Interference-free single-well heat extraction underground heat exchange device

Abstract

The utility model relates to the technical field of non-interference single well heat extraction, in particular to a non-interference single well heat extraction underground heat exchange device which comprises a stratum, a high-temperature heat storage layer arranged at the bottom of the stratum, a transformation well arranged in the stratum and a heat exchange mechanism arranged in the transformation well. The heat exchange mechanism comprises a well wall sleeve fixedly connected to the inner wall of the transformation well, a circulating pipeline is fixedly connected into the well wall sleeve, a heat insulation plate is fixedly connected between the inner walls of the circulating pipeline, the two sides of the top of the circulating pipeline communicate with a low-temperature water inlet pipe and a high-temperature water outlet pipe correspondingly, and the bottom of the circulating pipeline communicates with a heat exchanger. Compared with the prior art, a traditional gas heating furnace or an electric heating mode is effectively replaced, low-energy-consumption and low-emission water heating is achieved, and heat supply of residents is met; and meanwhile, dynamic balance of geothermal heat storage is guaranteed, and an efficient low-carbon heat supply structure integrating underground heat exchange, heat pump temperature rising and hot water circulation is constructed.

Description

Technical Field

[0001] This utility model relates to the field of downhole heat exchange technology, and in particular to a non-intrusive single-well heat extraction downhole heat exchange device. Background Technology

[0002] With the increasing demand for clean energy development and utilization, geothermal energy, as a green, renewable, and stable energy form, is receiving more and more attention in the energy sector. Medium-deep geothermal resources are characterized by high temperature, large reserves, and strong stability, and are widely used in areas such as district heating. Currently, the demand for heat energy in district heating is growing, especially in northern my country and high-altitude cold regions. Residential centralized heating typically relies on external heating stations to heat water before it is transported to residential areas through pipelines. However, the heat sources used for heating water still largely rely on coal-fired boilers, gas-fired furnaces, or electric heating combined with heat exchangers. These traditional heating methods generally suffer from high energy consumption, large carbon emissions, and high operating costs.

[0003] Currently, some regional heating systems or crude oil heating commonly use gas-fired boilers or electric heating methods to provide heat energy, especially in northern and cold regions of my country, where residential centralized heating still heavily relies on coal-fired boilers, gas-fired boilers, or electric heating systems. These traditional heating methods suffer from high energy consumption, high operating costs, low thermal efficiency, and serious carbon emissions. Existing technologies cannot be adapted to utilize the numerous abandoned or idle oil and gas wells in oil fields and industrial areas, combining downhole heat exchange with surface heat pumps to extract geothermal resources and meet the heating needs of residents or districts. This not only exacerbates energy shortages but also negatively impacts environmental protection and air quality, failing to meet current energy conservation, emission reduction, and dual-carbon goals. Therefore, there is an urgent need to develop a downhole, medium-deep geothermal heat exchange mechanism suitable for residential heating needs to achieve clean, low-carbon, and sustainable heating goals. Utility Model Content

[0004] In view of this, the purpose of this utility model is to propose a non-intrusive single-well heat extraction downhole heat exchange device to solve the problem that existing devices cannot be modified based on the large number of abandoned or idle oil and gas wells in oil fields and industrial areas, and can combine downhole heat exchange with ground heat pumps to efficiently obtain geothermal resources and meet the heating needs of residents or districts.

