US5159577A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Technique for reducing whirling of a drill string
Assignee: Halliburton Energy Services Inc
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Filing: 1991-09-05
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Granted: 1992-10-27
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Expires: 2011-09-05
Abstract
Abstract Improved techniques are provided for correcting signals from a downhole sensor on a drill collar eccentrically rotating within a borehole. The corrected sensor signal may be used to generate a well log which more accurately represents the conditions which the sensor would have generated had the tool been rotating such that the spacing between the sensor and the borehole well remained constant. The sensor signals are generated at time intervals of less than half the period of rotation of the drill collar. The frequency components of the time-varying sensor signals are plotted, and the frequency component attributable to the eccentric rotation between the drill collar and the borehole may be determined. The magnitude of this frequency component may be used to generate a correcting sensor signal, which then modifies the average sensor signal so that a more accurate well log may be obtained. The techniques of the present invention may be used to determine actual rotational speed of the drill collar and the spacing between the sensor and the wall, and are particularly well suited to determining a whirling condition in real time and alter drilling parameters in response thereto.
Inventors
- 👤 James R. Twist
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 17:37
CPC Classifications
G; G01; G01V; G01V1/00; G01V1/40; G01V1/44; G01V1/48; E; E21; E21B; E21B44/00; E21B47/00; G01V1/22; G01V11/00; G01V11/002; G01V3/00; G01V3/18
Claims Analysis
Total Claims: 23
Claim 1
Independent Claim
197 words
A method of monitoring downhole conditions and altering drilling of a borehole in response to periodic radial variations between a borehole wall and a sensor positioned on a rotating drill collar and whirling condition of the drill collar at the end of a drill string, the method comprising: (a) generating a plurality of discrete signals from the sensor indicative of a downhole condition; (b) transmitting the plurality of discrete signals to the surface; (c) averaging the transmitted signals to monitor downhole conditions as a function of time; (d) recording the plurality of discrete signals as a function of time to generate a plurality of time-varying sensor signal profiles; (e) detecting successive peaks in the plurality of sensor signal profiles attributable to changing radial spacing between the sensor and the borehole wall and whirling condition of the drill collar as the drill collar rotates within the borehole; (f) detecting a frequency shift in the detected peaks of the plurality of sensor signal profiles indicative of periodic changing radial spacing between the sensor and the borehole well and whirling condition of the drill collar; and (g) altering one or more drilling parameters in response to the detected frequency shift.
Claim 2
Independent Claim
197 words
A method of monitoring downhole conditions and altering drilling of a borehole in response to periodic radial variations between a borehole wall and a sensor positioned on a rotating drill collar and whirling condition of the drill collar at the end of a drill string, the method comprising: (a) generating a plurality of discrete signals from the sensor indicative of a downhole condition; (b) transmitting the plurality of discrete signals to the surface; (c) averaging the transmitted signals to monitor downhole conditions as a function of time; (d) recording the plurality of discrete signals as a function of time to generate a plurality of time-varying sensor signal profiles; (e) detecting successive peaks in the plurality of sensor signal profiles attributable to changing radial spacing between the sensor and the borehole wall and whirling condition of the drill collar as the drill collar rotates within the borehole; (f) detecting a frequency shift in the detected peaks of the plurality of sensor signal profiles indicative of periodic changing radial spacing between the sensor and the borehole well and whirling condition of the drill collar; and (g) altering one or more drilling parameters in response to the detected frequency shift.
Claim 3
Dependent Claim
56 words
The method as defined in claim 1, wherein step (f) includes determining the frequency components of the time-varying sensor signal profiles, detecting a frequency component indicative of the apparent rotational frequency of the drill string, and detecting a frequency shift in the detected rotational frequency component indicative of whirling of the drill collar in the borehole.
Claim 4
Dependent Claim
23 words
The method as defined in claim 1, wherein steps (a) and (b) are performed while rotating a drill bit to drill the borehole.
Claim 5
Dependent Claim
40 words
The method as defined in claim 1, wherein step (g) includes varying at least one drilling parameter from a group consisting of weight on bit, rotational speed of the drill string, and activation of a centralizer within the drill string.
Claim 6
Dependent Claim
24 words
The method as defined in claim 1, further comprising: selecting the downhole sensor from a group consisting of acoustic, gamma, neutron and electromagnetic sensors.
Claim 7
Dependent Claim
22 words
The method as defined in claim 1, further comprising: positioning a plurality of selected sensors circumferentially and axially within the drill collar.
Claim 8
Dependent Claim
39 words
The method as defined in claim 6, wherein steps (e) and (f) further comprise: determining the frequency components of the time-varying sensor signal profile; and detecting a shift in a frequency component indicative of whirling of the drill collar.
Claim 9
Dependent Claim
39 words
The method as defined in claim 1, further comprising: detecting the period between the detected peaks in the plurality of sensor signal profiles; and determining the apparent rotational speed of the drill collar in response to the detected period.
Claim 10
Independent Claim
169 words
A method of monitoring downhole conditions and altering drilling of a borehole in response to periodic radial variations between sensors positioned on a rotating drill collar at the end of a drill string, the method comprising: (a) generating a plurality of discrete signals from each of the plurality of sensors; (b) transmitting the plurality of discrete signals to the surface; (c) averaging the transmitted signals to monitor downhole conditions; (d) recording the plurality of discrete signals to generate a plurality of time-varying sensor signal profiles; (e) detecting successive peaks in the plurality of sensor signal profiles attributable to changing radial spacing between one or more of the plurality of sensors and the borehole wall as the drill collar rotates within the borehole; (f) detecting a frequency shift in the detected peaks of the plurality of sensor signal profiles indicative of periodic changing radial spacing between the one or more sensors and the borehole wall; and (g) altering one or more drilling parameters in response to the detected frequency shift.
