Patent US4213762A successfully refreshed from Google Patents.
US4213762A
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Determination of chromate ion in drilling mud filtrates
Assignee: ConocoPhillips Co
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Filing: 1978-12-14
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Granted: 1980-07-22
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Expires: 1998-12-14
Abstract
Abstract A method of determining the amount of chromate ion in drilling and mud filtrates containing lignosulfonates is disclosed. Briefly, the method comprises: (a) treating the filtrate with an effective amount of hydrogen peroxide to destroy any color bodies contributed by the lignosulfonate, and (b) measuring the amount of chromate ion in the filtrate by means of a spectrophotometer.
Inventors
- 👤 Donald L. Whitfill
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 09:56
CPC Classifications
G; G01; G01N; G01N31/00; E; E21; E21B; E21B49/00; E21B49/005; G01N21/00; G01N21/75; G01N21/77; G01N21/78
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
59 words
A method of determining the amount of chromate ion in an aqueous drilling mud filtrate containing organic color bodies such as lignosulfonate wherein the method comprises: (a) treating the aqueous filtrate with an effective amount of hydrogen peroxide to destroy said color bodies, and (b) measuring the amount of chromate ion in the filtrate by means of a spectrophotometer.
Claim 2
Independent Claim
59 words
A method of determining the amount of chromate ion in an aqueous drilling mud filtrate containing organic color bodies such as lignosulfonate wherein the method comprises: (a) treating the aqueous filtrate with an effective amount of hydrogen peroxide to destroy said color bodies, and (b) measuring the amount of chromate ion in the filtrate by means of a spectrophotometer.
Claim 3
Dependent Claim
32 words
The method of claim 1 wherein the mud filtrate contains about 0.7 to about 2.8 grams per liter of chromate ion and about 2.8 to about 28 grams per liter of lignosulfonate.
Claim 4
Dependent Claim
16 words
The method of claim 1 wherein the mud filtrate comes from a drilling mud containing bentonite.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1983-07-22 | 1984-01-21 | 1984-07-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-07-22 | 1988-01-21 | 1988-07-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-07-22 | 1992-01-21 | 1992-07-22 | $7700.00 | Window Closed / Lapsed |