A geothermal well and maintenance method

Abstract

The present invention relates to the field of geothermal energy utilization technology, and proposes a geothermal well and maintenance method, including a fixed casing, which is plugged into the well; an outer tube and an inner tube, the outer tube includes an upper section and a lower section connected to each other, and the inner tube includes a connecting section and a working section connected to each other, wherein the upper section is arranged in the fixed casing; the lower section extends to the outside of the fixed casing, and the lower section is sealed at one end away from the upper section; the connecting section is arranged in the upper section, and the connecting section extends to the outside of the well, and a cavity is formed between the upper section and the connecting section; the working section is arranged in the lower section, and there is a sealed chamber between the working section and the lower section, and the sealed chamber is filled with a heat exchange medium; the connecting section and the working section are both provided with a medium supply flow channel and a medium return flow channel. When the geothermal well of the present invention performs heat exchange, the heat loss can be reduced by isolating the cavity or filling the cavity with a heat preservation medium, thereby simplifying the heat preservation structure and reducing the construction difficulty, and at the same time, it will not be affected by factors such as freeze-thaw cycles and chemical corrosion.

Description

Technical Field

[0001] The present invention relates to the technical field of geothermal energy utilization, and in particular to a geothermal well and a maintenance method thereof. Background Art

[0002] Geothermal wells are a technology that uses geothermal resources for heating, cooling and hot water. It uses the relatively stable temperature of the ground as a heat source or cold source, and uses a geothermal heat pump system to achieve heating, cooling and hot water supply for buildings. With the development of related technologies, the application of geothermal energy has become more extensive, such as geothermal power generation, industrial drying and aquaculture.

[0003] At present, geothermal wells are mainly divided into two types: open systems and closed systems. In some projects, land resources are limited, so most of them will adopt vertical closed systems. This system has the advantage of small footprint and is suitable for areas with small land resources.

[0004] The existing invention patent application with application publication number CN117870180A discloses a medium-high temperature geothermal well open-type irrigation and production system and method, including a geothermal well body, a pressure water pipe and an extraction pipe, the upper end of the pressure water pipe is connected to a water source, a high-pressure water pump is installed on the pressure water pipe, the lower end of the pressure water pipe extends to a certain depth of the geothermal well body, the lower end of the extraction pipe extends to the upper part of the geothermal well body, and a water pump is installed at the lower end of the extraction pipe;

[0005] In this scheme, the water source is pressed into a geothermal well and mixed with geothermal water before being used. However, since geothermal water usually contains certain minerals and impurities, the application range of the extracted water is limited and the water temperature cannot be very high.

[0006] There is also a utility model patent with the authorization announcement number CN220135759U, which discloses a geothermal resource heat well structure. It includes a cementing casing and a heat extraction pipe, and an annular channel is formed between the heat extraction pipe and the cementing casing; the heat exchange medium flows into the annular channel along the inlet of the cementing casing and exchanges heat with the rock formations around the geothermal well;

[0007] This scheme is the same as the above scheme, both of which form a return-type geothermal energy utilization structure. However, the return-type geothermal energy utilization structure generally has a heat loss problem, that is, as the return water is closer to the ground, the water temperature will drop, which causes a large amount of heat loss.

[0008] The existing utility model patent with authorization announcement number CN207279994U discloses a heat exchanger in a geothermal well, which proposes an insulation solution for the return geothermal well heat exchange structure, that is, adding insulation additives to the cementing cement. However, this insulation method has a high construction cost and is not stable enough. This is mainly due to factors such as freeze-thaw cycles and chemical corrosion in the regional environment, which will affect the performance of the insulation additives and thus affect the stability of the cementing structure.

[0009] At the same time, lightweight materials such as vitrified microspheres and floating beads are prone to stratification and uneven mixing when mixed with cement, making process control difficult and construction difficult. Therefore, it is urgent to improve the existing geothermal well insulation structure. Summary of the invention

[0010] In view of this, the present invention proposes a geothermal well and maintenance method which has a simple structure, is easy to construct, and is not easily affected by external factors, so as to solve the problems of difficult construction, high cost and insufficient stability of existing geothermal well insulation measures.

[0011] The technical solution of the present invention is achieved in this way:

[0012] In one aspect, the present invention provides a geothermal well, comprising a fixed casing, which is inserted into the well and used to reinforce the well wall;

[0013] It also includes an outer tube and an inner tube, the outer tube includes an upper section and a lower section connected, and the inner tube includes a connecting section and a working section connected, wherein:

[0014] The upper section is arranged in a fixed casing;

[0015] The lower section extends outside the fixed sleeve, and one end of the lower section away from the upper section is sealed;

[0016] The connecting section is arranged in the upper section and extends outside the well, and a cavity is formed between the upper section and the connecting section;

[0017] The working section is arranged in the lower section, and a sealed chamber is provided between the working section and the lower section, and the sealed chamber is filled with a heat exchange medium;

[0018] The connecting section and the working section are both provided with a medium supply flow channel and a medium return flow channel to form a return heat exchange structure.

