Downhole throttling device for full-life-cycle mining and power supply method therefor

Abstract

A downhole throttling device for full-life-cycle mining and a power supply method therefor, relating to the technical field of oil production and gas production of oil and gas fields. The downhole throttling device comprises a thermoelectric power generation mechanism (1) for power generation and a throttling mechanism for throttling a fluid entering the thermoelectric power generation mechanism (1). The throttling mechanism comprises at least one throttling unit (3). The thermoelectric power generation mechanism (1) can generate electric energy from the temperature difference between a low-temperature fluid subjected to throttling expansion and a surrounding environment so as to be supplied to the downhole throttling device. The downhole throttling device has a simple structure and a flexible mounting mode, requires no manual intervention, and has low costs, and salvage and replacement of the downhole throttling device can be avoided.

Description

Underground throttling device for full life cycle mining and power supply method thereof

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit of Chinese patent application 202311758070.9 filed on December 19, 2023, the contents of which are incorporated herein by reference. Technical Field

[0003] The present invention relates to the technical field of oil and gas production in oil and gas fields, and in particular to a downhole throttling device for full life cycle production and a power supply method for the downhole throttling device for full life cycle production. Background Art

[0004] Downhole throttling gas production technology is one of the core technologies for low-cost development of oil and gas fields. It can effectively prevent the formation of hydrates, avoid ground heating and high-pressure gathering and transportation of gas pipelines, and the throttle is a key tool for downhole throttling and pressure reduction production. There are many types of throttles: slip-salvageable type, pre-set salvageable type, fixed short-section type, electric-set salvageable type, and electric gas nozzle remotely adjustable type. Among them, since the throttle is located at a great depth, providing power to it through ground equipment or existing downhole power supply technology will lead to problems such as complex structure, increased cost, and increased failure rate. Among them, the existing downhole power supply technology includes: (1) downhole battery power supply, which needs to be charged or salvaged and replaced later; (2) using fluid to drive the impeller to rotate to generate electricity. This technology is prone to getting stuck due to sand and scale during downhole oil and gas production, and also needs to be salvaged and replaced; (3) downhole temperature difference power generation, which is generally prone to extremely poor power generation effect due to the small temperature difference in the wellbore, and is difficult to be actually applied downhole. As for the patent "Downhole temperature difference power generation system based on vortex tube and its power generation method and design implementation method" (publication number: CN113153222A), the vortex tube used is relatively long. During the downhole mining process, sand, scale, and oil sludge can easily cause the vortex tube to be blocked, losing the power generation effect, and finally need to be removed and replaced.

[0005] In addition, in the later stages of oil and gas well production when throttling is no longer necessary or a throttle failure occurs, salvage is necessary to avoid affecting normal production. The current success rate of wireline salvage is only 60-70%. If salvage fails or is impossible, the throttle will need to be handled by pulling out the tubing, which is very expensive. In addition, the existing salvage-free throttles cannot accurately control the duration of the unsealing, which often leads to premature loss of the throttling effect and the need to re-deploy a new throttle, making it difficult to meet the needs of full life cycle mining. Moreover, the throttle salvage is complex and prone to failure, resulting in a long processing cycle, which will cause the loss of hundreds of millions of cubic meters of natural gas production and easily cause the gas well to be flooded, reducing the life of the gas well. Summary of the Invention

[0006] The purpose of the present invention is to solve the problems of complex power transmission structure and high cost of underground throttling devices, thereby avoiding the need to salvage and replace the throttle.

[0007] A first aspect of the present invention provides an underground throttling device for full life cycle mining, wherein the underground throttling device includes a temperature difference power generation mechanism for generating electricity and a throttling mechanism for throttling the fluid entering the temperature difference power generation mechanism, the throttling mechanism includes at least one throttling unit, and the temperature difference power generation mechanism can generate electrical energy to supply the underground throttling device through the temperature difference between the low-temperature fluid after throttling expansion and the surrounding environment.

[0008] Optionally, the downhole throttling device includes a control mechanism electrically connected to the temperature difference power generation mechanism, and the control mechanism is capable of adjusting the flow area of ​​the throttling unit.

