US3268017A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Drilling with two fluids
Assignee: Shell USA Inc
•
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 08:48
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)
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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 |