David Wayne Beard

US Patent:

6348792, Feb 19, 2002

Filed:

Oct 2, 2000

Appl. No.:

09/677359

Inventors:

David Beard - Houston TX
Arcady Reiderman - Houston TX

Assignee:

Baker Hughes Incorporated - Houston TX

International Classification:

G01V 300

US Classification:

324303, 324300, 324307

Abstract:

A side-looking NMR logging tool incorporates a permanent magnet arrangement having a magnetization direction oriented towards a side of the tool and a dipole RF antenna displaced towards the front of the tool. The magnet arrangement produces a shaped region of investigation in front of the tool wherein the magnetic field has a uniform field strength and the RF field has a uniform field strength in a direction orthogonal to the static field. The shaping of the static field is accomplished by the magnet arrangement comprising a plurality of magnets having parallel magnetization or by a single shaped magnet. The antenna arrangement includes a gapped core made of non-ferritic soft material for increasing the antenna efficiency. The magnet arrangement also reduces ringing in the core and the antenna. An optional RF shield is used to reduce NMR signals from borehole fluids.

US Patent:

6437564, Aug 20, 2002

Filed:

May 1, 2001

Appl. No.:

09/846971

Inventors:

Gregory Boris Itskovich - Houston TX
David Beard - Houston TX
Arcady Reiderman - Houston TX

Assignee:

Baker Hughes Incorporated - Houston TX

International Classification:

G01V 300

US Classification:

324303, 324300

Abstract:

The static magnetic field of a permanent magnet used in an NMR tool moves with the tool. NMR measurements made with a moving tool are affected by incomplete polarization of the nuclear spins in the region where the Larmor frequency of static field matches the RF signal frequency. Simulation results show that the in-phase and quadrature components of spin echo signals are affected by the velocity of lateral motion of a logging tool in a borehole. A phase drift indicator is obtained by summing the quadrature and in-phase components over a window and taking the ratio of the windowed sums. The phase drift indicator shows an increase with time. In a tool with a gradient magnetic field, the phase drift indicator increases with time even for no tool motion. The reduction in magnitude of spin echo data due to tool motion alone may be obtained by comparing the magnitude of simulated echoes with and without tool motion.

US Patent:

6445180, Sep 3, 2002

Filed:

Jun 28, 2000

Appl. No.:

09/605265

Inventors:

Arcady Reiderman - Houston TX
David Beard - Houston TX

Assignee:

Baker Hughes Incorporated - Houston TX

International Classification:

G01V 300

US Classification:

324303

Abstract:

A novel nuclear magnetic resonance (NMR) probe design for operating in a bore hole to obtaining the NMR characteristics of a region of interest adjacent the bore hole, characterized by a main RF antenna, a magnet, and a spoiler antenna. The spoiler antenna performs as an active shield for generating a resultant RF field that forcefully mismatches the static magnetic field inside the bore hole and substantially does not affects the RF field or antenna sensitivity in the region of interest.

US Patent:

6452388, Sep 17, 2002

Filed:

Jun 28, 2000

Appl. No.:

09/605463

Inventors:

Arcady Reiderman - Houston TX
David R. Beard - Houston TX

Assignee:

Baker Hughes Incorporated - Houston TX

International Classification:

G01V 300

US Classification:

324303, 324318, 324322, 324309

Abstract:

The present invention provides a novel use of a powdered high saturation flux density soft magnetic material as a NMR probe core material. The probe structural geometry facilitates the use of powdered material, which has a relatively low magnetic permeability.

US Patent:

6525535, Feb 25, 2003

Filed:

Nov 30, 2001

Appl. No.:

09/997451

Inventors:

Arcady Reiderman - Houston TX
David R. Beard - Houston TX

Assignee:

Baker Hughes Incorporated - Houston TX

International Classification:

G01V 300

US Classification:

324303, 324300

Abstract:

The invention is a method and apparatus for performing NMR measurements in MWD effective for large and small boreholes. The invention uses a magnet assembly to produce a generally oval static magnetic field. The invention also employs an antenna assembly comprised of a primary and secondary antenna to deliver a sequence of RF magnetic pulses. For small holes, the antenna assembly operates to substantially match the iso-lines of the static magnetic field within the rock formation during a transmission pulse. For large holes, the invention works in a side-looking mode and the antenna assembly operates both to match the iso-lines of the static magnetic field within the rock formation and to diminish the magnetic field within the borehole during a transmission pulse. The secondary antenna can also be used as a receiver of spin echo signals, or optionally, to make adjustments to the received signal.

US Patent:

6580273, Jun 17, 2003

Filed:

Feb 15, 2002

Appl. No.:

10/077488

Inventors:

Arcady Reiderman - Houston TX
David R. Beard - Houston TX

Assignee:

Baker Hughes Incorporated - Houston TX

International Classification:

G01V 300

US Classification:

324303, 324300

Abstract:

A side-looking NMR logging tool incorporates a permanent magnet arrangement having a magnetization direction oriented towards a side of the tool and a dipole RF antenna displaced towards the front of the tool. The magnet arrangement produces a shaped region of investigation in front of the tool wherein the magnetic field has a uniform field strength and the RF field has a uniform field strength in a direction orthogonal to the static field. The shaping of the static field is accomplished by the magnet arrangement comprising a plurality of magnets having parallel magnetization or by a single shaped magnet. The antenna arrangement includes a gapped core made of non-ferritic soft material for increasing the antenna efficiency. The magnet arrangement also reduces ringing in the core and the antenna. An optional RF shield is used to reduce NMR signals from borehole fluids.

US Patent:

6597170, Jul 22, 2003

Filed:

Jun 29, 2000

Appl. No.:

09/606998

Inventors:

David Beard - Houston TX
Gregory Itskovich - Houston TX
Arcady Reiderman - Houston TX
Songhua Chen - Katy TX

Assignee:

Baker Hughes Incorporated - Houston TX

International Classification:

G01V 300

US Classification:

324303

Abstract:

Pulse shaping is used for reducing the interference between echo trains of multiple frequency NMR logging applications in a gradient logging tool. The major contribution to the interference between different logging sequences comes from the sidelobes in the spectra of the excitation signal caused by modulating the RF signal with a square pulse. By shaping the tipping pulse in a CPMG pulse sequence, the interference between logging sequences at proximate frequencies is reduced. The shaped pulse may be a smooth function such as the Chebyshev function or it may be a composite of two rectangular pulses. In an alternate embodiment of the invention, the refocusing pulses are also shaped.

US Patent:

6897651, May 24, 2005

Filed:

May 15, 2003

Appl. No.:

10/439100

Inventors:

Arcady Reiderman - Houston TX, US
David R. Beard - Houston TX, US
Zinovy B. Krugliak - Houston TX, US

Assignee:

Baker Hughes Incorporated - Houston TX

International Classification:

G01V003/00

US Classification:

324303, 324306

Abstract:

The invention is a method of reducing the effects of non-formation signals in an NMR logging echo signal obtained within a borehole in an earth formation. The method obtains a non-formation signal by the application of at least an excitation pulse, and preferably also at least one refocusing pulse. The obtained signal is used to numerically construct a synthetic ringing signal sequence. The constructed signal can then be subtracted from an NMR echo signal to reduce the effects of ringing.