Patent US4476029A successfully refreshed from Google Patents.
US4476029A
Expired / Lapsed
US
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High temperature dispersant
Assignee: Dearborn Chemical Co
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Filing: 1982-05-26
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Granted: 1984-10-09
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Expires: 2002-05-26
Abstract
Abstract Improved dispersants are disclosed for water-based bentonite clay drilling fluids containing a waterloss controller and a weighting agent. The dispersant can be a polyacrylic acid having a molecular weight of from about 700 to about 50,000 and preferably about 4,000 to about 8,000 or it can be used in combination with a sulfonated polystyrene-maleic anhydride copolymer. The dispersants are able to be used at temperatures from about 70 DEG F. up to 500 DEG F.
Inventors
- 👤 Anita O. Sy
- 👤 Dionisio G. Cuisia
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 16:39
CPC Classifications
C; C09; C09K; C09K8/00; C09K8/02; C09K8/04; C09K8/14; C09K8/18; C09K8/22; C09K8/24
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
42 words
In a water-based bentonite clay drilling fluid containing a waterloss controller, a weighting agent, and a dispersant, the improvement wherein the dispersant is a high temperature dispersant comprising a polyacrylic acid having a molecular weight of from about 4,000 to about 8,000.
Claim 2
Dependent Claim
42 words
In a water-based bentonite clay drilling fluid containing a waterloss controller, a weighting agent, and a dispersant, the improvement wherein the dispersant is a high temperature dispersant comprising a polyacrylic acid having a molecular weight of from about 4,000 to about 8,000.
Claim 3
Dependent Claim
28 words
A drilling fluid according to claim 1, wherein the dispersant is added in an amount of from about 0.5 pounds per barrel to about 10 pounds per barrel.
Claim 4
Dependent Claim
28 words
A drilling fluid according to claim 1, wherein the dispersant further comprises a sulfonated polystyrene-maleic anhydride copolymer having a molecular weight of from about 3,000 to about 5,000.
Claim 5
Dependent Claim
49 words
A process of drilling a well in an earth formation comprising circulating in said well while drilling a water-based bentonite clay drilling fluid containing a waterloss control agent, a weighting agent and a dispersant which comprises a polyacrylic acid having molecular weight of from about 4,000 to about 8,000.
Claim 6
Dependent Claim
49 words
A process of drilling a well in an earth formation comprising circulating in said well while drilling a water-based bentonite clay drilling fluid containing a waterloss control agent, a weighting agent and a dispersant which comprises a polyacrylic acid having molecular weight of from about 4,000 to about 8,000.
Claim 7
Dependent Claim
29 words
A process according to claim 4, wherein the drilling fluid further comprises a sulfonated polystryene maleic anhydride copolymer having a molecular weight of from about 3,000 to about 5,000.
Claim 8
Dependent Claim
26 words
A process according to claim 4, wherein the temperature in the earth formation is at a temperature of from about 70° F. to about 500° F.
Claim 9
Dependent Claim
27 words
A process according to claim 4, wherein the dispersant is added in an amount of from about 0.5 pounds per barrel to about 10 pounds per barrel.
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) | 1987-10-09 | 1988-04-09 | 1988-10-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-10-09 | 1992-04-09 | 1992-10-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-10-09 | 1996-04-09 | 1996-10-09 | $7700.00 | Window Closed / Lapsed |