[0005] Based on the above objectives, this utility model provides a non-intrusive single-well heat extraction downhole heat exchange device, including a formation, a high-temperature thermal reservoir at the bottom of the formation, a modified well inside the formation, and a heat exchange mechanism inside the modified well. The heat exchange mechanism includes a well casing fixedly connected to the inner wall of the modified well, a circulation pipeline fixedly connected inside the well casing, and a heat insulation plate fixedly connected between the inner walls of the circulation pipeline. Low-temperature inlet pipes and high-temperature outlet pipes are respectively connected to the top two sides of the circulation pipeline, and a heat exchanger is connected to the bottom of the circulation pipeline. Two insulating plates are fixedly connected between the pipeline and the heat exchanger. Two connecting pipes are fixedly connected between the opposite surfaces of the two insulating plates. The heat exchanger is equipped with multiple first and second heat exchange inner tubes for heat exchange. The first and second heat exchange inner tubes are respectively connected to the two connecting pipes. A blind cap is fixedly connected to the bottom of the heat exchanger. The bottom ends of the first and second heat exchange inner tubes are respectively connected to the inner wall of the blind cap. A water pump is fixedly connected to the bottom of the blind cap. A high-temperature hot water pipe is fixedly connected to the bottom of the heat exchanger.

[0006] Preferably, the sidewall of the insulating plate has a communication opening, and the top two sides of the heat exchanger have water outlets.

[0007] Preferably, the outer diameter of the heat exchanger is smaller than the inner diameter of the well casing.

[0008] Preferably, the sidewall of the well casing is connected to a branch pipe for low-temperature circulating water.

[0009] Preferably, the high-temperature hot water pipe and the branch pipe are located inside the high-temperature thermal reservoir.

[0010] Preferably, the end of the high-temperature water outlet pipe away from the circulation pipeline is fixedly connected to the input end of the multi-source heat pump unit, the output end of the multi-source heat pump unit is fixedly connected to a heat exchanger, and the end of the low-temperature water inlet pipe away from the circulation pipeline is fixedly connected to the return end of the heat exchanger.

[0011] Preferably, after the water pump draws high-temperature underground water, it is transported to the interior of the heat exchanger and exchanges heat with the softened water in the second heat exchange inner tube and the first heat exchange inner tube.

[0012] The beneficial effects of this utility model are:

[0013] This medium-deep geothermal well's downhole heat exchange mechanism delivers low-temperature softened water through a low-temperature inlet pipe to the circulation pipeline within the well. After passing through a connecting pipe, the water enters the second heat exchange inner pipe and exchanges heat with the high-temperature formation water in the heat exchanger, raising the temperature of the softened water. Subsequently, the high-temperature softened water is transported through a high-temperature outlet pipe to a multi-source heat pump unit for further heating before being sent to the heat exchanger to exchange heat with water supplied by the water supply station. This raised water temperature is then output to residential areas for underfloor heating or to provide hot water. In addition to providing heating for residential areas, it can also heat crude oil, improving energy efficiency and increasing [the overall energy efficiency]. With its comprehensive service capabilities, the system effectively replaces traditional gas-fired or electric heating methods, achieving low-energy consumption and low-emission water heating. Simultaneously, low-temperature circulating water can be discharged through the top outlet of the heat exchanger and circulated to the high-temperature geothermal reservoir through branch pipes connected to the well casing sidewall for heat exchange, ensuring the dynamic balance of the geothermal reservoir. This constructs a highly efficient and low-carbon heating structure integrating downhole heat exchange, heat pump heating, and hot water circulation, making full use of idle oil and gas well resources without interfering with the natural flow of groundwater or causing thermal pollution. It possesses excellent technical adaptability and application value. Attached Figure Description

[0014] To more clearly illustrate the technical solutions in this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only for this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0015] Figure 1 This is a schematic diagram of the overall structure of this utility model;

[0016] Figure 2 This is a schematic diagram of the circulation pipeline and heat exchanger structure of this utility model;

[0017] Figure 3 This is a schematic diagram of the blind cap and water pump structure of this utility model;

[0018] Figure 4 This is a schematic diagram of the high-temperature hot water pipe and branch pipe structure of this utility model;

[0019] Figure 5 This is a schematic diagram of the softened water heat exchange structure of this utility model.

