US3988246A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Clay-free thixotropic wellbore fluid
Assignee: Chemical Additives Co
•
Filing: 1974-05-24
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Granted: 1976-10-26
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Expires: 1994-05-24
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
2026-10-24 12:04
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
66 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 mixtures of salts, at least about 0.50 grams of MgO, 0.15 to 30 grams of hydroxypropyl ether starch and 0.72 to 7.14 grams of a heteropolysaccharide prepared by the action of bacteria of the genus Xanthomonas on carbohydrates.
Claim 2
Dependent Claim
66 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 mixtures of salts, at least about 0.50 grams of MgO, 0.15 to 30 grams of hydroxypropyl ether starch and 0.72 to 7.14 grams of a heteropolysaccharide prepared by the action of bacteria of the genus Xanthomonas on carbohydrates.
Claim 3
Dependent Claim
34 words
The wellbore fluid according to claim 1 containing 1.0 to 7.0 grams of MgO, 0.9 to 12 grams of organic starch derivative and 0.72 to 3.57 grams of heteropolysaccharide per liter of wellbore fluid.
Claim 4
Dependent Claim
14 words
The wellbore fluid according to claim 1 containing an inorganic, insoluble particulate weighting material.
Claim 5
Dependent Claim
13 words
The wellbore fluid according to claim 3 containing an alkali salt of lignosulfonate.
Claim 6
Dependent Claim
57 words
A dry mix additive package for use in aqueous clay-free brine wellbore fluids comprising an intimate mixture of 0.72 to 7.14 parts by weight of heteropolysaccharide prepared by the action of bacteria of the genus Xanthomonas on carbohydrates, 0.50 to 15 parts by weight of MgO and 0.15 to 30 parts by weight of hydroxypropyl ether starch.
Claim 7
Dependent Claim
57 words
A dry mix additive package for use in aqueous clay-free brine wellbore fluids comprising an intimate mixture of 0.72 to 7.14 parts by weight of heteropolysaccharide prepared by the action of bacteria of the genus Xanthomonas on carbohydrates, 0.50 to 15 parts by weight of MgO and 0.15 to 30 parts by weight of hydroxypropyl ether starch.
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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) | 1979-10-26 | 1980-04-26 | 1980-10-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-10-26 | 1984-04-26 | 1984-10-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-10-26 | 1988-04-26 | 1988-10-26 | $7700.00 | Window Closed / Lapsed |