Geothermal energy utilization system for a subterranean wellbore and related methods

Abstract

The present application relates to geothermal energy utilization system of underground wellbore and related method. In the system, Peltier energy storage device is arranged in the underground wellbore flow channel; fluid storage device is connected with fluid injection device and geothermal comprehensive utilization device respectively; the inlet of underground wellbore flow channel is connected with fluid injection device, and the outlet is connected with geothermal comprehensive utilization device; fluid storage device is used for storing geothermal development fluid; fluid injection device is used for driving geothermal development fluid to enter underground wellbore flow channel for heat exchange, and the geothermal development fluid after heat exchange is connected with geothermal comprehensive utilization device; Peltier energy storage device is used for converting the heat of absorbed geothermal energy into electric energy and storing, and supplying the stored electric energy in the form of heat energy, and carrying out heat exchange with geothermal development fluid. Through Peltier energy storage device, geothermal energy is converted into electric energy, and electric energy is converted into heat energy, which guarantees the stable energy supply of geothermal energy and realizes geothermal power generation.

Description

Technical Field

[0001] This invention relates to the fields of new energy and geothermal energy technology, specifically to a geothermal energy utilization system and related methods for underground wells. Background Technology

[0002] Geothermal resources are a crucial renewable energy source. Currently, besides direct utilization as thermal energy, geothermal resources can also be used for geothermal power generation. Geothermal resource development is generally limited to areas with high-temperature geothermal resources. However, while high-temperature geothermal resources are suitable for geothermal power generation, their distribution is remote and overly dependent on geological conditions. Medium- and low-temperature geothermal resources are widely distributed, therefore, their development and utilization have broad practical significance. In existing technologies, because the temperatures of medium- and low-temperature geothermal resources are not high enough, direct utilization as thermal energy may lead to insufficient energy supply during peak energy consumption periods, resulting in unstable geothermal energy output. Furthermore, due to temperature threshold limitations, medium- and low-temperature geothermal resources cannot reach the temperature threshold for geothermal power generation, resulting in low power generation efficiency and relatively slow development. Summary of the Invention

[0003] The inventors have discovered that the low temperature of medium- and low-temperature geothermal resources restricts their direct use as thermal energy and for geothermal power generation, resulting in the ineffective utilization of a large amount of already explored medium- and low-temperature geothermal resources. Therefore, this invention proposes a system and method for underground wellbore energy storage to solve or partially solve the above problems. The technical solution proposed by this invention is as follows:

[0004] As a first aspect of the present invention, the present invention provides a geothermal energy utilization system for an underground well, wherein an underground well flow channel is formed within the underground well; the system includes: a Peltier energy storage device, a fluid injection device, a fluid storage device, and a geothermal comprehensive utilization device;

[0005] The Peltier energy storage device is installed within the underground wellbore flow channel;

[0006] The fluid storage device is connected to the fluid injection device and the geothermal integrated utilization device, respectively.

[0007] The inlet of the underground wellbore flow channel is connected to the fluid injection device, and the outlet is connected to the geothermal comprehensive utilization device;

[0008] The fluid storage device is used to store geothermal development fluids;

[0009] The fluid injection device is used to drive the geothermal development fluid into the underground wellbore flow channel for heat exchange, and to allow the heat-exchanged geothermal development fluid to be introduced into the geothermal comprehensive utilization device.

[0010] The Peltier energy storage device is used to convert the absorbed geothermal energy into electrical energy and store it, as well as to supply the stored electrical energy in the form of heat energy and exchange heat with the geothermal development fluid.

[0011] In one or more alternative embodiments, the system further includes: a composite energy supply device electrically connected to the Peltier energy storage device;

[0012] The composite energy supply device is used to provide electrical energy to the Peltier energy storage device;

[0013] The Peltier energy storage device is also used to store the electrical energy provided by the composite energy supply device.

[0014] In one or more alternative embodiments, the Peltier energy storage device includes a connected Peltier module and an energy storage module;

[0015] The Peltier module is used to convert the heat absorbed from geothermal energy into electrical energy and store it in the energy storage module, and to supply the electrical energy stored in the energy storage module as heat energy and exchange heat with the geothermal development fluid.

