# US 10,865,620 B1 · Downhole ultraviolet system for mitigating lost circulation > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,865,620 B1 - Document ID: US10865620B1 - Status: Granted - Kind: B1 - Application number: 16/720,982 - Filed: 2019-12-19 - Granted: 2020-12-15 - Earliest claimed: 2019-12-19 - Assignees: Saudi Arabian Oil Company - Applicants: Saudi Arabian Oil Company - Inventors: Jothibasu Ramasamy; Chinthaka Pasan Gooneratne - Web page: https://patentgrep.com/patent/US10865620B1 ## CPC - E21B 33/138: Plastering the borehole wall; Injecting into the formation - C09K 8/508: macromolecular compounds {(C09K8/512 takes precedence)} - C09K 8/512: containing cross-linking agents - E21B 21/003: {Means for stopping loss of drilling fluid (plastering the borehole wall E21B33/138)} - E21B 33/13: Methods or devices for cementing, for plugging holes, crevices or the like - E21B 41/00: Equipment or details not covered by groups E21B15/00 - E21B40/00 - E21B: EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS - C09K: MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE ## Abstract Method and systems for sealing a lost circulation zone of a subterranean well include extending a drill string into the subterranean well, the drill string having an ultraviolet system, an actuator, and a fluid flow path. The actuator is instructed to transmit an on signal to the ultraviolet system to switch the ultraviolet system to an on condition. In the on condition the ultraviolet system generates ultraviolet light directed towards the fluid flow path of the drill string. A loss circulation material is delivered into the fluid flow path of the drill string, the loss circulation material having an oligomer, a monomer, and a photo-initiator. The loss circulation material is exposed to the ultraviolet light to activate the loss circulation material. The loss circulation material is delivered to the lost circulation zone. ## Claims ### Claim 1 A method for sealing a lost circulation zone of a subterranean well, the method including: extending a drill string into the subterranean well, the drill string having an ultraviolet system, an actuator, and a fluid flow path; instructing the actuator to transmit an on signal to the ultraviolet system to switch the ultraviolet system to an on condition, where in the on condition the ultraviolet system generates ultraviolet light directed towards the fluid flow path of the drill string, where instructing the actuator to transmit the on signal to the ultraviolet system to switch the ultraviolet system to the on condition includes rotating the drill string in a predetermined on signal pattern; delivering a loss circulation material into the fluid flow path of the drill string, the loss circulation material having an oligomer, a monomer, and a photo-initiator; exposing the loss circulation material to the ultraviolet light to activate the loss circulation material; and delivering the loss circulation material to the lost circulation zone. ### Claim 2 (depends on 1) The method of claim 1, further including after exposing the loss circulation material to the ultraviolet light, instructing the actuator to transmit an off signal to the ultraviolet system to switch the ultraviolet system to an off condition by rotating the drill string in a predetermined off signal pattern. ### Claim 3 (depends on 1) The method of claim 1, where the photo-initiator is a benzyl dimethyl acetal, and where exposure to the ultraviolet irradiation by the ultraviolet system causes the benzyl dimethyl acetal to generate a free radical. ### Claim 4 (depends on 1) The method of claim 1, where the oligomer is a polyacrylate and the monomer is a styrene, and where exposure to the ultraviolet irradiation by the ultraviolet system triggers a polymerization reaction of the styrene and the polyacrylate. ### Claim 5 (depends on 1) The method of claim 1, further including forming a cross-linked polymer within the lost circulation zone and ceasing drilling of the subterranean well until the cross-linked polymer has hardened and set within the lost circulation zone. ### Claim 6 (depends on 5) The method of claim 5, further including after the cross-linked polymer has hardened and set within the lost circulation zone, resuming drilling of the subterranean well and drilling from a position uphole of the lost circulation zone to a position downhole of the lost circulation zone. ### Claim 7 (depends on 1) The method of claim 1, where the oligomer is a resin selected from a group consisting of unsaturated polyester resin, acrylated epoxy resin, acrylated polyurethane epoxy resin, acrylated styrene resin, and acrylated ether resin. ### Claim 8 (depends on 1) The method of claim 1, where the ultraviolet system includes a light emitting diode type ultraviolet light source. ### Claim 9 (depends on 1) The method of claim 1, where the actuator is a tubular actuator assembly, and the method includes securing the tubular actuator assembly to a downhole end of a joint of the drill string. ### Claim 10 (depends on 9) The method of claim 9, where the ultraviolet system is a tubular ultraviolet assembly that is located downhole of the tubular actuator assembly, and the method further includes securing a drill bit assembly to a downhole side of the tubular ultraviolet assembly. ### Claim 11 (depends on 1) The method of claim 1, where the actuator is a tubular actuator assembly having: an internal pipe member with a segment formed of a first material; an external pipe member circumscribing the internal pipe member; a bearing positioned between the internal pipe member and the external pipe member, the bearing formed of a second material, where the first material is reactive to the second material; where instructing the actuator to transmit the on signal to the ultraviolet system includes rotating the external pipe member relative to the internal pipe member and interpreting a pattern of a reaction of the segment as the bearing rotates past the segment. ### Claim 12 A system for sealing a lost circulation zone of a subterranean well, the system including: a drill string having an ultraviolet system, an actuator, and a fluid flow path; the actuator operable to transmit an on signal to the ultraviolet system to switch the ultraviolet system to an on condition, where in the on condition the ultraviolet system generates ultraviolet light directed towards the fluid flow path of the drill string; a predetermined on signal pattern defined by rotation of the drill string, the predetermined on signal pattern operable to instruct the actuator to transmit the on signal to the ultraviolet system to switch the ultraviolet system to the on condition; and a loss circulation material for delivery into the fluid flow path of the drill string, the loss circulation material having an oligomer, a monomer, and a photo-initiator operable to be activated upon exposure to an ultraviolet irradiation by the ultraviolet system. ### Claim 13 (depends on 12) The system of claim 12, further including a predetermined off signal pattern defined by rotation of the drill string, the predetermined off signal pattern operable to instruct the actuator to transmit an off signal to the ultraviolet system to switch the ultraviolet system to an off condition. ### Claim 14 (depends on 12) The system of claim 12, where the photo-initiator is a benzyl dimethyl acetal that is operable to generate a free radical when exposed to the ultraviolet irradiation by the ultraviolet system. ### Claim 15 (depends on 12) The system of claim 12, where the oligomer is a polyacrylate and the monomer is a styrene, and where exposure to the ultraviolet irradiation by the ultraviolet system is operable to trigger a polymerization reaction of the styrene and the polyacrylate. ### Claim 16 (depends on 12) The system of claim 12, further including a cross-linked polymer set within the lost circulation zone, the cross-linked polymer including the oligomer, and the monomer. ### Claim 17 (depends on 12) The system of claim 12, where the ultraviolet system includes a light emitting diode type ultraviolet light source. ### Claim 18 (depends on 12) The system of claim 12, where the actuator is a tubular actuator assembly secured to a downhole end of a joint of the drill string.