# US 11,442,196 B2 · Systems and methods to calibrate individual component measurement > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,442,196 B2 - Document ID: US11442196B2 - Status: Granted - Kind: B2 - Application number: 15/767,501 - Filed: 2015-12-18 - Published: 2018-10-11 - Granted: 2022-09-13 - Earliest claimed: 2015-12-18 - Assignees: Halliburton Energy Services, Inc. - Applicants: Halliburton Energy Services, Inc. - Inventors: Hsu-Hsiang Wu - Web page: https://patentgrep.com/patent/US11442196B2 ## CPC - G01V 13/00: Manufacturing, calibrating, cleaning, or repairing instruments or devices covered by groups G01V1/00 – G01V11/00 - G01V 3/26: operating with magnetic or electric fields produced or modified either by the surrounding earth formation or by the detecting device (with electromagnetic waves G01V3/30) - E21B 47/0228: using electromagnetic energy or detectors therefor - G01V: GEOPHYSICS; GRAVITATIONAL MEASUREMENTS; DETECTING MASSES OR OBJECTS; TAGS (means for indicating the location of accidentally buried, e.g. snow-buried, persons A63B29/02) - E21B: EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS ## Abstract Apparatus and procedures that provide calibration for measurement tools can be implemented in a number of applications. Tool constant matrices generated in such calibration procedures can be utilized in downhole ranging measurements. Additional apparatus, systems, and methods are can be used in a variety of applications. ## Claims ### Claim 1 A method comprising: determining a set of calibration coefficients for each sensor of a plurality of sensors of a ranging tool, wherein each one of the sensors is configured as a single component sensor, and wherein for each one of the individual sensors of the plurality of sensors the method further comprising: conducting magnetic field measurements, using the individual sensor, at four or more different azimuthal angles of the individual sensor with respect to a rotational position of the ranging tool relative to a line extending to a center of an excitation source from a center of the ranging tool, the excitation source having a current of a known value flowing in the excitation source, the ranging tool separated from the excitation source at a known distance from a center of the ranging tool to a center of the excitation source; selecting four of the magnetic field measurements corresponding to four azimuthal angles of the four or more different azimuthal angles of the individual sensor; generating, using a processor, the set of calibration coefficients for a tool constant matrix for the individual sensor using values determined for the four selected magnetic field measurements and a design matrix, wherein the design matrix is based on the known value of the current, the known distance from the center of the ranging tool to the center of the excitation source, the four azimuthal angles of the four or more different azimuthal angles, and a known orientation of the individual sensor; and storing, using a storage device, the set of calibration coefficients of the tool constant matrix for the individual sensor in a tool constant matrix library; and determining a ranging distance comprising: conducting second magnetic field measurements at a selected tool azimuth angle, using the plurality of sensors, in response to current flowing in a conductive structure, the ranging tool and the conductive structure disposed below a surface of earth; creating a second tool constant matrix using the set of calibration coefficients for each one of the individual sensors of the plurality of sensors from the tool constant matrix library; and processing values of the second magnetic field measurements, using the processor, to generate the ranging distance from the ranging tool to the conductive structure, the processing including: generating an inverse of the second tool constant matrix for the selected tool azimuthal angle; generating a second design matrix from a multiplication of a matrix of values from the second magnetic field measurements and the inverse of the second tool constant matrix; and generating the ranging distance based on a calculated value for a total magnetic field and a calculated value for a gradient magnetic field, including using a first set of two elements of the second design matrix to calculate the total magnetic field and using a second set of two elements of the second design matrix to calculate the gradient magnetic field. ### Claim 2 (depends on 1) The method of claim 1, further comprising forming a set of tool constant matrices for each one of the individual sensors, each matrix of the set of tool constant matrices generated for a different tool face angle of the respective individual sensor relative to the excitation source, wherein conducting the magnetic field measurements at the four or more different azimuthal angles comprises conducting magnetic field measurements at a plurality of different azimuthal angles in a range from 0° to 360°, and wherein forming the set of tool constant matrices for each one of the individual sensors for the different tool face angles relative to the excitation source includes forming the set of tool constant matrices at the plurality of different azimuthal angles; and storing coefficients of the set of tool constant matrices in the tool constant matrix library for each one of the individual sensors. ### Claim 3 (depends on 1) The method of claim 1, wherein the plurality of sensors are configured to sense in either a tangential direction or in a normal direction at the different azimuthal angles. ### Claim 4 (depends on 1) The method of claim 1, further comprising: prior to generating the ranging distance, selecting a third tool constant matrix from the tool constant matrix library; calculating a direction to the conductive structure using an application