[0009] Optionally, the throttling unit includes an air nozzle and a conical valve core arranged at the inlet of the temperature difference power generation mechanism, the valve core is coaxially arranged with the air nozzle, and the control mechanism can drive the valve core to move axially relative to the air nozzle to adjust the flow area of ​​the air nozzle.

[0010] Optionally, the control mechanism includes a motor and a controller electrically connected to the temperature difference power generation mechanism, the motor is connected to the valve core through a screw mechanism, and the controller can control the operation of the motor to adjust the flow area of ​​the throttling unit.

[0011] Optionally, it also includes a cathodic protection mechanism, the throttling mechanism includes an anode mechanism arranged corresponding to the throttling unit, the negative pole of the thermoelectric power generation mechanism is connected to the throttling unit through the anode mechanism, and the positive pole is connected to the cathodic protection mechanism; the anode mechanism can corrode and fuse when the current I passing through the anode mechanism is less than the protection current I0 of the anode mechanism.

[0012] In order to achieve the above-mentioned objectives, the second aspect of the present invention provides an underground throttling device for full life cycle mining, wherein the underground throttling device includes a thermoelectric power generation mechanism for generating electricity, a cathode protection mechanism, and a throttling mechanism for throttling the fluid entering the thermoelectric power generation mechanism, the throttling mechanism includes at least one throttling unit and an anode mechanism arranged corresponding to the throttling unit, the negative pole of the thermoelectric power generation mechanism is connected to the throttling unit through the anode mechanism, and the positive pole is connected to the cathode protection mechanism; the anode mechanism can corrode and fuse when the current I passing through the anode mechanism is less than the protection current I0 of the anode mechanism.

[0013] Optionally, the throttling unit includes a convex throttling seat with a hollow interior, the convex throttling seat is connected to the temperature difference power generation mechanism through the anode mechanism, and the inner cavity of the convex throttling seat is provided with a gas nozzle.

[0014] Optionally, the outer diameter of the gas nozzle is larger than the inner diameter of the convex throttle seat outlet.

[0015] Optionally, the inner cavity of the convex throttle seat is further provided with a hollow fastening stud, and the fluid is suitable for entering the air nozzle from the hollow fastening stud.

[0016] Further optionally, the inner diameter of the hollow fastening stud is larger than the inner diameter of the air nozzle.

[0017] Optionally, the throttling unit further includes a sealing structure, which includes a sealing ring arranged between the convex throttling seat and the temperature difference power generation mechanism and a sealing gasket arranged between the air nozzle and the convex throttling seat.

[0018] Optionally, the throttling unit further includes a prestressed mechanism arranged on the shoulder of the convex throttling seat.

[0019] Further optionally, there are multiple throttling units, and the multiple throttling units are connected in series. Along the flow direction of the fluid, the inner diameter of the gas nozzle at the front end is smaller than the inner diameter of the gas nozzle at the rear end.

[0020] Further optionally, when the material of the anode mechanism is the same, along the flow direction of the fluid, the volume of the anode mechanism located at the front end is smaller than the volume of the anode mechanism located at the rear end; or, when the volume of the anode mechanism is the same, along the flow direction of the fluid, the standard electrode potential of the anode mechanism located at the front end is smaller than the standard electrode potential of the anode mechanism located at the rear end; or, a control circuit is provided on the thermoelectric power generation mechanism, and the control circuit can adjust the current I passing through the anode mechanism.

[0021] Specifically, the temperature difference power generation mechanism is also provided with a rechargeable battery.

[0022] Optionally, an anode material layer is provided outside the anode mechanism, and the standard electrode potential of the anode material layer is greater than the standard electrode potential of the anode mechanism.

[0023] Optionally, the thermoelectric power generation mechanism includes a heat-conducting layer and a thermoelectric power generation layer arranged outside the heat-conducting layer, and the thermoelectric power generation layer contains a semiconductor material.

[0024] Further optionally, the thermoelectric power generation mechanism further includes a protective layer arranged outside the thermoelectric power generation layer.

[0025] Optionally, a sand prevention mechanism is provided in the fluid inflow direction of the throttling mechanism.

[0026] Optionally, the cathodic protection mechanism is a molded part made of high-silicon cast iron material.

