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CN-224214915-U - High-efficiency long-life middle-deep geothermal well central heat preservation pipe with direct-connection threads

CN224214915UCN 224214915 UCN224214915 UCN 224214915UCN-224214915-U

Abstract

The utility model discloses a high-efficiency long-life middle-deep geothermal well central heat preservation pipe with direct connection threads, which comprises an outer pipe and an inner pipe which are sleeved concentrically, wherein two ends of the inner pipe are welded on the outer pipe, one end of the outer pipe is thickened to form an outer thickened part on the radial outer side of the outer pipe, a trapezoid internal thread is arranged on the inner wall of the outer thickened part, the other end of the outer pipe is thickened to form an inner thickened part on the radial inner side of the outer pipe, a trapezoid external thread matched with the trapezoid internal thread is arranged on the outer wall of the inner thickened part, and the inner thickened part of one outer pipe is connected with the outer thickened part of the other outer pipe through threads to form a gas-tight special buckle to complete heat preservation pipe connection, so as to form a pipe column. The utility model can reduce the drilling diameter, reduce the pipe column well descending resistance, improve the well descending efficiency, and enhance the strength and the sealing performance of the threaded connection, thereby effectively prolonging the service life of the pipe column.

Inventors

  • LI YONGLI
  • LIU WENJING
  • ZHENG CHENGJIE
  • XIONG XIN

Assignees

  • 西安润威恒泰地热管技术有限公司

Dates

Publication Date
20260508
Application Date
20250625

Claims (10)

  1. 1. A central heat-insulating pipe of a middle-deep geothermal well with high efficiency and long service life and direct connection threads is characterized by comprising an outer pipe (1) and an inner pipe (2) which are concentrically sleeved, wherein two ends of the inner pipe (2) are welded on the outer pipe (1), one end of the outer pipe (1) is subjected to thickening treatment to form an outer thickened part on the radial outer side of the outer pipe, a trapezoid internal thread is arranged on the inner wall of the outer thickened part, the other end of the outer pipe (1) is subjected to thickening treatment to form an inner thickened part on the radial inner side of the outer pipe, a trapezoid external thread matched with the trapezoid internal thread is arranged on the outer wall of the inner thickened part, and the inner thickened part of one outer pipe (1) is connected with the outer thickened part of the other outer pipe (1) through threads to form a special air-tight buckle (3) to complete heat-insulating pipe connection, so as to form a pipe column.
  2. 2. The central heat preservation pipe of the middle-deep geothermal well with the high efficiency and long service life and the direct connection threads is characterized in that sealing interfaces (4) are arranged at welding positions of two ends of the outer pipe (1) and the inner pipe (2), and two different heat preservation pipes are tightly matched with each other through the sealing interfaces (4).
  3. 3. A high efficiency long life straight threaded mid-deep geothermal well central thermal insulation pipe according to claim 2, characterized in that a sealing ring (5) is provided between the sealing interfaces (4) of two different thermal insulation pipes.
  4. 4. The central insulating pipe for the middle-deep geothermal well with the high-efficiency long-service-life direct-connection threads, which is disclosed in claim 1, is characterized in that the diameter of the trapezoid internal threads is gradually reduced from the opening inwards.
  5. 5. The heat preservation pipe for the middle-deep geothermal well center of the direct-connection thread with high efficiency and long service life according to claim 4 is characterized in that the pitch of the trapezoid internal thread is 8-10 threads per inch, and the taper is 1:16.
  6. 6. A high efficiency long life straight threaded central insulating pipe for geothermal wells in deep layers according to claim 1 characterized in that a sealing interface (4) is provided at the transition joint of the outer thickened portion of one outer pipe (1) with the inner thickened portion of the other outer pipe (1).
  7. 7. The high-efficiency long-life directly-threaded central insulating pipe for a middle-deep geothermal well, according to claim 1, is characterized in that the height of the outer thickened portion of the outer pipe (1) is slightly larger than the wall thickness of the outer pipe (1).
  8. 8. The heat preservation pipe for the center of the middle-deep geothermal well with the high efficiency and long service life and the direct connection threads, according to claim 1, is characterized in that the thickness of the outer thickening part and the inner thickening part is larger than 5mm, and the thickness is larger than 100mm.
  9. 9. The high-efficiency long-life straight-connection threaded central insulating pipe for a middle-deep geothermal well, according to claim 1, wherein metal sealing shoulders are arranged on the inner wall of the outer thickening portion and the outer wall of the inner thickening portion.
  10. 10. The high-efficiency long-life directly-connected threaded central heat preservation pipe for the middle-deep geothermal well is characterized in that a heat preservation layer is arranged between the outer pipe (1) and the inner pipe (2).

