Geothermal well high-temperature area anti-rotational flow metal center pipe

Abstract

The utility model discloses a geothermal well high-temperature area anti-rotational flow metal central tube, the metal central tube also serves as a counterweight structure, the metal central tube is a stainless steel round tube, the bottom end of the stainless steel round tube is provided with a central tube end socket, and the bottom tube wall of the stainless steel round tube is provided with a plurality of central tube communicating holes; the central pipe communicating hole communicates the outside and the inside of the stainless steel circular pipe; a plurality of reinforcing prismatic tables protruding outwards are evenly distributed on the outer wall of the stainless steel round pipe, a plurality of turbulent flow resistance increasing grooves are formed in the outer surfaces of the reinforcing prismatic tables, and outer rotational flow preventing ribs are further arranged between every two adjacent reinforcing prismatic tables. A plurality of inner anti-rotational-flow vertical plates are evenly distributed on the inner wall of the bottom of the stainless steel round pipe and arranged between the left center pipe communicating hole and the right center pipe communicating hole which are adjacent to each other, and an anti-rotational-flow channel extending in the length direction of the stainless steel round pipe is formed between every two adjacent inner anti-rotational-flow vertical plates. A counter weight structure in the prior art is replaced by the stainless steel round pipe, the anti-rotational-flow structures are arranged on the inner wall and the outer wall, and the novel anti-rotational-flow metal center pipe is provided.

Description

Technical Field

[0001] The utility model relates to the field of geothermal wells, in particular to a swirl-proof metal central pipe in a high-temperature zone of a geothermal well. Background Art

[0002] As a renewable energy source, geothermal energy boasts advantages such as wide 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 a hole into the rock and soil, typically 2,000 to 3,000 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] At present, the central pipe used in geothermal wells mainly adopts PE central pipe, such as PETT and continuous glass fiber tape reinforced PE composite pipe, which has certain flexibility, heat resistance and pressure resistance. However, this type of PE central pipe still has the following defects: First, the material of this type of PE central pipe has a certain buoyancy. Its total length is basically the same as the length of the well wall, which needs to reach 2000m to 3000m. In order to ensure smooth lowering of the pipe, it is necessary to add a counterweight at the bottom of the PE central pipe. The counterweight is first lowered into the well to drag the PE central pipe downward and smoothly lower it into the well. After water is passed, the counterweight also needs to overcome the buoyancy of the PE central pipe itself to prevent the PE central pipe from floating upward. Therefore, the counterweight generally needs to be more than 1 t and is generally made of stainless steel iron blocks. Figure 8 This type of counterweight has a certain length, which increases the difficulty of going down the well and causes jamming when exiting the well. Secondly, since the bottom end of the central tube is not fixed and is a suspended structure, when the water flows downward along the outer wall of the central tube and upward along the inner wall of the central tube, if a vortex occurs and causes the tube wall to rotate, the position of the central tube will be shifted and impacted, affecting its use. Utility Model Content

[0004] The technical problem to be solved by the utility model is to provide a metal central pipe with reasonable design and capable of serving as a counterweight to prevent swirl flow in the high temperature zone of a geothermal well.

[0005] In order to solve the above technical problems, the technical solution of the utility model is: a metal central tube for preventing vortex flow in the high-temperature zone of a geothermal well is placed in the second high-temperature zone of the geothermal well pipe wall, and is characterized in that: the metal central tube also serves as a counterweight structure connected to the bottom end of the upper PE central tube, the metal central tube is a stainless steel round tube, the bottom end of the stainless steel round tube is provided with a central tube head, a plurality of central tube connecting holes are arranged on the bottom tube wall of the stainless steel round tube, the central tube connecting holes connect the outside and the inside of the stainless steel round tube; the outer wall of the stainless steel round tube is evenly distributed with a plurality of outwardly protruding reinforcing prisms, the reinforcing prisms are along the stainless steel The circular tube is extended in the length direction, and the outer surface of the reinforced prism is arranged with a flow interference resistance increasing groove, and an external anti-vortex flow rib is provided between the adjacent two reinforced prisms. The external anti-vortex flow rib is provided on the surface of the stainless steel circular tube and extends along the length direction of the stainless steel circular tube. The height of the external anti-vortex flow rib is lower than the height of the reinforced prism; the bottom inner wall of the stainless steel circular tube is evenly distributed with a plurality of internal anti-vortex flow vertical plates, and the internal anti-vortex flow vertical plates are provided between the two adjacent central tube connecting holes on the left and right, and an anti-vortex flow channel extending along the length direction of the stainless steel circular tube is formed between the adjacent two internal anti-vortex flow vertical plates.

