Patent US3268017A successfully refreshed from Google Patents.
US3268017A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Drilling with two fluids
Assignee: Shell USA Inc
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Filing: 1963-07-15
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Granted: 1966-08-23
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Expires: 1983-07-15
Abstract
No abstract record available.
Inventors
- 👤 Jack G Yarbrough
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 12:20
CPC Classifications
E; E21; E21B; E21B21/00; E21B21/12; E21B21/08
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
123 words
METHOD OF EXTENDING THE DEPTH OF A BOREHOLE IN THE EARTH BY DRILLING WHICH COMPRISES THE STEPS OF: (A) ROTATING A DRILL BIT IN END OF DUAL DRILL STRING TOM OF SAID BOREHOLE AT THE END OF A DUAL DRILL STRING HAVING SEPARATE UP-FLOW AND DOWN-FLOW PASSAGES, (B) ESTABLISHING AND MAINTAINING AN ANNULAR SUBSTANTIALLY STATIONARY COLUMN OF LIQUID THAT CONTAINS WALLCOATING MATERIAL BETWEEN THE WALL OF THE BOREHOLE AND SAID DUAL DRILL STRING AT A PRESSURE AT LEAST SUFFICIENT TO BALANCE SUBSTANTIALLY THE PRESSURE FLUIDS IN THE EARTH FORMATION ENCOUNTERED BY THE BOREHOLE, THE BOTTOM OF SAID UP-FLOW PASSAGE BEING IN COMMUNICATION WITH THE BOTTOM OF SAID LIQUID COLUMN SAID WITH THE SPACE AT THE BOTTOM OF THE BOREHOLE ADJOINING THE DRILL BIT,
Claim 2
Dependent Claim
123 words
METHOD OF EXTENDING THE DEPTH OF A BOREHOLE IN THE EARTH BY DRILLING WHICH COMPRISES THE STEPS OF: (A) ROTATING A DRILL BIT IN END OF DUAL DRILL STRING TOM OF SAID BOREHOLE AT THE END OF A DUAL DRILL STRING HAVING SEPARATE UP-FLOW AND DOWN-FLOW PASSAGES, (B) ESTABLISHING AND MAINTAINING AN ANNULAR SUBSTANTIALLY STATIONARY COLUMN OF LIQUID THAT CONTAINS WALLCOATING MATERIAL BETWEEN THE WALL OF THE BOREHOLE AND SAID DUAL DRILL STRING AT A PRESSURE AT LEAST SUFFICIENT TO BALANCE SUBSTANTIALLY THE PRESSURE FLUIDS IN THE EARTH FORMATION ENCOUNTERED BY THE BOREHOLE, THE BOTTOM OF SAID UP-FLOW PASSAGE BEING IN COMMUNICATION WITH THE BOTTOM OF SAID LIQUID COLUMN SAID WITH THE SPACE AT THE BOTTOM OF THE BOREHOLE ADJOINING THE DRILL BIT,
References Cited (Backward Citations)
US1585969A
Cited
US2425193A
Cited
US2657016A
Cited
US2786652A
Cited
US3075589A
Cited
US3040822A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1969-08-22 | 1970-02-21 | 1970-08-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1973-08-22 | 1974-02-21 | 1974-08-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1977-08-22 | 1978-02-21 | 1978-08-23 | $7700.00 | Window Closed / Lapsed |