US4247402A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Clay-free, thixotropic wellbore fluid
Assignee: Texas United Chemical Corp
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Filing: 1978-03-13
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Granted: 1981-01-27
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Expires: 1998-03-13
Abstract
Abstract A clay-free wellbore fluid having thixotropic properties, good surface handling characteristics and excellent subterranean characteristics such as particle handling gel strength, and low water loss has been devised by the combination of a heteropolysaccharide prepared by the action of bacteria of the genus Xanthomonas on carbohydrates, modified starch and MgO. In some situations a salt of lignosulfonate is added to maintain the desirable properties of the wellbore fluid.
Inventors
- 👤 Arlynn H. Hartfiel
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 21:04
CPC Classifications
C; C09; C09K; C09K8/00; C09K8/02; C09K8/04; C09K8/06; C09K8/08; Y; Y10; Y10S; Y10S507/00; Y10S507/925; Y10S507/926
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
59 words
An aqueous clay-free thixotropic wellbore fluid for use in subterranean formations in the earth comprising water, at least 1% by weight of a brine forming soluble salt or mixture of salts of potassium sodium or calcium, a stabilizing amount of MgO and a viscosifying amount of heteropolysaccharide prepared by the action by bacteria of the genus Xanthomonas on carbohydrates.
Claim 2
Dependent Claim
59 words
An aqueous clay-free thixotropic wellbore fluid for use in subterranean formations in the earth comprising water, at least 1% by weight of a brine forming soluble salt or mixture of salts of potassium sodium or calcium, a stabilizing amount of MgO and a viscosifying amount of heteropolysaccharide prepared by the action by bacteria of the genus Xanthomonas on carbohydrates.
Claim 3
Dependent Claim
27 words
The wellbore fluid according to claim 1 containing at least about 0.50 grams of MgO and 0.72 to 7.14 grams of heteropolysaccharide per liter of wellbore fluid.
Claim 4
Dependent Claim
20 words
The wellbore fluid according to claim 2 containing from 0.50 to 15 grams of MgO per liter of wellbore fluid.
Claim 5
Dependent Claim
19 words
The wellbore composition according to claim 3 containing 0.72 to 3.57 grams of heteropolysaccharide per liter of wellbore fluid.
Claim 6
Dependent Claim
50 words
A dry mix additive package for use in aqueous clay-free wellbore fluids comprising an intimate mixture of components thereof to provide 0.72 to 7.14 parts by weight of heteropolysaccharide prepared by the action of bacteria of the genus Xanthomonas on carbohydrates and 0.50 to 15 parts by weight of MgO.
Claim 7
Dependent Claim
50 words
A dry mix additive package for use in aqueous clay-free wellbore fluids comprising an intimate mixture of components thereof to provide 0.72 to 7.14 parts by weight of heteropolysaccharide prepared by the action of bacteria of the genus Xanthomonas on carbohydrates and 0.50 to 15 parts by weight of MgO.
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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) | 1984-01-27 | 1984-07-28 | 1985-01-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-01-27 | 1988-07-28 | 1989-01-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-01-27 | 1992-07-28 | 1993-01-27 | $7700.00 | Window Closed / Lapsed |