[0006] As an optimal technical solution, the metal central tube is composed of multiple stainless steel round tubes connected end to end, the top of the stainless steel round tube at the top is connected to the PE central tube, and the central tube head and the central tube connecting hole are both provided at the bottom of the stainless steel round tube; the wall thickness of the stainless steel round tube is 3mm-5mm, and the sum of the lengths of all stainless steel round tubes is 200m-300m.

[0007] As a preferred technical solution, the two stainless steel round tubes are connected by threads.

[0008] As a preferred technical solution, the flow-turbine resistance-increasing groove is a spherical pit or an elliptical pit.

[0009] As an optimal technical solution, the stainless steel round tube is connected to the bottom end of the PE central tube through a coupling, and the coupling includes a coupling body, one end of the coupling body is provided with a threaded end, and the other end of the coupling body is provided with a press-fit end, the outer surface of the threaded end is provided with an external thread threadedly connected to the stainless steel round tube, the press-fit end is provided with a press-fit ring groove, the end of the PE central tube is inserted into the press-fit ring groove, and the outer surface of the press-fit end is rolled with an extrusion groove that is concave inward to press the outer surface of the PE central tube.

[0010] As an optimal technical solution, the central tube head is a solid stainless steel head. The top thread of the stainless steel head is connected to the bottom end of the stainless steel round tube. The stainless steel head and the stainless steel round tube are welded at the fitting seam, and the bottom end of the stainless steel head is provided with a downhole cone head.

[0011] Due to the adoption of the above-mentioned technical solution, the beneficial effects of the present invention are as follows: the present invention replaces the counterweight structure in the prior art with a stainless steel round tube, so the counterweight structure can be eliminated. After the counterweight structure is eliminated, not only the cost of the counterweight structure is reduced, but also there is no need to reserve space for the counterweight structure in the well wall tube, which can shorten the total height of the well wall tube, and the possibility of the inner casing without counterweight getting stuck when it comes out of the well; at the same time, anti-vortex structures are provided on the outer wall and the inner wall of the stainless steel tube, which reduces the deviation effect of the vortex on the center tube, avoids the unstable collision of the center tube against the well wall, and extends the service life of the center tube. 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 schematic diagram of the exterior of a stainless steel round tube according to an embodiment of the present invention;

[0015] Figure 3 This is the cross section of the stainless steel round tube of the embodiment of the utility model Figure 1 ;

[0016] Figure 4 This is the cross section of the stainless steel round tube of the embodiment of the utility model Figure 2 ;

[0017] Figure 5 This is a cross-sectional view of the bottom of a stainless steel round tube according to an embodiment of the present invention;

[0018] Figure 6 This is a schematic diagram of the connection between the stainless steel round pipe and the PE central pipe in the embodiment of the utility model;

[0019] Figure 7 This is a schematic diagram of the connection between stainless steel round tubes in an embodiment of the present utility model;

[0020] Figure 8 is a schematic diagram of background technology;

[0021] In the figure: 100 - geothermal well pipe wall; 200 - PE central pipe; 300 - metal central pipe; 301 - stainless steel round pipe; 302 - central pipe head; 303 - central pipe connecting hole; 304 - reinforced prism; 305 - flow disturbance and resistance increasing groove; 306 - external anti-swirl flow rib; 307 - internal anti-swirl flow vertical plate; 308 - anti-swirl flow channel; 400 - coupling; 401 - coupling body; 402 - threaded end; 403 - press-fit end; 404 - extrusion groove. DETAILED DESCRIPTION

[0022] 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.

[0023] like Figure 1 As shown, the anti-vortex metal central pipe in the high-temperature zone of the geothermal well is placed in the second open high-temperature zone inside the geothermal well pipe wall 100. The metal central pipe 300 also serves as a counterweight structure connected to the bottom end of the upper PE central pipe 200. The metal central pipe 300 is a stainless steel round pipe 301. The bottom end of the stainless steel round pipe 301 is provided with a central pipe head 302. A plurality of central pipe connecting holes 303 are arranged on the bottom pipe wall of the stainless steel round pipe 301. The central pipe connecting holes 303 connect the outside and the inside of the stainless steel round pipe 301. A central pipe head 302 is used at the bottom end of the stainless steel round pipe 301 to seal the bottom end of the stainless steel round pipe 301 to guide the stainless steel round pipe 301 down the well smoothly. During use, cold water enters the deep part of the geothermal well pipe wall 100 through the outside of the central tube, moves to the second high-temperature zone below to absorb the high temperature from the surface of the geothermal well to raise the temperature, and then enters the interior of the central tube through the central tube connecting hole 303 at the bottom, flows upward, and guides the underground high-temperature heat to the heat exchanger, which provides heating for the building through the heat exchanger.

