Heat conduction type casing pipe for second-opening high-temperature area of geothermal well

Abstract

The utility model discloses a heat conduction type casing pipe for a second-opening high-temperature area of a geothermal well, a heat conduction well cementation material is arranged between the outer wall of the casing pipe and the inner wall of the geothermal well, the casing pipe is a metal heat conduction pipe, and a plurality of pits used for increasing the contact area with the heat conduction well cementation material are arranged on the surface of the metal heat conduction pipe; a plurality of multifunctional fin sets are further arranged on the outer wall of the metal heat conduction pipe in the length direction of the well wall pipe at intervals, each multifunctional fin set comprises a plurality of multifunctional fins evenly distributed in the circumferential direction of the metal heat conduction pipe, and the multifunctional fins are metal fins. According to the well wall pipe, the heat conduction performance of the metal heat conduction pipe, the heat conduction performance of the heat conduction well cementation material, the increased heat conduction area of the pits, the heat conduction effect, the well cementation effect, the deviation prevention effect, the protection effect and the like of the multifunctional fins are matched for use, and the well wall pipe with the high heat conduction effect and the good well cementation effect is achieved.

Description

Technical Field

[0001] The utility model relates to the technical field of geothermal wells, in particular to a heat-conducting well wall pipe in a second high-temperature zone of a geothermal well. Background Art

[0002] As a renewable energy source, geothermal energy boasts advantages such as widespread distribution, low cost, ease of extraction, cleanliness, and direct utilization. Promoting the utilization of geothermal energy is an effective measure for resource conservation and environmental protection, and a path to sustainable development for human society. Currently, geothermal energy utilization technology is continuously evolving, becoming a preferred option for building heating and cooling. Current geothermal technology involves drilling into the rock and soil layers, typically 2,000 to 4,500 meters underground. A central tube is inserted into the geothermal well wall. Through a heat exchanger, cold water enters the deep geothermal well wall, absorbing the underground heat. The water then flows upward from the insulated bottom of the central tube, channeling the underground heat to the heat exchanger, where it is used to heat the building.

[0003] In the prior art, CN 207019324 U discloses a deep rock heat absorption heat exchange pipe structure. The heat exchange pipe is a geothermal well wall pipe. In order to improve the heat absorption effect of the heat exchange pipe, fixed fins are fixedly installed on the outer wall of the heat exchange pipe. The fixed fins are fixed in the deep well wall, which can increase the contact area with the geothermal well and greatly improve the heat exchange efficiency. However, although the fixed fins can increase the contact area with the geothermal well, Figure 3 However, since the fixing fins extend horizontally outside the heat exchange tube, the heat exchange tube is prone to getting stuck or colliding with the well wall when the heat exchange tube is lowered into the well, hindering the smooth lowering of the heat exchange tube. In addition, the horizontal fixing fins affect the flow of the cementing material. The fixing material is blocked by the fixing fins, which easily leads to unfilled gaps between the fixing material and the outer wall of the heat exchange tube, affecting the stability of the fixation. Utility Model Content

[0004] The technical problem to be solved by the utility model is to provide a heat-conducting well wall pipe in the high-temperature zone of the second opening of a geothermal well with good heat-conducting effect and good cementing stability.

[0005] In order to solve the above technical problems, the technical solution of the utility model is as follows: a geothermal well second opening high temperature zone heat conduction well wall pipe is arranged in the high temperature zone of the geothermal well, and a heat conduction cementing material is arranged between the outer wall of the well wall pipe and the inner wall of the geothermal well. The well wall pipe is a metal heat conduction pipe, and the length of the metal heat conduction pipe is less than or equal to the depth of the second opening high temperature zone. The surface of the metal heat conduction pipe is arranged with a plurality of pits for increasing the contact area with the heat conduction cementing material; the outer wall of the metal heat conduction pipe is also provided with a multifunctional fin group, and the multifunctional fin group is arranged in multiple groups at intervals along the length direction of the well wall pipe, and each group of the multifunctional fin group includes a plurality of fins along the The multifunctional fins are evenly distributed around the metal heat-conducting pipe, and the multifunctional fins are metal fins. The bottom ends of the multifunctional fins are fixed to the outer wall of the metal heat-conducting pipe, and the top ends of the multifunctional fins extend upward to contact the outer wall of the metal heat-conducting pipe. The middle parts of the multifunctional fins protrude in a smooth arched structure away from the outer wall of the metal heat-conducting pipe. The arched structure also serves as an anti-deflection protective cover to prevent the well wall pipe from colliding with the outer wall due to excessive eccentricity. The multifunctional fins are squeezed and fixed by the heat-conducting cementing material and also serve as a fixed thermal bridge to increase the heat conduction area and cementing area between the metal heat-conducting pipe and the heat-conducting cementing material.