[0027] Optionally, the downhole throttling device further comprises a rubber sleeve sealing mechanism, a slip anchoring mechanism and a fishing head which are sequentially connected to the temperature difference power generation mechanism, and the rubber sleeve sealing mechanism, the slip anchoring mechanism, the fishing head and the temperature difference power generation mechanism are in communication.

[0028] Optionally, the slip anchoring mechanism includes a slip, an upper slip seat and a lower slip seat, one end of the slip is connected to the upper slip seat, and the other end is connected to the lower slip seat.

[0029] The third aspect of the present invention provides a power supply method for an underground throttling device for full life cycle mining, and the power supply method for the underground throttling device includes the following steps: the underground fluid is expanded after being depressurized by the throttling mechanism and enters the temperature difference power generation mechanism, and the temperature difference power generation mechanism can use the temperature difference between the low-temperature fluid after throttling expansion and the surrounding environment to generate electricity, thereby powering the underground throttling device.

[0030] Furthermore, the downhole throttling device includes a throttling mechanism and a cathodic protection mechanism for throttling the fluid entering the thermoelectric power generation mechanism, the throttling mechanism includes at least one throttling unit and an anode mechanism corresponding to the throttling unit. The power supply method further includes the following steps:

[0031] When the current I passing through the anode mechanism is greater than or equal to the protection current I0 of the anode mechanism, the anode mechanism does not corrode, and the fluid continues to enter the thermoelectric power generation mechanism through the throttling mechanism; when the current I passing through the anode mechanism is less than the protection current I0 of the anode mechanism, the anode mechanism corrodes and melts, and finally the fluid directly enters the thermoelectric power generation mechanism.

[0032] Further optionally, the throttling mechanism includes a plurality of throttling units and the anode mechanism corresponding to each of the throttling units, and the plurality of throttling units are connected in series; wherein, when the materials of the anode mechanisms are the same, along the flow direction of the fluid, the volume of the anode mechanism at the front end is larger than the volume of the anode mechanism at the rear end; or, when the volumes of the anode mechanisms are the same, along the flow direction of the fluid, the standard electrode potential of the anode mechanism at the front end is smaller than the standard electrode potential of the anode mechanism at the rear end; or, a control circuit is provided on the thermoelectric power generation mechanism, and the control circuit can adjust the magnitude of the current I passing through the anode mechanism; the flow The fluid enters the thermoelectric power generation mechanism through multiple throttling units to enable the thermoelectric power generation mechanism to generate electricity. When the current I passing through the first anode mechanism is greater than or equal to the protection current I0 of the anode mechanism, the anode mechanism does not corrode, and the fluid continues to enter the thermoelectric power generation mechanism through multiple throttling units; when the current I of the first anode mechanism is less than the protection current I0 of the anode mechanism, the anode mechanism corrodes and melts, and the fluid enters the thermoelectric power generation mechanism through the remaining throttling units; when the current I passing through the second anode mechanism is less than the protection current I0 of the anode mechanism, the anode mechanism corrodes and melts, until multiple anode mechanisms are corroded and melted.

[0033] Optionally, when the downhole throttling device needs to lose its throttling effect prematurely or the throttling mechanism is blocked by scaling and cannot work normally, after the agent is pumped into the downhole throttling device, the gas well is closed, and after the agent reacts and dissolves with the anode mechanism or scale, the gas well is opened to release the gas and then produce.

[0034] A fourth aspect of the present invention provides a method for controlling a downhole throttling device for full life cycle mining, the method comprising the following steps:

[0035] The fluid in the mining well enters the thermoelectric power generation mechanism through the throttling mechanism to enable the thermoelectric power generation mechanism to generate electricity. When the current I passing through the anode mechanism is greater than or equal to the protection current I0 of the anode mechanism, the anode mechanism does not corrode, and the fluid continues to enter the thermoelectric power generation mechanism through the throttling mechanism; when the current I passing through the anode mechanism is less than the protection current I0 of the anode mechanism, the anode mechanism corrodes and melts, and finally the fluid directly enters the thermoelectric power generation mechanism.