[0024] In the existing technology, PE pipes are mainly used for geothermal wells of 2500m-3000m. In order to ensure the smooth installation and use of the central pipe, a counterweight needs to be connected at the bottom. Therefore, the utility model provides a new metal central pipe 300 that does not require a counterweight, which can eliminate the original counterweight and has the characteristics of reasonable design and low cost.

[0025] The central tube structure of the present invention is composed of the original PE tube in the prior art plus a stainless steel round tube 301. The stainless steel round tube 301 is arranged at the bottom end of the PE tube to replace a certain length of the original PE tube. The central tube is placed in the well wall tube as a whole, wherein the stainless steel round tube 301 is close to the bottom end of the well wall tube. Since the stainless steel round tube 301 has a large weight, it can replace the counterweight structure in the prior art, so the counterweight structure can be cancelled. After the counterweight structure is cancelled, not only the cost of the counterweight structure is reduced, but also the well wall tube no longer needs to reserve space for the counterweight structure, which can shorten the total height of the well wall tube, and the inner casing without counterweight can also reduce the possibility of jamming when it is out of the well; the stainless steel round tube 301 itself has good heat resistance and pressure resistance, and can be a better replacement for PE tube for use in geothermal wells.

[0026] In the existing technology, for a 2500m geothermal well, the high-temperature zone at the bottom of the inner casing generally uses about 300m of continuous glass fiber tape reinforced PE composite pipe, and the rest can use ordinary PE pipe. This continuous glass fiber tape reinforced PE composite pipe has good heat resistance and pressure resistance, but due to the high cost of this composite pipe, its use is limited, and this composite pipe also needs to be equipped with a counterweight at the bottom before it can be used.

[0027] In this embodiment, a stainless steel round tube 301 can be used to replace the original continuous glass fiber tape reinforced PE composite pipe at the bottom of the geothermal well. Different sizes can be replaced according to the wall thickness of the stainless steel round tube 301.

[0028] The metal central tube 300 is composed of multiple stainless steel circular tubes 301 connected end to end. The top of the stainless steel circular tube 301 at the top is connected to the PE central tube 200. The central tube head 302 and the central tube connecting hole 303 are both provided at the bottom of the stainless steel circular tube 301. The wall thickness of the stainless steel circular tube 301 is 3mm-5mm, and the total length of all stainless steel circular tubes 301 is 200m-300m. In this embodiment, the stainless steel round tube 301 is a φ108mm round tube, which is closest to the size of the φ110mm PE tube used underground. When the wall thickness of the stainless steel round tube 301 is 3mm, the sum of the lengths of all the stainless steel round tubes 301 is 300m. According to calculations, the weight of all the stainless steel round tubes 301 at this time is much greater than 1t, achieving the purpose of counterweight, which is used to overcome buoyancy and realize the smooth lowering of the inner casing into the well; when the wall thickness of the stainless steel is 4mm, the sum of the lengths of all the stainless steel round tubes 301 is 250m. According to calculations, the weight of all the stainless steel round tubes 301 at this time is much greater than 1t, which is used to overcome buoyancy and realize the smooth lowering of the inner casing into the well; when the wall thickness of the stainless steel is 5mm, the sum of the lengths of all the stainless steel round tubes 301 is 200mm. According to calculations, the weight of all the stainless steel round tubes 301 at this time is much greater than 1t, which is used to overcome buoyancy and realize the smooth lowering of the inner casing into the well. In the existing technology, the φ110mm continuous glass fiber tape reinforced PE composite pipe costs about 180 yuan / meter, while the replacement φ108mm stainless steel round pipe 301 costs about 110 yuan / meter. The cost of the stainless steel round pipe 301 is significantly lower than the original continuous glass fiber tape reinforced PE composite pipe in the existing technology.

