpolymer being further characterized as having a molecular weight below 1,000,000.
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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) | 1988-03-04 | 1988-09-03 | 1989-03-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-03-04 | 1992-09-03 | 1993-03-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-03-04 | 1996-09-03 | 1997-03-05 | $7700.00 | Window Closed / Lapsed |