# US 11,077,521 B2 · Creating radial slots in a subterranean formation > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,077,521 B2 - Document ID: US11077521B2 - Status: Granted - Kind: B2 - Application number: 15/522,968 - Filed: 2015-10-30 - Published: 2018-09-27 - Granted: 2021-08-03 - Earliest claimed: 2014-10-30 - Assignees: Schlumberger Technology Corporation - Applicants: Schlumberger Technology Corporation - Inventors: Bernard Montaron; Douglas Pipchuk - Web page: https://patentgrep.com/patent/US11077521B2 ## CPC - B23K 26/106: {inside the workpiece} - B23K 26/38: by boring or cutting - E21B 36/00: Heating, cooling or insulating arrangements for boreholes or wells, e.g. for use in permafrost zones - E21B 43/11: Perforators; Permeators - B23K 2101/10: Pipe-lines - E21B 36/003: {Insulating arrangements} - B23K: SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM - E21B: EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS ## Abstract A laser cutting apparatus conveyable within a casing lining at least a portion of a wellbore that extends into a subterranean formation. The laser cutting apparatus includes a housing, a deflector, a motor, a sensor, and a processing device. The deflector rotates relative to the housing to direct a laser beam to form a radial slot extending through the casing and into the subterranean formation. The motor rotates the deflector. The sensor generates information related to depth of the radial slot in real-time as the radial slot is formed by the laser beam. The processing device receives the information generated by the sensor and causes the motor to rotate the deflector based on the received information. ## Claims ### Claim 1 An apparatus, comprising: a laser cutting apparatus conveyable within a casing lining at least a portion of a wellbore that extends into a subterranean formation, wherein the laser cutting apparatus comprises: a housing; a deflector operable for rotation relative to the housing to direct a laser beam to form a radial slot extending through the casing and into the subterranean formation; a motor operable to rotate the deflector; a sensor operable to generate information related to a penetration depth of the radial slot into the subterranean formation in real-time as the radial slot is formed by the laser beam; a body connected to and rotatable by operation of the motor, and wherein the deflector and the sensor are each connected to and rotate with the body; and a processing device operable to receive the information generated by the sensor and cause the motor to rotate the deflector based on the received information. ### Claim 2 (depends on 1) The apparatus of claim 1 wherein the sensor is a light sensor operable to detect reflection of a portion of the laser beam from an end of the radial slot, and wherein the processing device is further operable to determine the penetration depth of the radial slot in real-time based on time of travel of the laser beam from the deflector to the light sensor. ### Claim 3 (depends on 1) The apparatus of claim 1 wherein the sensor is an acoustic sensor operable to emit an acoustic signal into the radial slot and detect reflection of the acoustic signal from an end of the radial slot. ### Claim 4 (depends on 1) The apparatus of claim 1 wherein the sensor is an electromagnetic sensor operable to emit an electromagnetic signal into the radial slot and detect reflection of the electromagnetic signal from an end of the radial slot. ### Claim 5 (depends on 1) The apparatus of claim 1 wherein the sensor comprises a signal emitter and a signal receiver, wherein the signal emitter is operable to emit a signal into the radial slot, wherein the signal receiver is operable to receive the signal reflected by an end of the radial slot, and wherein the processing device is further operable to determine the penetration depth of the radial slot in real-time based on a duration of travel of the signal between the signal emitter and the signal receiver. ### Claim 6 (depends on 1) The apparatus of claim 1 wherein: the wellbore extends from a wellsite surface; the laser cutting apparatus is conveyable within the casing via coiled tubing operable to communicate a fluid from the wellsite surface to the laser cutting apparatus; the fluid is substantially transparent to the laser beam; the deflector is operable to direct the laser beam along a first radial path; and the laser cutting apparatus further comprises a nozzle operable to discharge the fluid along a second radial path that at least partially overlaps the first radial path. ### Claim 7 A method, comprising: conveying a laser cutting apparatus within a casing lining at least a portion of a wellbore that extends into a subterranean formation; transmitting a laser beam to a deflector of the laser cutting apparatus; and operating a motor of the laser cutting apparatus to control rotation of a body connected to the deflector and at least one sensor of the laser cutting apparatus, thus directing the laser beam deflected by the deflector to form a radial slot extending through the casing to a predetermined depth within the subterranean formation, including operating the motor to sequentially rotate the deflector to each one of a plurality of angular positions and to maintain the deflector at each successive one of the plurality of angular positions until the laser beam