[0016] In one or more alternative embodiments, the Peltier module includes a plurality of Peltier components connected in series and / or in parallel.

[0017] In one or more alternative embodiments, the Peltier assembly includes: a thermally conductive insulating material layer, a heat source output terminal, and a cold source output terminal;

[0018] The heat source output terminal and the cold source output terminal are electrically connected, and the thermally conductive insulating material layer is respectively disposed on the outer surface of the heat source output terminal and the cold source output terminal;

[0019] The heat source output terminal is electrically connected to the energy storage module;

[0020] The heat source output end is located in the outflow direction of the geothermal development fluid, and the cold source output end is located in the inflow direction of the geothermal development fluid.

[0021] In one or more optional embodiments, the system further includes: a Peltier module controller;

[0022] The Peltier energy storage device also includes a signal receiving module connected to the Peltier module;

[0023] The Peltier module controller is connected to the signal receiving module and is used to send control signals to the signal receiving module so that the signal receiving module can control the Peltier module to convert the absorbed geothermal energy into electrical energy, or to convert the stored electrical energy into thermal energy.

[0024] In one or more optional embodiments, the underground wellbore includes an injection well, a horizontal well, and a production well connected in sequence;

[0025] The Peltier energy storage device is installed inside the horizontal well;

[0026] The inlet of the injection well is connected to the fluid injection device, and the outlet of the production well is connected to the geothermal integrated utilization device.

[0027] In one or more alternative embodiments, the fluid injection device includes a booster pump;

[0028] The booster pump is used to pressurize the geothermal development fluid and drive it to flow into the injection well.

[0029] As a second aspect of the present invention, the present invention provides a method for utilizing geothermal energy in underground wells, comprising:

[0030] Geothermal energy is converted into electrical energy and stored through a Peltier energy storage device.

[0031] The geothermal development fluid from the fluid storage device is injected into the underground wellbore flow channel via a fluid injection device.

[0032] The stored electrical energy is supplied as heat through the Peltier energy storage device and exchanged with the geothermal development fluid, so that the heat-exchanged geothermal development fluid is introduced into the geothermal integrated utilization device.

[0033] As a third aspect of the present invention, the present invention provides a method for developing medium and low temperature geothermal resources, characterized in that it uses the above-mentioned underground well geothermal energy utilization system.

[0034] As a fourth aspect of the present invention, the present invention provides an application of the above-mentioned underground well geothermal energy utilization system in the development of medium and low temperature geothermal resources.

[0035] Based on the above technical solution, the beneficial effects of the present invention compared with the prior art are as follows:

[0036] The geothermal energy utilization system for underground wells provided in this invention uses a Peltier energy storage device to convert excess geothermal energy during extraction into electrical energy and store it. When geothermal energy supply is insufficient during peak energy demand periods, the Peltier energy storage device converts the stored electrical energy into heat energy to heat the geothermal development fluid and the formation, ensuring a stable geothermal energy supply. When using medium- and low-temperature geothermal resources for geothermal power generation, the Peltier energy storage device heats the geothermal development fluid and the formation, raising the temperature of the medium- and low-temperature geothermal resources to reach the temperature threshold for geothermal power generation. This allows a large amount of already explored medium- and low-temperature geothermal resources to be used for geothermal power generation. Attached Figure Description

[0037] One or more embodiments are illustrated by way of example with reference numerals in the accompanying drawings. These illustrations do not constitute a limitation on the embodiments. Elements with the same reference numerals in the drawings are denoted as similar elements. Unless otherwise stated, the figures in the drawings are not to be limited by scale.

[0038] Figure 1 This is a schematic diagram of the structure of the geothermal energy utilization system for underground wells provided in an embodiment of the present invention;

[0039] Figure 2 This is a schematic diagram of the Peltier energy storage device provided in an embodiment of the present invention;

[0040] Figure 3 This is a schematic diagram of the structure of the Peltier assembly provided in an embodiment of the present invention;

[0041] Figure 4 This is a schematic flowchart of a method for utilizing geothermal energy in an underground well, provided in an embodiment of the present invention.

