US4297880A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Downhole pressure measurements of drilling mud
Assignee: Lockheed Martin Corp
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Filing: 1980-02-05
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Granted: 1981-11-03
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Expires: 2000-02-05
Abstract
Abstract Pressure measurements of drilling mud inside the drill string and outside by transducers mounted in an instrumentation sub near the drill bit provide rapid notice of the instrusion of fluids or solids into the borehole and also permit appropriate adjusting of the mud pumping pressure.
Inventors
- 👤 Eugene L. Berger
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 12:56
CPC Classifications
E; E21; E21B; E21B21/00; E21B21/08; E21B47/00; E21B47/06; E21B47/10
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
99 words
Intrusion detection means for detecting the intrusion into a well bore of material having a density different from that of the drilling mud comprising: a drill string having an instrumentation sub as a part thereof; said instrumentation sub having a passage for drilling mud therein; a first pressure transducer in said instrumentation sub exposed to the pressure of the drilling mud in said passage and producing an electrical signal representative thereof; and a second pressure transducer in said instrumentation sub exposed to the pressure of the drilling mud outside said instrumentation sub and producing an electrical signal representative thereof.
Claim 2
Dependent Claim
99 words
Intrusion detection means for detecting the intrusion into a well bore of material having a density different from that of the drilling mud comprising: a drill string having an instrumentation sub as a part thereof; said instrumentation sub having a passage for drilling mud therein; a first pressure transducer in said instrumentation sub exposed to the pressure of the drilling mud in said passage and producing an electrical signal representative thereof; and a second pressure transducer in said instrumentation sub exposed to the pressure of the drilling mud outside said instrumentation sub and producing an electrical signal representative thereof.
Claim 3
Dependent Claim
22 words
Apparatus in accordance with claim 1 wherein: said first and second pressure transducers are located in the wall of said instrumentation sub.
Claim 4
Dependent Claim
23 words
Apparatus in accordance with claim 1 wherein: said first and second pressure transducers are located in an instrumentation package in said instrumentation sub.
Claim 5
Dependent Claim
32 words
Apparatus in accordance with claims 2 or 3 wherein: said second pressure transducer is a differential pressure transducer which is also exposed to the pressure of the drilling mud in said passage.
References Cited (Backward Citations)
US2924432A
Cited
US3422672A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1984-11-02 | 1985-05-04 | 1985-11-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-11-02 | 1989-05-04 | 1989-11-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-11-02 | 1993-05-04 | 1993-11-03 | $7700.00 | Window Closed / Lapsed |