# US 10,502,857 B2 · Device for measuring resistivity in a wellbore > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,502,857 B2 - Document ID: US10502857B2 - Status: Granted - Kind: B2 - Application number: 14/974,203 - Filed: 2015-12-18 - Published: 2016-06-23 - Granted: 2019-12-10 - Earliest claimed: 2014-12-19 - Assignees: Schlumberger Technology Corporation - Applicants: Schlumberger Technology Corporation - Inventors: Didier Fouillou - Web page: https://patentgrep.com/patent/US10502857B2 ## CPC - G01V 3/20: operating with propagation of electric current - E21B 47/00: Survey of boreholes or wells (monitoring pressure or flow of drilling fluid E21B21/08) - G01V 3/38: Processing data, e.g. for analysis, for interpretation, for correction - G01V 13/00: Manufacturing, calibrating, cleaning, or repairing instruments or devices covered by groups G01V1/00 – G01V11/00 - 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 The disclosure relates to a device for measuring resistivity to be mounted on a downhole tool and comprising: a watertight body, a first electrode and a second electrode electrically insulated from the first electrode and surrounding the first electrode, arranged in the body at a proximal end of the device, an electrical connecting module arranged in the body and comprising a first contacting element electrically coupled to the first electrode and a second contacting element electrically coupled to the second electrode, surrounding the first contacting element, with interposition of an electrically insulating material between the first and second contacting element; wherein the electrical connecting module projects from the body at a distal end of the device so as to form an electrical interface. ## Claims ### Claim 1 A device for measuring resistivity adapted to be mounted on a downhole tool intended to be lowered in a wellbore and comprising: a watertight body, a first electrode, a second electrode electrically insulated from the first electrode and surrounding the first electrode with respect to a reference axis of the device, and a third electrode insulated from the first and second electrodes and disposed between the first and the second electrodes so that the electrodes are concentric electrodes, arranged in the body at a proximal end of the device relative to the reference axis, wherein the first, second and third electrodes are used to perform resistivity measurements, an electrical connecting module arranged in the body and comprising a first contacting element electrically coupled to the first electrode, a second contacting element electrically coupled to the second electrode and a third contacting element electrically coupled to the third electrode, wherein the second contacting element has a generally hollow cylindrical shape, and is configured so that it surrounds the first contacting element with respect to the reference axis, with interposition of an electrically insulating material between the first and second contacting element, wherein the third contacting element is arranged between the first and second contacting elements with interposition of an electrically insulating material on each side of the third contacting element, wherein the third contacting element has a generally hollow cylindrical shape, and is positioned so as to surround the first contacting element wherein the second contacting element is configured to surround the third contacting element; wherein the contacting elements projects from the body at a distal end of the device so as to form an electrical interface. ### Claim 2 (depends on 1) The device of claim 1, wherein an electrically insulating material is interposed between the second contacting element and the body. ### Claim 3 (depends on 1) The device of claim 1, wherein the contacting elements are configured so that the first contacting element projects further from the distal end of the body than the second one. ### Claim 4 (depends on 1) The device of claim 1, wherein the body comprises a first part arranged around the electrical connecting module and a second part arranged around the electrodes and attached to the first part. ### Claim 5 (depends on 4) The device of claim 4, wherein the second part is overmolded on the first part. ### Claim 6 (depends on 5) The device of claim 5, wherein the first part of the body is made of a glass material, a ceramic material and/or a metallic material and the second part of the body is made of a thermoplastic material. ### Claim 7 (depends on 4) A manufacturing method of the device of claim 4, comprising: electrically coupling the electrical connecting module mounted in a first body part to first, second and third electrodes, overmolding a second body part on the first body part and the electrodes so that the first and second body parts form a watertight body. ### Claim 8 (depends on 1) The device of claim 1, wherein the body is at least partly constituted of a glass material, a ceramic material and/or a metallic material. ### Claim 9 (depends on 1) The device of claim 1, wherein at the proximal end of the device, at least a seal is interposed between two adjacent electrodes. ### Claim 10 (depends on 1) The device of claim 1, wherein each of the electrodes is forming part of a surface situated at the proximal end of the device. ### Claim 11 (depends on 1) A downhole tool intended to be lowered in a wellbore, comprising a collar including a housing and a device according to claim 1 arranged in the housing such that the proximal end of the device is situated outside of the collar while the distal end is situated inside of the collar. ### Claim 12 (depends on 11) The downhole tool of claim 11, wherein at least a peripheral seal is inserted between the body of the device and the collar so that a drilling fluid present in the wellbore does not contact the distal end of the device. ### Claim 13 (depends on 11) The downhole tool of claim 11, wherein at least one of the contacting elements of the electrical interface of the device is coupled to an electrical source, the downhole tool comprising a resistivity sensor for measuring a resistivity of an earth formation surrounding the wellbore and including the electrodes of the device.