[0006] As a preferred technical solution, the heat-conducting cementing material is a mixture of cementing mud and metal material, and the metal material is metal powder or metal spherical particles.

[0007] As a preferred technical solution, the multifunctional fins extend obliquely from bottom to top, and the inclination directions of the multiple multifunctional fins in the same group are consistent and also serve as circumferential guides for guiding the circumferential movement of the heat-conducting cementing material.

[0008] As a preferred technical solution, the two adjacent groups of multifunctional fins are staggered and tilted in opposite directions, so that the circumferential movement directions of the thermal conductive cementing materials on the upper and lower sides are opposite.

[0009] As a preferred technical solution, the multifunctional fin is an integrally formed elastic fin with slight deformation, one end of the elastic fin is welded and fixed to the outer wall of the metal heat pipe, and the other end of the elastic fin rests on the surface of the metal heat pipe.

[0010] As a preferred technical solution, the pit is a spherical pit or an elliptical pit.

[0011] Due to the adoption of the above technical solution, the beneficial effect of the utility model is as follows: the utility model combines the thermal conductivity of the metal heat pipe, the thermal conductivity of the heat-conducting cementing material, the increased heat conduction area of the pits, the thermal conductivity effect, cementing effect, anti-deviation effect and protection effect of the multifunctional fins, etc., to achieve a well wall pipe with high thermal conductivity and good cementing effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] The following drawings are only intended to illustrate and explain the present invention, and are not intended to limit the scope of the present invention.

[0013] Figure 1 It is a structural schematic diagram of an embodiment of the utility model;

[0014] Figure 2 This is a rendering of the arrangement of multifunctional fins on the metal heat conducting pipe according to an embodiment of the utility model;

[0015] Figure 3 It is a structural diagram of background technology;

[0016] In the figure: 1-geothermal well; 2-metal heat pipe; 3-thermal cementing material; 4-pit; 5-multifunctional fin. DETAILED DESCRIPTION

[0017] The present invention is further described below with reference to the accompanying drawings and examples. In the detailed description that follows, certain exemplary embodiments of the present invention are described by way of illustration only. It goes without saying that those skilled in the art will recognize that the described embodiments may be modified in various ways without departing from the spirit and scope of the present invention. Therefore, the drawings and description are illustrative in nature and are not intended to limit the scope of the claims.

[0018] like Figure 1 and Figure 2 As shown, the second high-temperature zone heat-conducting well wall pipe of the geothermal well is arranged in the high-temperature zone of the geothermal well 1. The geothermal well 1 in this embodiment is a vertical well.

[0019] To enhance the heat conduction and heat exchange of the wellbore pipe, four methods are used to achieve this: 1. The wellbore pipe uses a metal heat pipe 2. The metal heat pipe 2 can be a strong stainless steel pipe with good thermal conductivity. At the same time, since the second high-temperature zone is a location where energy can be utilized, the length of the metal heat pipe 2 is less than or equal to the depth of the second high-temperature zone and is completely located within the second high-temperature zone. The top of the metal heat pipe 2 is connected to the insulation pipe. 2. A heat-conducting cementing material 3 is provided between the outer wall of the metal heat pipe 2 and the inner wall of the geothermal well 1. The heat-conducting cementing material 3 is a mixture of cementing mud and a metal material. The metal material is metal powder or metal spherical particles. The metal powder can be silver powder with good thermal conductivity. The heat-conducting cementing material 3 not only achieves the cementing effect of the wellbore pipe, but also has good thermal conductivity, which can fully transfer the heat from the geothermal well 1 to the surface of the metal heat pipe 2, and the heat-conducting cementing material 3 can also achieve a thermal bridge effect. Third, the surface of the metal heat-conducting pipe 2 is provided with a plurality of dimples 4 for increasing the contact area with the heat-conducting cementing material 3. These dimples 4 are spherical or elliptical in shape and serve two purposes: they not only increase the contact area between the metal heat-conducting pipe 2 and the heat-conducting cementing material, improving heat conduction, but also enhance the strength of the metal heat-conducting pipe 2. Fourth, the outer wall of the metal heat-conducting pipe 2 is also provided with a multifunctional fin group. Multiple groups of these multifunctional fin groups are arranged at intervals along the length of the wellbore pipe. Each group of these multifunctional fin groups includes a plurality of multifunctional fins 5 evenly distributed along the circumference of the metal heat-conducting pipe 2. These multifunctional fins 5 are metal fins and are connected to the exterior of the metal heat-conducting pipe 2 to enhance thermal conductivity.