[0042] In the picture:

[0043] 1 is a geothermal comprehensive utilization device;

[0044] 2 is a fluid storage device;

[0045] 3 is a fluid injection device;

[0046] 4 is the injection well;

[0047] 5 is the underground well shaft flow channel;

[0048] 6 is a Peltier energy storage device, 61 is a Peltier module, 611 is a Peltier component, 6111 is a thermally conductive insulating material layer, 6112 is a heat source output terminal, 6113 is a cold source output terminal, 6114 is a P-type semiconductor, 6115 is an N-type semiconductor, 62 is an energy storage module, and 621 is an energy storage component.

[0049] 7 is the Peltier module controller;

[0050] 8 represents a horizontal well;

[0051] 9 indicates the flow direction of the geothermal development fluid;

[0052] 10 is a composite energy supply device, 101 is an energy supply module, 102 is a transmission module, and 103 is a power generation module;

[0053] 11 is a production well;

[0054] 12 represents the power transmission terminal. Detailed Implementation

[0055] To facilitate understanding of the present invention, a more detailed description is provided below with reference to the accompanying drawings and specific embodiments. It should be noted that when an element is described as "connected" to another element, it can be directly connected to the other element, or there may be one or more intermediate elements between them. The terms "upper," "lower," "inner," "outer," "vertical," "horizontal," etc., used in this specification to indicate orientation or positional relationships are based on the orientation or positional relationships shown in the accompanying drawings and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0056] Unless otherwise defined, all technical and scientific terms used in this specification have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the invention. The term "and / or" as used in this specification includes any and all combinations of one or more of the associated listed items.

[0057] Furthermore, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0058] Example 1

[0059] This invention provides a geothermal energy utilization system for an underground well, wherein an underground well flow channel 5 is formed within the underground well; see reference. Figure 1 As shown, the system includes: a Peltier energy storage device 6, a fluid injection device 3, a fluid storage device 2, and a geothermal comprehensive utilization device 1;

[0060] The Peltier energy storage device 6 is installed inside the underground wellbore flow channel 5;

[0061] The fluid storage device 2 is connected to the fluid injection device 3 and the geothermal integrated utilization device 1, respectively.

[0062] The inlet of the underground wellbore flow channel 5 is connected to the fluid injection device 3, and the outlet is connected to the geothermal comprehensive utilization device 1;

[0063] Fluid storage device 2 is used to store geothermal development fluids;

[0064] The fluid injection device 3 is used to drive the geothermal development fluid into the underground wellbore flow channel 5 for heat exchange, and to allow the geothermal development fluid after heat exchange to enter the geothermal comprehensive utilization device 1;

[0065] The Peltier energy storage device 6 is used to convert the absorbed geothermal energy into electrical energy and store it, as well as to supply the stored electrical energy in the form of heat energy and exchange heat with the geothermal development fluid.

[0066] In this embodiment of the invention, the aforementioned geothermal development fluid is a heat exchange medium used in geothermal energy extraction, for example, it can be a carbon dioxide fluid, generally supercritical CO2. The geothermal development fluid is stored in the aforementioned fluid storage device 2, and during geothermal development, it is referred to... Figure 1 As shown in the diagram, the four arrows indicate the flow direction of the geothermal development fluid in the underground wellbore flow channel. The flow direction 9 of the geothermal development fluid is: from the fluid storage device 2, it flows sequentially through the fluid injection device 3 and the underground wellbore flow channel 5 before flowing into the geothermal comprehensive utilization device 1. When the geothermal development fluid flows in the underground wellbore flow channel 5, it passes through the Peltier energy storage device 6 installed within the underground wellbore flow channel 5, and the excess geothermal energy in the geothermal development fluid is converted into electrical energy and stored by the Peltier energy storage device 6.

[0067] Geothermal energy development is unaffected by weather or time of day, resulting in a surplus of geothermal energy during periods of low demand. The Peltier energy storage device 6 can convert this excess geothermal energy into electrical energy for storage, thus preventing energy waste.

[0068] In this embodiment of the invention, the above-mentioned geothermal comprehensive utilization device 1 is used to process and utilize the geothermal energy extracted by the energy storage system of the underground well, for example, to directly supply the extracted geothermal energy in the form of heat energy, or to use the extracted geothermal energy for geothermal power generation.