[0036] Further optionally, the throttling mechanism includes a plurality of throttling units and the anode mechanism corresponding to each throttling unit, and the plurality of throttling units are connected in series; wherein,

[0037] When the materials of the anode mechanisms are the same, along the flow direction of the fluid, the volume of the anode mechanism at the front end is larger than the volume of the anode mechanism at the rear end;

[0038] Alternatively, when the volumes of the anode mechanisms are the same, along the flow direction of the fluid, the standard electrode potential of the anode mechanism located at the front end is smaller than the standard electrode potential of the anode mechanism located at the rear end;

[0039] Alternatively, the thermoelectric power generation mechanism is provided with a control circuit, and the control circuit is capable of adjusting the magnitude of the current I passing through the anode mechanism;

[0040] The fluid enters the thermoelectric power generation mechanism through multiple throttling units to enable the thermoelectric power generation mechanism to generate electricity. When the current I passing through the first anode mechanism is greater than or equal to the protection current I0 of the anode mechanism, the anode mechanism is not corroded, and the fluid continues to enter the thermoelectric power generation mechanism through multiple throttling units; when the current I of the first anode mechanism is less than the protection current I0 of the anode mechanism, the anode mechanism corrodes and melts, and the fluid enters the thermoelectric power generation mechanism through the remaining throttling units; when the current I passing through the second anode mechanism is less than the protection current I0 of the anode mechanism, the anode mechanism corrodes and melts, until multiple anode mechanisms are corroded and melted.

[0041] Optionally, when the downhole throttling device needs to lose its throttling effect prematurely or the throttling mechanism is blocked by scaling and cannot work normally, after the agent is pumped into the downhole throttling device, the gas well is closed, and after the agent reacts and dissolves with the anode mechanism or scale, the gas well is opened to release the gas and then produce.

[0042] Through the above technical solution, the beneficial effects of the present invention are:

[0043] The downhole throttling device provided by the present invention includes a thermoelectric power generation mechanism, a throttling mechanism, etc. The thermoelectric power generation mechanism generates electricity by generating electricity through the temperature difference between the heat absorbed by the fluid throttling and the geothermal heat. The temperature difference is reliable, directly utilizing the fluid throttling expansion effect and geothermal energy, and easily controlling the power generation effect according to the throttling production output of the mining well. For example, through the synergistic effect of the thermoelectric power generation mechanism and the cathode protection mechanism, the negative potential of the anode mechanism is increased, thereby protecting the anode mechanism from corrosion. Moreover, as the production capacity of the mining well decreases, the temperature difference between the throttling mechanism and the mining well decreases or disappears. When the power provided by the thermoelectric power generation mechanism is insufficient to protect the anode mechanism, the anode mechanism corrodes and melts, causing the throttling unit to fall, thereby opening a larger production channel for the next production step, avoiding the need to salvage and replace the downhole throttling device, and being able to achieve automatic control without the need for human intervention, meeting the full life cycle of the mining well. The downhole throttling device has a simple structure, a flexible installation method, no need for human intervention, and low cost.

[0044] In an optional embodiment, the downhole throttling device provided by the present invention is provided with a plurality of throttling units connected in series, and along the flow direction of the fluid, the inner diameter of the gas nozzle located at the front end that contacts the fluid first is smaller than the inner diameter of the gas nozzle located at the rear end. As the production capacity of the gas well decreases, the gas nozzle with a smaller inner diameter falls off first, and the gas nozzle with a larger inner diameter falls off later, which can meet the gas production needs of the gas well throughout its life cycle, not only avoiding the salvage and replacement of the throttling device, but also avoiding the treatment method of lifting the tubing string and repairing the well, thereby realizing a downhole throttling device that meets the lifelong application of the gas well without affecting the later plunger gas lift drainage and gas production of the gas well.

[0045] Other advantages of the present invention and the technical effects of the preferred embodiments will be further described in the following specific embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] The accompanying drawings, which constitute part of the present invention, are intended to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are intended to explain the present invention and do not constitute an undue limitation of the present invention. In the accompanying drawings:

[0047] FIG1 is a schematic structural diagram of a specific embodiment of a downhole throttling device according to the present invention;

[0048] FIG2 is a cross-sectional view of the downhole throttling device shown in FIG1 of the present invention;

[0049] FIG3 is a schematic structural diagram of a second specific embodiment of a downhole throttling device according to the present invention;

[0050] FIG4 is a schematic structural diagram of a third specific embodiment of the downhole throttling device of the present invention.