Description

High-efficiency long-life middle-deep geothermal well central heat preservation pipe with direct-connection threads Technical Field The utility model belongs to the technical field of manufacturing of heat insulation pipes, and particularly relates to a high-efficiency long-life middle-deep geothermal well central heat insulation pipe with direct-connection threads. Background In geothermal applications, each insulating tube needs to be connected by a collar due to the limited length of the insulating tube. However, the collar acts as a larger thermal bridge, becoming a critical location for heat loss. In addition, the coupling has a thicker outer diameter, so that not only is the resistance and the risk of borehole enlargement increased during the well descending process increased, but also the investment cost is increased. At the same time, it also exacerbates the swirling effect and flow resistance of the fluid within the tube. More importantly, high-speed cyclone is easy to form due to abrupt change of pipe diameter in the coupling, so that local corrosion rate is increased, perforation failure is easy to occur, and large economic loss is brought. Disclosure of utility model The utility model aims to provide a high-efficiency long-life middle-deep geothermal well central heat preservation pipe with direct connection threads, which can reduce the drilling diameter, reduce the well-descending resistance of a pipe column, improve the well-descending efficiency, and simultaneously enhance the strength and the sealing performance of the threaded connection, thereby effectively prolonging the service life of the pipe column. In order to achieve the above purpose, the present utility model provides the following technical solutions: A central insulating pipe of a middle-deep geothermal well with high efficiency and long service life and direct connection threads comprises an outer pipe and an inner pipe which are sleeved concentrically, wherein two ends of the inner pipe are welded on the outer pipe, one end of the outer pipe is thickened to form an outer thickened part on the radial outer side of the outer pipe, a trapezoid internal thread is arranged on the inner wall of the outer thickened part, the other end of the outer pipe is thickened to form an inner thickened part on the radial inner side of the outer pipe, a trapezoid external thread matched with the trapezoid internal thread is arranged on the outer wall of the inner thickened part, and the inner thickened part of one outer pipe is connected with the outer thickened part of the other outer pipe through threads to form a special airtight buckle to complete the connection of the insulating pipe, so as to form a pipe column. Furthermore, sealing interfaces are arranged at welding positions at two ends of the outer tube and the inner tube, and the two different heat preservation tubes are tightly matched with each other through the sealing interfaces. Further, a sealing ring is provided between said sealing interfaces 4 of two different insulating pipes. Further, the diameter of the trapezoid internal thread is gradually reduced from the opening inwards. Further, the pitch of the trapezoid internal thread is 8-10 teeth per inch, and the taper is 1:16. Further, a sealing interface is provided at the transition joint of the outer thickened portion of one of the outer tubes with the inner thickened portion of the other outer tube. Further, the height of the outer thickened portion of the outer tube is slightly greater than the wall thickness of the outer tube. Further, the thickness of the outer thickening part and the inner thickening part is larger than 5mm, and the thickness is larger than 100mm. Further, metal sealing shoulders are arranged on the inner wall of the outer thickening portion and the outer wall of the inner thickening portion. Further, an insulating layer is arranged between the outer tube and the inner tube. Compared with the prior art, the utility model has the following beneficial effects: According to the utility model, the trapezoidal internal threads and the trapezoidal external threads are respectively arranged at the two ends of the outer tube, so that a coupling is not required when the heat-insulating tubes are connected, the number of threads is greatly reduced, and the efficiency of well descending operation is improved. And the outer diameter of the pipe wall is smaller, so that the influence caused by a thicker pipe diameter is avoided, and the difficulty of drilling operation is reduced. In addition, the whole pipe column has no obvious heat dissipation point, and the heat preservation effect is greatly improved. The trapezoidal internal threads and the trapezoidal external threads of the two different heat preservation pipes are connected to form the airtight special buckle with the sealing of the processing surface, so that the airtight of the tubular structure is obviously enhanced, the smooth flow of liquid in the tubu