# US 2025/0093076 A1 · Closed well loop for a geothermal system > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2025/0093076 A1 - Document ID: US20250093076A1 - Status: Published application - Kind: A1 - Application number: 18/824,954 - Filed: 2024-09-05 - Published: 2025-03-20 - Earliest claimed: 2023-09-20 - Assignees: Schlumberger Technology Corporation - Applicants: Schlumberger Technology Corporation - Inventors: Ashley Bernard Johnson - Web page: https://patentgrep.com/patent/US20250093076A1 ## CPC - F24T 10/15: using bent tubes; using tubes assembled with connectors or with return headers - F16L 59/065: using vacuum (F16L59/075 takes precedence) - F24T 10/17: using tubes closed at one end, i.e. return-type tubes - Y02E 10/10: Geothermal energy - F24T: GEOTHERMAL COLLECTORS; GEOTHERMAL SYSTEMS - F16L: PIPES; JOINTS OR FITTINGS FOR PIPES; SUPPORTS FOR PIPES, CABLES OR PROTECTIVE TUBING; MEANS FOR THERMAL INSULATION IN GENERAL - Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION ## Abstract A closed well loop is provided for a geothermal system. The closed well loop includes a well (single well) that traverses a subterranean formation to extract heat from the subterranean formation. The well includes a section having an inner pipe that is supported inside an outer pipe in a pipe-in-pipe arrangement. The inner pipe has an interior flow channel that defines a first flow path for circulating working fluid, and the annulus between the inner pipe and the outer pipe defines a second flow path for the circulating working fluid. The well can be configured to extract heat from the subterranean formation and transfer heat to the circulating working fluid that flows in the first and second flow paths. The inner pipe can include a thermally-insulative piping system that reduces the amount of heat transferred from the circulating fluid that flows in the first and second flow paths within the well. ## Claims ### Claim 1 A closed well loop for a geothermal system, the closed well loop comprising: a well that traverses a subterranean formation to extract heat from the subterranean formation, wherein the well includes a section with an inner pipe that is supported inside an outer pipe in a pipe-in-pipe arrangement; wherein the inner pipe has an interior flow channel that defines a first flow path for circulating working fluid; wherein an annulus between the inner pipe and the outer pipe defines a second flow path for the circulating working fluid; and wherein the inner pipe includes a thermally-insulative piping system that reduces the amount of heat transferred from the hotter circulating fluid to the cooler circulating fluid that flows in the first and second flow paths. ### Claim 2 (depends on 1) A closed well loop according to claim 1, wherein: the thermally-insulative piping system includes a continuous layer of thermally-insulating material applied to or otherwise disposed about the inner diameter surface of the inner pipe for at least part of the section. ### Claim 3 (depends on 1) A closed well loop according to claim 1, wherein: the thermally-insulative piping system includes a continuous layer of thermally-insulating material applied to or otherwise disposed about the outer diameter surface of the inner pipe for at least part of the section. ### Claim 4 (depends on 1) A closed well loop according to claim 1, wherein: the thermally-insulative piping system includes a vacuum insulated pipe that forms the inner pipe for at least part of the section. ### Claim 5 (depends on 1) A closed well loop according to claim 1, wherein: the well is further configured to extract heat from the subterranean formation and transfer heat to the circulating working fluid that flows in the first and second flow paths. ### Claim 6 (depends on 5) A closed well loop according to claim 5, wherein: the section of the well that includes the pipe-in-pipe arrangement comprises a vertical section; and the well further includes at least one lateral section that extends laterally and downward away from the vertical section, wherein the at least one lateral section is configured to extract heat from the subterranean formation and transfer heat to the circulating working fluid that flows in the first and second flow paths of the well. ### Claim 7 (depends on 6) A closed well loop according to claim 6, wherein: a part of the at least one lateral section is configured to extract heat from the subterranean formation and transfer heat to the circulating working fluid that flows in the first and second flow paths of the well. ### Claim 8 (depends on 1) A closed well loop according to claim 1, wherein: the first flow path defined by the interior flow channel of the inner pipe is configured to carry cooler circulating working fluid downward within the well from the surface toward the hot zone of the subterranean formation; and the second flow path defined by the annulus between the inner pipe and the outer pipe is configured to carry hotter circulating