[0029] See also Figure 2 and Figure 3The outer wall of the stainless steel round tube 301 is evenly distributed with a plurality of outwardly protruding reinforcing prisms 304, and the reinforcing prisms 304 are extended along the length direction of the stainless steel round tube 301. The outer surface of the reinforcing prisms 304 is arranged with interference flow resistance increasing grooves 305; an external anti-vortex flow rib 306 is also provided between two adjacent reinforcing prisms 304, and the external anti-vortex flow rib 306 is provided on the surface of the stainless steel round tube 301 and extends along the length direction of the stainless steel round tube 301. The height of the external anti-vortex flow rib 306 is lower than the height of the reinforcing prism 304, that is, the diameter formed by the plurality of the external anti-vortex flow ribs 306 is smaller than the diameter formed by the plurality of the reinforcing prisms 304. The outer anti-vortex ribs 306, the reinforcing prisms 304, and the flow-turbine resistance-increasing grooves 305 cooperate as a whole to make the outer surface of the central tube uneven, thereby hindering the rotation of the water flow, reducing the impact of the vortex on the deviation of the central tube, avoiding the unstable impact of the central tube on the well wall, and extending the service life of the central tube.

[0030] The reinforcing prism 304 has two functions: first, it is used to enhance the strength of the stainless steel round tube 301. Since the reinforcing prism 304 extends to the top and bottom ends along the length direction of the metal central tube 300, it does not affect the downward movement of the central tube. Second, an inwardly concave groove structure is formed between two adjacent reinforcing prisms 304, and the outer anti-vortex flow rib 306 is added in the groove part. The outer end height of the outer anti-vortex flow rib 306 is lower than the outer end height of the reinforcing prism 304. Here, the reinforcing prism 304 can protect the outer anti-vortex flow rib 306, reduce the contact and collision between the outer anti-vortex flow rib 306 and the well wall pipe, and reduce the deformation of the outer anti-vortex flow rib 306. The outer anti-swirl rib is a strip structure with a width much smaller than the reinforcing prism 304. Its main function is to prevent water from spiraling along the outer surface of the pipe wall. Although the reinforcing prism 304 has a certain protective effect on the outer anti-swirl rib, there is still a possibility that the outer anti-swirl rib will contact the well wall when actually going down the well. When the outer anti-swirl rib contacts the well wall, even if the outer edge of the surface is deformed, it still does not affect the effect of preventing water from rotating, and it can also prevent the well wall from directly contacting the outer wall of the metal pipe, thereby protecting the outer wall of the metal pipe. The reinforcing prism 304 and the outer anti-swirl rib 306 can be roll-formed integrally with the central pipe, and the strength and stability of the structure are both good. Of course, the outer anti-swirl rib 306 can also be welded. The flow-disturbing and resistance-increasing grooves 305 are composed of spherical pits, elliptical pits or pits of various shapes, and the depths are inconsistent and the positions are arranged in disorder. The flow-disturbing and resistance-increasing grooves 305 are arranged on the surface of the reinforced prism 304. Their function is to disturb the water flow passing through, change the direction of the water flow, and avoid the formation of vortex.

[0031] Since the bottom end of the stainless steel circular tube 301 is not fixed and is in a suspended state, the bottom end is the part most easily affected by the vortex. When a vortex occurs at the bottom end, the water flows continuously upward and backward, which can easily cause the entire center tube to shift. Therefore, in addition to the anti-vortex design of the outer wall as a whole, an anti-vortex design is also required at the inner bottom end. The internal and external anti-vortex designs work together to improve the stability of the center tube. Therefore, the bottom inner wall of the stainless steel circular tube 301 is evenly distributed with a plurality of internal anti-vortex vertical plates 307, and several of the internal anti-vortex vertical plates 307 point to the center of the stainless steel circular tube 301. The internal anti-vortex vertical plates 307 are arranged between the two adjacent center tube connecting holes 303 on the left and right. An anti-vortex flow channel 308 extending along the length direction of the stainless steel circular tube 301 is formed between the two adjacent internal anti-vortex vertical plates 307. See Figure 4 and Figure 5 The inner anti-swirl plate 307 is provided on the inner wall of the stainless steel circular tube 301 and is staggered with the corresponding central tube connecting hole 303. Its function is to separate the water flow entering the interior through the central tube connecting hole 303 and guide the water flow entering the stainless steel circular tube 301 to move vertically upward along the stainless steel circular tube 301, thereby preventing the water flow entering the interior through the central tube connecting hole 303 from swirling due to the change of direction.