penetrates the subterranean formation to the predetermined depth at the respective angular position based on a penetration depth measured by the at least one sensor, such that the radial slot extends through a predetermined angle encompassing the plurality of angular positions. ### Claim 8 (depends on 7) The method of claim 7 wherein each of the plurality of angular positions corresponds to a width of the laser beam. ### Claim 9 (depends on 7) The method of claim 7 wherein: the wellbore extends from a wellsite surface; conveying the laser cutting apparatus within the casing is via coiled tubing; the method further comprises communicating a fluid from the wellsite surface to the laser cutting apparatus via the coiled tubing; the fluid is substantially transparent to the laser beam; the deflector is operable to direct the laser beam along a first radial path at each of the plurality of angular positions; the method further comprises discharging the fluid from a nozzle of the laser cutting apparatus along a second radial path at each of the plurality of angular positions; and the second radial path at least partially overlaps the first radial path. ### Claim 10 (depends on 7) The method of claim 7 further comprising measuring the penetration depth of the laser beam into the subterranean formation in real-time at each of the plurality of angular positions using the at least one sensor of the laser cutting apparatus. ### Claim 11 (depends on 10) The method of claim 10 wherein measuring the penetration depth comprises: emitting a signal into the radial slot; receiving the signal reflected by an end of the radial slot; and determining depth of the radial slot based on a duration of travel of the signal. ### Claim 12 (depends on 10) The method of claim 10 wherein the at least one sensor comprises at least one of a light sensor, an acoustic sensor, and an electromagnetic sensor. ### Claim 13 A method, comprising: conveying a laser cutting apparatus within a casing lining at least a portion of a wellbore that extends into a subterranean formation; transmitting a laser beam to a deflector of the laser cutting apparatus; and operating a motor of the laser cutting apparatus to repeatedly rotate a body connected to the deflector and at least one sensor of the laser cutting apparatus through a plurality of cycles, wherein each of the plurality of cycles comprises a first substantially continuous rotation of the deflector through a predetermined angle in a first rotational direction and a second substantially continuous rotation of the deflector through the predetermined angle in a second rotational direction, thus directing the laser beam deflected by the deflector to form a radial slot extending radially through the casing and, with each successive one of the plurality of cycles, extend the radial slot to a predetermined depth within the subterranean formation based on a penetration depth measured by the at least one sensor, such that opposing first and second sides of the radial slot are angularly disposed at the predetermined angle. ### Claim 14 (depends on 13) The method of claim 13 wherein operating the motor further comprises decreasing angular velocity of the first and second substantially continuous rotations of the deflector during one or more of the plurality of cycles. ### Claim 15 (depends on 14) The method of claim 14 wherein the angular velocity of the first and second substantially continuous rotations of the deflector is decreased during one or more of the plurality of cycles by an amount to deliver a substantially constant amount of energy per unit length of the subterranean formation being cut at the penetration depth of the laser beam in that one of the plurality of cycles. ### Claim 16 (depends on 13) The method of claim 13 wherein: the wellbore extends from a wellsite surface; conveying the laser cutting apparatus within the casing is via coiled tubing; the method further comprises communicating a fluid from the wellsite surface to the laser cutting apparatus via the coiled tubing; the fluid is substantially transparent to the laser beam; the deflector is operable to direct the laser beam along a first radial path as the deflector is moved through the first and second substantially continuous rotations; the method further comprises discharging the fluid from a nozzle of the laser cutting apparatus along a second radial path as the deflector is moved through the first and second substantially continuous rotations; and the second radial path at least partially overlaps the first radial path at each point of the first and second substantially continuous rotations of the deflector. ### Claim 17 (depends on 13) The method of claim 13 further comprising measuring the penetration depth of the laser beam into the subterranean formation at least once during each of the plurality of cycles using the at least one sensor of the laser cutting apparatus. ### Claim 18 (depends on 17) The method of claim 17 wherein measuring the penetration depth comprises: emitting a signal into the radial slot; receiving the signal reflected by an end of the radial slot; and determining depth of the radial slot based on a duration of travel of the signal. ### Claim 19 (depends on 17) The method of claim 17 wherein the at least one sensor comprises at least one of a light sensor, an acoustic sensor, and an electromagnetic sensor.