# US 11,306,576 B2 · Directional drilling device and method for calibrating same > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,306,576 B2 - Document ID: US11306576B2 - Status: Granted - Kind: B2 - Application number: 16/940,038 - Filed: 2020-07-27 - Published: 2020-11-26 - Granted: 2022-04-19 - Earliest claimed: 2016-02-08 - Assignees: Smart Drilling GmbH - Applicants: Smart Drilling GmbH - Inventors: Werner Vorhoff - Web page: https://patentgrep.com/patent/US11306576B2 ## CPC - E21B 44/005: {Below-ground automatic control systems} - E21B 7/04: Directional drilling - E21B 7/06: Deflecting the direction of boreholes - E21B 47/024: of devices in the borehole (determining slope or direction of the borehole E21B47/022) - E21B 49/00: Testing the nature of borehole walls; Formation testing; Methods or apparatus for obtaining samples of soil or well fluids, specially adapted to earth drilling or wells - E21B 47/07: Temperature - E21B 47/18: through the well fluid {, e.g. mud pressure pulse telemetry} - E21B: EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS ## Abstract A directional drilling device includes a housing, a drive shaft extending through the housing, a plurality of magnetic field sensors positioned in the housing and in signal communication with a control device also positioned in the housing, wherein the magnetic field sensors are configured to determine a magnetic interference declination influenced by a magnetic interference field as a magnetic interference flux density and to transmit a magnetic interference declination value corresponding to a magnetic interference flux density to the control device, and a directional control device coupled to the housing and controllable by the control device to control a position of the directional drilling device, wherein the control device is configured to generate a correction value based on the magnetic interference declination value, and wherein the correction value corresponds to a deviation of the magnetic interference flux density from a reference magnetic flux density measured at a reference standard. ## Claims ### Claim 1 A directional drilling device, comprising: a housing; a drive shaft extending through the housing, wherein a drill bit is coupled to an end of the drive shaft; a plurality of magnetic field sensors positioned in the housing and in signal communication with a control device also positioned in the housing, wherein the magnetic field sensors are configured to determine a magnetic interference declination influenced by a magnetic interference field as a magnetic interference flux density and to transmit a magnetic interference declination value corresponding to a magnetic interference flux density to the control device; and a directional control device coupled to the housing and controllable by the control device to control a position of the directional drilling device; wherein the control device is configured to generate a correction value based on the magnetic interference declination value, and wherein the correction value corresponds to a deviation of the magnetic interference flux density from a reference magnetic flux density measured at a reference standard. ### Claim 2 (depends on 1) The directional drilling device of claim 1, wherein the magnetic field sensors are configured to determine a magnetic position declination influenced by an altered alignment of the direction drilling device as a magnetic position flux density. ### Claim 3 (depends on 2) The directional drilling device of claim 2, wherein the magnetic field sensors are configured to transmit a position value corresponding to the magnetic position declination to the control device. ### Claim 4 (depends on 3) The directional drilling device of claim 3, wherein the control device is configured to generate a correction factor corresponding to the position value for returning the directional drilling device to a predefined position. ### Claim 5 (depends on 4) The directional drilling device of claim 4, wherein the control device is configured to store the correction value and the correction factor in a memory of the control device. ### Claim 6 (depends on 1) The directional drilling device of claim 1, wherein the magnetic field sensors are configured to determine a plurality of the magnetic interference declinations as magnetic interference flux densities in the direction of X, Y, and Z axes. ### Claim 7 (depends on 1) The directional drilling device of claim 1, wherein the magnetic field sensors are calibrated by a homogenous magnetic field generated by a Helmholtz coil. ### Claim 8 A directional drilling device, comprising: a housing; a drive shaft extending through the housing, wherein a drill bit is coupled to an end of the drive shaft; a plurality of magnetic field sensors positioned in the housing and in signal communication with a control device also positioned in the housing, wherein the magnetic field sensors are configured to determine a magnetic interference declination influenced by a magnetic interference field as a magnetic interference flux density and to transmit a magnetic interference declination value corresponding to the magnetic interference flux density to the control device, and wherein the magnetic field sensors are calibrated by homogenous magnetic field generated by a Helmholtz coil; and a directional control device coupled to the housing and controllable by the control device to control a position of the directional drilling device; wherein the control device is configured to generate a correction value based on the magnetic interference declination value. ### Claim 9 (depends on 8) The directional drilling device of claim 8, wherein the correction value corresponds to a deviation of the magnetic interference flux density from a reference magnetic flux density measured at a reference standard. ### Claim 10 (depends on 8) The directional drilling device of claim 8, wherein the magnetic field sensors are configured to determine a magnetic position declination influenced by an altered alignment of the direction drilling device as a magnetic position flux density. ### Claim 11 (depends on 10) The directional drilling device of claim 10, wherein the magnetic field sensors are configured to transmit a position value corresponding to the magnetic position declination to the control device. ### Claim 12 (depends on 11) The directional drilling device of claim 11, wherein the control device is configured to generate a correction factor corresponding to the position value for returning the directional drilling device to a predefined position. ### Claim 13 (depends on 12) The directional drilling device of claim 12, wherein the control device is configured to store the correction value and the correction factor in a memory of the control device. ### Claim 14 (depends on 8) The directional drilling device of claim 8, wherein the magnetic field sensors are configured to determine a plurality of the magnetic interference declinations as magnetic interference flux densities in the direction of X, Y, and Z axes. ### Claim 15 A method for operating a directional drilling device, comprising: (a) determining a magnetic interference declination influenced by a magnetic interference field as a magnetic interference flux density; (b) determining a magnetic interference declination value corresponding to the magnetic interference flux density; (c) generating a correction value based on the magnetic interference declination value, wherein the correction value corresponds to a deviation of the magnetic interference flux density from a reference magnetic flux density measured at a reference standard; and (d) controlling a direction of the directional drilling device based on the correction value. ### Claim 16 (depends on 15) The method of claim 15, further comprising: (e) transmitting the magnetic interference declination value from a plurality of magnetic field sensors of the directional drilling device to a control device of the direction drilling device, wherein the control device is configured to generate the correction value. ### Claim 17 (depends on 16) The method of claim 16, wherein the plurality of magnetic field sensors are calibrated by a homogenous magnetic field generated by a Helmholtz coil. ### Claim 18 (depends on 15) The method of claim 15, further comprising: (e) determining a magnetic position declination influenced by an altered alignment of the direction drilling device as a magnetic position flux density; and (f) generating a correction factor based on the magnetic position declination for returning the directional drilling device to a predefined position. ### Claim 19 (depends on 18) The method of claim 18, further comprising: (g) storing the correction value and the correction factor in a memory of a control device of the direction drilling device. ### Claim 20 (depends on 15) The method of claim 15, wherein (a) comprises determining a plurality of the magnetic interference declinations as magnetic interference flux densities in the direction of X, Y, and Z axes.