[0020] This embodiment realizes multiple functions by innovatively designing the multifunctional fin 5, and has the effects of heat conduction, cementing, anti-deviation and protection. The multifunctional fin 5 is a strip structure, the bottom end of the multifunctional fin 5 is fixed to the outer wall of the metal heat-conducting pipe 2, the top end of the multifunctional fin 5 extends upward to contact the outer wall of the metal heat-conducting pipe 2, and the middle part of the multifunctional fin 5 protrudes toward the outer wall away from the metal heat-conducting pipe 2 to form a smooth arch structure. The arch structure also serves as an anti-deflection protective cover to prevent the well wall pipe from colliding with the outer wall due to excessive eccentricity. This arch structure has a certain external supporting force, and multiple arch structures cooperate to form a ring-like structure, which can avoid the metal heat-conducting pipe 2 from being excessively eccentric to one side of the well wall, resulting in a smaller cementing space on one side affecting the stability of subsequent cementing. At the same time, the arch structure can support the well wall surface and reduce the wear of the metal heat-conducting pipe 2; and when the metal heat-conducting pipe 2 is lowered into the well, even if the arch structure contacts the well wall, since the arch structure is an arc structure, the arc structure can quickly overcome obstacles without jamming, and the top end of the multifunctional fin 5 is a non-fixed square. The multifunctional fin 5 is connected in the form of a screw thread, and when the arch structure is stuck, it is used to apply downward pressure, so that the top of the multifunctional fin 5 is forced upward, the arch structure shrinks, and the obstacle can be quickly passed; the multifunctional fin 5 is squeezed and fixed by the heat-conducting cementing material 3, and also serves as a fixed thermal bridge that increases the heat conduction area and cementing area between the metal heat-conducting pipe 2 and the heat-conducting cementing material 3. During cementing, the heat-conducting cementing material 3 is squeezed downward from the bottom of the metal heat-conducting pipe 2 by high pressure into the gap between the metal heat-conducting pipe 2 and the well wall. At this time, since the surface of the multifunctional fin 5 is an arc-shaped structure, the heat-conducting cementing material 3 can move along the arc surface, and the heat-conducting cementing material 3 itself has fluidity and high pressure resistance, so it can quickly fill the interior of the multifunctional fin 5 without any gaps. After the heat-conducting cementing material 3 solidifies, due to the presence of the multifunctional fin 5, the contact area between the metal heat-conducting pipe 2 and the heat-conducting cementing material 3 is increased, thereby achieving further utilization of heat.

[0021] In order to avoid the formation of an unfilled cavity inside the metal heat pipe 2, the present invention further improves the structure of the multifunctional fin 5. The multifunctional fin 5 extends obliquely from bottom to top. The inclination direction of the multifunctional fins 5 in the same group is consistent and also serves as a circumferential guide for guiding the circumferential movement of the heat-conducting cementing material 3. Figure 2 When the heat-conducting cementing material 3 moves vertically upward from the bottom, it also moves circumferentially along the inclined surface when passing through the guide member. The existence of this circumferential position causes the heat-conducting cementing material 3 to move laterally. The laterally moving heat-conducting cementing material 3 can laterally enter the cavity between the multifunctional fins 5 and the metal heat-conducting pipe 2, ensuring the stability of cementing.