of the third tool constant matrix to the second magnetic field measurements; and selecting a second set of calibration coefficients for the second tool constant matrix based on the calculated direction. ### Claim 5 (depends on 1) The method of claim 1, wherein using the plurality of sensors includes: using at least two sensors with measurements in one stationary position of the ranging tool, or using at least two azimuthal measurements taken with one sensor of the plurality of sensors due to a rotation operation of the ranging tool. ### Claim 6 (depends on 1) The method of claim 1, further comprising generating a ranging direction using a ratio of the first set of two elements of the second design matrix used to calculate the total magnetic field. ### Claim 7 A machine-readable storage device having instructions stored thereon, which, when performed by a machine, cause the machine to perform operations, the operations comprising: determining a set of calibration coefficients for each sensor of a plurality of sensors of a ranging tool, wherein each one of the sensors is configured as a single component sensor, and wherein for each one of the individual sensors of the plurality of sensors the operations further comprise: conducting magnetic field measurements, using the individual sensor, at four or more different azimuthal angles of the individual sensor with respect to a rotational position of the ranging tool relative to a line extending to a center of an excitation source from a center of the ranging tool, the excitation source having a current of a known value flowing in the excitation source, the ranging tool separated from the excitation source at a known distance from a center of the ranging tool to a center of the excitation source; selecting four of the magnetic field measurements corresponding to four azimuthal angles of the four or more different azimuthal angles of the individual sensor; generating, using a processor, the set of calibration coefficients for a tool constant matrix for the individual sensor using values determined for the four selected magnetic field measurements and a design matrix, wherein the design matrix is based on the known value of the current, the known distance from the center of the ranging tool to the center of the excitation source, the four azimuthal angles of the four or more different azimuthal angles, and a known orientation of the individual sensor; and storing, using a storage device, the set of calibration coefficients of the tool constant matrix for the individual sensor in a tool constant matrix library; and determining a ranging distance comprising: conducting second magnetic field measurements at a selected tool azimuth angle, using the plurality of sensors, in response to current flowing in a conductive structure, the ranging tool and the conductive structure disposed below a surface of earth; creating a second tool constant matrix using the set of calibration coefficients for each one of the individual sensors of the plurality of sensors from the tool constant matrix library; and processing values of the second magnetic field measurements, using the processor, to generate the ranging distance from the ranging tool to the conductive structure, the processing including: generating an inverse of the second tool constant matrix for the selected tool azimuthal angle; generating a second design matrix from a multiplication of a matrix of values from the second magnetic field measurements and the inverse of the second tool constant matrix; and generating the ranging distance based on a calculated value for a total magnetic field and a calculated value for a gradient magnetic field, including using a first set of two elements of the second design matrix to calculate the total magnetic field and using a second set of two elements of the second design matrix to calculate the gradient magnetic field. ### Claim 8 (depends on 7) The machine-readable storage device of claim 7, wherein the operations further comprise: forming a set of tool constant matrices for each one of the individual sensors of the one or more sensors, each matrix of the set of tool constant matrices generated for a different tool face angle of the respective individual sensor relative to the excitation source, wherein conducting the magnetic field measurements at the four or more different azimuthal angles comprises conducting magnetic field measurements at a plurality of different azimuthal angles in the range from 0° to 360°, and wherein forming the set of tool constant matrices for each one of the individual sensors for the different tool face angles relative to the excitation source includes forming the set of tool constant matrices at the plurality of different azimuthal angles; and storing coefficients of the set of tool constant matrices in the tool constant matrix library for each one of the individual sensors. ### Claim 9 (depends on 7) The machine-readable storage device of claim 7, wherein the plurality of sensors are configured to sense in either a tangential direction or in a normal direction at the different azimuthal angles. ### Claim 10 (depends on 7) The machine-readable storage device of claim 7, wherein the operations further comprise: prior to generating the ranging distance, selecting a third tool constant matrix from the tool constant matrix library; calculating a ranging direction to the conductive structure using an application of the selected third tool constant matrix to the second magnetic field measurements; and selecting a second set of calibration coefficients for the second tool constant matrix from the tool constant library based on the calculated ranging direction. ### Claim 11 (depends on 7) The machine-readable storage device of claim 7, wherein using the plurality of sensors incudes: using at least two sensors with measurements in