# US 12,000,227 B1 · Untethered near-wellbore stimulation > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,000,227 B1 - Document ID: US12000227B1 - Status: Granted - Kind: B1 - Application number: 18/092,831 - Filed: 2023-01-03 - Granted: 2024-06-04 - Earliest claimed: 2023-01-03 - Assignees: Saudi Arabian Oil Company - Applicants: Saudi Arabian Oil Company - Inventors: Ahmed Y. Bukhamseen; Saad AlMutairi; Fahd Ibrahim AlGhunaimi - Web page: https://patentgrep.com/patent/US12000227B1 ## CPC - E21B 31/005: {using vibrating or oscillating means} - E21B 37/00: Methods or apparatus for cleaning boreholes or wells (E21B21/00 takes precedence) - E21B 43/26: by forming crevices or fractures - E21B 47/09: Locating or determining the position of objects in boreholes or wells {, e.g. the position of an extending arm}; Identifying the free or blocked portions of pipes - E21B 47/095: by detecting an acoustic anomalies, e.g. using mud-pressure pulses - E21B 47/138: {Devices entrained in the flow of well-bore fluid for transmitting data, control or actuation signals} - E21B 47/26: Storing data down-hole, e.g. in a memory or on a record carrier - E21B: EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS ## Abstract A stimulation tool for dislodging material from a perforation formed through a tubular disposed in a wellbore includes a main body formed at least in part from a material that is buoyant in a wellbore fluid, a ballast, a magnet, and a pressure pulse generator. The tool is configured to descend downhole by force of gravity when the ballast is attached and couple, by the magnet, to an interior surface of the tubular upon arrival at a downhole location proximate the perforation. When the tool is coupled by the magnet to the interior of the tubular, the tool transmits pressure pulses from the pressure pulse generator into the perforation, thereby dislodging material from the perforation. The tool de-couples from the interior surface and releases the ballast, thereby permitting the tool to ascend uphole, driven at least partially by a buoyant force exerted by the wellbore fluids. ## Claims ### Claim 1 An untethered stimulation tool for dislodging material from a perforation formed through a tubular disposed in a wellbore, the untethered stimulation tool comprising: a main body, wherein the main body is formed at least in part from a material that is buoyant in a wellbore fluid; a ballast; a magnet; and a pressure pulse generator, wherein the untethered stimulation tool is configured to: by a force of gravity when the ballast is attached to the untethered stimulation tool, descend from a wellhead downhole within the tubular; couple, by the magnet, to an interior surface of the tubular upon arrival of the untethered stimulation tool at a downhole location proximate the perforation; when the untethered stimulation tool is coupled by the magnet to the interior of the tubular, transmit pressure pulses from the pressure pulse generator into the perforation, thereby dislodging material from the perforation; and de-couple from the interior surface and release the ballast, thereby permitting the untethered stimulation tool to ascend uphole, driven at least partially by a buoyant force exerted by the wellbore fluids. ### Claim 2 (depends on 1) The untethered stimulation tool of claim 1, further comprising a power boost circuit to charge a capacitor to switch a state of the magnet. ### Claim 3 (depends on 2) The tool of claim 2, wherein the power boost circuit powers the pressure pulse generator. ### Claim 4 (depends on 1) The untethered stimulation tool of claim 1, wherein the de-coupling the untethered stimulation tool is by switching the magnet. ### Claim 5 (depends on 1) The untethered stimulation tool of claim 1, wherein the releasing the ballast is by switching the magnet. ### Claim 6 (depends on 1) The untethered stimulation tool of claim 1, wherein the magnet is a first magnet and wherein the untethered stimulation tool further comprises a second magnet, and wherein the releasing the ballast is by switching the second magnet. ### Claim 7 (depends on 1) The untethered stimulation tool of claim 1, wherein the untethered stimulation tool further comprises a controller, and wherein: the controller comprises: a processor; and a storage medium, wherein the storage medium comprises instructions to direct the processor to: measure data correlating to a depth in the wellbore; release the ballast at a target depth; switch a state of the magnet; and activate the pressure pulse generator. ### Claim 8 (depends on 7) The untethered stimulation tool of claim 7, further comprising a pressure sensor to collect data correlating to depth. ### Claim 9 (depends on 7) The untethered stimulation tool of claim 7, further comprising a casing collar locator to collect data correlating to depth. ### Claim 10 (depends on 7) The untethered stimulation tool of claim 7, further comprising a pressure sensor to collect data correlating to depth. ### Claim 11 (depends on 1) The untethered stimulation tool of claim 1, wherein the tubular comprises a metallic wellbore casing. ### Claim 12 (depends on 1) The untethered stimulation tool of claim 1, wherein the pressure pulse generator comprises a piezoelectric actuator. ### Claim 13 A method for stimulating a near-wellbore area, comprising: dropping an untethered stimulation tool from a wellhead into a tubular disposed in a wellbore at least partially filled with a wellbore fluid, the untethered stimulation tool comprising: a main body, wherein the main body is formed at least in part from a material that is buoyant in the wellbore fluid; a ballast; a magnet; and a pressure pulse generator, wherein the untethered stimulation tool is configured to, when the ballast is attached to the untethered stimulation tool, descend downhole within the tubular by a force of gravity; coupling the untethered stimulation tool by the magnet to an interior surface of the tubular upon arrival of the untethered stimulation tool at a downhole location proximate the perforation; when the untethered stimulation tool is coupled by the magnet to the interior of the tubular, activate a pressure pulse generator to transmit pressure pulses into the perforation, thereby dislodging material from the perforation; de-coupling the untethered stimulation tool from the interior surface; after de-coupling the untethered stimulation tool, releasing the ballast, thereby permitting the untethered stimulation tool to ascend uphole, driven at least partially by a buoyant force exerted by the wellbore fluids; and after releasing the ballast, retrieving the untethered stimulation tool at the wellhead. ### Claim 14 (depends on 13) The method of claim 13, wherein the untethered stimulation tool further comprises a power boost circuit to charge a capacitor to switch a state of the magnet. ### Claim 15 (depends on 14) The method of claim 14, wherein the power boost circuit powers the pressure pulse generator. ### Claim 16 (depends on 13) The method of claim 13, wherein the de-coupling the untethered stimulation tool is by switching the magnet. ### Claim 17 (depends on 13) The method of claim 13, wherein the releasing the ballast is by switching the magnet. ### Claim 18 (depends on 13) The method of claim 13, wherein the magnet is a first magnet and wherein the untethered stimulation tool further comprises a second magnet, and wherein the releasing the ballast is by switching the second magnet. ### Claim 19 (depends on 13) The method of claim 13, wherein the untethered stimulation tool further comprises a controller, and wherein: the controller comprises: a processor; and a storage medium, wherein the storage medium comprises instructions to direct the processor to: measure data correlating to a depth in the wellbore; release the ballast at a target depth; switch a state of the magnet; and activate the pressure pulse generator. ### Claim 20 (depends on 13) The method of claim 13, further comprising determining a depth of the untethered stimulation tool. ### Claim 21 (depends on 13) The method of claim 13, wherein the tubular comprises a metallic wellbore casing. ### Claim 22 (depends on 13) The method of claim 13, wherein the pressure pulse generator comprises a piezoelectric actuator.