[0019] On the basis of the above technical solution, preferably, the working section includes a plurality of medium pipes and connecting walls, wherein:

[0020] A plurality of medium pipelines are arranged in a ring array, and connecting walls are arranged between the medium pipelines;

[0021] Four quadrant points are set based on the cross section of the medium pipeline, and the side of the connecting wall is connected to the quadrant point position of the medium pipeline; or,

[0022] The two connecting walls on both sides of the same medium pipeline do not correspond to the quadrant point positions. One side of the two connecting walls has three quadrant points of the medium pipeline, and the other side has one quadrant point of the medium pipeline.

[0023] The inner cavity of the medium pipeline is the medium supply flow channel; the middle channel surrounded by the medium pipeline and the connecting wall is the medium return flow channel.

[0024] On the basis of the above technical solution, preferably, the connecting section includes a plurality of single tubes, and the medium pipeline is connected to each single tube through an intermediate channel;

[0025] The inner cavity of the single tube connected to the middle channel is the medium return flow channel.

[0026] On the basis of the above technical solution, preferably, six medium pipelines are arranged in a ring array, and the flow cross-sectional area of ​​the middle channel is the same as the flow cross-sectional area of ​​the inner cavity of the six medium pipelines; or,

[0027] The flow cross-sectional area of ​​the middle channel is the same as the flow cross-sectional area of ​​the inner cavities of the five medium pipes. Among the six medium pipes, one medium pipe is installed with a temperature sensor and is used for injecting a cleaning agent.

[0028] On the basis of the above technical solution, preferably, a cleaning assembly is further included, the cleaning assembly includes a slide cylinder and a cleaning mechanism, wherein:

[0029] The slide cylinder is slidably arranged on the outer wall of the outer tube, and the cleaning mechanism is arranged on the slide cylinder;

[0030] When the working section is working, the slide cylinder and the cleaning mechanism are located outside the upper section;

[0031] When the working section stops working, the slide cylinder and the cleaning mechanism are located outside the lower section to clean the outer wall of the lower section.

[0032] On the basis of the above technical solution, preferably, the cleaning component also includes an air bag and a fluid pipeline, wherein:

[0033] An air bag is provided at each end of the slide tube, and is used to seal the slide tube and the outer tube to form a cleaning chamber;

[0034] An inflation pipeline penetrating the slide cylinder is provided on one side of the airbag;

[0035] The cleaning mechanism is an ultrasonic transducer;

[0036] One end of the fluid pipeline is connected to and penetrates the slide tube, and the other end extends to the outside of the well.

[0037] On the basis of the above technical solution, preferably, the slide cylinder is provided with two end plates, wherein:

[0038] An end plate is provided at each end of the slide tube, and the end plate is slidably matched with the outer tube;

[0039] The airbag is in a ring-shaped structure, one end of the airbag abuts against the slide cylinder and one of the end plates, the other end of the airbag abuts against the outer tube, and the cross section of the airbag is in an arc-shaped structure.

[0040] On the basis of the above technical solution, preferably, the cleaning assembly further includes a wall tube and a ring tube, and the slide cylinder is provided with a partition, wherein,

[0041] The wall tube is arranged in close contact with the inner wall of the slide tube, the two ends of the wall tube are close to an air bag respectively, and the top end of the wall tube is a closed structure;

[0042] The fluid pipeline is close to the top of the wall tube and is connected and connected with the inner cavity of the wall tube;

[0043] The ring tube is connected and penetrated with the lower end of the wall tube, the ring tube is fixedly connected with the slide tube and surrounds the outer tube, and a spray hole is opened in the ring tube;

[0044] The partition is located between the ring tube and the air bag on the bottom side, and the air bag on the bottom side abuts against the partition;

[0045] Fluid lines, wall tubes and loop tubes are used for the supply and removal of liquids and the supply of gases.

[0046] On the basis of the above technical solution, preferably, it further comprises a flow valve, and the cavity is filled with a cleaning agent;

[0047] The circulation valve is arranged in the cavity, and the circulation valve is connected and communicated with the cleaning cavity;

[0048] The other end of the fluid pipeline is connected and penetrates the cavity;

[0049] When the working section is working, the slide cylinder and the cleaning mechanism are located outside the upper section;

[0050] When the working section stops working, the slide cylinder and the cleaning mechanism are partially located outside the lower section, and partially located outside the upper section, so as to be connected with the cavity through the flow valve.

[0051] In one aspect, the present invention provides a maintenance method for the above-mentioned geothermal well, comprising the following steps:

[0052] S1. In one of the medium pipelines, a plurality of temperature sensors are arranged in an axial array to detect the temperature at different positions of the medium pipeline;

[0053] S2. When the temperature is abnormal, the medium pipeline cannot meet the heat exchange requirements, and maintenance is carried out at this time;

[0054] S3, driving the cleaning mechanism to slide with the slide tube, so that the slide tube and the cleaning mechanism correspond to the lower section of the outer tube;

[0055] S4, cleaning the outer wall of the lower section by a cleaning mechanism to remove sediment;

[0056] S5. After cleaning is completed, the cleaning mechanism is driven to slide by the slide tube so that the slide tube and the cleaning mechanism correspond to the upper section of the outer tube;

[0057] S6, supplying a cleaning agent through a medium pipeline provided with a temperature sensor, and then performing water circulation to clean the working medium flow channel;

[0058] S7. The geothermal well is put back into operation.