a stationary position of the ranging tool, or using at least two azimuthal measurements taken with one sensor of the plurality of sensors due to a rotation operation of the ranging tool. ### Claim 12 (depends on 7) The machine-readable storage device of claim 7, wherein the operations comprise generating a ranging direction using a ratio of the first set of two elements of the second design matrix used to calculate the total magnetic field. ### Claim 13 A system comprising: a current generator coupled to an excitation source to provide a current to the excitation source, the current having a known value; a plurality of sensors disposed on a ranging tool; and a processor configured to determine a set of calibration coefficients for each one of the plurality of sensors, each one of the plurality of sensors configured as a single component sensor, wherein for each one of the individual sensors of the plurality of sensors the processor is configured to: conduct magnetic field measurements, using the individual sensor, at four or more different azimuthal angles of the individual sensor with respect to a rotational position of the ranging tool relative to a line extending to a center of the excitation source from a center of the ranging tool, the ranging tool separated from the excitation source at a known distance from the center of the ranging tool to the center of the excitation source; select four of the magnetic field measurements corresponding to four azimuthal angles of the four or more different azimuthal angles of the individual sensor; generate the set of calibration coefficients for a tool constant matrix for the individual sensor using values determined for the four selected magnetic field measurements and a design matrix, wherein the design matrix is based on the known value of the current, the known distance from the center of the ranging tool to the center of the excitation source, the four azimuthal_angles of the four or more different azimuthal angles, and a known orientation of the individual sensor; and store, using a storage device, the set of calibration coefficients of the tool constant matrix for the individual sensor in a tool constant matrix library; wherein the processor is arranged, for each of the plurality of sensors, to generate a ranging distance from the ranging tool to a conductive structure, including the processor arranged to: receive values of second magnetic field measurements of the plurality of sensors for a selected tool azimuth angle in response to current flowing in the conductive structure, the ranging tool and the conductive structure disposed below a surface of the earth; create a second tool constant matrix using the set of calibration coefficients for each one of the individual sensors of the plurality of sensors from the tool constant matrix library; generate an inverse of the second tool constant matrix for the selected tool azimuthal angle; generate a second design matrix from a multiplication of a matrix of the values from the second magnetic field measurements and the inverse of the tool constant matrix; and generate the ranging distance based on a calculated value for a total magnetic field and a calculated value for a gradient magnetic field, including by use of a first set of two elements of the second design matrix to calculate the total magnetic field and use of a second set of two elements of the second design matrix to calculate the gradient magnetic field. ### Claim 14 (depends on 13) The system of claim 13, wherein the processor is arranged to: form a set of tool constant matrices for each one of the individual sensors, each matrix of the set of tool constant matrices generated for a different tool face angle of the respective individual sensor relative to the excitation source, wherein receiving values of the magnetic field measurements at the four or more different azimuthal angles comprises receiving values of magnetic field measurements at a plurality of different azimuthal angles in the range from 0° to 360°, and wherein forming the set of tool constant matrices for each one of the individual sensors for the different tool face angles relative to the excitation source includes tool constant matrices at the plurality of different azimuthal angles; and store coefficients of the set of tool constant matrices in the tool constant matrix library for each one of the individual sensors. ### Claim 15 (depends on 13) The system of claim 13, wherein the plurality of sensors are configured to sense in either a tangential direction or in a normal direction at the different azimuthal angles. ### Claim 16 (depends on 13) The system of claim 13, wherein the processor is arranged to: prior to generation of the ranging distance, select a third tool constant matrix from the tool constant matrix library; calculate a ranging direction to the conductive structure using an application of the selected third tool constant matrix to the second magnetic field measurements; and select a second set of calibration coefficients for the second tool constant matrix from the tool constant library based on the calculated ranging direction. ### Claim 17 (depends on 13) The system of claim 13, wherein the plurality of sensors includes at least two sensors to conduct measurements in one stationary position of the ranging tool or one sensor of the plurality of sensors to conduct measurements at two or more azimuthal measurements corresponding to a rotation operation of the ranging tool, wherein the plurality of sensors are arranged only oriented normally with respect to a center of the ranging tool or only oriented tangentially with respect to the center of the ranging tool, and wherein the processor is arranged to generate a ranging direction by use of a ratio of the two elements of the second design matrix used to calculate the total magnetic field.