An apparatus for removing scale from a geothermal reservoir and a pipeline without a pump and its usage method

Abstract

The present invention discloses a device for descaling a geothermal reservoir and a transportation pipeline without pumping and its usage method, which relates to the technical field of geothermal equipment. The present invention includes a ground surface and a geothermal well. The geothermal well is divided into a production well and a reinjection well. The structures of the production well and the reinjection well are the same. The geothermal well is installed on the ground surface, and a part of the geothermal well is located above the ground surface. The upper end surface of the geothermal well is fixedly connected with a clamping plate, and the upper surface of the clamping plate is fixedly connected with a support seat. By dividing the geothermal well into a production well and a reinjection well, the present invention regularly pumps and lifts the water in the production well (reinjection well), then extracts, exchanges heat, and removes sand from the geothermal water. The treated tail water is reinjected, and a descaling agent is added through a pumping device to descale the production well and the pipeline inside it. The well water is then reinjected into the reinjection well, and a descaling agent is added through the pumping device. This cycle continues until the descaling is successful.

Description

Technical Field

[0001] The present invention belongs to the technical field of geothermal equipment, and particularly relates to a scale removal device and a usage method for a geothermal reservoir and a transportation pipeline without a pump. Background Art

[0002] A reservoir refers to a stratum, rock mass or tectonic zone buried underground with effective voids and permeability, in which the stored geothermal fluid can be exploited. The geothermal reservoir is abbreviated as a reservoir, and it can store geothermal energy through the convection and enrichment of heat-carrying fluids. Therefore, a very important feature of the geothermal reservoir is that after heat exchange, the reservoir fluid (tail water) is reinjected into the reservoir layer. After reinjection, the reservoir fluid passes through the bottom heating zone of the reservoir layer, and under the condition of strong and continuous conductive heat flow supply, the reinjected reservoir fluid (tail water) is heated. The geothermal reservoir is different from oil reservoirs, gas reservoirs and groundwater reservoirs. In the geothermal reservoir, the originally existing fluid can be supplemented by the surrounding reservoir fluid and heated. This replenishment process is very important in the movement of the geothermal reservoir. For the "heat extraction without water extraction" utilization mode, and scaling is one of the main problems existing in the development and utilization of geothermal fluids. During the exploitation process, the temperature and pressure of the geothermal fluid change from the reservoir to the wellhead, resulting in a change in the solubility of minerals. Some minerals will precipitate from the fluid due to supersaturation, clogging the wellbore or pipeline, and reducing the exploitation efficiency of geothermal energy. In order to reduce the development and utilization risks of geothermal fields and save economic costs, a scale removal device and method without a pump are needed.

[0003] However, during the exploitation process of the geothermal reservoir, a large amount of scale is easily generated in the pipelines in the geothermal well and the reservoir layer. Over time, it will clog the pipelines and the reservoir layer, reducing the exploitation efficiency of geothermal energy. The present invention proposes a scale removal device and a usage method for a geothermal reservoir and a transportation pipeline without a pump in view of the above problems. Summary of the Invention

[0004] The purpose of the present invention is to provide a scale removal device and a usage method for a geothermal reservoir and a transportation pipeline without a pump, and solve the problem that during the exploitation process of the existing geothermal reservoir, a large amount of scale is easily generated in the pipelines in the geothermal well and the reservoir layer. Over time, it will clog the pipelines and the reservoir layer, reducing the exploitation efficiency of geothermal energy.

[0005] To solve the above technical problems, the present invention is realized through the following technical solutions:

[0006] The present invention relates to a device for descaling a geothermal reservoir and a transportation pipeline without a pump, which includes a ground surface and a geothermal well. The geothermal well is divided into a production well and a reinjection well. The structures of the production well and the reinjection well are the same. The ground surface is provided with a geothermal well, and a part of the geothermal well is located above the ground surface. The upper end surface of the geothermal well is fixedly connected with a clamping plate, and the upper surface of the clamping plate is fixedly connected with a support seat. A reinjection pipe and a water extraction pipe are installed in the support seat. The lower ends of the reinjection pipe and the water extraction pipe are located inside the geothermal well. The upper end of the water extraction pipe is communicated with a water outlet pipe, and the upper end of the reinjection pipe is also communicated with a water inlet pipe. In the above structure, the geothermal well can be used as both a production well and a reinjection well, and their functions can be interchanged.

[0007] Preferably, an exhaust device is installed on the upper surface of the support seat, and the exhaust device is communicated with the geothermal well. In the above structure, the exhaust device can discharge the gas in the geothermal well.