[0059] The geothermal well and maintenance method of the present invention have the following beneficial effects compared with the prior art:

[0060] (1) By arranging an inner tube inside the outer tube, when heat exchange is performed, the lower section of the outer tube and the working section of the inner tube perform heat exchange work. When water flows back through the connecting section, since the connecting section is located in the upper section of the outer tube, a cavity is formed between the connecting section and the upper section. In this way, thermal insulation work can be achieved through the cavity. At the same time, the gap between the upper section and the fixed sleeve can also be further insulated to reduce heat loss; and the top of the upper section can be sealed, or a heat-insulating medium can be filled into the cavity to further reduce heat loss. In this way, the heat-insulating structure is simplified, the construction difficulty is reduced, and it will not be affected by factors such as freeze-thaw cycles and chemical corrosion;

[0061] (2) The working section and the lower section exchange heat through a heat exchange medium, which can prevent the working section from directly contacting the geothermal water to prevent corrosion problems in the working section. This makes it suitable for heating working media with high standards and avoids problems such as pipeline damage and groundwater infiltration that affect the working medium.

[0062] (3) The working section is composed of multiple medium pipes and connecting walls, and the connecting walls on both sides of the medium pipe correspond to the quadrant points of the medium pipe cross section, or two opposite connecting walls have three quadrant points of the medium pipe cross section on one side and one quadrant point of the medium pipe cross section on the other side, which allows the medium pipe to have more area to contact the heat exchange medium, thereby improving the heat exchange efficiency; at the same time, in this case, the diameter of the lower section of the outer pipe can be appropriately increased to improve the overall heat exchange efficiency;

[0063] (4) There are multiple medium pipes, and in some embodiments, six medium pipes are provided. To ensure the maximum heat exchange efficiency, the flow cross-sectional area of ​​the middle channel enclosed by the medium pipes and the connecting wall is the same as the inner cavity flow cross-sectional area of ​​the six medium pipes, so that the efficiency of medium supply and supply can be maximized; in some scenarios, the flow cross-sectional area of ​​the middle channel is configured to be the same as the inner cavity flow cross-sectional area of ​​five medium pipes, so that one medium pipe can be vacated for installing a temperature sensor for temperature detection, so as to determine whether the heat exchange of the local source heat well is stable, thereby facilitating maintenance; and the vacated medium pipe is used to inject a cleaning agent to clean the medium flow channel of the local source heat well;

[0064] (5) By providing a slidable cleaning assembly on the outer tube, the lower section can be cleaned regularly to prevent the mineral crystallization in the geothermal water from affecting the heat exchange efficiency and to avoid interfering with the normal heat exchange work of the local source heat well;

[0065] (6) By setting a circulation valve, when the cleaning component is cleaning, the cleaning agent can be directly injected through the cavity and flow through the circulation valve to the cleaning cavity formed by the cleaning component, thereby improving the convenience of injecting the cleaning chemical agent. The cleaning chemical agent can be returned to the cavity through the fluid pipeline and the wall tube, and the agent can be pumped out by the pump in the outside. In this way, there is no need to deploy a large-lift pump in the well, thereby reducing the space occupied in the well. BRIEF DESCRIPTION OF THE DRAWINGS

[0066] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0067] Figure 1 A three-dimensional diagram of a geothermal well according to the present invention;

[0068] Figure 2 A top view of the geothermal well of the present invention;

[0069] Figure 3 It is a cross-sectional perspective view of the geothermal well of the present invention;

[0070] Figure 4 An exploded diagram of the geothermal well of the present invention;

[0071] Figure 5 It is a stereoscopic diagram of the lower section and the working section of the geothermal well of the present invention;

[0072] Figure 6 A cross-sectional view of a cleaning assembly for a geothermal well according to the present invention;

[0073] Figure 7 It is a stereoscopic diagram of the cooperation structure of the cleaning assembly and the outer pipe of the geothermal well of the present invention;

[0074] Figure 8 This is a fluid pipeline connection structure diagram of the geothermal well of the present invention;

[0075] Fig. 9 This is an application state diagram of the geothermal well of the present invention;

[0076] Fig.10 This is a side view of the geothermal well of the present invention after the fixed casing is removed;

[0077] Fig.11 For the present invention Fig.10 Middle AA section view;

[0078] Fig.12 For the present invention Fig.11 A cut-off diagram of ;

[0079] Fig.13 A cross-sectional view of a distribution flow valve for a geothermal well according to the present invention;

[0080] Fig.14 For the present invention Fig.13 A cut-off diagram of ;

[0081] Fig.15 A cross-sectional view of the working state of the geothermal well of the present invention;

[0082] Fig.16 For the present invention Fig.15 A cut-off diagram of ;

[0083] Fig.17 This is a structural diagram of the connection between the medium pipeline and the connection wall of the geothermal well of the present invention;

