# US 2020/0392829 A1 · Marking and sensing a borehole wall > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2020/0392829 A1 - Document ID: US20200392829A1 - Status: Published application - Kind: A1 - Application number: 16/898,491 - Filed: 2020-06-11 - Published: 2020-12-17 - Earliest claimed: 2019-06-16 - Assignees: Novatek IP, LLC - Applicants: Novatek IP, LLC - Inventors: Jonathan D. Marshall; David C. Hoyle; Scott Richard Woolston - Web page: https://patentgrep.com/patent/US20200392829A1 ## CPC - E21B 10/322: {cutter shifted by fluid pressure (E21B10/345 takes precedence)} - E21B 45/00: Measuring the drilling time or rate of penetration - E21B 7/28: Enlarging drilled holes, e.g. by counterboring - E21B 10/32: with expansible cutting tools - E21B 47/013: Devices specially adapted for supporting measuring instruments on drill bits - E21B 47/08: Measuring diameters or related dimensions at the borehole - E21B: EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS ## Abstract A downhole drilling apparatus, passing through a subterranean borehole, may mark an inner wall of the borehole with a marking element. A sensor, spaced axially from the marking element on the drilling apparatus, may subsequently sense the marking as it passes. A rate of penetration of the drilling apparatus may be calculated by dividing an axial distance, between the marking element and the sensor, by a time interval, between when the marking element marks the inner wall and when the marking is sensed by the sensor. Alternately, a second sensor, spaced axially from the first, may also sense the marking. A rate of penetration may then be calculated by dividing an axial distance, between the two sensors, by a time interval, between when the two sensors sense the marking. ## Claims ### Claim 1 A downhole drilling assembly, comprising: a marking element capable of marking an inner wall of a borehole; and a sensor, spaced axially from the marking element, capable of sensing the marking of the inner wall. ### Claim 2 (depends on 0) The downhole drilling assembly of claim 0, wherein the marking element comprises at least one of an extendable cutter, a laser, a fluid jet and an ink jet. ### Claim 3 (depends on 0) The downhole drilling assembly of claim 0, further comprising a processor capable of calculating a rate of penetration. ### Claim 4 (depends on 0) The downhole drilling assembly of claim 0, wherein the marking element comprises a radially extendable cutting element capable of degrading an inner wall of a borehole. ### Claim 5 (depends on 4) The downhole drilling assembly of claim 4, further comprising a reamer spaced axially from the sensor and extending radially farther than the extendable cutting element when the radially extendable cutting element is fully extended. ### Claim 6 (depends on 4) The downhole drilling assembly of claim 4, further comprising two radially extendable cutting elements spaced axially from each other and extendable together. ### Claim 7 (depends on 6) The downhole drilling assembly of claim 6, wherein the sensor is disposed axially between the two cutting elements. ### Claim 8 (depends on 0) The downhole drilling assembly of claim 0, further comprising a second sensor spaced axially from the sensor, the second sensor capable of sensing the marking of the inner wall. ### Claim 9 (depends on 0) The downhole drilling assembly of claim 0, wherein the sensor comprises at least one of an ultrasonic sensor, a resistivity sensor or a physical caliper. ### Claim 10 (depends on 0) The downhole drilling assembly of claim 0, wherein the sensor is spaced circumferentially from the marking element. ### Claim 11 A method for downhole drilling, comprising: marking an inner wall of a borehole with a marking element; and sensing the marking of the inner wall with a sensor spaced axially from the marking element. ### Claim 12 (depends on 11) The method for downhole drilling of claim 11, wherein the marking comprises extending a cutting element radially from an assembly to degrade an inner wall of a borehole. ### Claim 13 (depends on 12) The method for downhole drilling of claim 12, further comprising calculating a rate of penetration by: dividing an axial distance, between the cutting element and the sensor, by a time interval, between when the cutting element marks the inner wall and when the marking is sensed by the sensor. ### Claim 14 (depends on 13) The method for downhole drilling of claim 13, wherein when the cutting element marks the inner wall is determined by detecting extension of the cutting element. ### Claim 15 (depends on 12) The method for downhole drilling of claim 12, further comprising reaming degradation from the inner wall with a second cutting element spaced axially from the cutting element and radially extendable therewith. ### Claim 16 (depends on 11) The method for downhole drilling of claim 11, further comprising calculating a rate of penetration by: dividing an axial distance, between the marking element and the sensor, by a time interval, between when the marking element marks the inner wall and when the marking is sensed by the sensor. ### Claim 17 (depends on 11) The method for downhole drilling of claim 11, further comprising sensing the marking of the inner wall with a second sensor spaced axially from the sensor. ### Claim 18 (depends on 17) The method for downhole drilling of claim 17, further comprising calculating a rate of penetration by: dividing an axial distance, between the sensor and the second sensor, by a time interval, between when the marking is sensed by the sensor and when the marking is sensed by the second sensor. ### Claim 19 (depends on 11) The method for downhole drilling of claim 11, wherein marking the inner wall comprises varying a radius of the borehole and sensing the marking comprises identifying changes in standoff from the inner wall. ### Claim 20 (depends on 11) The method for downhole drilling of claim 11, wherein marking the inner wall comprises varying a radius of the borehole and sensing the marking comprises measuring a distance to the inner wall.