[0008] Preferably, pressure gauges, scale inhibitor pumping pipes and gate valves are installed on the circumferential sides of the water outlet pipe and the water inlet pipe. The scale inhibitor pumping pipe is located between the pressure gauge and the gate valve, and the gate valve is located on the side close to the geothermal well. In the above structure, the gate valve can control the flow rates of the water outlet pipe and the water inlet pipe, and the pressure gauge can monitor the pressure value in the pipeline.

[0009] Preferably, a gate valve is also installed on the circumferential side of the scale inhibitor pumping pipe to facilitate the control of the unit internal flow rate of the scale inhibitor pumping pipe.

[0010] Preferably, one end of the water outlet pipe is fixedly connected with a sand removal and heat extraction device to facilitate operations such as extraction, heat exchange and sand removal of the pumped-back water.

[0011] Preferably, a geothermal heat pump is also installed on the lower end surface of the water extraction pipe. The function of the geothermal heat pump is to transfer low-grade heat energy to high-grade heat energy by inputting a small amount of high-grade energy from shallow terrestrial energy.

[0012] Preferably, a plurality of filter pipes are provided on the circumferential side of the geothermal well, and the filter pipes are located at the lower end of the geothermal well. Groundwater can enter the bottom of the geothermal well through the filter pipes.

[0013] The present invention also relates to a method for using a device for descaling a geothermal reservoir and a transportation pipeline without a pump, which includes the following steps:

[0014] Step 1: When the device is scale-free, pump and reinject the water in the production well and the reinjection well of the geothermal well. The well water passes through the water extraction pipe and the water outlet pipe in sequence, and then calculate the water output of the water extraction pipe and the water outlet pipe per unit time to obtain the initial water output per unit time of the device.

[0015] Step 2: When the scale accumulates in the device, the pumped well water is passed through a sand removal and heat extraction device for extraction, heat exchange, and sand removal operations. Then, the heat-exchanged geothermal tail water is successively backfilled into the production well through the water inlet pipe and the reinjection pipe. While backfilling, a scale inhibitor is added to the water inlet pipe through the scale inhibitor pumping pipe. The scale inhibitor enters the production well along with the geothermal tail water. The scale inhibitor reaches the pump section and the heat reservoir section at the bottom of the production well successively as the geothermal tail water migrates. The scale inhibitor reacts chemically with the scaling site, generating gases soluble in water and chemically green-friendly components, which enter the bottom of the production well or are discharged outside the well along with the well water.

[0016] Step 3: After reacting for a period of time, the production well is pumped and lifted again and the scale inhibitor is continuously pumped in. According to the water output, the scale removal effect of the geothermal reservoir at the bottom of the production well and the pipeline such as the water inlet pipe is detected and compared, and then the pumping and lifting continue.

[0017] Step 4: The lifted water is backfilled into the production well after slag removal and sand removal, and the scale inhibitor is pumped into the production well. After reacting for a period of time, it is lifted again to remove scale from the pipeline. After slag removal and sand removal, it is injected into the reinjection well while the scale inhibitor is pumped in, and they are lifted alternately. This is repeated until the water output reaches the initial value or is close to the initial value, then the scale removal is successful.

[0018] The present invention has the following beneficial effects:

[0019] In the present invention, the geothermal well is divided into a production well and a reinjection well. By regularly pumping and lifting the production well (reinjection well), then extracting, heat-exchanging, and sand-removing the geothermal water, the treated tail water is backfilled and a scale inhibitor is added through a pumping device to remove scale from the production well and the pipeline inside it. Then, the reinjection well (production well) is pumped and lifted again, the geothermal water is extracted, heat-exchanged, and sand-removed, and then the well water is backfilled into the reinjection well while the scale inhibitor is added through the pumping device. They are lifted alternately multiple times until the water output of the production well (reinjection well) reaches the initial value or is close to the initial value during lifting, then the scale removal is successful.

[0020] Of course, it is not necessary for any product implementing the present invention to achieve all the above-mentioned advantages simultaneously. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for describing the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0022] Figure 1 It is a schematic structural diagram of a scale removal device for a geothermal heat reservoir and a pipeline without pumping in the present invention.

[0023] In the accompanying drawings, the list of components represented by each reference numeral is as follows:

[0024] 1 - foundation surface, 2 - sand removal and heat extraction device, 3 - water outlet pipe, 4 - gate valve, 5 - scale inhibitor pumping pipe, 6 - pressure gauge, 7 - water inlet pipe, 8 - support base, 9 - clamping plate, 10 - reinjection pipe, 11 - filter pipe, 12 - ground heat pump, 13 - water extraction pipe, 14 - geothermal well, 15 - exhaust device. Specific embodiments

[0025] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0026] In the description of the present invention, it should be understood that the terms "upper", "middle", "outer", "inner", "periphery" and other orientation or positional relationships are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the components or elements referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention.

