Device, method and system for achieving low-temperature heat storage through taking, filling and huff-puff and medium

Abstract

The invention discloses a device, method and system for achieving low-temperature heat storage through taking, filling and huff-puff and a medium. The device comprises a heat exchange plate, a heat pump, a water taking well and a recharge well, wherein the water taking well and the recharge well are arranged on a preset-temperature heat storage tank; the water taking well is connected with a fluid input port of the heat exchange plate, and a fluid output port of the heat exchange plate is communicated with the recharge well through the pressure pump; the recharge well is communicated with the water intake well through a preset temperature heat storage tank; the heat exchange plate transmits the temperature to the heat pump through the circulating pump and the first pipeline, the heat pump is heated to the preset temperature, and the heat pump is connected with user heating equipment through the circulating pump and the second pipeline. In the non-heating time period, fluid in the recharge well is pumped out, and waste heat of the power plant is used for heating; the fluid is recharged into the water taking well for heat storage; and in the heating time period, fluid in the water taking well is pumped out, and heating is conducted on the user under the action of the heat exchange plate and the heat pump. Therefore, low-temperature heat storage is effectively utilized, and a large amount of facility cost is saved.

Description

Technical Field

[0001] The present invention relates to the technical field of geothermal resource exploration and development, and in particular to a device, method, system and medium for realizing low-temperature heat storage by pumping and pouring. Background Art

[0002] Geothermal refers to geothermal energy, geothermal fluids and their useful components inside the earth that can be used economically by humans. The global geothermal resources are 1.4×1023KJ, which is 50,000 times the total amount of oil and gas resources in the world. China's direct geothermal utilization (mainly in the shallow and medium layers, ranking first) installed capacity reached 40.6 GW, accounting for 38% of the world; the United States' indirect geothermal utilization power generation installed capacity (mainly in the deep and medium layers, ranking first) is 3.45 GW, accounting for 24% of the world.

[0003] In the existing technology, geothermal development methods mainly include three modes: closed (self-injection and U-shaped horizontal wells), semi-closed, and open (conventional vertical well extraction and horizontal well extraction and injection). In the current domestic geothermal development, the balanced development technology of thick-layer high-permeability heat storage extraction and injection is mature. For example, the CFD large-scale sandstone geothermal heating project relies on the high-permeability thick-layer heat storage resources of the Guantao Formation. It plans 7 platforms, drills 40 wells, and the water output of a single well is 100m3 / h. The dynamic water level is stable after 5 years of operation, and the sustainability is good. However, the exploration and development of targets such as medium-shallow low-temperature heat storage faces difficulties. For low-temperature heat storage with good physical properties (<60℃) (Table 1), the construction is easy and the cost is low, but due to the low temperature, an effective development model has not been formed, especially in the northern winter, it cannot be directly used; therefore, a device, method, system and medium for extraction and injection throughput to achieve low-temperature heat storage are needed.

[0004]

[0005]

[0006] Table 1 Summary of the invention

[0007] The embodiments of the present invention at least partially solve the technical problem that low-temperature heat storage cannot be developed in the prior art by providing a device, method, system and medium for realizing low-temperature heat storage through filling and discharge, and realize the technical effect of external energy heating and burying and reusing low-temperature heat storage.

[0008] In the first aspect, to solve the above technical problems, the embodiments of the present invention provide the following technical solutions:

[0009] A device for realizing low-temperature heat storage by pumping and pouring, comprising:

[0010] Heat exchange plates, heat pumps, water intake wells and recharging wells arranged on a heat storage reservoir at a preset temperature;

[0011] The water intake well is connected to the fluid input port of the heat exchange plate, and the fluid output port of the heat exchange plate is connected to the reinjection well through a pressure pump; the reinjection well is connected to the water intake well through the preset temperature heat storage reservoir;

[0012] The heat exchange plate transfers the temperature to the heat pump through the circulation pump and the first pipeline. The heat pump is heated to a preset temperature and connected to the user's heating equipment through the circulation pump and the second pipeline.