[0051] FIG5 is a schematic structural diagram of a specific embodiment of the anode mechanism of the downhole throttling device of the present invention.

[0052] FIG6 is a partial structural diagram of the downhole throttling device of the present invention.

[0053] FIG7 is a cross-sectional view taken along line AA in FIG6.

[0054] Explanation of the accompanying symbols: 1-thermoelectric power generation mechanism, 10-controller, 11-output shaft, 12-motor, 2-cathodic protection mechanism, 3-throttling unit, 31-convex throttling seat, 32-gas nozzle, 33-hollow fastening stud, 34-sealing ring, 35-sealing gasket, 36-prestressed mechanism, 37-valve core, 4-anode mechanism, 5-sand control mechanism, 6-rubber cylinder sealing mechanism, 7-slip anchoring mechanism, 71-slip, 72-upper slip seat, 73-lower slip seat, 8-fishing head, 9-spacer ring, A-production channel, B-input channel. DETAILED DESCRIPTION

[0055] The following describes the specific embodiments of the present invention in detail with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present invention and are not intended to limit the present invention.

[0056] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "connection" and "connected" should be understood in a broad sense. For example, they may refer to fixed connection, detachable connection, or integral connection; they may refer to direct connection, indirect connection via an intermediate medium, abutment, internal communication between two elements, or interaction between two elements. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0057] It should be understood that the terms "upper," "lower," "front," "back," "inner," and "outer," etc., indicating directions or positional relationships, are based on the directions or positional relationships shown in the accompanying drawings and are intended solely to facilitate and simplify the description of the present invention. They are not intended to indicate or imply that the devices or elements referred to must have a specific orientation, be constructed, or operate in a specific orientation. Therefore, they should not be construed as limitations on the present invention. Furthermore, the terms "first" and "second" are used solely for descriptive purposes and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features indicated. Therefore, features designated "first" or "second" may explicitly or implicitly include one or more of the aforementioned features.

[0058] Referring to Figures 1 to 7, the present solution provides an underground throttling device for full life cycle mining, wherein the underground throttling device includes a temperature difference power generation mechanism 1 for generating electricity and a throttling mechanism for throttling the fluid entering the temperature difference power generation mechanism 1, the throttling mechanism includes at least one throttling unit 3, and the temperature difference power generation mechanism 1 can generate electrical energy through the temperature difference between the low-temperature fluid after throttling expansion and the surrounding environment to supply the underground throttling device.

[0059] The downhole throttling device can throttle and reduce the pressure of downhole oil and gas, which causes the temperature of the oil and gas to rise. The at least one throttling unit 3 of the throttling mechanism can throttle the oil and gas, causing it to expand and cool, forming a lower-temperature fluid. This fluid forms a temperature difference with the surrounding environment. The thermoelectric power generation mechanism 1 can generate electrical energy from the temperature difference between the throttled fluid and the surrounding environment. This electrical energy can be used to power the downhole throttling device, thus eliminating the need for surface equipment to power it, simplifying the structure, reducing costs, and reducing failure rates.

[0060] It should be noted that the reason why the downhole fluid becomes a low-temperature fluid after throttling expansion is that the volume of the fluid expands after throttling and needs to absorb heat to reduce its own temperature; the surrounding environment refers to the downhole geothermal environment.

[0061] In some embodiments, the downhole throttling device includes a control mechanism electrically connected to the temperature difference power generation mechanism 1, and the control mechanism is capable of adjusting the flow area of ​​the throttling unit 3. The control mechanism can be driven by electrical energy and can adjust the flow area of ​​the throttling unit 3 to adjust the pressure of the fluid after passing through the throttling unit 3, ensuring that the transported oil and gas is within an appropriate pressure range.

