A corrosion protection system for geothermal well pump pipes

Abstract

This application discloses an anti-corrosion system for geothermal well pump pipes. Cathodic protection is achieved through strips. After the strips are arranged on the geothermal well pump pipes, an anti-corrosion coating is applied to the geothermal well pump pipes to prevent corrosion. After the geothermal well pump pipes are lowered into the wellhead, the air in the wellbore is first extracted through the nitrogen injection port, and then nitrogen is injected to protect the geothermal well pump pipes above the water surface at the wellhead from oxidation and corrosion. Based on the strips, the anti-corrosion coating, and the nitrogen injection port, the purpose of anti-corrosion of geothermal well pump pipes can be achieved.

Description

Technical Field

[0001] This application relates to the field of new energy technology, and in particular to an anti-corrosion system for geothermal well pump pipes. Background Technology

[0002] Geothermal resources are a clean and renewable energy source with large reserves, wide distribution, and good stability. Developing and utilizing geothermal resources is of great significance for energy conservation and emission reduction. Geothermal heating is an important way to develop and utilize geothermal resources.

[0003] Geothermal resources are buried deep in the earth. They are typically brought to the surface for use by drilling geothermal wells and then extracting geothermal water through deep well pumps and pipes. However, due to the complex chemical composition of geothermal water and its strong corrosiveness, corrosion holes will appear in the geothermal well pump pipes after one to three years of use. This will reduce the water output of the geothermal well, and if the corrosion becomes severe, it may stop producing water altogether, requiring the geothermal system to be shut down and the deep well pump and pipes to be replaced. However, the cost of replacing deep well pumps and pipes is high, which in turn leads to high operation and maintenance costs for geothermal wells.

[0004] Therefore, how to reduce the operation and maintenance costs of geothermal wells has become an urgent problem to be solved in this field. Summary of the Invention

[0005] This application provides an anti-corrosion system for geothermal well pump pipes, with the aim of reducing the operation and maintenance costs of geothermal wells.

[0006] To achieve the above objectives, this application provides the following technical solution:

[0007] A corrosion protection system for a geothermal well pump pipe, the geothermal well pump pipe being composed of at least two pump pipe sections, the corrosion protection system comprising: an anti-corrosion coating, a geothermal well casing, a strip, a wellhead device, and a nitrogen injection port;

[0008] The strips are arranged around the outer surface of the sub-pump tube, and each strip is in a closed loop shape in the sub-pump tube;

[0009] An anti-corrosion coating is provided on the outside of the sub-pump pipe;

[0010] The geothermal well casing is fitted over the geothermal well pump pipe located below and at the geothermal wellhead.

[0011] The wellhead device is installed at the geothermal wellhead where the geothermal well pump pipe is located. The wellhead device is located above the geothermal well casing. The inlet of the wellhead device is connected to the nitrogen injection port, which is used to inject nitrogen.

[0012] The outlet connection of the wellhead device is a flexible rubber connector, which is used to isolate the geothermal well pump pipe located below the geothermal wellhead from the geothermal water delivery pipe located above the geothermal wellhead.

[0013] Optionally, the geothermal well pump pipe located below the wellhead device includes: a geothermal well pump pipe on the horizontal plane and a geothermal well pump pipe below the horizontal plane;

[0014] The strips are set at intervals of 3 to 5 meters on the geothermal well pump pipes on the horizontal plane, and at intervals of 1 to 3 meters on the geothermal well pump pipes below the horizontal plane.

[0015] Optionally, the outer surface of each segment of the sub-pump tube is provided with the strip, and the strip is located at the middle position of the sub-pump tube.

[0016] Optionally, the outer surface of the sub-pump tube is provided with strips at intervals of one or more segments, and the strips are located in the middle of the sub-pump tube.

[0017] Optionally, the multiple sub-pump pipes are connected by flanges, and copper wires are provided at the flange connections for connecting the upper and lower sub-pump pipes.

[0018] Optionally, the flanges are connected by bolts, and a rubber gasket is provided at the connection.

[0019] Optionally, the anti-corrosion coating is made of epoxy resin paint.

[0020] Optionally, the inlet of the wellhead device is connected to the nitrogen injection port via a valve, which is used to control the flow rate of nitrogen.

[0021] Optionally, the strip is made of magnesium, zinc, aluminum, or their alloys.

[0022] Optionally, the wall thickness of the geothermal well pump pipe shall not be less than 5 mm.