[0013] Optionally, a desander is provided between the water intake well and the heat exchange plate.

[0014] Optionally, a filter is further provided between the heat exchange plate and the reinjection well.

[0015] Optionally, the above-mentioned device also includes a constant-pressure water replenishment device, and the above-mentioned constant-pressure water replenishment device is connected to the above-mentioned first pipeline and the above-mentioned second pipeline respectively.

[0016] In a second aspect, a method for realizing low-temperature heat storage by filling and discharging is provided, comprising the above-mentioned device for realizing low-temperature heat storage by filling and discharging, the method comprising:

[0017] During the non-heating period, the fluid in the re-injection well is extracted and heated using the waste heat of the power plant; the fluid is re-injected into the water well for heat storage;

[0018] During the heating period, the fluid in the water well is extracted, and heating is provided to the user based on the action of the heat exchange plate and the heat pump.

[0019] Optionally, the above method further includes:

[0020] The mechanism models of heat loss in the wellbore and the top and bottom cap layers are established. Through numerical simulation, the heat storage rate of the above-mentioned reinjection wells reinjected into the heat storage reservoir during the non-heating period is predicted.

[0021] Optionally, the above method further includes:

[0022] The geothermal well network used for the above-mentioned heating adopts an inverse inclined seven-point well network.

[0023] Optionally, the above method further includes:

[0024] Establish the relationship formulas between water intake, reinjection intensity and permeability respectively;

[0025] Based on the above relationship formula, the recharge rate and water intake rate that meet the preset requirements are selected.

[0026] In a third aspect, a system for realizing low-temperature heat storage by filling and discharging is provided, comprising the above-mentioned device for realizing low-temperature heat storage by filling and discharging, the system comprising:

[0027] The heat storage module is used to extract the fluid in the above-mentioned reinjection well during the non-heating period and heat it with the waste heat of the power plant; and reinject the above-mentioned fluid into the above-mentioned water well for heat storage;

[0028] The heating execution module is used to extract the fluid in the water well during the heating period, and provide heating to the user based on the action of the heat exchange plate and the heat pump.

[0029] In a fourth aspect, a computer-readable storage medium is provided, on which a computer program is stored, and when the program is executed by a processor, the steps corresponding to the above method in the second aspect are implemented.

[0030] One or more technical solutions provided in the embodiments of the present invention have at least the following technical effects or advantages:

[0031] The waste heat from power plants in summer is used to heat the low-temperature fluid, so as to realize the storage and reuse of the low-temperature heat storage area and avoid the waste of heat resources. At the same time, the injection and recharging method is proposed. Compared with directly injecting waste heat into the recharging well, the injection and recharging interchange recharging prevents the heat from spreading to distant formations, which can reduce heat loss. As a result, the overall temperature of the heat storage is increased, further achieving the purpose of effectively utilizing the low-temperature heat storage. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0033] Figure 1 A schematic diagram of the structure of a device for realizing low-temperature heat storage by filling and discharging provided by the present invention;

[0034] Figure 2 A flow chart of a method for realizing low-temperature heat storage by filling and discharging provided by the present invention;

[0035] Figure 3 It is a schematic diagram of the wellbore heat loss and top and bottom cap layer heat loss mechanism model in the present invention;

[0036] Figure 4 It is a schematic diagram of heat loss calculation results in the present invention;

[0037] Figure 5 This is a schematic diagram of the well network used in the present invention;

[0038] Figure 6 This is a schematic diagram of the reverse-slant seven-spot well pattern in the present invention;

[0039] Figure 7It is a schematic diagram of the relationship between water intake intensity and permeability in the present invention;

[0040] Figure 8 It is a schematic diagram of the relationship between the reinjection intensity and the permeability in the present invention;

[0041] Fig. 9 A schematic diagram of the structure of a system for realizing low-temperature heat storage by filling and discharging provided by the present invention.