fluid, which has been heated by thermal energy extracted from the hot zone of the subterranean formation, upward within the well away from the hot zone of the subterranean formation toward the surface. ### Claim 9 (depends on 1) A closed well loop according to claim 1, wherein: the first flow path defined by the interior flow channel of the inner pipe is configured to carry hotter circulating fluid, which has been heated by thermal energy extracted from the hot zone of the subterranean formation, upward within the well away from the hot zone of the subterranean formation toward the surface; and the second flow path defined by the annulus between the inner pipe and the outer pipe is configured to carry cooler circulating working fluid downward within the well from the surface toward the hot zone of the subterranean formation. ### Claim 10 (depends on 1) A closed well loop according to claim 1, wherein: the outer pipe includes pipe that is part of casing that lines a wellbore wall of the section. ### Claim 11 A closed well loop for a geothermal system, the closed well loop comprising: a well that traverses a subterranean formation to extract heat from the subterranean formation, wherein the well includes a vertical section with at least one lateral section that extends from the vertical section; wherein the vertical section includes an inner pipe that is supported inside an outer pipe in a pipe-in-pipe arrangement, wherein the inner pipe has an interior flow channel that defines a first flow path for circulating working fluid, wherein an annulus between the inner pipe and the outer pipe defines a second flow path for the circulating working fluid, and wherein the inner pipe includes a thermally-insulative piping system that reduces the amount of heat transferred from the hotter circulating fluid to the cooler circulating fluid that flows in the first and second flow paths within the well. ### Claim 12 (depends on 11) A closed well loop according to claim 11, wherein: the at least one lateral section extends laterally and downward away from the vertical section. ### Claim 13 (depends on 12) A closed well loop according to claim 12, wherein: at least part of the at least one lateral section is configured to support convective circulation of the circulating fluid. ### Claim 14 (depends on 12) A closed well loop according to claim 12, wherein: the inner pipe extends to a depth in the vertical section below intersection of the least one lateral section and the vertical section. ### Claim 15 (depends on 14) A closed well loop according to claim 14, wherein: the at least one lateral section has a toe segment that is located at, or extends to, a depth below bottom of the vertical section. ### Claim 16 (depends on 15) A closed well loop according to claim 15, further comprising: at least one lateral injection manifold that extends laterally and downward from the vertical section and intersects the toe segment of a corresponding lateral section. ### Claim 17 (depends on 16) A closed well loop according to claim 16, further comprising: an isolation packer disposed within the vertical section; wherein the at least one lateral injection manifold intersects the vertical section below the isolation packer; and wherein the at least one lateral section intersects the vertical section above the isolation packer. ### Claim 18 (depends on 11) A closed well loop according to claim 11, wherein: the thermally-insulative piping system includes a continuous layer of thermally-insulating material applied to or otherwise disposed about the inner diameter surface of the inner pipe for at least part of the vertical section. ### Claim 19 (depends on 11) A closed well loop according to claim 11, wherein: the thermally-insulative piping system includes a continuous layer of thermally-insulating material applied to or otherwise disposed about the outer diameter surface of the inner pipe for at least part of the vertical section. ### Claim 20 (depends on 11) A closed well loop according to claim 11, wherein: the thermally-insulative piping system includes a vacuum insulated pipe that forms the inner pipe for at least part of the vertical section. ### Claim 21 (depends on 11) A closed well loop according to claim 11, wherein: the first flow path defined by the interior flow channel of the inner pipe is configured to carry cooler circulating working fluid downward within the well from the surface toward the hot zone of the subterranean formation; and the second flow path defined by the annulus between the inner pipe and the outer pipe is configured to carry hotter circulating fluid, which has been heated by thermal energy extracted from the hot zone of the subterranean formation, upward within the well away from the hot zone of the subterranean formation toward the surface. ### Claim 22 (depends on 11) A closed well loop according to claim 11, wherein: the outer pipe includes pipe that is part of casing that lines the wellbore wall of the vertical section.