[0020] The diagram is marked as follows:

[0021] 1. Modified well; 2. Well casing; 3. Circulation pipeline; 4. Insulation plate; 5. Low temperature water inlet pipe; 6. High temperature water outlet pipe; 7. Heat exchanger; 8. Insulation plate; 9. First heat exchange inner tube; 10. Second heat exchange inner tube; 11. Blind cap; 12. Water pump; 13. High temperature hot water pipe; 14. Connecting pipe; 15. Connecting port; 16. Water outlet; 17. Branch pipe; 18. Formation; 19. High temperature thermal reservoir. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of this utility model clearer, the present utility model will be further described in detail below with reference to specific embodiments.

[0023] It should be noted that, unless otherwise defined, the technical or scientific terms used in this utility model should have the ordinary meaning understood by one of ordinary skill in the art to which this utility model pertains. The terms "first," "second," and similar terms used in this utility model do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Terms such as "comprising" or "including" mean that the element or object preceding the word encompasses the elements or objects listed following the word and their equivalents, without excluding other elements or objects. Terms such as "connected" or "linked" are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. Terms such as "upper," "lower," "left," and "right" are used only to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0024] like Figures 1 to 5As shown, a non-interference single-well heat extraction downhole heat exchange device includes a formation 18, a high-temperature heat reservoir 19 at the bottom of the formation 18, a modified well 1 inside the formation 18, and a heat exchange mechanism inside the modified well 1. The heat exchange mechanism includes a well casing 2 fixedly connected to the inner wall of the modified well 1, a circulation pipeline 3 fixedly connected inside the well casing 2, heat insulation plates 4 fixedly connected between the inner walls of the circulation pipeline 3, a low-temperature water inlet pipe 5 and a high-temperature water outlet pipe 6 respectively connected to the top two sides of the circulation pipeline 3, a heat exchanger 7 connected to the bottom of the circulation pipeline 3, two isolation plates 8 fixedly connected between the connection between the circulation pipeline 3 and the heat exchanger 7, and two connecting pipes 14 fixedly connected between the opposite faces of the two isolation plates 8. The heat exchanger 7 is internally equipped with multiple first heat exchange inner tubes 9 and second heat exchange inner tubes 10 for heat exchange. The first heat exchange inner tubes 9 and second heat exchange inner tubes 10 are respectively connected to two connecting pipes 14. A blind cover 11 is fixedly connected to the bottom of the heat exchanger 7. The bottom ends of the first heat exchange inner tubes 9 and second heat exchange inner tubes 10 are respectively connected to the inner wall of the blind cover 11. A water pump 12 is fixedly connected to the bottom of the blind cover 11. The water pump 12 draws high-temperature underground water and delivers it to the interior of the heat exchanger 7 to exchange heat with the softened water in the second heat exchange inner tubes 10 and the first heat exchange inner tubes 9. A high-temperature hot water pipe 13 is fixedly connected to the bottom of the heat exchanger 7. A connecting port 15 is opened on the side wall of the insulation plate 8. Water outlets 16 are opened on both sides of the top of the heat exchanger 7.

[0025] Low-temperature softened water is transported through the low-temperature inlet pipe 5 to the circulation pipeline 3 inside the modified well 1. The softened water then flows sequentially through the connecting pipe 14 into the second heat exchange inner pipe 10. Simultaneously, the high-temperature hot reservoir 19 at the bottom of the formation 18 enters the high-temperature hot water pipe 13 under formation pressure. When the accumulated water enters the area where the water pump 12 is located, the water pump 12 is submerged by the high-temperature water and starts operating, transporting the high-temperature formation water to the heat exchanger 7. In the heat exchanger 7, the water exchanges heat with the low-temperature softened water flowing between the first heat exchange inner pipe 9 and the second heat exchange inner pipe 10, causing the softened water temperature to rise from low temperature to high temperature. After heat exchange, the softened water flows through the blind cap 11 from the first heat exchange inner pipe 9 to the second heat exchange inner pipe 10, then enters the connecting pipe 14 and returns to the upper part of the circulation pipeline 3. The heat insulation plate 4 is used to isolate the low-temperature inlet water and the heated high-temperature water in the circulation pipeline 3 to prevent heat loss.