[0042] Figure numerals: 1. heat storage tank; 2. water intake well; 3. reinjection well; 4. heat exchange plate; 5. heat pump; 6. booster pump; 7. desander; 8. filter; 9. constant pressure water replenishment device. DETAILED DESCRIPTION

[0043] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0044] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. 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.

[0045] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0046] In the description of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "disposed" and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0047] It should be understood that the embodiments of the present invention and the specific features in the embodiments are detailed descriptions of the technical solutions of the present application, rather than limitations of the technical solutions of the present application. In the absence of conflict, the embodiments of the present application and the technical features in the embodiments may be combined with each other.

[0048] The technical solution of the embodiment of the present invention is to solve the above technical problems, and the overall idea is as follows:

[0049] Heat is stored in water wells located in low-temperature heat storage areas. Since the physical properties of the low-temperature heat storage area where the water wells are located cannot reach the required temperature, in the non-heating season, the waste heat from the summer power plant is used to heat the water in the recharge wells, bury it, and transfer it to the water wells for reuse, thereby effectively mobilizing the low-temperature heat storage and saving a lot of facility costs.

[0050] In an embodiment of the present invention, there is provided Figure 1 A device for realizing low-temperature heat storage by pumping and pouring is shown, comprising:

[0051] A heat exchange plate, a heat pump, a water intake well and a reinjection well arranged on a preset temperature heat storage reservoir; the water intake well is connected to the fluid input port of the heat exchange plate, and the fluid output port of the heat exchange plate is connected to the reinjection well through a pressure pump; the reinjection well is connected to the water intake well through the preset temperature heat storage reservoir; the heat exchange plate transfers the temperature to the heat pump through a circulation pump and a first pipeline, the heat pump is heated to the preset temperature, and is connected to the user's heating equipment through the circulation pump and the second pipeline.

[0052] It should be noted that this embodiment is mainly used for heating equipment. Specifically, heat is stored by using a water well set in a low-temperature heat storage area. Since the physical properties of the low-temperature heat storage area where the water well is located cannot reach the temperature required for heating, the waste heat of the power plant is used for heating and then re-injected into the water well for heat storage. As a result, the overall temperature of the heat storage rises, so that water can be taken for heating without the support of a large number of heat pumps or without the need for heat pumps (the specific number of heat pumps depends on the heating conditions of the waste heat of the power plant). The main function of the plate heat exchanger is heat exchange. Specifically, it is mainly used to transfer heat from the water well to the fluid in the first pipeline, and then the circulating pump transports the fluid to the heat pump, so that the heat pump is heated to a preset temperature (60°C), and the fluid in the second pipeline is transported to the user's heating equipment.

[0053] Furthermore, if Figure 1 As shown, a desander is also provided between the water intake well and the heat exchange plate.

[0054] It should be noted that the water in the water well needs to be pumped out to the heat exchanger and booster pump, and finally recharged to the recharge well. The water in the water well is likely to contain debris, so a desander is set to separate the debris from the water flow, protect the mechanical equipment from wear, reduce the deposition of heavy objects in the pipelines and trenches, and reduce the number of cleaning times required due to the large accumulation of debris in the digester.

[0055] Furthermore, if Figure 1 As shown, a filter is also provided between the heat exchange plate and the reinjection well.

[0056] It should be noted that the filters between the heat exchange plate and the recharge well mainly include primary filters and fine filters. The primary filter can be a plate-type primary filter, a bag-type primary filter or a pleated primary filter, etc. Its function is to remove dust and impurities generated in the heating equipment to protect the normal operation of the equipment; prevent fine dust and impurities from causing wear and blockage on the equipment, thereby extending the service life of the equipment; and protect the health of operators and reduce pollution to the environment. The fine filter can be a glass fiber filter, a polypropylene fiber filter or a wood pulp fiber filter, etc., and its function is to effectively remove fine particles, bacteria, viruses and other impurities, further improving the quality and efficiency of the heating equipment.