[0022] In order to avoid the unidirectional spiral motion caused by the circumferential motion, the two adjacent groups of multifunctional fins 5 are staggered and arranged, and the inclination directions of the two adjacent groups of multifunctional fins 5 are opposite, so that the circumferential movement directions of the thermal conductive cementing materials 3 on the upper and lower sides are opposite. Figure 2 When passing through the multifunctional fins 5 of the lower layer, the thermal conductive cementing material 3 moves to the left, and when continuing upward and passing through the multifunctional fins 5 of the upper layer, the thermal conductive cementing material 3 moves to the right. This left-right method is used to avoid the thermal conductive cementing material 3 from exhibiting a unidirectional spiral motion, which affects the stability of the well wall pipe.

[0023] The multifunctional fin 5 is an integrally formed elastic fin with slight deformation. One end of the elastic fin is welded and fixed to the outer wall of the metal heat-conducting tube 2, and the other end of the elastic fin rests on the surface of the metal heat-conducting tube 2. The slight deformation of the fin has a flexible buffering effect, avoiding rigid contact with the well wall and causing significant damage.

[0024] The above shows and describes the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions are merely illustrative of the principles of the present invention. Various changes and improvements may be made to the present invention without departing from the spirit and scope of the present invention. Such changes and improvements are intended to fall within the scope of the present invention. The scope of protection claimed in this invention is defined by the appended claims and their equivalents.

Claims

1. The geothermal well secondary high temperature zone heat conduction well wall pipe is installed in the high temperature zone of the geothermal well, and its characteristics are: A heat-conducting cementing material is provided between the outer wall of the well wall pipe and the inner wall of the geothermal well. The well wall pipe is a metal heat-conducting pipe. The length of the metal heat-conducting pipe is less than or equal to the depth of the second high-temperature zone. The surface of the metal heat-conducting pipe is provided with a plurality of pits for increasing the contact area with the heat-conducting cementing material. The outer wall of the metal heat-conducting pipe is also provided with a multifunctional fin group. The multifunctional fin group is arranged in multiple groups at intervals along the length direction of the well wall pipe. Each group of the multifunctional fin group includes a plurality of multifunctional fins uniformly distributed along the circumference of the metal heat-conducting pipe. The multifunctional fins The multifunctional fin is a metal fin, the bottom end of the multifunctional fin is fixed to the outer wall of the metal heat-conducting pipe, the top end of the multifunctional fin extends upward to contact the outer wall of the metal heat-conducting pipe, and the middle part of the multifunctional fin protrudes in a smooth arched structure away from the outer wall of the metal heat-conducting pipe. The arched structure also serves as an anti-deflection protective cover to prevent the well wall pipe from colliding with the outer wall due to excessive eccentricity. The multifunctional fin is squeezed and fixed by the heat-conducting cementing material and also serves as a fixed thermal bridge to increase the heat conduction area and cementing area between the metal heat-conducting pipe and the heat-conducting cementing material.

2. The geothermal well secondary high temperature zone heat conduction well wall pipe according to claim 1, characterized in that: The heat-conducting cementing material is a mixture of cementing mud and metal material, and the metal material is metal powder or metal spherical particles.

3. The geothermal well secondary high temperature zone heat conduction well wall pipe according to claim 1, characterized in that: The multifunctional fins extend obliquely from bottom to top, and the inclination directions of the plurality of multifunctional fins in the same group are consistent and also serve as circumferential guides for guiding the circumferential movement of the heat-conducting cementing material.

4. The geothermal well secondary high temperature zone heat conduction well wall pipe according to claim 3, characterized in that: The two adjacent groups of multifunctional fins are staggered and tilted in opposite directions, so that the circumferential movement directions of the thermal conductive cementing materials on the upper and lower sides are opposite.

5. The geothermal well secondary high temperature zone heat conduction well wall pipe according to claim 1, characterized in that: The multifunctional fin is an integrally formed elastic fin with slight deformation. One end of the elastic fin is welded and fixed to the outer wall of the metal heat-conducting pipe, and the other end of the elastic fin rests on the surface of the metal heat-conducting pipe.

6. The geothermal well secondary high-temperature zone heat-conducting well wall pipe according to claim 1, characterized in that: The pit is a spherical pit or an elliptical pit.

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