[0026] Subsequently, the heated, high-temperature softened water is transported through high-temperature outlet pipe 6 to the multi-source heat pump unit on the ground. After further heating in the heat pump unit, it flows into the heat exchanger. At the same time, water from the water supply station is also supplied to the heat exchanger, where it exchanges heat with the high-temperature softened water. This raises the water temperature before it is supplied to residential areas for use. Thus, it can not only provide heating for residential areas but also, through the connection of the crude oil collection pipeline from the oil well to the input end of the heat exchanger, it can cooperate with the heated, high-temperature softened water for heat exchange operations. The heated crude oil can then be used by the oilfield's combined station. To prevent crude oil from solidifying due to low temperature in the pipeline, ensure its fluidity, realize the dual heat energy utilization of residential heating and oilfield transportation, improve energy utilization efficiency, and enhance the comprehensive service capabilities of the system, the low-temperature softened water in the heat exchanger will flow back into the low-temperature inlet pipe 5 and be reheated. At the same time, the unused tailwater in the circulation pipeline 3 will be discharged through the outlets 16 set on both sides of the top of the heat exchanger 7. Some of the low-temperature softened water can also be circulated to the high-temperature thermal reservoir 19 through the branch pipe 17 connected to the side wall of the well casing 2, forming a closed loop of downhole heat extraction circulation.

[0027] The entire structure uses the modified well 1 as the medium-deep geothermal utilization carrier. Geothermal energy is recovered through the downhole heat exchange mechanism, and then combined with the ground multi-source heat pump to achieve efficient and clean heating of water. This creates a regional heating structure with geothermal energy as the core, which has the advantages of green energy utilization such as low energy consumption, low operating cost and low carbon emissions.

[0028] Further, see attached document. Figure 1 and Figure 4 As shown, the outer diameter of the high-temperature hot water pipe 13 is smaller than the inner diameter of the well casing 2;

[0029] By designing the outer diameter of the high-temperature hot water pipe 13 to be smaller than the inner diameter of the well casing 2, an annular cavity is formed between the high-temperature hot water pipe 13 and the well casing 2, thus reserving sufficient space for the downward flow of low-temperature circulating water. This facilitates the smooth flow of the low-temperature circulating water after heat exchange into the branch pipe 17 located on the side wall of the well casing 2 under the action of gravity, thereby improving the smoothness and stability of the downhole heat exchange circulation.

[0030] Further, see attached document. Figure 4 As shown, the sidewall of the well casing 2 is connected to a branch pipe 17 for low-temperature return water, and the high-temperature hot water pipe 13 and the branch pipe 17 are located inside the high-temperature thermal reservoir 19.

[0031] After heat exchange, the high-temperature circulating water is directly discharged into the high-temperature thermal reservoir 19 through the branch pipe 17, realizing dynamic water replenishment and balance regulation inside the thermal reservoir, effectively preventing the thermal reservoir from drying up, pressure decaying or heat loss, and further ensuring long-term and stable geothermal utilization efficiency and groundwater resource security.

[0032] Further, see attached document. Figure 5 As shown, the end of the high-temperature water outlet pipe 6 away from the circulation pipeline 3 is fixedly connected to the input end of the multi-source heat pump unit, and the output end of the multi-source heat pump unit is fixedly connected to a heat exchanger. The end of the low-temperature water inlet pipe 5 away from the circulation pipeline 3 is fixedly connected to the return end of the heat exchanger.

[0033] By connecting the high-temperature outlet pipe 6 to the input end of the multi-source heat pump unit, the softened water after primary heating in the well is further heated to a higher temperature by the multi-source heat pump unit, realizing secondary energy utilization and cascade enhancement. The output end of the multi-source heat pump unit is connected to a heat exchanger, which can use the heated softened water to exchange heat with external water. At the same time, the return end of the heat exchanger is connected to the low-temperature inlet pipe 5, forming a softened water circulation path, improving thermal energy utilization efficiency, reducing energy waste, and constructing an integrated closed-loop heating system, which significantly improves the cleanliness and energy efficiency of industrial heating.