[0084] Fig.18 This is a second connection structure diagram of the medium pipeline and the connection wall of the geothermal well of the present invention;

[0085] In the figure: 1, fixed sleeve; 2, outer tube; 21, upper section; 22, lower section; 3, inner tube; 31, connecting section; 311, single tube; 32, working section; 321, medium pipeline; 322, connecting wall; 4, cleaning component; 41, slide cylinder; 411, end plate; 412, partition; 42, cleaning mechanism; 43, air bag; 431, inflation pipeline; 44, fluid pipeline; 45, wall tube; 46, annular tube; 401, spray hole; 5, circulation valve; 100, sealing chamber; 200, cavity; 300, middle channel; 400, cleaning chamber; O, quadrant point. DETAILED DESCRIPTION

[0086] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0087] like Figures 1 to 18 As shown, the geothermal well of the present invention includes a fixed casing 1, an outer pipe 2, an inner pipe 3, a cleaning assembly 4 and a circulation valve 5.

[0088] like Figure 1 As shown, the fixed casing 1 is inserted into the well to reinforce the well wall;

[0089] Specifically, a base material such as concrete is filled between the well wall and the fixed casing 1 to further improve the structural strength.

[0090] like Figures 1 to 5 As shown, the outer tube 2 includes an upper section 21 and a lower section 22 connected to each other, and the inner tube 3 includes a connecting section 31 and a working section 32 connected to each other, wherein the upper section 21 is arranged in the fixed casing 1; the lower section 22 extends to the outside of the fixed casing 1, and one end of the lower section 22 away from the upper section 21 is sealed; the connecting section 31 is arranged in the upper section 21, and the connecting section 31 extends to the outside of the well, and a cavity 200 is formed between the upper section 21 and the connecting section 31; the working section 32 is arranged in the lower section 22, and a sealed chamber 100 is provided between the working section 32 and the lower section 22, and the sealed chamber 100 is filled with a heat exchange medium; the connecting section 31 and the working section 32 are both provided with a medium supply flow channel and a medium return flow channel to form a return heat exchange structure;

[0091] As in the above structure, when it is working, the lower section 22 is immersed in the geothermal water, and the working medium flows in the medium supply flow channel and the medium return flow channel in the connecting section 31 and the working section 32. When the medium flows into the working section 32, the heat exchange medium in the sealed chamber 100 transfers the heat of the geothermal water to the working medium flowing through the working section 32, thereby realizing the heat exchange work;

[0092] When the working medium is transported back through the medium return flow channel, since the connecting section 31 is located in the upper section 21, and the upper section 21 is located in the fixed sleeve 1, the air in the cavity 200 and the gap between the upper section 21 and the fixed sleeve 1 will play a heat insulation role, thereby reducing the heat loss of the working medium and improving the heat utilization efficiency;

[0093] Furthermore, the top of the upper section 21 may be sealed, and / or a heat-insulating medium may be filled into the cavity 200 to further reduce heat loss, thereby simplifying the heat-insulating structure and reducing the difficulty of construction. At the same time, the heat-insulating structure will not be affected by factors such as freeze-thaw cycles and chemical corrosion, thereby effectively improving the reliability of geothermal well applications.

[0094] At the same time, heat exchange is carried out between the working section 32 and the lower section 22 through a heat exchange medium, which can avoid direct contact of the working section 32 with geothermal water to prevent corrosion problems in the working section 32. This makes it suitable for heating working media with high standards and avoids problems such as pipeline damage and groundwater infiltration that affect the working medium.

[0095] like Figure 3 and Fig.17 As shown, the working section 32 includes a plurality of medium pipelines 321 and a connecting wall 322, wherein the plurality of medium pipelines 321 are arranged in a ring array, and a connecting wall 322 is arranged between the medium pipelines 321 and the medium pipelines 321; four quadrant points O are set based on the cross section of the medium pipeline 321, and the side of the connecting wall 322 is connected to the quadrant point O position of the medium pipeline 321;

[0096] The middle channel 300 formed by the medium pipeline 321 and the connecting wall 322 is a medium return flow channel;

[0097] As in the above structure, the medium pipeline 321 is used for inputting the working medium. Through the arrangement of the medium pipeline 321 and the connecting wall 322, the medium pipeline 321 protrudes outwards to have more area to contact with the heat exchange medium, thereby improving the heat conduction efficiency and making full use of the geothermal energy.

[0098] In this case, the diameter of the lower section 22 can be increased so that the lower section 22 has an area equivalent to the medium pipeline 321 and the connecting wall 322 to contact the heat exchange medium and the geothermal water;

[0099] In this structure, not only is the working medium heated when flowing through the medium pipeline 321, but also when flowing back through the intermediate channel 300, the heat of the heat exchange medium is transferred to the working medium again through the connecting wall 322, so that the working medium is heated up a second time. This can effectively avoid the problem of heat loss caused by heat exchange between the input working medium and the output working medium, so that the output working medium has a higher temperature.

