Inertially-stabilized magnetometer measuring apparatus for use in a borehole rotary environment
First Claim
1. A measurement apparatus for making magnetic and gravity component measurements in a borehole, including measurements made while the apparatus is rotating about the borehole axis, comprising:
- a) a magnetic field component sensing device having at least two axes of sensitivity normal to the borehole axis and normal to each other, b) a gravity field component sensing device having at least two axes of sensitivity normal to the borehole axis and normal to each other, c) an inertial angular rotation sensing device having an axis of sensitivity along the borehole axis to sense inertial angular motion about the borehole axis, d) control, power and processing circuitry to operate said sensing devices and to process the outputs of said sensing devices to obtain stabilized component data in a coordinate system that does not rotate with the said measurement apparatus, e) and including a rotary drive mechanism, having a gimbal to support said a), b) and c) sensing devices, said rotary drive mechanism controlled by said c) inertial angular rotation sensing device, for example a gyroscope, to rotate said a) sensing device about the borehole axis, or to permit stabilization of the gimbal and the sensitive axes of said a) sensing device with respect to a fixed coordinate system, for example inertial space.
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Accused Products
Abstract
A measurement apparatus for making magnetic and gravity component measurements in a borehole, including measurements made while the apparatus is rotating about the borehole axis, comprising a magnetic field component sensing device having at least two axes of sensitivity normal to the borehole axis and normal to each other, a gravity field component sensing device having at least two axes of sensitivity normal to the borehole axis and normal to each other, an inertial angular rotation sensing device having an axis of sensitivity along the borehole axis to sense inertial angular motion about the borehole axis, control, power and processing circuitry to operate said sensing devices and to process the outputs of said sensing devices to obtain stabilized component data in a coordinate system that does not rotate with the said measurement apparatus, communication circuitry to transmit output data to auxiliary equipment at the surface or in the borehole, and support structure to support the sensing devices.
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Citations
15 Claims
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1. A measurement apparatus for making magnetic and gravity component measurements in a borehole, including measurements made while the apparatus is rotating about the borehole axis, comprising:
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a) a magnetic field component sensing device having at least two axes of sensitivity normal to the borehole axis and normal to each other, b) a gravity field component sensing device having at least two axes of sensitivity normal to the borehole axis and normal to each other, c) an inertial angular rotation sensing device having an axis of sensitivity along the borehole axis to sense inertial angular motion about the borehole axis, d) control, power and processing circuitry to operate said sensing devices and to process the outputs of said sensing devices to obtain stabilized component data in a coordinate system that does not rotate with the said measurement apparatus, e) and including a rotary drive mechanism, having a gimbal to support said a), b) and c) sensing devices, said rotary drive mechanism controlled by said c) inertial angular rotation sensing device, for example a gyroscope, to rotate said a) sensing device about the borehole axis, or to permit stabilization of the gimbal and the sensitive axes of said a) sensing device with respect to a fixed coordinate system, for example inertial space. - View Dependent Claims (3, 4, 5, 15)
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2. A measurement apparatus for making magnetic and gravity component measurements in a borehole, including measurements made while the apparatus is rotating about the borehole axis, comprising:
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a) a magnetic field component sensing device having at least two axes of sensitivity normal to the borehole axis and normal to each other, b) a gravity field component sensing device having at least two axes of sensitivity normal to the borehole axis and normal to each other, c) an inertial angular rotation sensing device having an axis of sensitivity along the borehole axis to sense inertial angular motion about the borehole axis, d) a rotary drive mechanism to rotate the said sensing devices about the borehole axis or to permit stabilization of the sensitive axes of said sensing devices with respect to a fixed coordinate system, e) control, power and processing circuitry to operate said sensing devices and to process the outputs of said sensing devices to obtain data for the operation of said rotary drive mechanism to achieve stabilized component data in a coordinate system that does not rotate with the said measurement apparatus, f) communication circuitry to transmit output data to auxiliary equipment at the surface or in the borehole, and g) support structure to support the elements a) through d). - View Dependent Claims (6, 14)
i) pendulous ii) non-pendulous.
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7. The method of making magnetic and gravity component measurements in a borehole, including measurements made while measurement apparatus is rotating about one axis extending lengthwise of the borehole, including the steps:
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a) said apparatus provided to have a magnetic field component sensing device having at least two axes of sensitivity normal to the borehole axis and normal to each other, b) said apparatus provided to have a gravity field component sensing device having at least two axes of sensitivity normal to the borehole axis and normal to each other, c) said apparatus provided to have an inertial angular rotation sensing device having an axis of sensitivity along the borehole axis to sense inertial angular motion about the borehole axis, d) providing control, power and processing circuitry to operate said sensing devices and to process the outputs of said sensing devices to obtain stabilized component data in a coordinate system that does not rotate with the said measurement apparatus, e) and providing and operating communication circuitry to transmit output data to auxiliary equipment at the surface or in the borehole, f) and providing a rotary drive mechanism, having a gimbal to support said a), b) and c) sensing devices, said rotary drive mechanism controlled by said c) inertial angular rotation sensing device, for example a gyroscope, to rotate said a) sensing device about the borehole axis, or to permit stabilization of the gimbal and the sensitive axes of said a) sensing device with respect to a fixed coordinate system, for example inertial space, and wherein one of the following modes of operation and control for the drive mechanism is provided;
x1) Stabilized directly to the inherent null output of the inertial angular rotation sensing device, x2) Stabilized in any fixed position about the borehole axis using the inertial angular rotation sensing device referenced to one of the following;
a. referenced to accelerometer data b. referenced to magnetometer data c. referenced to a rotation angle sensor provided as part of the rotary drive mechanism, x3) Continuous or intermittent rotation but controlled accurately to any selected rate or to any desired number of stopping points. - View Dependent Claims (8, 9, 10, 11, 12, 13)
x1) Stabilized directly to the inherent null output of the inertial angular rotation sensor x2) Stabilized in any fixed position about the borehole axis using the inertial angular rotation sensor referenced to one of the following;
a. referenced to accelerometer data b. referenced to magnetometer data c. referenced to a rotation angle sensor provided as part of the rotary drive means, x3) Continuous or intermittent rotation but controlled accurately to any selected rate or to any desired number of stopping points.
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Specification