[0069] Methods for directly supplying extracted geothermal energy as heat include:

[0070] The extracted geothermal energy is used to heat water and supply it as hot water. The supplied hot water is used to provide heating for user areas or directly for bathing.

[0071] In one or more alternative embodiments, the fluid storage device 2 is disposed on the ground and may be a pressure tank. The fluid outlet of the fluid storage device 2 is connected to the inlet of the fluid injection device 3 via a pipeline.

[0072] In one or more alternative embodiments, reference is made to Figure 1 As shown, the geothermal energy utilization system of the underground well also includes a composite energy supply device 10 that is electrically connected to the Peltier energy storage device 6.

[0073] The aforementioned composite energy supply device 10 includes an energy supply module 101, a transmission module 102, and a power generation module 103. The energy supply module 101 and the transmission module 102 can be cables. The composite energy supply module 101 is used to provide electrical energy to the Peltier energy storage device 6; the transmission module 102 is used to transmit electrical energy to the power transmission terminal 12 and then connect it to the power grid; the power generation module 103 is used to generate electricity.

[0074] In one or more alternative embodiments, the specific type of the composite energy supply device 10 can be reasonably selected according to environmental conditions. For example, a solar photovoltaic power generation device can be selected in places with sufficient sunshine, and a wind power generation device can be selected in places with abundant wind.

[0075] The composite energy supply device 10 provides electrical energy to the Peltier energy storage device 6, which in turn stores the electrical energy supplied by the composite energy supply device 10. When the composite energy supply device 10 generates excess power, the excess power can be stored in the Peltier energy storage device 6, thus avoiding energy waste. For example, if a solar photovoltaic power generation device generates more power than it consumes during the period of strongest sunlight, the excess power can be transferred to the Peltier energy storage device for storage.

[0076] The geothermal energy utilization system of the underground well provided in this embodiment of the invention, together with the above-mentioned composite energy supply device 10, forms a composite energy supply system, which together provides geothermal energy and / or electrical energy to the power consumption area.

[0077] In this embodiment of the invention, the Peltier energy storage device 6 stores excess geothermal energy as electrical energy, and also stores auxiliary energy from the composite energy supply device 10, thereby reducing the waste of geothermal and electrical energy. The Peltier energy storage device 6 supplies the stored electrical energy as heat to heat the geothermal development fluid, enabling timely replenishment of geothermal resources when geothermal energy supply is insufficient during peak energy consumption periods, achieving stable geothermal energy supply, peak-shaving output of geothermal energy, and improving the utilization rate of geothermal energy.

[0078] When geothermal resources are used for geothermal power generation, the medium and low temperature geothermal resources do not reach the temperature threshold for geothermal power generation. By using the Peltier energy storage device 6 to supply the stored electrical energy in the form of heat energy, the geothermal development fluid and the strata are heated and the temperature of the medium and low temperature geothermal resources can be increased to reach the temperature threshold for geothermal power generation. This allows a large number of medium and low temperature geothermal resources that have been explored but are not convenient to be supplied directly in the form of heat energy to be effectively utilized.

[0079] It should be noted that the temperature threshold for geothermal power generation refers to the temperature difference between the heat transfer medium used to develop geothermal energy and the ground, which needs to reach about 80 to 90 degrees Celsius before geothermal power generation can be carried out.

[0080] In one or more alternative embodiments, reference is made to Figure 2 As shown, the Peltier energy storage device 6 includes a connected Peltier module 61 and an energy storage module 62.

[0081] The Peltier module is used to convert the absorbed geothermal energy into electrical energy and store it in the energy storage module 62, and to supply the electrical energy stored in the energy storage module 62 as heat energy and exchange heat with the geothermal development fluid. The Peltier module 61 can utilize the Peltier effect to generate heat when energized, thereby heating the geothermal development fluid; the Peltier module 61 can also utilize the inverse effect of the Peltier effect to convert heat energy into electrical energy.

[0082] The Peltier module 61 includes several Peltier components 611 connected in series and / or parallel. The Peltier components 611 can be connected in series individually, or two or more Peltier components 611 can be connected in parallel first and then connected in series as a whole. The specific connection method is set according to actual needs.

