Patent US4478727A successfully refreshed from Google Patents.
US4478727A
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Sodium styrene sulfonate-co-sodium-n-(4-sulfophenyl)-maleimide- an improved viscosity control additive
Assignee: ExxonMobil Technology and Engineering Co
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Filing: 1982-09-13
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Granted: 1984-10-23
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Expires: 2002-09-13
Abstract
Abstract A new copolymer of sodium styrene sulfonate-co-sodium-N-(4-sulfophenyl)-maleimidehas been found to be an improved viscosity control additive for water-based drilling muds.
Inventors
- 👤 S. Richard Turner
- 👤 Thad O. Walker
- 👤 Warren A. Thaler
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 07:29
CPC Classifications
C; C09; C09K; C09K8/00; C09K8/02; C09K8/04; C09K8/14; C09K8/18; C09K8/22; C09K8/24
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
144 words
A water-based drilling mud which comprises: (a) water; (b) about 4 to about 30 lbs/bbl. of a clay; (c) about 1 to about 30 lbs/bbl of a lignosulfonate; (d) weighting material of sufficent quantity necessary to achieve the desired density; (e) about 0.25 to about 5 lbs/bbl. of a sodium styrene sulfonate co-sodium-N-(4-sulfophenyl)-maleimide copolymer, said copolymer being (1) prepared by copolymerization of sodium styrene sulfonate and sodium-N-(4-sulfophenyl)-maleimide and having an Mn of about 10,000 to about 100,000, or (2) prepared by modification of a preformed alternating styrene/maleic anhydride copolymer by sequentially sulfonating the styrene pendant unit with SO 3 followed by addition of sulfanilic acid to the enchained succinic anhydride units, said preformed copolymer having a molecular weight of from 1,000 to 500,000; and (f) base of sufficient quantity to adjust the pH of the water-based drilling mud to about 10 to about 10.5.
Claim 2
Dependent Claim
144 words
A water-based drilling mud which comprises: (a) water; (b) about 4 to about 30 lbs/bbl. of a clay; (c) about 1 to about 30 lbs/bbl of a lignosulfonate; (d) weighting material of sufficent quantity necessary to achieve the desired density; (e) about 0.25 to about 5 lbs/bbl. of a sodium styrene sulfonate co-sodium-N-(4-sulfophenyl)-maleimide copolymer, said copolymer being (1) prepared by copolymerization of sodium styrene sulfonate and sodium-N-(4-sulfophenyl)-maleimide and having an Mn of about 10,000 to about 100,000, or (2) prepared by modification of a preformed alternating styrene/maleic anhydride copolymer by sequentially sulfonating the styrene pendant unit with SO 3 followed by addition of sulfanilic acid to the enchained succinic anhydride units, said preformed copolymer having a molecular weight of from 1,000 to 500,000; and (f) base of sufficient quantity to adjust the pH of the water-based drilling mud to about 10 to about 10.5.
Claim 3
Dependent Claim
26 words
A water-based drilling mud according to claim 1 wherein said sodium styrene sulfonate co-sodium-N-(4-sulfophenyl)-maleimide copolymer is prepared by the copolymerization of sodium styrene sulfonate and sodium-N-(4-sulfophenyl)-maleimide.
Claim 4
Dependent Claim
13 words
A water-based drilling mud according to claim 1 wherein said clay is Bentonite.
Claim 5
Dependent Claim
14 words
A water-based drilling mud according to claim 1 wherein said base is sodium hydroxide.
Claim 6
Dependent Claim
23 words
A water-based drilling mud according to claim 1 wherein said sodium styrene sulfonate-co-sodium-N-(4-sulfophenyl)-maleimide copolymer is prepared by modification of preformed styrene-maleic anhydride copolymer.
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) | 1987-10-23 | 1988-04-23 | 1988-10-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-10-23 | 1992-04-23 | 1992-10-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-10-23 | 1996-04-23 | 1996-10-23 | $7700.00 | Window Closed / Lapsed |