[0062] In some embodiments, the throttling unit 3 includes a gas nozzle 32 and a tapered valve core 37 disposed at the inlet of the thermoelectric power generation mechanism 1. The valve core 37 is coaxially disposed with the gas nozzle 32, and the control mechanism is capable of driving the valve core 37 to move axially relative to the gas nozzle 32 to adjust the flow area of ​​the gas nozzle 32. As shown in FIG6 , the gas nozzle 32 allows oil and gas to pass through. The valve core 37 is capable of moving axially relative to the gas nozzle 32 under the control of the control mechanism, and the valve core 37 is insertable into the gas nozzle 32. One end of the valve core 37, which can be inserted into the gas nozzle 32, is tapered. Depending on the length of the valve core 37 inserted into the gas nozzle 32, the flow area of ​​the annular space formed between the valve core 37 and the gas nozzle 32 also varies. That is, by adjusting the relative position of the valve core 37 and the gas nozzle 32, the actual flow area at the gas nozzle 32 can be adjusted.

[0063] In some embodiments, the control mechanism includes a motor 12 and a controller 10 electrically connected to the thermoelectric power generation mechanism 1. The motor 12 is connected to the valve core 37 via a screw mechanism. The controller 10 is capable of controlling the operation of the motor 12 to adjust the flow area of ​​the throttling unit 3. The thermoelectric power generation mechanism 1 can provide power to the controller 10 and the motor 12. The controller 10 controls the operation of the motor 12, such as controlling its speed and direction of rotation. The motor 12 is connected to an output shaft 11, which is provided with an external thread. The valve core 37 is provided with an internal threaded hole. The output shaft 11 is threadedly connected to the valve core 37. The valve core 37 can only move axially and not rotate under the restraint of the control mechanism housing. Therefore, when the output shaft 11 rotates, the valve core 37 can move axially. In other words, the output shaft 11 and the valve core 37 form a screw mechanism, which can convert the torque output by the motor 12 into linear movement of the valve core 37, thereby adjusting the flow area at the air nozzle 32.

[0064] Among them, in some embodiments, the downhole throttling device also includes a cathodic protection mechanism 2, the throttling mechanism includes an anode mechanism 4 arranged corresponding to the throttling unit 3, the negative pole of the thermoelectric power generation mechanism 1 is connected to the throttling unit 3 through the anode mechanism 4, and the positive pole is connected to the cathodic protection mechanism 2; the anode mechanism 4 can corrode and fuse when the current I passing through the anode mechanism 4 is less than the protection current I0 of the anode mechanism 4.

[0065] On the other hand, in one embodiment of the present invention, referring to FIG1 , an underground throttling device for full life cycle mining includes a thermoelectric power generation mechanism 1 for generating electricity, a cathode protection mechanism 2, and a throttling mechanism for throttling the fluid entering the thermoelectric power generation mechanism 1. The throttling mechanism includes at least one throttling unit 3 and an anode mechanism 4 corresponding to the throttling unit 3. The negative pole of the thermoelectric power generation mechanism 1 is connected to the throttling unit 3 through the anode mechanism 4, and the positive pole is connected to the cathode protection mechanism 2. The anode mechanism 4 can corrode and fuse when the current I passing through the anode mechanism 4 is less than the protection current I0 of the anode mechanism 4.

[0066] In the present invention, the downhole throttling device can be applied to oil, gas, and water production in various production wells (oil wells, gas wells, water wells, and oil and gas wells), such as vertical wells, directional wells, and horizontal wells. A throttling channel for fluid passage is formed within the throttling mechanism, the inlet of the throttling mechanism is connected to the input channel B, and the outlet is connected to the production channel A. The inner diameter of the throttling channel is smaller than the inner diameter of the production channel A, and the inner diameter of the throttling channel is also smaller than the inner diameter of the input channel B. The thermoelectric power generation mechanism 1 is a hollow structure, and the inner cavity forms part of the production channel A. The throttling mechanism can include one throttling unit 3, or it can include multiple throttling units 3, each throttling unit 3 is connected to the inner wall of the thermoelectric power generation mechanism 1 via a corresponding anode mechanism 4. The cathode protection mechanism 2 is a hollow structure, and the specific location of the cathode protection mechanism 2 is not limited. The inner cavity of the cathode protection mechanism 2 can be part of the input channel B (i.e., the cathode protection mechanism 2 is located below the throttling mechanism) or part of the production channel A (i.e., the cathode protection mechanism 2 is located above the throttling mechanism).