[0023] The technical solution provided in this application includes strips surrounding the outer surface of the sub-pump pipe, each strip forming a closed loop within the sub-pump pipe; an anti-corrosion coating is provided on the outside of the sub-pump pipe; the geothermal well casing is fitted around the geothermal wellhead and the geothermal well pump pipe located below the geothermal wellhead; a wellhead device is installed at the geothermal wellhead where the geothermal well pump pipe is located, positioned above the geothermal well casing, with its inlet connected to a nitrogen injection port for injecting nitrogen; and a rubber flexible connector is connected to the outlet of the wellhead device for insulation. Cathodic protection is achieved between the geothermal well pump pipe located below the geothermal wellhead and the geothermal water delivery pipe located above the geothermal wellhead through strips. After the strips are installed on the geothermal well pump pipe, an anti-corrosion coating is applied to the geothermal well pump pipe to prevent corrosion. After the geothermal well pump pipe is lowered into the wellhead, the air in the wellbore is first extracted through the nitrogen injection port, and then nitrogen is injected to protect the geothermal well pump pipe above the water surface at the wellhead from oxidation and corrosion. Based on the strips, anti-corrosion coating, and nitrogen injection port, the purpose of corrosion protection for the geothermal well pump pipe can be achieved. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 A schematic diagram of the architecture of an anti-corrosion system for a geothermal well pump pipe provided in an embodiment of this application;

[0026] Figure 2 A detailed schematic diagram of a geothermal well pump pipe flange connection provided in this application embodiment;

[0027] Figure 3 A schematic diagram of the installation position of cathodic protection for a geothermal well pump pipe is provided for an embodiment of this application;

[0028] Figure 4 This is a cross-sectional view of the cathodic protection installation of a geothermal well pump pipe provided in an embodiment of this application. Detailed Implementation

[0029] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0030] In this application, the terms "comprising," "including," or any other variations thereof are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0031] This invention provides an anti-corrosion system for geothermal well pump pipes, see [link / reference]. Figures 1 to 4 , Figure 1 This is a schematic diagram of the anti-corrosion system for geothermal well pump pipes. The anti-corrosion system includes: anti-corrosion coating 1, geothermal well casing 2, strip 3, wellhead device 4, and nitrogen injection port 5; the geothermal well pump pipe 6 consists of at least two sections of pump pipe 7.

[0032] The strips 3 are arranged around the outer surface of the sub-pump tube 7, and each strip 3 forms a closed loop in the sub-pump tube 7.

[0033] An anti-corrosion coating 1 is provided on the outside of the sub-pump pipe 7;

[0034] The geothermal well casing 2 is set outside the geothermal well pump pipe 6 located at the geothermal wellhead and below the geothermal wellhead;

[0035] A wellhead device 4 is installed at the geothermal wellhead where the geothermal well pump pipe 6 is located. The wellhead device 4 is located above the geothermal well casing 2. The inlet of the wellhead device 4 is connected to the nitrogen injection port 5, which is used to inject nitrogen.

[0036] The outlet of the wellhead device 4 is connected to a rubber flexible connection 8, which is used to isolate the geothermal well pump pipe 6 located below the geothermal wellhead from the geothermal water delivery pipe 13 located above the geothermal wellhead.

[0037] It should be noted that the strips 3 are arranged around the outer surface of the sub-pump pipe 7, and each strip 3 forms a closed loop in the sub-pump pipe 7; an anti-corrosion coating 1 is provided on the outside of the sub-pump pipe 7; the geothermal well casing 2 is sleeved on the outside of the geothermal wellhead and the geothermal well pump pipe 6 located below the geothermal wellhead; a wellhead device 4 is provided at the geothermal wellhead where the geothermal well pump pipe 6 is located, the wellhead device 4 is located above the geothermal well casing 2, the inlet of the wellhead device 4 is connected to the nitrogen injection port 5, the nitrogen injection port 5 is used to inject nitrogen; the outlet of the wellhead device 4 is connected to the rubber flexible connector 8, the rubber flexible connector 8 is used for isolation. The geothermal well pump pipe 6 located below the geothermal wellhead and the geothermal water delivery pipe 13 located above the geothermal wellhead are cathodic protected by strips 3. After the strips 3 are arranged on the geothermal well pump pipe 6, an anti-corrosion coating 1 is applied to the geothermal well pump pipe 6 to prevent corrosion. After the geothermal well pump pipe 6 is lowered into the wellhead, the air in the wellbore is first extracted through the nitrogen injection port 5, and then nitrogen is injected to protect the geothermal well pump pipe 6 above the water surface at the wellhead from oxidation and corrosion. Based on the strips 3, the anti-corrosion coating 1, and the nitrogen injection port 5, the purpose of corrosion protection of the geothermal well pump pipe 6 can be achieved.

[0038] It should also be noted that the length of each section of pump pipe 7 is 3 to 5 meters.

[0039] In this application, the anti-corrosion coating 1 needs to be reapplied after each heating season. Before applying the anti-corrosion coating 1, the oil, ash, rust and iron oxide scale and other impurities on the outer surface of the geothermal well pump pipe 6 should be removed. After the pipe is derusted, the primer is applied first, then the first coat of topcoat and finally the second coat of topcoat, thus completing the application of the anti-corrosion coating 1.

