US4239629A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Carboxymethylhydroxyethyl cellulose in drilling, workover and completion fluids
Assignee: Drilling Specialties Co
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Filing: 1978-06-05
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Granted: 1980-12-16
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Expires: 1998-06-05
Abstract
Abstract Certain carboxymethylhydroxyethyl cellulose (CMHEC) solutions in waters of various salinities are gelled by dichromate ion at a pH of about 5 or less, thus forming a drilling fluid or component thereof. In an embodiment a CMHEC water solution is gelled using an alkali metal dichromate, e.g., Na 2 Cr 2 O 7 .2H 2 O.
Inventors
- 👤 Charles A. Sauber
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 19:12
CPC Classifications
C; C09; C09K; C09K8/00; C09K8/50; C09K8/504; C09K8/506; C09K8/508; C09K8/514; C08; C08K; C08K3/00; C08K3/18; C08K3/24; C09K8/02; C09K8/04; C09K8/06; C09K8/08; C09K8/10; C09K8/512; Y; Y10; Y10S; Y10S507/00; Y10S507/903; Y10S507/925
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
61 words
A gel obtained in a water of any salinity by bringing together a viscosity increasing amount of carboxymethylhydroxyethyl cellulose and a compound selected from the group consisting of alkali metal and ammonium dichromates, in the absence of a reducing agent, said compound being present in the approximate range of from about 0.25 to about 5 pounds per barrel of the gel.
Claim 2
Dependent Claim
61 words
A gel obtained in a water of any salinity by bringing together a viscosity increasing amount of carboxymethylhydroxyethyl cellulose and a compound selected from the group consisting of alkali metal and ammonium dichromates, in the absence of a reducing agent, said compound being present in the approximate range of from about 0.25 to about 5 pounds per barrel of the gel.
Claim 3
Dependent Claim
33 words
The gel of claim 1 wherein the carboxymethylhydroxyethyl cellulose has a carboxymethyl D.S. in the approximate range of 0.1 to 0.9 and an hydroxethyl M.S. in the approximate range of 0.2 to 2.7.
Claim 4
Dependent Claim
24 words
A gel according to claim 1 wherein the metallic dichromatic compound is sodium dichromate dihydrate, Na 2 Cr 2 O 7 .2H 2 O.
Claim 5
Dependent Claim
16 words
The gel of claim 1 wherein the compound is selected from sodium, ammonium, and potassium dichromates.
Claim 6
Dependent Claim
24 words
The gel of claim 4 wherein the pH of the solution is less than about 5 to insure an acid or dichromate-ion forming medium.
Claim 7
Independent Claim
63 words
A method for producing a gelled polysaccharide which comprises bringing together in aqueous solution a viscosity increasing amount of carboxymethylhydroxyethyl cellulose and a compound selected from the group consisting of alkali metal and ammonium dichromates, in the absence of a reducing agent, said compound being present in the approximate range of from about 0.25 to about 5 pounds per barrel of the gel.
Claim 8
Independent Claim
63 words
A method for producing a gelled polysaccharide which comprises bringing together in aqueous solution a viscosity increasing amount of carboxymethylhydroxyethyl cellulose and a compound selected from the group consisting of alkali metal and ammonium dichromates, in the absence of a reducing agent, said compound being present in the approximate range of from about 0.25 to about 5 pounds per barrel of the gel.
Claim 9
Dependent Claim
34 words
A method according to claim 6 wherein the carboxymethylhydroxyethyl cellulose has a carboxymethyl D.S. in the approximate range of 0.1 to 0.9 and a hydroxyethyl M.S. in the approximate range of 0.2 to 2.7.
Claim 10
Dependent Claim
25 words
A well drilling operation in which a drilling fluid is employed which comprises circulating in said well while drilling a gel according to claim 1.
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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) | 1983-12-16 | 1984-06-16 | 1984-12-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-12-16 | 1988-06-16 | 1988-12-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-12-16 | 1992-06-16 | 1992-12-16 | $7700.00 | Window Closed / Lapsed |