[0067] By using the downhole throttling device of the basic embodiment of the present invention, the downhole throttling device is placed at a predetermined depth of the wellbore of the mining well for production. The fluid in the downhole reservoir enters the throttling mechanism through the wellbore of the mining well, is throttled, and expands to absorb heat, so that a temperature difference is formed between the throttling mechanism and the geothermal heat of the mining well. The thermoelectric power generation mechanism 1 uses the temperature difference to generate electricity to obtain electrical energy. The negative electrode of the thermoelectric power generation mechanism 1 is connected to the throttling unit 3 through the anode mechanism 4, and the positive electrode is connected to the cathode protection mechanism 2 to form a circuit. Then, the thermoelectric power generation mechanism 1 generates a continuous current I, so that the potential of the anode mechanism 4 is higher than the negative potential of the cathode protection mechanism 2, which can ensure that the anode mechanism 4 is not Corrosion, at this time the current I flowing through the anode mechanism 4 is greater than or equal to the protection current I0 of the anode mechanism 4; as the production capacity of the mining well decreases, the temperature difference between the throttling mechanism and the geothermal energy of the mining well decreases, and the current I generated by the thermoelectric power generation mechanism 1 decreases until it is less than the protection current I0 of the anode mechanism 4. The potential of the cathodic protection mechanism 2 increases, and the potential of the anode mechanism 4 is the lowest and begins to corrode, and then the anode mechanism 4 melts, causing the throttling unit 3 to fall down, automatically opening the production channel A, avoiding the need to salvage and replace the underground throttling device, and can realize automatic control without human intervention, meeting the full life cycle gas production of the mining well.

[0068] It should be noted that, in the present invention, the protection current I0 of the anode mechanism 4 refers to the minimum current value required to prevent corrosion of the anode mechanism 4 when current flows through the anode mechanism 4. When the current I flowing through the anode mechanism 4 is greater than or equal to the protection current I0, the anode mechanism 4 will not corrode. When the current I flowing through the anode mechanism 4 is less than the protection current I0, the anode mechanism 4 will corrode and fuse, and the throttling unit 3 will fall.

[0069] In the present invention, the protective current I0 of different anode mechanisms 4 is different, and the magnitude of the protective current I0 of the anode mechanism 4 is related to the material, structure, and size of the anode mechanism 4. The standard electrode potential of the anode mechanism 4 is less than the standard electrode potential of the material of the downhole throttling device body (the material of the downhole throttling device body contains steel and / or iron). Exemplarily, the material of the anode mechanism 4 can be lithium, magnesium, sodium, aluminum, zinc, manganese, indium, or chromium, and can also be an alloy of at least two of the aforementioned metals. There is no limitation on the shape and structure of the anode mechanism 4. As a specific embodiment of the anode mechanism 4, the anode mechanism 4 can be a shear nail.

[0070] In the present invention, as a preferred embodiment of the throttling unit 3, referring to Figure 2, the throttling unit 3 includes a convex throttling seat 31 with a hollow interior. The convex throttling seat 31 is connected to the temperature difference power generation mechanism 1 through the anode mechanism 4. The inner cavity of the convex throttling seat 31 is provided with an air nozzle 32 so that the fluid entering the throttling unit 3 can be throttled through the air nozzle 32.

[0071] In the present invention, the convex throttle seat 31 is a rotating body with a convex cross-section. It includes a large-diameter throttle seat section and a small-diameter throttle seat section. As a specific embodiment of connecting the convex throttle seat 31 to the thermoelectric generator 1, the inner cavity connecting the thermoelectric generator 1 and the convex throttle seat 31 is configured as a convex inner cavity that fits into the convex throttle seat 31, thereby improving the stability and robustness of the throttle mechanism.

[0072] In the present invention, as another preferred embodiment of the air nozzle 32, referring to FIG2, the outer diameter of the air nozzle 32 is larger than the inner diameter of the outlet of the convex throttle seat 31, which can prevent the air nozzle 32 from moving along the flow direction of the fluid under the action of the fluid, thereby preventing the air nozzle 32 from falling off from the convex throttle seat 31 and entering the inner cavity of the thermoelectric power generation mechanism 1, avoiding the premature failure of the throttling mechanism causing loss of production, and improving the firmness and service life of the air nozzle 32.