[0083] In one or more alternative embodiments, reference is made to Figure 3 As shown, the Peltier assembly 611 includes: a thermally conductive insulating material layer, a heat source output terminal 6112, and a cold source output terminal 6113; the heat source output terminal 6112 and the cold source output terminal 6113 are electrically connected, and the thermally conductive insulating material layer is respectively disposed on the outer surface of the heat source output terminal 6112 and the cold source output terminal 6113; the thermally conductive insulating material layer may be made of thermally conductive insulating ceramic.

[0084] The heat source output terminal 6112 is electrically connected to the energy storage module 62. The energy storage module 62 can store electrical energy. When the geothermal energy supply is insufficient during peak energy consumption periods, the stored electrical energy will be supplied in the form of heat energy, that is, the heat will be released through the heat source output terminal 6112 to heat the geothermal development fluid.

[0085] The heat source output end 6112 is located in the outflow direction of the geothermal development fluid, and the cold source output end 6113 is located in the inflow direction of the geothermal development fluid. Thus, the heat source output end 6112 is in contact with the fluid outflow end, and the cold source output end 6113 is in contact with the fluid inflow end. When the geothermal development fluid is heated by the Peltier energy storage device 6, the geothermal development fluid contacts and exchanges heat with the heat source output end 6112 before flowing out of the underground wellbore flow channel 5.

[0086] In this embodiment of the invention, reference is made to Figure 3The earpiece assembly shown above also includes a P-type semiconductor 6114 and an N-type semiconductor 6115 disposed between the heat source output terminal 6112 and the cold source output terminal 6113, with the P-type semiconductor 6114 positioned above the N-type semiconductor 6115. The P-type semiconductor 6114 is the negative electrode, and the N-type semiconductor 6115 is the positive electrode. When current flows through the circuit formed by the P-type semiconductor 6114 and the N-type semiconductor 6115, heat will be released at the heat source output terminal 6112 at the junction of the two different conductors due to the Peltier effect.

[0087] In this embodiment of the invention, reference is made to Figure 3 As shown, in a Peltier assembly 611, two heat source output terminals 6112 are provided, one above the other. The upper end of the upper heat source output terminal 6112 is flush with the upper end of the thermally conductive insulating material, and the lower end is flush with the lower end of the P-type semiconductor 6114. The upper end of the lower heat source output terminal 6112 is flush with the upper end of the N-type semiconductor 6115, and the lower end is flush with the lower end of the thermally conductive insulating material layer. A cold source output terminal 6113 is provided, the upper end of which is flush with the upper end of the P-type semiconductor 6114, and the lower end of which is flush with the lower end of the N-type semiconductor 6115.

[0088] In one or more alternative embodiments, reference is made to Figure 3 As shown, the energy storage module 62 includes several energy storage components 621 arranged side by side, and each energy storage component 621 can be a battery pack. The several energy storage components 621 are connected in parallel to ensure that the energy storage module 62 can still work normally even if some of the energy storage components 621 are damaged.

[0089] In one or more alternative embodiments, reference is made to Figure 1 As shown, the geothermal energy utilization system of the underground well also includes: Peltier module controller 7;

[0090] The Peltier energy storage device 6 also includes a signal receiving module (not shown in the figure) connected to the Peltier module 61; the signal receiving module is disposed between the Peltier module 61 and the energy storage module 62.

[0091] In a specific example, the signal receiving module may include an energy storage switch (not shown in the figure) and a power supply switch (not shown in the figure). When the energy storage switch is turned on, the Peltier energy storage device 6 begins to absorb heat and convert the absorbed heat into electrical energy for storage, or begins to store the electrical energy provided by the aforementioned composite power supply device 10. When the power supply switch is turned on, the Peltier energy storage device 6 begins to convert the stored electrical energy into heat energy and release it.

[0092] The Peltier module controller 7 is connected to the signal receiving module and is used to send control signals to the signal receiving module, so that the signal receiving module can control the Peltier module 61 to convert the absorbed geothermal energy into electrical energy, or to convert the stored electrical energy into heat energy. Specifically, it can be:

[0093] When there is a surplus of geothermal energy, the Peltier module controller 7 sends a control signal to the signal receiving module to turn on the energy storage switch of the Peltier energy storage device 6, converting the excess geothermal energy into electrical energy and storing it; after the energy storage is completed, the Peltier module controller 7 sends a control signal to the signal receiving module to turn off the energy storage switch of the Peltier energy storage device 6.

