Baker Hughes Corporation

Baker Hughes, a Ge Compnay, LLC

Luis M Pelegri

Stanislav W Forgang

Randy Gold

Michael Rabinovich

Bill H Corley

Michael S Crosskno

Leonty Abraham Tabarovsky

Gulamabbas A Merchant

Cynthia Xue

Alexandre N Bespalov

Stephen V Painchaud

Tsili Wang

Hans-Martin Maurer

Vladimir S Mogilatov

Michael B Rabinovich

An apparatus for modifying an output signal indicative of a downhole parameter that may include a carrier conveyable in a wellbore; a negative error compensator; and an output signal device. The negative error compensator may be configured to modify the output of the device to increase or decrease a characteristic of the output signal from the output signal device. Also, a method for modifying an output signal indicative of a downhole parameter that may include modifying a characteristic of an output signal produced by a output signal device in a wellbore using a negative error compensator.

Current-to-voltage converters with dynamic feedback

Disclosed is a method for determining calibration factors of an induction tool that includes three receiver coils, each having a distinct orientation. The method includes: placing the induction logging tool in a first position at a first height above a surface of the earth; performing a first set of measurements of conductivity using the receiver coils with the induction logging tool in the first position at the first height; placing the induction logging tool in a second position at a second height above the surface of the earth; performing a second set of measurements of conductivity using the receiver coils with the induction logging tool in the second position at the second height; and determining the calibration factors that correct conductivity measurements performed by the induction logging tool in a borehole penetrating the earth using the first and second sets of measurements.

Triaxial induction calibration without prior knowledge of the calibration area's ground conductivity

An apparatus, method and computer-readable medium are provided for estimating a resistivity property of an earth formation. A logging tool includes a first antenna arrangement and a second antenna arrangement of the logging tool; and at least one device for maintaining the first antenna arrangement and the second antenna arrangement in proximity to a wall of the borehole. The first antenna arrangement and the second antenna arrangement may be at substantially the same axial location on the logging tool. Alternately, the first antenna arrangement and the second antenna arrangement may be at different axial positions on the logging tool. Extendible arms of the logging tool are configured to extend one or more of the first antenna arrangement and the second antenna arrangement against a face of the borehole.

Method and apparatus for reducing effect of tool eccentricity in a borehole on multi-axial induction measurements

Measurements made with a multicomponent logging system oriented in a horizontal position above the surface of the earth must satisfy certain relationships. These relationships are used to establish calibration errors in the system.

Calibration of XX, YY and ZZ induction tool measurements

A reactance is introduced into a flow path of axial currents in an induction logging tool. The reactance may be a capacitor or an inductor. A transmitter antenna is operated at a frequency defined by a cutoff frequency related to the reactance.

Borehole conductivity simulator verification and transverse antenna balancing

Multi-component induction measurements are made using a resistivity logging tool in an anistropic earth formation. The X-signal (quadrature) is insensitive to borehole eccentricity. A subset of the multi-component measurements are inverted to first determine horizontal resistivities. Using the determined horizontal resistivities and another subset of the multi-component measurements, the vertical resistivities are obtained. Results of using the in-phase signals are comparable to those obtained using multifrequency focusing of quadrature signals.

Methods and apparatus for determination of a formation resistivity property using eccentered measurements

Calibration of the arrays of a multicomponent induction logging tool is achieved by positioning the tool horizontally above ground. The upper and lower housings of the tool are connected by a borehole conductivity simulator which as a resistance comparable to that of a borehole. Axial and radial positioning of the transmitter coils is done by monitoring outputs at receiver coils to achieve a minimum.

Borehole conductivity simulator verification and transverse coil balancing

An apparatus, method and computer-readable medium for evaluating an earth formation are disclosed. A logging tool which has two coplanar antennas disposed at a known distance from an axis of the logging tool is conveyed into a borehole. The presence of a borehole effect is determined from a difference between outputs of the two antennas. The borehole effect may include eccentering of the logging tool in the borehole. Measurements made by an additional antenna and/or the two coplanar antennas may be corrected for the effects of eccentering. Horizontal and vertical formation resistivity as well as additional petrophysical properties may be determined.

Method and apparatus for detecting borehole effects due to eccentricity of induction instruments

Measurements made by a multi-component induction logging tool are corrected for tool eccentricity in a deviated borehole. The eccentricity angle is determined from single frequency skin-effect corrected data and is then used to correct multifrequency data. Multifrequency focusing is then applied to the corrected multifrequency data. An inversion is then used to recover formation resistivity and relative dip and azimuth of the borehole.

Correction of multi-component measurements for tool eccentricity in deviated wells

In a multicomponent logging tool, a coil is electrically isolated by open circuiting another, substantially orthogonal coil.

Mutual shielding of collocated induction coils in multi-component induction logging instruments

A multicomponent induction logging tool is positioned within an alignment loop and the transmitter is activated at a number of rotation angles of the tool. Misalignment between the transmitter and receiver coils can be determined from the induced signals in the receiver coil.

Cross-component alignment measurement and calibration

Misalignment of the transmitter and receiver coils of an induction logging tool is determined by positioning the logging tool with a coil axially encompassing the transmitter coil and/or the receiver coil, and activating the transmitter at a plurality of rotational angles.

Correction of misalignment of antennas in a downhole logging tool

Misalignment of the transmitter and receiver antennas of an induction logging tool is determined by positioning the logging tool with a conducting loop magnetically coupled to the transmitter antenna and/or the receiver antenna, and activating the transmitter at a plurality of rotational angles.

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Humble, TX, United States of America

Luis M Pelegri