# US 10,502,860 B2 · Method for placement of surface electrodes for electromagnetic telemetry > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,502,860 B2 - Document ID: US10502860B2 - Status: Granted - Kind: B2 - Application number: 15/775,594 - Filed: 2016-11-03 - Published: 2018-11-22 - Granted: 2019-12-10 - Earliest claimed: 2015-11-13 - Assignees: Schlumberger Technology Corporation - Applicants: Schlumberger Technology Corporation - Inventors: Gaelle Jannin; Jiuping Chen; Andrew G. Brooks; David Kirk Conn; Luis Eduardo DePavia; Liang Sun; Michael W. Schwartz; Richard Hunter - Web page: https://patentgrep.com/patent/US10502860B2 ## CPC - G01V 3/34: Transmitting data to recording or processing apparatus; Recording data - E21B 47/125: using earth as an electrical conductor (by electromagnetic energy E21B47/13) - E21B 47/13: by electromagnetic energy, e.g. radio frequency - G01V 3/08: operating with magnetic or electric fields produced or modified by objects or geological structures or by detecting devices (with electromagnetic waves G01V3/12) - G01V 3/18: specially adapted for well-logging - 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) - G01V 3/28: using induction coils - 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 A method for placement of electrodes includes determining spatial distribution of a signal caused by generating an electromagnetic field in an instrument disposed in drill string used to drill a wellbore. The electromagnetic field comprises encoded measurements from at least one sensor associated with the instrument. Voltages induced by noise are measured across at least one pair of spaced apart electrodes placed at a plurality of positions spaced apart from a surface location of the wellbore. A spatial distribution of noise is estimated using the measured voltages. Positions for placement of at least two electrodes are selected using the spatial distribution of signal and the spatial distribution of noise. ## Claims ### Claim 1 A method for placement of electrodes, comprising: determining spatial distribution of a signal caused by generating an electromagnetic field in an instrument disposed in drill string used to drill a wellbore, the electromagnetic field comprising encoded measurements from at least one sensor associated with the instrument; measuring voltages induced by noise across at least one pair of spaced apart electrodes placed at a plurality of positions spaced apart from a surface location of the wellbore; estimating a spatial distribution of noise using the measured voltages; and selecting positions for placement of at least two electrodes using the spatial distribution of signal and the spatial distribution of noise. ### Claim 2 (depends on 1) The method of claim 1 wherein the generating an electromagnetic field comprises imparting a time varying voltage across in insulating gap between electrically conductive components of the instrument. ### Claim 3 (depends on 1) The method of claim 1 wherein the generating an electromagnetic field comprises imparting a time varying electric current through a toroidal coil forming part of the instrument. ### Claim 4 (depends on 1) The method of claim 1 wherein the estimating the spatial distribution of noise is performed while an electromagnetic telemetry device in the wellbore is switched off or on. ### Claim 5 (depends on 4) The method of claim 4 wherein the estimating the spatial distribution of noise comprises generating a noise map comprising the spatial distribution of noise. ### Claim 6 (depends on 5) The method of claim 5, further comprising identifying null noise zones in the generated noise map, wherein the electrode placement is determined based on the identified null noise zones. ### Claim 7 (depends on 5) The method of claim 5, wherein generating the noise map comprises: identifying one or more noise sources at a rig site; and modeling each of the noise sources as an equivalent dipole or bipole. ### Claim 8 (depends on 7) The method of claim 7 wherein at least four parameters are used to represent each of the noise sources, the four parameters including two dimensional coordinate distances from the surface end of the wellbore, a polarization angle, and a dipole moment. ### Claim 9 (depends on 7) The method of claim 7, further comprising: comparing the measured voltages and the generated noise map; and identifying dipole or bipole parameters for each of the noise sources that result in the generated noise map most closely matching the measured voltages. ### Claim 10 A method for communicating measurements from a sensor in a wellbore to Earth's surface, comprising: moving a wellbore instrument coupled to a drill string along an interior of a wellbore, the wellbore instrument including at least one sensor; generating an electromagnetic field in the wellbore instrument, the electromagnetic field comprising encoded measurements from the at least one sensor; measuring a signal corresponding to an amplitude and/or phase of the electromagnetic field, wherein the measuring the signal comprises measuring voltage induced across at least one pair of electrodes deployed proximate Earth's surface, the electrodes deployed at positions selected by determining spatial distribution of the electromagnetic field, measuring voltages induced by noise across at least one pair of spaced apart electrodes placed at a plurality of positions spaced apart from a surface location of the wellbore, estimating a spatial distribution of noise using the measured voltages and selecting positions for placement of the at least one pair of electrodes using the spatial distribution of the electromagnetic field and the spatial distribution of noise; and decoding the measurements from the measured signal. ### Claim 11 (depends on 10) The method of claim 10 wherein the estimating the spatial distribution of noise is performed while an electromagnetic telemetry device in the wellbore is switched off. ### Claim 12 (depends on 11) The method of claim 11 wherein the estimating the spatial distribution of noise comprises generating a noise map comprising the spatial distribution of noise. ### Claim 13 (depends on 12) The method of claim 12, further comprising identifying null noise zones in the generated noise map, wherein the selecting positions for placement of the at least one pair of electrodes is determined based on the identified null noise zones. ### Claim 14 (depends on 12) The method of claim 12, wherein generating the noise map comprises: identifying one or more noise sources at a rig site; and modeling each of the noise sources as an equivalent dipole or bipole. ### Claim 15 (depends on 14) The method of claim 14 wherein at least four parameters are used to represent each of the noise sources, the four parameters including two dimensional coordinate distances from the surface end of the wellbore, a polarization angle, and a dipole moment. ### Claim 16 (depends on 14) The method of claim 14, further comprising: comparing the measured voltages and the generated noise map; and identifying dipole or bipole parameters for each of the noise sources that result in the generated noise map most closely matching the measured voltages. ### Claim 17 (depends on 10) The method of claim 10 wherein the generating an electromagnetic field comprises imparting a time varying voltage across in insulating gap between electrically conductive components of the instrument. ### Claim 18 (depends on 10) The method of claim 10 wherein the generating an electromagnetic field comprises imparting a time varying electric current through a toroidal coil forming part of the instrument.