[0094] When the local geothermal energy supply is insufficient, the Peltier module controller 7 sends a control signal to the signal receiving module to turn on the power supply switch of the Peltier energy storage device 6, converting the stored electrical energy into thermal energy to heat the geothermal development fluid and maintain a stable output of geothermal energy; when the power supply is sufficient, the Peltier module controller 7 sends a control signal to the signal receiving module to turn off the power supply switch of the Peltier energy storage device 6.

[0095] In this embodiment of the invention, the Peltier module controller 7 can also control the Peltier energy storage device 6 to store the electrical energy provided by the composite energy supply device 10. Specifically, it can be:

[0096] When the power generation of the composite energy supply device 10 exceeds the power consumption, a control signal is sent to the signal receiving module through the Peltier module controller 7 to open the energy storage switch of the Peltier energy storage device 6. The excess electrical energy is then input into the Peltier energy storage device 6 and stored through the energy supply module 101 of the composite energy supply device 10.

[0097] In this embodiment of the invention, the control signal can be an electromagnetic signal, and the signal receiving module can be an electromagnetic signal receiving element.

[0098] In one or more optional embodiments, the geothermal energy utilization device for the underground wellbore further includes: a temperature acquisition element (not shown in the figure) disposed within the underground wellbore, the temperature acquisition element being used to acquire temperature values ​​at different locations within the underground wellbore. For example, temperature acquisition elements are disposed in different areas of the energy storage module 62 of the Peltier energy storage device 6 to acquire the temperature values ​​of the energy storage module 62.

[0099] In one or more alternative embodiments, reference is made to Figure 1 As shown, the underground well includes an injection well 4, a horizontal well 8, and a production well 11 connected in sequence; the injection well 4 and the horizontal well 8 are both perpendicular to the ground and are connected in the middle through the horizontal well 8. The injection well 4, the horizontal well 8, and the production well 11 together form an underground U-shaped geothermal well.

[0100] The Peltier energy storage device 6 is installed inside the horizontal well 8 and is in a passable state when the geothermal energy supply is sufficient, ensuring that the geothermal development fluid can flow smoothly through the horizontal well 8.

[0101] The inlet of injection well 4 is connected to fluid injection device 3, and the outlet of production well 11 is connected to geothermal comprehensive utilization device 1. During geothermal extraction, geothermal development fluid flows from fluid injection device 3 into production well 11, flows through horizontal well 8, and then flows out of production well 11 into geothermal comprehensive utilization device 1.

[0102] In one or more optional embodiments, the fluid injection device 3 includes a booster pump (not shown) for pressurizing the geothermal development fluid. When the geothermal development fluid flows in the production well 11, its flow direction is from bottom to top, thus requiring external force. By pressurizing the geothermal development fluid with the booster pump, not only can the geothermal development fluid be driven into the injection well 4, but it can also overcome its own gravity and flow upwards while flowing in the production well 11.

[0103] To provide a clearer explanation of the geothermal energy utilization system using an underground well provided in this embodiment of the invention, the process of utilizing geothermal energy using this underground well system is described in detail below:

[0104] (1) Store sufficient geothermal development fluid in the fluid storage device 2, and open the fluid outlet of the fluid storage device 2 to allow the geothermal development fluid to flow into the fluid injection device 3;

[0105] (2) The geothermal development fluid of the fluid storage device 2 is injected into the underground wellbore flow channel 5 through the fluid injection device 3;

[0106] (3) When there is a surplus of geothermal energy supply during the low energy consumption period, the excess geothermal energy is converted into electrical energy and stored through the Peltier energy storage device 6.

[0107] (4) When the geothermal energy supply is insufficient during peak energy consumption periods, the stored electrical energy is supplied in the form of heat energy through the Peltier energy storage device 6 and exchanged with the geothermal development fluid.

[0108] (5) The geothermal development fluid after heat exchange flows out of the underground wellbore flow channel 5 and into the geothermal comprehensive utilization device 1 to realize the development and utilization of geothermal energy.