[0034] Those skilled in the art should understand that the discussion of any of the above embodiments is merely exemplary and is not intended to imply that the scope of the present invention (including the claims) is limited to these examples; within the framework of the present invention, the technical features of the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other variations of the different aspects of the present invention as described above, which are not provided in the details for the sake of brevity.

[0035] This utility model is intended to cover all such substitutions, modifications, and variations that fall within the broad scope of the appended claims. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. A non-interference single-well heat extraction downhole heat exchange device, comprising a formation (18), wherein a high-temperature thermal reservoir (19) is provided at the bottom of the formation (18), and a modified well (1) is provided inside the formation (18), characterized in that: The modified well (1) is equipped with a heat exchange mechanism, which includes a well casing (2) fixedly connected to the inner wall of the modified well (1). A circulation pipeline (3) is fixedly connected inside the well casing (2). A heat insulation plate (4) is fixedly connected between the inner walls of the circulation pipeline (3). A low-temperature water inlet pipe (5) and a high-temperature water outlet pipe (6) are respectively connected to the top two sides of the circulation pipeline (3). A heat exchanger (7) is connected to the bottom of the circulation pipeline (3). Two isolation plates (8) are fixedly connected between the connection between the circulation pipeline (3) and the heat exchanger (7). The two isolation plates (8) are fixedly connected to each other on opposite sides. The heat exchanger (7) is connected to two connecting pipes (14). The heat exchanger (7) is provided with multiple first heat exchange inner tubes (9) and second heat exchange inner tubes (10) for heat exchange. The first heat exchange inner tubes (9) and second heat exchange inner tubes (10) are respectively connected to the two connecting pipes (14). The bottom of the heat exchanger (7) is fixedly connected to a blind cap (11). The bottom ends of the first heat exchange inner tubes (9) and second heat exchange inner tubes (10) are respectively connected to the inner wall of the blind cap (11). The bottom of the blind cap (11) is fixedly connected to a water pump (12). The bottom of the heat exchanger (7) is fixedly connected to a high-temperature hot water pipe (13).

2. The non-interference single-well heat extraction downhole heat exchange device according to claim 1, characterized in that, The side wall of the insulating plate (8) is provided with a communication port (15), and the top two sides of the heat exchanger (7) are provided with water outlets (16).

3. The non-interference single-well heat extraction downhole heat exchange device according to claim 1, characterized in that, The outer diameter of the heat exchanger (7) is smaller than the inner diameter of the well casing (2).

4. The non-interference single-well heat extraction downhole heat exchange device according to claim 1, characterized in that, The sidewall of the well casing (2) is connected to a branch pipe (17) for low-temperature circulating water return.

5. The non-interference single-well heat extraction downhole heat exchange device according to claim 4, characterized in that, The high-temperature hot water pipe (13) and the branch pipe (17) are located inside the high-temperature thermal reservoir (19).

6. The non-interference single-well heat extraction downhole heat exchange device according to claim 1, characterized in that, The high-temperature water outlet pipe (6) is fixedly connected at one end away from the circulation pipeline (3) to the input end of the multi-source heat pump unit. The output end of the multi-source heat pump unit is fixedly connected to a heat exchanger. The low-temperature water inlet pipe (5) is fixedly connected at one end away from the circulation pipeline (3) to the return end of the heat exchanger.

7. The non-interference single-well heat extraction downhole heat exchange device according to claim 1, characterized in that, After the water pump (12) draws in the high-temperature underground water, it will transport it to the interior of the heat exchanger (7) and exchange heat with the softened water in the second heat exchange inner tube (10) and the first heat exchange inner tube (9).

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