[0040] In this application, the geothermal well pump pipe 6 is specifically a 20# seamless steel pipe.

[0041] In some specific embodiments, the geothermal well pump pipe 6 adopts the method of sacrificial anode protection of cathode. The geothermal well pump pipe 6 is equipped with protective charge. In order to prevent the charge from being lost through the geothermal well pump pipe, a rubber flexible connection 8 is added here.

[0042] Furthermore, the geothermal well pump pipe 6 located below the wellhead device 4 includes: a geothermal well pump pipe 6 on the horizontal plane and a geothermal well pump pipe 6 below the horizontal plane;

[0043] Strips 3 are installed at intervals of 3 to 5 meters on the geothermal well pump pipe 6 on the horizontal plane, and strips 3 are installed at intervals of 1 to 3 meters on the geothermal well pump pipe 6 below the horizontal plane.

[0044] It should be noted that the geothermal well pump pipe 6 located below the wellhead device 4 includes: geothermal well pump pipe 6 on the horizontal plane and geothermal well pump pipe 6 below the horizontal plane; the geothermal well pump pipe 6 on the horizontal plane is provided with strips 3 at intervals of 3 to 5 meters, and the geothermal well pump pipe 6 below the horizontal plane is provided with strips 3 at intervals of 1 to 3 meters. Since the corrosion of the geothermal well pump pipe 6 is mainly due to the corrosion of geothermal water, the corrosion below the water surface is more severe and there are more anions, while the corrosion above the water surface is mainly due to air oxidation and is weaker. Therefore, reducing the number of strips 3 on the geothermal well pump pipe 6 above the water surface and increasing the number of strips 3 on the geothermal well pump pipe 6 below the water surface can not only achieve the purpose of corrosion prevention, but also save economic costs.

[0045] It should also be noted that strip 3 is welded to the outer surface of geothermal well pump pipe 6.

[0046] Specifically, each sub-pump tube 7 has a strip 3 on its outer surface, and the strip 3 is located in the middle of the sub-pump tube 7.

[0047] It should be noted that each sub-pump pipe 7 has a strip 3 on its outer surface. The strip 3 is located in the middle of the sub-pump pipe 7. The strip 3 on the outer surface of each sub-pump pipe 7 can prevent each sub-pump pipe 7 from being corroded, thus making the corrosion resistance more effective.

[0048] Specifically, strips 3 are provided on the outer surface of sub-pump tubes 7 at intervals of one or more segments, with the strips 3 located in the middle of the sub-pump tubes 7.

[0049] It should be noted that strips 3 are provided on the outer surface of sub-pump pipes 7 at intervals of one or more. The strips 3 are located in the middle of the sub-pump pipes 7, which can save economic costs while ensuring that the sub-pump pipes 7 are not corroded.

[0050] It should also be noted that, since the length of the sub-pump pipe 7 is generally 3 to 5 meters, in order to save costs, strips 3 can be installed on the outer surface of the sub-pump pipe 7 at intervals of 6 to 10 meters.

[0051] Furthermore, the multi-segment sub-pump pipe 7 is connected by flange 9, and a copper wire 10 is provided at the flange 9 connection point. The copper wire 10 is used to connect the upper and lower sub-pump pipes 7.

[0052] It should be noted that the multi-segment sub-pump pipe 7 is connected by flange 9, and a copper wire 10 is provided at the flange 9 connection. The copper wire 10 is used to connect the upper and lower sub-pump pipes 7. In order to ensure the effect of cathodic protection, that is, to determine the effect of corrosion prevention, the upper and lower sub-pump pipes 7 are connected by copper wire 10 so that the potential of each segment of pump pipe 7 is uniform.

[0053] It should also be noted that two symmetrical copper wires 10 are used to connect the upper and lower sub-pump pipes 7 at the flange 9 connection.

[0054] Specifically, the flanges 9 are connected by bolts 11, and a rubber gasket is provided at the connection.

[0055] It should be noted that the flanges 9 are connected by bolts 11, and rubber gaskets are provided at the connection points to make the connection between each section of the sub-pump pipe 7 tighter, preventing geothermal water from flowing out of the geothermal well pump pipe 6. After the heating season ends, since the flange 9 connection is a detachable head, the sub-pump pipe 7 can be disassembled by removing the bolts 11, making it convenient for users to clean the sub-pump pipe 7.

[0056] Specifically, the anti-corrosion coating 1 is made of epoxy resin paint.

[0057] It should be noted that the material of anti-corrosion coating 1 is epoxy resin paint. Epoxy resin paint has advantages such as wear resistance, pressure resistance, water resistance, mildew resistance, impermeability and strong adhesion. Therefore, the material of anti-corrosion coating 1 is epoxy resin paint, which makes the geothermal well pump pipe corrosion resistant.