[0027] Please refer to Figure 1 As shown, the present invention is a scale removal device for geothermal reservoirs and pipelines without pumping, including a foundation surface 1 and a geothermal well 14. The geothermal well 14 is divided into a production well and a reinjection well, and the structures of the production well and the reinjection well are the same. The foundation surface 1 is provided with the geothermal well 14, a part of the geothermal well 14 is located above the foundation surface 1, the upper end surface of the geothermal well 14 is fixedly connected with a clamping plate 9, and the upper surface of the clamping plate 9 is fixedly connected with a support base 8. The support base 8 is internally provided with a reinjection pipe 10 and a water extraction pipe 13. The lower ends of the reinjection pipe 10 and the water extraction pipe 13 are located inside the geothermal well 14. The upper end of the water extraction pipe 13 is communicated with a water outlet pipe 3, and the upper end of the reinjection pipe 10 is also communicated with a water inlet pipe 7. In the above structure, the geothermal well 14 can be used as both a production well and a reinjection well, and the functions of the two can be interchanged.

[0028] Among them, an exhaust device 15 is installed on the upper surface of the support base 8, and the exhaust device 15 is communicated with the geothermal well 14. In the above structure, the exhaust device 15 can discharge the gas in the geothermal well 14.

[0029] Among them, pressure gauges 6, scale inhibitor pumping pipes 5 and gate valves 4 are installed on the circumferential sides of the water outlet pipe 3 and the water inlet pipe 7. The scale inhibitor pumping pipe 5 is located between the pressure gauge 6 and the gate valve 4, and the gate valve 4 is located on the side close to the geothermal well 14. In the above structure, the gate valve 4 can control the flow rates of the water outlet pipe 3 and the water inlet pipe 7, and the pressure gauge 6 can monitor the pressure values in the pipeline.

[0030] Among them, a gate valve 4 is also installed on the circumferential side of the descaling agent pumping pipe 5 to facilitate the control of the flow rate per unit time of the descaling agent pumping pipe 5.

[0031] Among them, one end of the water outlet pipe 3 is fixedly connected with a sand removal and heat extraction device 2 to facilitate operations such as extraction, heat exchange, and sand removal of the pumped-back water.

[0032] Among them, a ground heat pump 12 is also installed on the lower end surface of the water extraction pipe 13. The function of the ground heat pump 12 is to transfer low-grade heat energy to high-grade heat energy by inputting a small amount of high-grade energy from shallow terrestrial energy.

[0033] Among them, a number of filter pipes 11 are provided on the circumferential side of the geothermal well 14. The filter pipes 11 are located at the lower end of the geothermal well 14, and groundwater can enter the bottom of the geothermal well 14 through the filter pipes 11.

[0034] The present invention relates to a method for using a geothermal heat reservoir and a descaling device for a pipeline without a pump, comprising the following steps:

[0035] Step 1: When the device is scale-free, pump water and pump it back in the production well and the injection well in the geothermal well 14. The well water passes through the water extraction pipe 13 and the water outlet pipe 3 in sequence, and then calculate the water output of the water extraction pipe 13 and the water outlet pipe 3 per unit time to obtain the initial water output per unit time of the device.

[0036] Step 2: When scale accumulates in the device, pump the extracted well water through the sand removal and heat extraction device 2 for operations such as extraction, heat exchange, and sand removal, and then pump the well water back into the production well through the water inlet pipe 7 and the injection pipe 10 in sequence. While injecting, add a descaling agent into the water inlet pipe 7 through the descaling agent pumping pipe 5. The descaling agent enters the production well along with the well water, and the descaling agent reaches the pump body section and the carbonate heat reservoir section at the bottom of the production well successively as the well water migrates. The descaling agent reacts chemically with the scaling part, generating gases soluble in water and chemically friendly components, and entering the bottom of the production well or being discharged outside the well along with the well water.

[0037] Step 3: After reacting for a period of time, pump water and pump it back in the production well again and continue to pump in the descaling agent. According to the water output, detect and compare the descaling effect of the geothermal reservoir at the bottom of the production well and the pipeline such as the water inlet pipe 7, and then continue to pump water and pump it back.

[0038] Step 4: Pump the pumped-back water back into the production well after removing slag and sand, and pump a descaling agent into the production well. After reacting for a period of time, pump it back again to descale the pipeline. After removing slag and sand, inject it into the injection well while pumping in the descaling agent, and pump it back to each other. Repeat this process until the water output reaches the initial value or is close to the initial value, then the descaling is successful.

[0039] It should be noted that during the pumping process of the device, a water pump is required. Since the depths of the geothermal wells 14 are different, the output powers of the water pumps used are also different, and the specific situation shall be subject to the actual use.

[0040] It should be further noted that during the pumping and surging process, the openings of the respective gate valves 4 should be opened to the maximum and kept consistent.

