US4290899A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Thermal stabilizer for non-clay wellbore fluids
Assignee: Union Carbide Corp
•
Filing: 1979-01-04
•
Granted: 1981-09-22
•
Expires: 1999-01-04
Abstract
Abstract Calcined dolomite stabilizes aqueous solutions of viscosifiers, such as polysaccharides, exposed to temperatures as high as 200° F. (93° C.) for prolonged periods.
Inventors
- 👤 Thomas R. Malone
- 👤 Talmage D. Foster, Jr., deceased
- 👤 executrix Sue T. Foster
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 22:58
CPC Classifications
C; C09; C09K; C09K8/00; C09K8/02; C09K8/04; C09K8/14; C09K8/18; C09K8/20; C09K8/206; Y; Y10; Y10S; Y10S507/00; Y10S507/925
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
94 words
In the method of drilling, workover or completion of oil and gas wells using an aqueous polysaccharide solution non-clay well bore fluid, said polysaccharide being a viscosifier and selected from the class consisting of hydroxyalkyl cellulose having 2 to 4 carbons in the alkyl, carboxymethyl hydroxyethyl cellulose, hydroxyalkylated guar gum, xanthan gum or hydroxyethyl carboxyethyl cellulose wherein said wellbore fluid is injected into the wells in contact with the formation, the improvement which comprises incorporating into said solution about 0.5 to about 13% by weight of calcined dolomite, based on the weight of polysaccharide.
Claim 2
Dependent Claim
94 words
In the method of drilling, workover or completion of oil and gas wells using an aqueous polysaccharide solution non-clay well bore fluid, said polysaccharide being a viscosifier and selected from the class consisting of hydroxyalkyl cellulose having 2 to 4 carbons in the alkyl, carboxymethyl hydroxyethyl cellulose, hydroxyalkylated guar gum, xanthan gum or hydroxyethyl carboxyethyl cellulose wherein said wellbore fluid is injected into the wells in contact with the formation, the improvement which comprises incorporating into said solution about 0.5 to about 13% by weight of calcined dolomite, based on the weight of polysaccharide.
Claim 3
Dependent Claim
20 words
Method claimed in claim 1 wherein the polysaccharide is an hydroxyalkyl cellulose having 2 to 4 carbons in the alkyl.
Claim 4
Dependent Claim
12 words
Method claimed in claim 2 wherein the hydroxyalkyl cellulose is hydroxyethyl cellulose.
Claim 5
Dependent Claim
25 words
Method claimed in claim 1 wherein the calcined dolomite contains at least about 40% by weight of MgO based on the weight of calcined dolomite.
Claim 6
Dependent Claim
29 words
Method claimed in claim 3 wherein the calcined dolomite is present at a concentration of about 0.5 to about 5.0% by weight based on the weight of hydroxyethyl cellulose.
Claim 7
Dependent Claim
11 words
Method claimed in claim 1 wherein the polysaccharide is carboxymethyl cellulose.
Claim 8
Dependent Claim
12 words
Method claimed in claim 1 wherein the polysaccharide is carboxymethyl hydroxyethyl cellulose.
Claim 9
Dependent Claim
12 words
Method claimed in claim 1 wherein the polysaccharide is hydroxyalkylated guar gum.
Claim 10
Dependent Claim
11 words
Method claimed in claim 1 wherein the polysaccharide is xanthan gum.
Claim 11
Dependent Claim
12 words
Method claimed in claim 1 wherein the polysaccharide is hydroxyethyl carboxyethyl cellulose.
References Cited (Backward Citations)
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US4025443A
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US3993570A
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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) | 1984-09-21 | 1985-03-23 | 1985-09-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-09-21 | 1989-03-23 | 1989-09-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-09-21 | 1993-03-23 | 1993-09-22 | $7700.00 | Window Closed / Lapsed |