Patent US4664818A successfully refreshed from Google Patents.
US4664818A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Drilling mud additive
Assignee: MILPARK 3900 ESSEX LANE HOUSTON TEXAS 77027 A GENERAL PARTNERSHIP OF TEXAS
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Filing: 1985-07-26
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Granted: 1987-05-12
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Expires: 2005-07-26
Abstract
Abstract An additive for drilling in water-sensitive shales comprising a partially hydrolyzed acrylamide-acrylate copolymer, potassium chloride and a polyanionic cellulose.
Inventors
- 👤 William S. Halliday
- 👤 Vincent M. Thielen
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 18:14
CPC Classifications
C; C09; C09K; C09K8/00; C09K8/02; C09K8/04; C09K8/14; C09K8/18; C09K8/22; C09K8/24; C09K2208/00; C09K2208/12
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
143 words
A process for drilling a borehole that encounters a water-sensitive shale, with the borehole being drilled by operating a drilling means, and circulating therein a drilling fluid, when the encountering of borehole instability due to the interaction of the water and water-sensitive shale is at least imminent, circulating as the drilling fluid an aqueous brine solution that contains from about 0.2 to about 2.0 pounds of an additive per barrel, the additive comprising: (a) 27% by weight of a partially hydrolyzed polyacrylate-polyacrylamide copolymer having a molecular weight of at least three million and which is from about 20 to about 50% hydrolyzed; (b) 70% by weight of potassium chloride; (c) 3% by weight of a low to medium viscosity carboxymethylcellulose; with the aqueous solution being circulated so that the shale is contacted by the solution and stabilized by the adsorption of the polymer.
Claim 2
Dependent Claim
143 words
A process for drilling a borehole that encounters a water-sensitive shale, with the borehole being drilled by operating a drilling means, and circulating therein a drilling fluid, when the encountering of borehole instability due to the interaction of the water and water-sensitive shale is at least imminent, circulating as the drilling fluid an aqueous brine solution that contains from about 0.2 to about 2.0 pounds of an additive per barrel, the additive comprising: (a) 27% by weight of a partially hydrolyzed polyacrylate-polyacrylamide copolymer having a molecular weight of at least three million and which is from about 20 to about 50% hydrolyzed; (b) 70% by weight of potassium chloride; (c) 3% by weight of a low to medium viscosity carboxymethylcellulose; with the aqueous solution being circulated so that the shale is contacted by the solution and stabilized by the adsorption of the polymer.
Claim 3
Dependent Claim
18 words
The process of claim 1 wherein the additive is introduced into the process in a flowable particulate form.
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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) | 1990-05-11 | 1990-11-10 | 1991-05-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-05-11 | 1994-11-10 | 1995-05-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-05-11 | 1998-11-10 | 1999-05-12 | $7700.00 | Window Closed / Lapsed |