[0100] In some embodiments, Fig.18 As shown, the two connecting walls 322 on both sides of the same medium pipeline 321 do not correspond to the position of the quadrant point O. One side of the two connecting walls 322 has three quadrant points O of the medium pipeline 321, and the other side has one quadrant point O of the medium pipeline 321. The inner cavity of the medium pipeline 321 is a medium supply flow channel.

[0101] As set up in the above structure, this structure further increases the contact area between the medium pipeline 321 and the heat exchange medium, thereby increasing the heating rate;

[0102] In this structure, the area of ​​the medium pipeline 321 used for spacing between the input working medium and the output working medium is also reduced, thereby reducing the heat exchange rate between the input working medium and the output working medium;

[0103] The area of ​​the connecting wall 322 used for spacing between the heat exchange medium and the output working medium is increased, so that the temperature of the output working medium can be further increased during the secondary heating.

[0104] like Figure 1 and Figure 2 As shown, the connecting section 31 includes a plurality of single tubes 311, and the medium pipeline 321 and the intermediate channel 300 are each connected to and penetrated by a single tube 311; the inner cavity of the single tube 311 connected to the intermediate channel 300 is a medium return flow channel;

[0105] As in the above structure, when heat exchange is performed, the working medium with low temperature is input through the single pipe 311 connected to the medium pipeline 321. When the working medium flows through the medium pipeline 321, it will be heated by the heat exchange medium. The heated working medium can be refluxed through the intermediate channel 300.

[0106] This structure has the advantage of being simple in structure and reducing the difficulty of assembly because the connecting section 31 located in the upper section 21 adopts multiple single tubes 311. This structure is also convenient for converging working media from multiple sources, thereby improving the convenience of heating.

[0107] In some embodiments, the single tube 311 and the medium pipeline 321 are used for the output of the working medium, while the intermediate channel 300 is used for the input of the working medium. In this way, the structure of multiple medium pipelines 321 and the single tube 311 can be used to achieve the diversion of the high-temperature working medium during output, thereby improving the convenience of utilization.

[0108] like Figure 2 As shown, six medium pipes 321 are arranged in a ring array, and the flow cross-sectional area of ​​the middle channel is the same as the flow cross-sectional area of ​​the inner cavity of the six medium pipes 321;

[0109] As in the above structure, in a specific application, six medium pipelines 321 may be provided. In this case, in order to ensure the flow efficiency of the working medium, the flow volume of the six medium pipelines 321 may be configured to be the same as the flow volume of the middle channel 300;

[0110] In some embodiments, the cross-sectional area of ​​the middle channel 300 is set as small as possible, and the medium pipes 321 are configured in even numbers, and the ends of each two medium pipes 321 away from the single pipe 311 are connected through a U-shaped pipe, so as to realize a U-shaped heat exchange pipeline, so that when the working medium circulates, it will be heated twice;

[0111] For this structure, both ends of the middle channel 300 can be closed, and heat exchange medium can also be injected into the middle channel 300, and holes can be opened on the connecting wall 322, so that the end of the medium pipeline 321 is immersed in the heat exchange medium to fully heat the working medium flowing through the medium pipeline 321.

[0112] In some embodiments, the flow cross-sectional area of ​​the middle channel 300 is the same as the inner cavity flow cross-sectional area of ​​the five medium pipes 321. Among the six medium pipes 321, one medium pipe 321 is installed with a temperature sensor and is used to inject a cleaning agent.

[0113] As in the above structure, when the working medium is input, it is transported only through five medium pipes 321, and another medium pipe 321 is installed with a detection component, mainly a temperature sensor, to detect the temperature of the medium pipe 321 at different positions, so as to judge the heat exchange efficiency of the heat exchange medium, and thus judge whether the heat exchange of the local source heat well is stable, so as to facilitate maintenance;

[0114] The vacated medium pipeline 321 is used to inject a cleaning agent to clean the medium flow channel of the local source heat well, specifically to flush the medium pipeline 321, the single tube 311 and the intermediate channel 300, so as to ensure the heat exchange efficiency;

[0115] During the joint maintenance of multiple wells, relevant detection data can also be used to compare the operating conditions of multiple geothermal wells to determine which geothermal wells require maintenance.

[0116] like Figure 3 and Figure 6 As shown, the cleaning assembly 4 includes a slide 41 and a cleaning mechanism 42, wherein the slide 41 is slidably arranged on the outer wall of the outer tube 2, and the cleaning mechanism 42 is arranged on the slide 41; when the working section 32 is working, the slide 41 and the cleaning mechanism 42 are located on the outer side of the upper section 21; when the working section 32 stops working, the slide 41 and the cleaning mechanism 42 are located on the outer side of the lower section 22 to clean the outer wall of the lower section 22;

[0117] As in the above structure, in the local source heat well, the lower section 22 of the outer tube 2 and the working section 32 of the inner tube 3 are used for the main heat exchange work;

[0118] Specifically, the lower section 22 of the outer tube 2 is immersed in geothermal water. During long-term use, impurities such as minerals will crystallize on the lower section 22, which will affect the heat exchange work. Therefore, it is necessary to clean the crystals.