[0058] Furthermore, the inlet of the wellhead device 4 is connected to the nitrogen injection port 5 via valve 12, which is used to control the flow rate of nitrogen.

[0059] It should be noted that the inlet of the wellhead device 4 is connected to the nitrogen injection port 5 through valve 12. Valve 12 is used to control the flow rate of nitrogen. First, the air in the wellbore is extracted through the nitrogen injection port 5, and then nitrogen is injected through the nitrogen injection port to prevent the sub-pump pipe 7 from being oxidized and corroded.

[0060] Specifically, strip 3 is composed of magnesium, zinc, aluminum and their alloys.

[0061] It should be noted that strip 3 is made of magnesium, zinc, aluminum and their alloys, and strip 3 is 50mm wide and 2mm thick.

[0062] Specifically, the wall thickness of the geothermal well pump pipe 6 shall not be less than 5mm.

[0063] It should be noted that the wall thickness of the geothermal well pump pipe 6 is not less than 5mm. In order to save economic costs, the wall thickness of the geothermal well pump pipe 6 is 5mm to 10mm.

[0064] The points that need protection in this invention are:

[0065] 1. The connection between nitrogen injection port 5 and wellhead device 4 is as follows: the control in the wellbore is extracted through nitrogen injection port 5, and then nitrogen is injected through nitrogen injection port 5 to protect the geothermal well pump pipe from oxidation and corrosion.

[0066] 2. The connection method between strip 3 and geothermal well pump pipe 6;

[0067] 3. The connection method between the rubber flexible connector 8 and the wellhead device 4;

[0068] 4. Connection method between copper wire 10 and sub-pump pipe 7;

[0069] 5. Apply anti-corrosion coating 1.

[0070] The various embodiments in this specification are described in a progressive manner. Similar or identical parts between embodiments can be referred to mutually. Each embodiment focuses on describing the differences from other embodiments. In particular, for system or system embodiments, since they are basically similar to method embodiments, the description is relatively simple, and relevant parts can be referred to the descriptions in the method embodiments. The systems and system embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. Those skilled in the art can understand and implement this without creative effort.

[0071] Those skilled in the art will further recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of both. To clearly illustrate the interchangeability of hardware and software, the components and steps of the various examples have been generally described in terms of functionality in the foregoing description. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementations should not be considered beyond the scope of this invention.

[0072] The various embodiments in this specification are described in a progressive manner. Each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0073] The above description of the disclosed embodiments enables those skilled in the art to make or use this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A corrosion protection system for a geothermal well pump pipe, characterized by The geothermal well pump pipe is composed of at least two sub-pump pipes, and the anti-corrosion system comprises an anti-corrosion coating, a geothermal well casing, a strip, a wellhead device and a nitrogen injection inlet. The strip is arranged around the outer surface of the sub-pump pipe, and each strip is in a closed ring shape around the sub-pump pipe. An anti-corrosion coating is arranged outside the sub-pump pipe. The geothermal well casing is arranged outside the geothermal well pump pipe below the geothermal wellhead. The wellhead device is arranged at the geothermal wellhead where the geothermal well pump pipe is located, and the wellhead device is located above the geothermal well casing. The outlet of the wellhead device is connected to a rubber flexible connection, which is used to isolate the geothermal well pump pipe below the geothermal wellhead from the geothermal water conveying pipe above the geothermal wellhead, and to prevent the loss of electric charge through the geothermal well pump pipe. The geothermal well pump pipe below the wellhead device comprises a geothermal well pump pipe on the horizontal plane and a geothermal well pump pipe below the horizontal plane. The strips are arranged at intervals of 3-5 meters on the geothermal well pump pipe on the horizontal plane, and at intervals of 1-3 meters on the geothermal well pump pipe below the horizontal plane.

2. The system of claim 1, wherein, The outer surface of each sub-pump pipe is provided with the strip, which is located at the middle position of the sub-pump pipe.

3. The system of claim 1, wherein, The outer surface of each sub-pump pipe is provided with the strip, which is located at the middle position of the sub-pump pipe.

4. The system of claim 1, wherein, The sub-pump pipes are connected by flanges, and copper wires are arranged at the flange connections for connecting the upper and lower sub-pump pipes.

5. The system of claim 4, wherein, The flanges are connected by bolts, and rubber pads are arranged at the connections.

6. The system of claim 1, wherein, The material of the anti-corrosion coating is epoxy resin paint.

7. The system of claim 1, wherein, The inlet of the wellhead device is connected to the nitrogen injection inlet through a valve, which is used to control the flow of nitrogen.

8. The system of claim 1, wherein, The strip is composed of magnesium, zinc, aluminum and their alloy materials.

9. The system of claim 1, wherein, The wall thickness of the geothermal well pump pipe is not less than 5 mm.

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