[0109] In this embodiment of the invention, when the geothermal energy supply is sufficient, the Peltier energy storage device 6 is in a closed state, which does not affect the normal geothermal extraction process. The process of realizing geothermal energy utilization includes:

[0110] (1) Store sufficient geothermal development fluid in the fluid storage device 2, and open the fluid outlet of the fluid storage device 2 to allow the geothermal development fluid to flow into the fluid injection device 3;

[0111] (2) The geothermal development fluid is pressurized by the fluid injection device 3 and driven to flow into the underground wellbore flow channel 5;

[0112] (3) After the geothermal development fluid exchanges heat with the stratum, it flows out of the underground wellbore flow channel 5 and then flows into the geothermal comprehensive utilization device 1 to realize the development and utilization of geothermal energy.

[0113] In this embodiment of the invention, the electrical energy stored in the Peltier energy storage device 6 can also come from the composite energy supply device 10. When the power generation of the composite energy supply device 10 exceeds the power consumption, the excess electrical energy is stored through the Peltier storage device.

[0114] The geothermal energy utilization system for underground wells provided in this embodiment of the invention stores excess geothermal energy through the Peltier energy storage device 6. Combined with the auxiliary energy supply of the composite energy supply device 10, the stored electrical energy is supplied as heat when the supply of medium and low temperature geothermal energy is insufficient, maintaining a stable output of geothermal energy, realizing peak-shifting energy supply, and improving the development and utilization efficiency of medium and low temperature geothermal energy. By heating the geothermal development fluid, the temperature of medium and low temperature geothermal resources is increased, broadening the temperature threshold for geothermal power generation from medium and low temperature geothermal resources, and realizing the development of medium and low temperature geothermal resources with previously low production capacity or poor efficiency.

[0115] Example 2

[0116] This invention provides a method for utilizing geothermal energy in underground wells, referring to... Figure 4 As shown, the method includes:

[0117] S101: Geothermal energy is converted into electrical energy and stored through the Peltier energy storage device 6;

[0118] S102: The geothermal development fluid of the fluid storage device 2 is injected into the underground wellbore flow channel 5 through the fluid injection device 3;

[0119] S103: The stored electrical energy is supplied in the form of heat energy through the Peltier energy storage device 6 and exchanged with the geothermal development fluid, so that the geothermal development fluid after heat exchange is introduced into the geothermal comprehensive utilization device 1.

[0120] In this embodiment of the invention, the geothermal energy utilization method of the underground well corresponds to the geothermal energy utilization system of the underground well described in Embodiment 1 above. Its specific implementation process can refer to the process of realizing geothermal energy utilization by applying the geothermal energy utilization system of the underground well in Embodiment 1 above. The repeated parts will not be described again here.

[0121] In this embodiment of the invention, the process of converting geothermal energy into electrical energy and storing it through the Peltier energy storage device 6 specifically includes:

[0122] The Peltier module controller 7 sends a control signal to the Peltier energy storage device 6 to open the energy storage switch of the Peltier energy storage device 6, and the Peltier energy storage device 6 absorbs the heat in the geothermal development fluid and converts it into electrical energy for storage.

[0123] In this embodiment of the invention, the process of supplying stored electrical energy as heat energy through the Peltier energy storage device 6 specifically includes:

[0124] The Peltier module controller 7 sends a control signal to the Peltier energy storage device 6 to turn on the power supply switch of the Peltier energy storage device 6. The stored electrical energy is converted into heat energy through the Peltier storage device to heat the geothermal development fluid and achieve stable output of geothermal energy.

[0125] Example 3

[0126] This invention also provides a method for developing medium- and low-temperature geothermal resources, using the geothermal energy utilization system of the underground well described in Embodiment 1.

[0127] In this embodiment of the invention, the method for developing medium and low temperature geothermal resources corresponds to the geothermal energy utilization system of the underground well described in Embodiment 1 above. Its specific implementation process can refer to the process of using the geothermal energy utilization system of the underground well in Embodiment 1 to realize geothermal energy utilization. The repeated parts will not be described again here.

[0128] Example 4

[0129] This invention also provides an application of the underground well geothermal energy utilization system described in Embodiment 1 above in the development of medium and low temperature geothermal resources.