[0119] When performing heat exchange work, the cleaning component 4 stays outside the upper section 21 of the outer tube 2, and when cleaning is required, it needs to be moved to the corresponding lower section 22. At this time, the sliding of the slide 41 makes the cleaning mechanism 42 correspond to the lower section 22, so that the crystals on the lower section 22 can be cleaned.

[0120] like Figure 6 , Figure 7 and Figures 10-12 As shown, the cleaning assembly 4 also includes an airbag 43 and a fluid pipeline 44, wherein one airbag 43 is provided at each end of the slide 41, for sealing the slide 41 and the outer tube 2 to form a cleaning chamber 400; an air-filling pipeline 431 penetrating the slide 41 is provided on one side of the airbag 43; the cleaning mechanism 42 is an ultrasonic transducer; one end of the fluid pipeline 44 is connected to the slide 41, and the other end extends to the outside of the well;

[0121] As in the above structure, when the cleaning component 4 stays outside the upper section 21, the airbag 43 is not inflated. Only when the cleaning component 4 corresponds to the lower section 22, the airbag 43 is inflated through the inflation pipeline 431. At this time, the airbag 43 expands to seal the two ends of the cleaning cavity 400.

[0122] At the same time, a chemical agent is injected into the sealed cleaning chamber 400 through the fluid pipeline 44 to dissolve the crystals attached to the lower section 22, and mechanical vibration is induced by the ultrasonic transducer, thereby cleaning the crystals;

[0123] Specifically, the inflation pipeline 431 is connected to an air pump to implement inflation and deflation operations.

[0124] like Figure 3 and Figure 6 As shown, the slide 41 is provided with two end plates 411, wherein one end plate 411 is provided at each end of the slide 41, and the end plate 411 is slidably matched with the outer tube 2; the airbag 43 is an annular structure, one end of the airbag 43 abuts against the slide 41 and one of the end plates 411, and the other end of the airbag 43 abuts against the outer tube 2, and the cross-section of the airbag 43 is an arc-shaped structure.

[0125] As in the above structure, the end plate 411 is used to install the airbag 43, and the airbag 43 is configured as a ring structure with an arc-shaped cross-section, so that when the airbag 43 is inflated, it will press against the outer tube 2 for sealing; and after the airbag 43 is deflated, it will retract and move closer to the inner wall of the end plate 411 and the slide tube 41, so that when the cleaning mechanism 42 slides, the airbag 43 can be prevented from rubbing against the outer tube 2 to cause damage.

[0126] like Figure 5 As shown, the cleaning assembly 4 also includes a wall tube 45 and an annular tube 46, and the slide 41 is provided with a partition 412, wherein the wall tube 45 is arranged in contact with the inner wall of the slide 41, and both ends of the wall tube 45 are close to an air bag 43, and the top of the wall tube 45 is a closed structure; the fluid pipeline 44 is close to the top of the wall tube 45, and is connected and connected with the inner cavity of the wall tube 45; the annular tube 46 is connected and connected with the lower end of the wall tube 45, and the annular tube 46 is fixedly connected to the slide 41 and surrounds the outer tube 2, and the annular tube 46 is provided with a spray hole 401; the partition 412 is located between the annular tube 46 and the air bag 43 on the bottom side, and the air bag 43 on the bottom side abuts the partition 412; the fluid pipeline 44, the wall tube 45 and the annular tube 46 are used for supplying and discharging liquid, and supplying gas;

[0127] As in the above structure, during cleaning, the cleaning chemical agent is supplied through the fluid pipeline 44, and the chemical agent flows through the wall tube 45 and the ring tube 46, and is dispersed through the spray hole 401. After the chemical agent fills the cleaning chamber 400 and is cleaned by the ultrasonic transducer, the cleaned crystals are deposited. At this time, the chemical agent and the crystals can be extracted through the ring tube 46, the wall tube 45 and the fluid pipeline 44.

[0128] Specifically, the fluid pipeline 44 extends outside the well and is connected in series with a water pump to discharge the cleaning chemicals to avoid contaminating groundwater; the water pump is also used to pump in the chemicals;

[0129] In this structure, by setting the partition 412, when the airbag 43 abuts against the partition 412, the sealing effect can be improved, and sediments and chemicals can be prevented from entering between the partition 412 and the lower end plate 411 as much as possible, so as to reduce the leakage of the agent after the airbag 43 retracts.

[0130] In some embodiments, a three-way valve is provided at the end of the fluid pipeline 44, one of the pipe ports of the three-way valve is connected to the wall tube 45 through the fluid pipeline 44, one end is connected to the water pump, and the other end is connected to the air pump;

[0131] In this way, when cleaning, after some chemicals and crystals are extracted, air is pumped through the air pump, which plays an aeration role. This can lift the deposited crystals and mix them into the chemicals, so that the subsequent extraction is cleaner;

[0132] In some embodiments, the deposited crystals can also be lifted by repeatedly extracting and pumping back the agent;

[0133] In this structure, the wall tube 45 is provided, which not only facilitates the dispersion of the reagent through the ring tube 46, but also improves the aeration effect, so that the deposited crystals can be fully floated, making the discharge cleaner;

[0134] At the same time, the wall tube 45 is provided so that the fluid pipeline 44 only needs to be connected to the upper end of the slide tube 41, which reduces the length of the fluid pipeline 44 and reduces the risk of damage and failure of the fluid pipeline 44 due to entanglement and other problems.