[0032] See also Figure 6 The stainless steel round tube 301 is connected to the bottom end of the PE central tube 200 through a coupling 400. The coupling 400 includes a coupling body 401. One end of the coupling body 401 is provided with a threaded end 402. The other end of the coupling body 401 is provided with a press-fit end 403. The outer surface of the threaded end 402 is provided with an external thread threadedly connected to the stainless steel round tube 301. The press-fit end 403 is provided with a press-fit ring groove. The end of the PE central tube 200 is inserted into the press-fit ring groove. The outer surface of the press-fit end 403 is rolled to provide an extrusion groove 404 that is concave inward and presses the outer surface of the PE central tube 200. During connection, first completely insert the end of the PE central pipe 200 into the press-fitting ring groove, and roll the inwardly concave extrusion groove 404 on the outer surface of the press-fitting end 403. The extrusion groove 404 is an annular circumferential groove provided on the outer surface of the press-fitting end 403. The extrusion groove 404 is concave and deformed inward to compress the outer surface of the PE central pipe 200 to complete the connection between the PE central pipe 200 and the coupling 400. Then, the end of the stainless steel round pipe 301 is threadedly connected to the coupling 400. In order to ensure the reliability of the connection, the two can be further welded at the joint.

[0033] See also Figure 7 The two stainless steel round tubes 301 are connected by threads.

[0034] See also Figure 5The center tube head 302 is a solid stainless steel head. The top thread of the stainless steel head is connected to the bottom end of the stainless steel round tube 301. The stainless steel head and the stainless steel round tube 301 are welded at the fitting seam. The bottom end of the stainless steel head is provided with a downhole cone head.

[0035] 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 anti-swirl metal central tube in the high-temperature zone of the geothermal well is placed in the high-temperature zone of the geothermal well pipe wall, and is characterized by: The metal center tube also serves as a counterweight structure connected to the bottom end of the upper PE center tube, and the metal center tube is a stainless steel circular tube. The bottom end of the stainless steel circular tube is provided with a center tube head, and a plurality of center tube connecting holes are arranged on the bottom tube wall of the stainless steel circular tube, and the center tube connecting holes connect the outside and the inside of the stainless steel circular tube; the outer wall of the stainless steel circular tube is evenly distributed with a plurality of outwardly protruding reinforcing prisms, and the reinforcing prisms are extended along the length direction of the stainless steel circular tube, and the outer surface of the reinforcing prisms is arranged with interference flow resistance increasing grooves, and an outer anti-vortex flow rib is also provided between two adjacent reinforcing prisms. The outer anti-vortex flow rib is provided on the surface of the stainless steel circular tube and extends along the length direction of the stainless steel circular tube. The height of the outer anti-vortex flow rib is lower than the height of the reinforcing prism; the bottom inner wall of the stainless steel circular tube is evenly distributed with a plurality of inner anti-vortex flow vertical plates, and the inner anti-vortex flow vertical plates are provided between the two adjacent center tube connecting holes on the left and right, and an anti-vortex flow channel extending along the length direction of the stainless steel circular tube is formed between the two adjacent inner anti-vortex flow vertical plates.

2. The geothermal well high temperature zone anti-swirl flow metal central tube according to claim 1, characterized in that: The metal central tube is composed of multiple stainless steel round tubes connected end to end. The top of the stainless steel round tube at the top is connected to the PE central tube. The central tube head and the central tube connecting hole are both provided at the bottom of the stainless steel round tube. The wall thickness of the stainless steel round tube is 3mm-5mm, and the total length of all stainless steel round tubes is 200m-300m.

3. The geothermal well high temperature zone anti-swirl flow metal central tube according to claim 2, characterized in that: The two stainless steel round pipes are connected by threaded connection.

4. The geothermal well high temperature zone anti-swirl flow metal central tube according to claim 1, characterized in that: The flow-turbine resistance-increasing groove is a spherical pit or an elliptical pit.

5. The geothermal well high temperature zone anti-swirl flow metal central tube according to claim 1, characterized in that: The stainless steel round pipe is connected to the bottom end of the PE central pipe through a coupling. The coupling includes a coupling body. One end of the coupling body is provided with a threaded end, and the other end of the coupling body is provided with a press-fit end. The outer surface of the threaded end is provided with an external thread that is threadedly connected to the stainless steel round pipe. The press-fit end is provided with a press-fit ring groove. The end of the PE central pipe is inserted into the press-fit ring groove. The outer surface of the press-fit end is rolled to provide an extrusion groove that is concave inward and presses the outer surface of the PE central pipe.

6. The metal central tube for preventing swirl flow in the high temperature zone of a geothermal well according to claim 1, characterized in that: The central tube head is a stainless steel head with a solid interior. The top thread of the stainless steel head is connected to the bottom end of the stainless steel round tube. The stainless steel head and the stainless steel round tube are welded at the fitting seam. The bottom end of the stainless steel head is provided with a downhole cone head.

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