[0130] In this embodiment of the invention, the specific process of developing medium and low temperature geothermal resources using the underground well geothermal energy utilization system can refer to the process of developing medium and low temperature geothermal resources using the underground well geothermal energy utilization system in Embodiment 1 above. The repetitions will not be repeated here.

[0131] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; under the concept 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 different aspects of the present invention as described above, which are not provided in detail for the sake of brevity; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A geothermal energy utilization system for an underground well, wherein an underground well flow channel is formed within the underground well; characterized in that, The system includes: a Peltier energy storage device, a fluid injection device, a fluid storage device, and a geothermal comprehensive utilization device; The Peltier energy storage device is installed within the underground wellbore flow channel; The fluid storage device is connected to the fluid injection device and the geothermal integrated utilization device, respectively. The inlet of the underground wellbore flow channel is connected to the fluid injection device, and the outlet is connected to the geothermal comprehensive utilization device; The fluid storage device is used to store geothermal development fluids; The fluid injection device is used to drive the geothermal development fluid into the underground wellbore flow channel for heat exchange, and to allow the heat-exchanged geothermal development fluid to be introduced into the geothermal comprehensive utilization device. The Peltier energy storage device is used to convert the absorbed geothermal energy into electrical energy and store it, as well as to supply the stored electrical energy in the form of heat energy and exchange heat with the geothermal development fluid.

2. The system according to claim 1, characterized in that, The system also includes: a composite energy supply device electrically connected to the Peltier energy storage device; The composite energy supply device is used to provide electrical energy to the Peltier energy storage device; The Peltier energy storage device is also used to store the electrical energy provided by the composite energy supply device.

3. The system according to claim 2, characterized in that, The Peltier energy storage device includes a connected Peltier module and an energy storage module; The Peltier module is used to convert the heat absorbed from geothermal energy into electrical energy and store it in the energy storage module, and to supply the electrical energy stored in the energy storage module as heat energy and exchange heat with the geothermal development fluid.

4. The system according to claim 3, characterized in that, The Peltier module includes several Peltier components connected in series and / or in parallel.

5. The system according to claim 4, characterized in that, The Peltier assembly includes: a thermally conductive insulating material layer, a heat source output terminal, and a cold source output terminal; The heat source output terminal and the cold source output terminal are electrically connected, and the thermally conductive insulating material layer is respectively disposed on the outer surface of the heat source output terminal and the cold source output terminal; The heat source output terminal is electrically connected to the energy storage module; The heat source output end is located in the outflow direction of the geothermal development fluid, and the cold source output end is located in the inflow direction of the geothermal development fluid.

6. The system according to claim 3, characterized in that, The system also includes: a Peltier module controller; The Peltier energy storage device also includes a signal receiving module connected to the Peltier module; The Peltier module controller is connected to the signal receiving module and is used to send control signals to the signal receiving module so that the signal receiving module can control the Peltier module to convert the absorbed geothermal energy into electrical energy, or to convert the stored electrical energy into thermal energy.

7. The system according to any one of claims 1-6, characterized in that, The underground wellbore includes an injection well, a horizontal well, and a production well connected in sequence. The Peltier energy storage device is installed inside the horizontal well; The inlet of the injection well is connected to the fluid injection device, and the outlet of the production well is connected to the geothermal integrated utilization device.

8. The system according to any one of claims 1-6, characterized in that, The fluid injection device includes a booster pump; The booster pump is used to pressurize the geothermal development fluid and drive it to flow into the injection well.

9. A method for utilizing geothermal energy in an underground well, using the geothermal energy utilization system for an underground well as described in any one of claims 1-8, characterized in that, include: Geothermal energy is converted into electrical energy and stored through a Peltier energy storage device. The geothermal development fluid from the fluid storage device is injected into the underground wellbore flow channel via a fluid injection device. The stored electrical energy is supplied as heat through the Peltier energy storage device and exchanged with the geothermal development fluid, so that the heat-exchanged geothermal development fluid is introduced into the geothermal integrated utilization device.

10. A method for developing medium- and low-temperature geothermal resources, characterized in that, Geothermal energy utilization system using underground wells as described in any one of claims 1-8.

11. The application of a geothermal energy utilization system for underground wells as described in any one of claims 1-8 in the development of medium and low temperature geothermal resources.

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