[0135] In some embodiments, Figure 8 , Fig. 9 , Figures 13-16 As shown, the cavity 200 is filled with a cleaning agent; the circulation valve 5 is arranged in the cavity 200, and the circulation valve 5 is connected and communicated with the cleaning cavity 400; the other end of the fluid pipeline 44 is connected and communicated with the cavity 200; when the working section 32 is working, the slide 41 and the cleaning mechanism 42 are located outside the upper section 21; when the working section 32 stops working, the slide 41 and the cleaning mechanism 42 are partially located outside the lower section 22, and partially located outside the upper section 21, so as to communicate with the cavity 200 through the circulation valve 5;

[0136] As in the above structure, in this embodiment, the cavity 200 is not sealed or filled with a heat-insulating medium, but is used to pre-store a cleaning agent;

[0137] In this way, after the cleaning component 4 corresponds to the lower section 22 and completes the sealing through the airbag 43, the flow valve 5 is opened, and the cleaning agent in the cavity 200 will automatically flow into the cleaning cavity 400 to facilitate the cleaning work;

[0138] In this embodiment, the other end of the fluid pipeline 44 does not extend outside the well, but is connected to and communicates with the cavity 200, and the fluid pipeline 44 needs to be connected in series with a pump;

[0139] In this way, after cleaning, the cleaning agent can be sent back into the cavity 200 by using a pump in conjunction with the fluid pipeline 44. At this time, a water pump is connected to the pump through an external pump, and the pump pipe is extended into the cavity 200 to extract the agent. After cleaning, the pump pipe is pulled out. In this way, the fluid pipeline 44 only needs a small pump to pump water. It does not need to be extended outside the well, nor does it need to be installed with a large-lift pump in the well, which reduces the space occupied in the well.

[0140] The maintenance method of the geothermal well of the present invention comprises the following steps:

[0141] S1. In one of the medium pipelines 321, a plurality of temperature sensors are arranged in an axial array to detect the temperature at different positions of the medium pipeline 321;

[0142] S2. When the temperature is abnormal, the medium pipeline 321 cannot meet the heat exchange requirements, and maintenance is performed at this time;

[0143] S3, the slide cylinder 41 drives the cleaning mechanism 42 to slide, so that the slide cylinder 41 and the cleaning mechanism 42 correspond to the lower section 22 of the outer tube 2;

[0144] S4, cleaning the outer wall of the lower section 22 by the cleaning mechanism 42 to remove sediment;

[0145] S5. After cleaning is completed, the cleaning mechanism 42 is driven to slide by the slide 41 so that the slide 41 and the cleaning mechanism 42 correspond to the upper section 21 of the outer tube 2;

[0146] S6, supplying cleaning agent into the medium pipeline 321 provided with a temperature sensor, and then performing water circulation to clean the working medium flow channel;

[0147] S7. The geothermal well is put back into operation.

[0148] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A geothermal well, comprising a fixed casing (1), wherein the fixed casing (1) is inserted into the well and used to reinforce the well wall; Features: It also comprises an outer tube (2) and an inner tube (3), wherein the outer tube (2) comprises an upper section (21) and a lower section (22) connected to each other, and the inner tube (3) comprises a connecting section (31) and a working section (32) connected to each other, wherein: The upper section (21) is arranged in the fixed sleeve (1); The lower section (22) extends outside the fixed sleeve (1), and one end of the lower section (22) away from the upper section (21) is sealed; The connecting section (31) is arranged in the upper section (21), and the connecting section (31) extends outside the well, and a cavity (200) is formed between the upper section (21) and the connecting section (31); The working section (32) is arranged in the lower section (22), and a sealed chamber (100) is provided between the working section (32) and the lower section (22), and the sealed chamber (100) is filled with a heat exchange medium; The connecting section (31) and the working section (32) are both provided with a medium supply flow channel and a medium return flow channel to form a return heat exchange structure; The working section (32) comprises a plurality of medium pipelines (321) and a connecting wall (322), wherein the plurality of medium pipelines (321) are arranged in a ring array, and the connecting wall (322) is arranged between the medium pipelines (321) and the medium pipelines (321); four quadrant points are set based on the cross section of the medium pipeline (321), and the side of the connecting wall (322) is connected to the quadrant point positions of the medium pipeline (321); Alternatively, the two connecting walls (322) on both sides of the same medium pipeline (321) do not correspond to the quadrant point positions, one side of the two connecting walls (322) has three quadrant points of the medium pipeline (321), and the other side has one quadrant point of the medium pipeline (321); the inner cavity of the medium pipeline (321) is the medium supply channel; and the middle channel (300) enclosed by the medium pipeline (321) and the connecting wall (322) is the medium return channel.

2. The geothermal well according to claim 1, characterized in that: The connecting section (31) comprises a plurality of single tubes (311), and the medium pipeline (321) and the intermediate channel (300) are each connected to and communicated with one of the single tubes (311); The inner cavity of the single tube (311) connected to the intermediate channel (300) is the medium return flow channel.