[0041] In the description of this specification, the descriptions referring to terms such as "one embodiment", "example", "specific example", etc. mean that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in a suitable manner in any one or more embodiments or examples.

[0042] The preferred embodiments of the present invention disclosed above are only used to help explain the present invention. The preferred embodiments do not describe all the details in detail, nor do they limit the present invention to only the specific implementation manners. Obviously, many modifications and changes can be made according to the content of this specification. These embodiments are selected and specifically described in this specification in order to better explain the principle and practical application of the present invention, so that those skilled in the relevant technical field can well understand and utilize the present invention. The present invention is only limited by the claims and their full scope and equivalents.

Claims

1. A method for using a scale removal device without a pump for a geothermal reservoir and a transportation pipeline, characterized in that, A scale removal device for a geothermal reservoir and a transportation pipeline without pumping, comprising a ground surface (1) and a geothermal well (14). The geothermal well (14) is divided into a production well and a reinjection well, and the structures of the production well and the reinjection well are the same. The ground surface (1) is provided with the geothermal well (14), and a part of the geothermal well (14) is located above the ground surface (1). The upper end surface of the geothermal well (14) is fixedly connected with a clamping plate (9), and the upper surface of the clamping plate (9) is fixedly connected with a support seat (8). A reinjection pipe (10) and a water extraction pipe (13) are installed in the support seat (8). The lower ends of the reinjection pipe (10) and the water extraction pipe (13) are located inside the geothermal well (14). The upper end of the water extraction pipe (13) is communicated with a water outlet pipe (3), and the upper end of the reinjection pipe (10) is also communicated with a water inlet pipe (7). A geothermal pump (12) is further installed on the lower end surface of the water extraction pipe (13). Including the following steps: Step 1: When the device is scale-free, pump and lift the water in the production well and the reinjection well of the geothermal well (14). The well water passes through the water extraction pipe (13) and the water outlet pipe (3) in sequence, and then calculate the water output of the water extraction pipe (13) and the water outlet pipe (3) per unit time to obtain the initial water output per unit time of the device. One end of the water outlet pipe (3) is fixedly connected with a sand removal and heat extraction device (2). Step 2: When scale accumulates in the device, pump the extracted well water through the sand removal and heat extraction device (2) to perform operations of extraction, heat exchange and sand removal. Then, the well water is reinjected into the production well through the water inlet pipe (7) and the reinjection pipe (10) in sequence. While reinjecting, add a scale inhibitor through the scale inhibitor pumping pipe (5) to the water inlet pipe (7). The scale inhibitor enters the production well along with the well water. The scale inhibitor reaches the pump body section and the carbonate rock geothermal reservoir section at the bottom of the production well successively as the well water migrates. The scale inhibitor reacts chemically with the scaling part, generating gas soluble in water and chemically green-friendly components, and enters the bottom of the production well or is discharged out of the well along with the well water. Step 3: After reacting for a period of time, pump and lift the production well again and continue to pump in the scale inhibitor. According to the water output, detect and compare the scale removal effect of the geothermal reservoir at the bottom of the production well and the pipeline such as the water inlet pipe (7), and then continue to pump and lift the water. Step 4: Backfill the lifted water into the production well after removing slag and sand, and pump a scale inhibitor into the production well. After reacting for a period of time, lift the water again to remove scale from the pipeline. After removing slag and sand, inject it into the reinjection well and pump a scale inhibitor at the same time, reciprocatingly lifting and injecting, and repeat this process until the water output reaches the initial value or is close to the initial value, then the scale removal is successful.

2. The usage method of a geothermal reservoir and a scale removal device for a transportation pipeline without a pump according to claim 1, characterized in that An exhaust device (15) is installed on the upper surface of the support seat (8), and the exhaust device (15) is communicated with the geothermal well (14).

3. The usage method of a geothermal reservoir and a descaling device for a transportation pipeline without a pump according to claim 1, characterized in that Pressure gauges (6), scale inhibitor pumping pipes (5) and gate valves (4) are installed on the circumferential sides of the water outlet pipe (3) and the water inlet pipe (7). The scale inhibitor pumping pipe (5) is located between the pressure gauge (6) and the gate valve (4), and the gate valve (4) is located on the side close to the geothermal well (14).

4. The method of using a scale removal device for a geothermal reservoir and a transportation pipeline without a pump according to claim 3, characterized in that A gate valve (4) is also installed on the circumferential side of the scale inhibitor pumping pipe (5).

5. The method of using a scale removal device without a pump for a geothermal reservoir and a conveying pipeline according to claim 1, characterized in that, A plurality of filter pipes (11) are arranged on the circumferential side of the geothermal well (14), and the filter pipes (11) are located at the lower end of the geothermal well (14).

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