[0057] Furthermore, if Figure 1 As shown, the device also includes a constant pressure water replenishment device, which is connected to the first pipeline and the second pipeline respectively.

[0058] It should be noted that during the operation of the heating equipment, the water in the first pipe and the second pipe will expand due to heat, causing the pressure in the pipe to increase. If there is no constant pressure water replenishment device, the pipe may rupture, deform, and other problems, affecting the heating effect and the life of the equipment. The function of the constant pressure water replenishment device is to balance the pressure in the pipe, keep the total volume of the pipe unchanged, and avoid excessive pressure shock to the pipe. In addition, the constant pressure water replenishment device can also replenish the water reduced by evaporation in time, ensure the stability of the water level in the pipe, and avoid cavitation, water hammer and other phenomena in the equipment. Thereby ensuring the normal operation of the equipment and extending its service life.

[0059] Based on the same inventive concept, an embodiment of the present invention provides a method for realizing low-temperature heat storage by filling and discharging, such as Figure 2 As shown, the method includes the above-mentioned device for realizing low-temperature heat storage by taking in and pouring out, and the method includes steps S101-S102:

[0060] Step S101, during the non-heating period, the fluid in the recharge well is extracted and heated using the waste heat of the power plant; the fluid is recharged to the water intake well for heat storage;

[0061] It should be noted that during non-heating periods, such as summer, the heating equipment does not need to work, and the water temperature drawn from the water well is low at this time, requiring multiple heat pumps to heat it up. The power plant needs to work uninterruptedly in both summer and winter, so the residual heat will continue to be generated. At this time, the physical characteristics of the low-temperature heat storage area can be used to bring the residual heat into the low-temperature heat storage through water, thereby increasing the overall temperature and storing it effectively.

[0062] Step S102: During the heating period, the fluid in the water well is extracted, and the heat exchange plate and the heat pump are used to heat the user.

[0063] It should be noted that when heating is needed in winter, the temperature inside the low-temperature heat storage will rise due to the long-term continuous input of heat into the power plant. If it rises to 60°C, it can be put into use without the need for a heat pump to heat up. If it is slightly lower than 60°C, the number of heat pumps required is also excellent relative to the normal temperature fluid, thereby improving energy reuse and avoiding waste.

[0064] Furthermore, the method further comprises:

[0065] The mechanism models of heat loss in the wellbore and the top and bottom cap layers are established. Through numerical simulation, the heat storage rate of the recharge well to the heat storage reservoir during the non-heating period is predicted.

[0066] It should be noted that the model Figure 3 As shown, the purpose of its establishment is to evaluate the heat loss. The establishment of a specific heat loss model belongs to the prior art and will not be described here. hole is the ambient temperature, T hole is the outer wall temperature of cement ring, r ti is the inner radius of the oil pipe, r to is the outer radius of the oil pipe, r ins is the radius of the inner wall of the wellbore, r ci is the inner radius of the casing, r co is the outer radius of the casing, r h is the borehole radius. Based on this model, it can be seen that the heat storage rate can reach about 80%, of which 18.6% is heat loss in the wellbore and 0.6% is heat loss in the top and bottom cover layers. The heat recovery rate in the heating season is expected to be about 72%. Figure 4 shown.

[0067] Furthermore, the method further comprises:

[0068] The geothermal well network used for heating adopts an inverted seven-point well network.

[0069] It should be noted that the current geothermal development blocks are difficult to recharge due to poor physical properties and local sand body superposition, resulting in a ratio of water wells to recharge wells of about 1:2. Figure 5 The reverse seven-point well pattern was used to optimize the deployment of the extraction and injection well network. Considering the differences in physical properties in the source direction, a reverse-inclined seven-point well pattern was designed, as shown in Supplementary Figure 6. The ratio of the number of extraction and injection wells was designed to be 1:1.7, thereby effectively improving the ratio of the number of extraction and injection wells.