3. The geothermal well according to claim 1, characterized in that: Six medium pipes (321) are arranged in a ring array, and the flow cross-sectional area of ​​the intermediate channel (300) is the same as the flow cross-sectional area of ​​the inner cavity of the six medium pipes (321); or, The flow cross-sectional area of ​​the intermediate channel (300) is the same as the inner cavity flow cross-sectional area of ​​the five medium pipes (321). Among the six medium pipes (321), one of the medium pipes (321) is installed with a temperature sensor and is used for injecting a cleaning agent.

4. The geothermal well according to claim 3, characterized in that: It also includes a cleaning assembly (4), the cleaning assembly (4) including a slide cylinder (41) and a cleaning mechanism (42), wherein: The slide cylinder (41) is slidably arranged on the outer wall of the outer tube (2), and the cleaning mechanism (42) is arranged on the slide cylinder (41); When the working section (32) is working, the slide cylinder (41) and the cleaning mechanism (42) are located outside the upper section (21); When the working section (32) stops working, the slide cylinder (41) and the cleaning mechanism (42) are located outside the lower section (22) to clean the outer wall of the lower section (22).

5. The geothermal well according to claim 4, characterized in that: The cleaning assembly (4) further comprises an air bag (43) and a fluid pipeline (44), wherein: The airbag (43) is provided at each end of the slide cylinder (41) and is used to seal the slide cylinder (41) and the outer tube (2) to form a cleaning chamber (400); An inflation pipeline (431) penetrating the slide cylinder (41) is provided on one side of the air bag (43); The cleaning mechanism (42) is an ultrasonic transducer; One end of the fluid pipeline (44) is connected to and penetrates the slide tube (41), and the other end extends to the outside of the well.

6. The geothermal well according to claim 5, characterized in that: The slide cylinder (41) is provided with two end plates (411), wherein: The end plate (411) is provided at each end of the slide tube (41), and the end plate (411) is slidably matched with the outer tube (2); The airbag (43) is an annular structure, one end of the airbag (43) abuts against the slide cylinder (41) and one of the end plates (411), the other end of the airbag (43) abuts against the outer tube (2), and the cross-section of the airbag (43) is an arc-shaped structure.

7. The geothermal well according to claim 5, characterized in that: The cleaning assembly (4) further comprises a wall tube (45) and a ring tube (46), and the slide cylinder (41) is provided with a partition plate (412), wherein: The wall tube (45) is arranged in close contact with the inner wall of the slide tube (41), the two ends of the wall tube (45) are respectively close to one of the air bags (43), and the top end of the wall tube (45) is a closed structure; The fluid pipeline (44) is close to the top end of the wall tube (45) and is connected to and communicates with the inner cavity of the wall tube (45); The annular tube (46) is connected and penetrated with the lower end of the wall tube (45), the annular tube (46) is fixedly connected with the slide cylinder (41) and surrounds the outer tube (2), and the annular tube (46) is provided with a spray hole (401); The partition (412) is located between the ring tube (46) and the airbag (43) on the bottom side, and the airbag (43) on the bottom side abuts against the partition (412); The fluid pipeline (44), the wall tube (45) and the ring tube (46) are used for supplying and discharging liquid and supplying gas.

8. The geothermal well according to any one of claims 5 to 7, characterized in that: It also includes a circulation valve (5), and the cavity (200) is filled with a cleaning agent; The circulation valve (5) is arranged in the cavity (200), and the circulation valve (5) is connected and communicates with the cleaning cavity (400); The other end of the fluid pipeline (44) is connected to and communicates with the cavity (200); When the working section (32) is working, the slide cylinder (41) and the cleaning mechanism (42) are located outside the upper section (21); When the working section (32) stops working, the slide cylinder (41) and the cleaning mechanism (42) are partially located outside the lower section (22) and partially located outside the upper section (21) so as to be connected with the cavity (200) through the circulation valve (5).

9. The method for maintaining a geothermal well according to any one of claims 4 to 8, characterized in that: The following steps are involved: S1. In one of the medium pipelines (321), a plurality of temperature sensors are arranged in an axial array to detect the temperature at different positions of the medium pipeline (321); S2. When abnormal temperature is detected, the medium pipeline (321) cannot meet the heat exchange requirement, and maintenance is performed at this time; S3, driving the cleaning mechanism (42) to slide with the slide cylinder (41), so that the slide cylinder (41) and the cleaning mechanism (42) correspond to the lower section (22) of the outer tube (2); S4, cleaning the outer wall of the lower section (22) by the cleaning mechanism (42) to remove sediment; S5. After the cleaning is completed, the slide cylinder (41) drives the cleaning mechanism (42) to slide, so that the slide cylinder (41) and the cleaning mechanism (42) correspond to the upper section (21) of the outer tube (2); S6, supplying a cleaning agent into the medium pipeline (321) provided with a temperature sensor, and then performing water circulation to clean the working medium flow channel; S7. The geothermal well is put back into operation.

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