Claim 11
Independent Claim
169 words
A method of monitoring downhole conditions and altering drilling of a borehole in response to periodic radial variations between sensors positioned on a rotating drill collar at the end of a drill string, the method comprising: (a) generating a plurality of discrete signals from each of the plurality of sensors; (b) transmitting the plurality of discrete signals to the surface; (c) averaging the transmitted signals to monitor downhole conditions; (d) recording the plurality of discrete signals to generate a plurality of time-varying sensor signal profiles; (e) detecting successive peaks in the plurality of sensor signal profiles attributable to changing radial spacing between one or more of the plurality of sensors and the borehole wall as the drill collar rotates within the borehole; (f) detecting a frequency shift in the detected peaks of the plurality of sensor signal profiles indicative of periodic changing radial spacing between the one or more sensors and the borehole wall; and (g) altering one or more drilling parameters in response to the detected frequency shift.
Claim 12
Dependent Claim
56 words
The method as defined in claim 9, wherein step (f) includes determining the frequency components of the time-varying sensor signal profiles, detecting a frequency component indicative of the apparent rotational frequency of the drill string, and detecting a frequency shift in the detected rotational frequency component indicative of whirling of the drill collar in the borehole.
Claim 13
Dependent Claim
23 words
The method as defined in claim 9, wherein steps (a) and (b) are performed while rotating a drill bit to drill the borehole.
Claim 14
Dependent Claim
38 words
The method as defined in claim 9, wherein step (g) includes varying at least one drilling parameter from a group consisting of weight-on-bit, rotational speed of a drill string, and activation of a centralizer within the drill string.
Claim 15
Dependent Claim
24 words
The method as defined in claim 9, further comprising: selecting the downhole sensor from a group consisting of acoustic, gamma, neutron and electromagnetic sensors.
Claim 16
Dependent Claim
22 words
The method as defined in claim 9, further comprising: positioning a plurality of selected sensors circumferentially and axially within the drill collars.
Claim 17
Independent Claim
172 words
A method of altering drilling of a borehole in response to periodic radial variations between a borehole wall and a rotating drill collar at the end of a drill string and the whirling of the drill collar in the borehole, the method comprising: (a) generating a plurality of discrete signals from the sensor; (b) transmitting the plurality of discrete signals to the surface; (c) recording the plurality of discrete signals as a function of time to generate a plurality of time-varying sensor signal profiles; (d) detecting successive peaks in the plurality of sensor signal profiles attributable to changing radial spacing and whirling condition between the sensor and the borehole wall as the drill collar rotates within the borehole; (e) detecting a frequency shift in the detected peaks of the plurality of sensor signal profiles indicative of periodic changing radial spacing between the sensor and the borehole wall and changing of the whirling condition of the drill collar; and (f) altering one or more drilling parameters in response to the detected frequency shift.
Claim 18
Independent Claim
172 words
A method of altering drilling of a borehole in response to periodic radial variations between a borehole wall and a rotating drill collar at the end of a drill string and the whirling of the drill collar in the borehole, the method comprising: (a) generating a plurality of discrete signals from the sensor; (b) transmitting the plurality of discrete signals to the surface; (c) recording the plurality of discrete signals as a function of time to generate a plurality of time-varying sensor signal profiles; (d) detecting successive peaks in the plurality of sensor signal profiles attributable to changing radial spacing and whirling condition between the sensor and the borehole wall as the drill collar rotates within the borehole; (e) detecting a frequency shift in the detected peaks of the plurality of sensor signal profiles indicative of periodic changing radial spacing between the sensor and the borehole wall and changing of the whirling condition of the drill collar; and (f) altering one or more drilling parameters in response to the detected frequency shift.
Claim 19
Dependent Claim
49 words
The method as defined in claim 15, wherein step (e) includes determining the frequency components of the time-varying sensor signal profiles, detecting a frequency component indicative of the apparent rotational frequency of the drill string, and rotational frequency component indicative of whirling of the drill collar in the borehole.
Claim 20
Dependent Claim
23 words
The method as defined in claim 15, wherein steps (a) and (b) are performed while rotating a drill bit to drill the borehole.
Claim 21
Dependent Claim
38 words
The method as defined in claim 15, wherein step (f) includes varying at least one drilling parameter from a group consisting of weight-on-bit, rotational speed of the drill string, and activation of a centralizer within the drill string.
Claim 22
Dependent Claim
35 words
The method as defined in claim 15, further comprising: selecting the downhole sensor from a group consisting of acoustic, gamma, neutron and electromagnetic sensors; and averaging the transmitted signals to monitor a downhole borehole condition.
Claim 23
Dependent Claim
22 words
The method as defined in claim 15, further comprising: positioning a plurality of selected sensors circumferentially and axially within the drill collar.
References Cited (Backward Citations)
GB318343A
Cited
US3876016A
Cited
US4017859A
Cited
US4661933A
Cited
US4698501A
Cited
US4773263A
Cited
GB2179736A
Cited
US4864129A
Cited
US4829176A
Cited
US4894534A
Cited
EP0282402A2
Cited
US4903245A
Cited
US5058077A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1995-10-27 | 1996-04-27 | 1996-10-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-10-27 | 2000-04-27 | 2000-10-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-10-27 | 2004-04-27 | 2004-10-27 | $7700.00 | Window Closed / Lapsed |