Daniel M Woo

US Patent:

6575033, Jun 10, 2003

Filed:

Oct 1, 1999

Appl. No.:

09/410634

Inventors:

Sverre Knudsen - Trondheim, NO
Arne Berg - Kattem, NO
James R. Dunphy - South Glastonbury CT
Daniel Woo - Missouri City TX

Assignee:

Weatherford/Lamb, Inc. - Houston TX

International Classification:

G01P 1508

US Classification:

7351426, 7351416

Abstract:

A highly sensitive accelerometer for determining the acceleration of a structure includes a mass within a housing suspended by opposing support members. The support members are alternately wound around a pair of fixed mandrels and the mass in a push pull arrangement. At least a portion of one of the support members comprises a transducer capable measuring the displacement of the mass within the housing. An embodiment of the invention employs optical fiber coils as the support members for use in interferometric sensing processes. Arrays of such interferometer based accelerometers may be multiplexed using known techniques.

US Patent:

6789424, Sep 14, 2004

Filed:

Feb 14, 2003

Appl. No.:

10/366900

Inventors:

Sverre Knudsen - Trondheim, NO
Arne Berg - Kattem, NO
James R. Dunphy - South Glastonbury CT
Daniel Woo - Missouri City TX

Assignee:

Weatherford/Lamb, Inc. - Houston TX

International Classification:

G01P 1508

US Classification:

7351426, 25022714, 25022718

Abstract:

A highly sensitive accelerometer for determining the acceleration of a structure includes a mass within a housing suspended by opposing support members. The support members are alternately wound around a pair of fixed mandrels and the mass in a push pull arrangement. At least a portion of one of the support members comprises a transducer capable measuring the displacement of the mass within the housing. An embodiment of the invention employs optical fiber coils as the support members for use in interferometric sensing processes. Arrays of such interferometer based accelerometers may be multiplexed using known techniques.

US Patent:

7013729, Mar 21, 2006

Filed:

Sep 2, 2004

Appl. No.:

10/933132

Inventors:

Sverre Knudsen - Trondheim, NO
Arne Berg - Kattem, NO
James R. Dunphy - South Glastonbury CT, US
Daniel Woo - Missouri City TX, US

Assignee:

Weatherford/Lamb, Inc. - Houston TX

International Classification:

G01P 15/08

US Classification:

7351426, 25022714, 25022718

Abstract:

A highly sensitive accelerometer for determining the acceleration of a structure includes a mass within a housing suspended by opposing support members. The support members are alternately wound around a pair of fixed mandrels and the mass in a push pull arrangement. At least a portion of one of the support members comprises a transducer capable measuring the displacement of the mass within the housing. An embodiment of the invention employs optical fiber coils as the support members for use in interferometric sensing processes. Arrays of such interferometer based accelerometers may be multiplexed using known techniques.

US Patent:

8050144, Nov 1, 2011

Filed:

Jul 8, 2009

Appl. No.:

12/499759

Inventors:

Daniel M. Woo - Missouri City TX, US

Assignee:

Geospace Technologies LP - Houston TX

International Classification:

H04R 11/00

US Classification:

367187, 367183, 367185

Abstract:

A vertical geophone that includes a lower frequency spring, which forms part of the geophone electrical circuit, that is positioned directly on the lower end cap This arrangement eliminates the “spring supported by a spring” arrangement of prior art geophones to minimize geophone distortion and simplify tuning of the frequency springs. A contact spring is positioned between the lower frequency spring and the lower pole piece for forming part of the geophone electrical circuit. One surface of contact spring includes a plurality of wiper surfaces that ensure consistent sliding electrical contact against either the bottom surface of the lower pole piece or the upper surface of the lower frequency spring. The obverse surface of the contact spring is preferably spot welded to the other adjacent member.

US Patent:

8098546, Jan 17, 2012

Filed:

Jul 8, 2009

Appl. No.:

12/499741

Inventors:

Daniel M. Woo - Missouri City TX, US

Assignee:

Geospace Technologies, LP - Houston TX

International Classification:

H04R 9/00
H04R 11/00

US Classification:

367182, 367185

Abstract:

A geophone utilizing an Alnico-9 magnet and having an improved sensitivity over Alnico-9 geophones of prior art through the lengthening of the parasitic air gap between the upper and lower pole pieces which, results in less magnetic flux leakage. The flux concentration through the geophone coils is increased and shifted towards the ends of the magnet. The increase of sensitivity of geophone of the present invention over prior art geophones may exceed 3 dB. The axial length of the coil bobbin is increased, and the positions of the electrical coils are moved towards the ends of the magnet to align with the shifted magnetic flux.

US Patent:

8208347, Jun 26, 2012

Filed:

Jul 8, 2009

Appl. No.:

12/499751

Inventors:

Daniel M. Woo - Missouri City TX, US

Assignee:

Geospace Technologies, LP - Houston TX

International Classification:

H04R 9/02

US Classification:

367182

Abstract:

A geophone in which a coil bobbin assembly ideally includes a provision for receiving a third coil winding between the upper and lower coils. A third mass-tuning coil is wound around the bobbin whose purpose is to adjust the overall mass of the bobbin assembly with greater accuracy and precision than can be achieved by machining techniques alone. Mass is adjusted by adding or subtracting one or more turns of wire in the tuning coil. The tuning coil is preferably electrically shorted for increasing geophone damping.

US Patent:

20040184352, Sep 23, 2004

Filed:

Mar 20, 2003

Appl. No.:

10/393170

Inventors:

Daniel Woo - Missouri City TX, US

International Classification:

H04R001/00

US Classification:

367/149000

Abstract:

A pressure compensated hydrophone for measuring dynamic pressures is disclosed. The hydrophone includes a compliant hollow mandrel with a single optical fiber coiled around at least a portion of the mandrel. The mandrel further includes at least one pressure relief valve for compensating for changes in hydrostatic pressure. The pressure relief valve includes a micro-hole, which allows hydrostatic pressures or low frequency pressure events to couple into the interior of the mandrel to provide compensation against such pressure. Higher frequencies pressure events of interest do not couple through the micro-hole and therefore only act only on the exterior of the mandrel, allowing for their detection. Because (quasi) hydrostatic events are compensated for, the mandrel may be made particularly compliant, rendering the singular fiber optic coil particularly sensitive to the detection of the higher frequency signals of interest.

US Patent:

20040202401, Oct 14, 2004

Filed:

Mar 9, 2004

Appl. No.:

10/796569

Inventors:

Arne Berg - Kattem, NO
Sverre Knudsen - Trondheim, NO
Geir Havsgard - Trondheim, NO
Daniel Woo - Missouri City TX, US
James Dunphy - South Glastonbury CT, US

International Classification:

G02B006/26

US Classification:

385/012000

Abstract:

An acoustic sensor, such as a hydrophone, is deployable in a fluidic media having high temperature, high pressure, and/or potentially caustic chemicals. The hydrophone includes a housing filled with an internal fluid and containing a sensing mandrel. The sensing mandrel senses the acoustic pressure transmitted to the internal fluid through a diaphragm. The sensing mandrel preferably includes a polymer tubular mandrel having a coil of optical fiber wound and bonded to its outer surface. The sensing mandrel can be suspended within the housing instead of being rigidly attached thereto. To relieve pressure created by thermal expansion of the internal fluid, the flexible diaphragm, a filler member, a pressure compensator, or combinations thereof can be used. The filler member is mounted in the hydrophone and reduces the amount of internal fluid required in the housing. The compensator may be a bellows or a buffer tube.