[0070] Furthermore, the method further comprises:

[0071] Establish the relationship formulas of water intake, reinjection intensity and permeability respectively; select the reinjection speed and water intake speed that meet the preset requirements based on the relationship formula. In detail, based on historical data, fit the water intake, reinjection intensity and permeability respectively, so as to obtain the relationship formula, such as Figure 7 and Figure 8 Then filter out the specific values ​​that meet the requirements.

[0072] Based on the same inventive concept, an embodiment of the present invention provides a system for realizing low-temperature heat storage by filling and discharging, such as Fig. 9 As shown, the system includes the above-mentioned device for realizing low-temperature heat storage by taking in and pouring out, and includes:

[0073] The heat storage module is used to extract the fluid in the recharge well during the non-heating period and heat it with the waste heat of the power plant; the fluid is recharged to the water well for heat storage;

[0074] The heating execution module is used to extract the fluid in the water well during the heating period, and provide heating to users based on the action of the heat exchange plate and the heat pump.

[0075] Based on the same inventive concept, this embodiment provides a computer-readable storage medium on which a computer program is stored, characterized in that when the program is executed by a processor, a method for realizing low-temperature heat storage by filling and discharging is implemented.

[0076] The present invention is described with reference to flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0077] Although the preferred embodiments of the present invention have been described, those skilled in the art may make other changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention.

[0078] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A device for low-temperature heat storage by filling and discharging, characterized in that: The device comprises: Heat exchange plates, heat pumps, water intake wells and recharging wells arranged on a heat storage reservoir at a preset temperature; The water intake well is connected to the fluid input port of the heat exchange plate, and the fluid output port of the heat exchange plate is connected to the recharging well through a pressure pump; the recharging well is connected to the water intake well through the preset temperature heat storage reservoir; The heat exchange plate transfers the temperature to the heat pump through the circulation pump and the first pipeline. The heat pump is heated to a preset temperature and is connected to the user's heating equipment through the circulation pump and the second pipeline.

2. The device according to claim 1, characterized in that A desander is also provided between the water intake well and the heat exchange plate.

3. The device according to claim 1, characterized in that A filter is also provided between the heat exchange plate and the reinjection well.

4. The device according to claim 1, characterized in that The device also includes a constant-pressure water replenishment device, which is communicated with the first pipeline and the second pipeline respectively.

5. A method for realizing low-temperature heat storage by pumping and pouring, characterized in that: It comprises a device for realizing low-temperature heat storage by pumping and pouring as claimed in any one of claims 1 to 4; The method comprises: During the non-heating period, the fluid in the re-injection well is extracted and heated by the waste heat of the power plant; the fluid is re-injected into the water well for heat storage; During the heating period, the fluid in the water well is extracted, and the heat exchange plate and the heat pump are used to provide heating to the user.

6. The method according to claim 5, characterized in that The method further comprises: A heat loss mechanism model of the wellbore and the top and bottom cap layers is established; through numerical simulation, the heat storage rate of the reinjection well to the heat storage reservoir during the non-heating period is predicted.

7. The method according to claim 5, characterized in that The method further comprises: The geothermal well network used for heating adopts an inversely inclined seven-point well network.

8. The method according to claim 5, characterized in that The method further comprises: Establish the relationship formulas between water intake, reinjection intensity and permeability respectively; Based on the relationship formula, the recharge rate and water intake rate that meet the preset requirements are selected.

9. A system for realizing low-temperature heat storage by pumping and pouring, characterized in that: It comprises a device for realizing low-temperature heat storage by pumping and pouring as claimed in any one of claims 1 to 4; The system comprises: The heat storage module is used to extract the fluid in the re-injection well during the non-heating period and heat it with the waste heat of the power plant; and re-inject the fluid into the water well for heat storage; The heating execution module is used to extract the fluid in the water well during the heating period, and provide heating to the user based on the action of the heat exchange plate and the heat pump.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the program is executed by a processor, the steps corresponding to the method according to any one of claims 5 to 8 are implemented.

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