[0073] It should be noted that, in the present invention, the inner diameter refers to the inner diameter, and the outer diameter refers to the outer diameter.

[0074] In the present invention, in order to further improve the firmness of the air nozzle 32 , preferably, as shown in FIG. 2 , the inner cavity of the convex throttle seat 31 is further provided with a hollow fastening stud 33 , and the fluid is suitable for entering the air nozzle 32 from the hollow fastening stud 33 .

[0075] In the present invention, the inner diameter of the hollow fastening stud 33 can be the same as or different from the inner diameter of the gas nozzle 32. Preferably, the inner diameter of the hollow fastening stud 33 is larger than the inner diameter of the gas nozzle 32 to improve the throttling effect of the gas nozzle 32.

[0076] In the present invention, in order to further improve the sealing performance and throttling effect of the throttling unit 3, preferably, as shown in FIG2 , the throttling unit 3 further includes a sealing structure, which includes a sealing ring 34 disposed between the convex throttling seat 31 and the thermoelectric power generation mechanism 1, and a sealing gasket 35 disposed between the air nozzle 32 and the convex throttling seat 31. There is no particular limitation on the specific position of the sealing ring 34. The sealing ring 34 can be disposed at the small-diameter section of the throttling seat or at the large-diameter section of the throttling seat, as long as the sealing performance between the convex throttling seat 31 and the thermoelectric power generation mechanism 1 is improved; the sealing gasket 35 can be disposed between the outlet of the air nozzle 32 and the outlet of the convex throttling seat 31.

[0077] In the present invention, as another preferred embodiment of the throttling unit 3, as shown in FIG2 , the throttling unit 3 further includes a prestressing mechanism 36 disposed on the shoulder of the convex throttling seat 31. When the anode mechanism 4 melts, the prestressing mechanism 36 can push the convex throttling seat 31 downward, causing it to fall. This prevents the anode mechanism 4 from melting but preventing the convex throttling seat 31 from falling due to the influence of fluid or scale. The prestressing mechanism 36 can be any conventional choice in the art, such as a spring.

[0078] It should be noted that, referring to FIG2 , the shoulder of the convex throttle seat 31 refers to the position of the upper end of the large-diameter section of the throttle seat excluding the small-diameter section of the throttle seat in the horizontal direction.

[0079] In the present invention, as a preferred embodiment of the throttling mechanism, multiple throttling units 3 are connected in series. Along the fluid flow direction, the inner diameter of the front nozzle 32 is smaller than the inner diameter of the rear nozzle 32. It should be noted that the front nozzle 32 is the nozzle 32 that first contacts the fluid, while the rear nozzle 32 is the nozzle 32 that contacts the fluid later. When the fluid enters the throttling mechanism, it enters the thermoelectric power generation mechanism 1 through the front nozzle 32 with a smaller inner diameter and the rear nozzle 32 with a larger inner diameter. As the production capacity of the mining well continues to decrease, the anode mechanism 4 corresponding to the gas nozzle 32 with a small inner diameter is preferably melted, causing the convex throttling seat 31 connected to it to fall downward; as the production capacity of the mining well continues to decrease, the throttling unit 3 will repeat the above-mentioned falling of the convex throttling seat 31 according to the change in the production capacity of the mining well, and the inner diameter of the throttling channel in the throttling mechanism will continue to increase until all the throttling units 3 fall, so that the input channel B and the production channel A are directly connected, which can meet the gas production needs of the mining well throughout its life cycle, not only avoiding the salvage and replacement of the throttling device, but also avoiding the treatment method of lifting the tubing string to repair the well, so that a throttling device can meet the lifelong application of the mining well without affecting the plunger gas lift drainage and gas production in the later stage of the mining well.

[0080] In the present invention, when multiple throttling units 3 are connected in series, they can be directly connected in series along the flow direction of the fluid, or the convex throttling seat 31 where the air nozzle 32 with a small inner diameter is located can be nested on the convex throttling seat 31 where the air nozzle 32 with a large inner diameter is located.

[0081] In the present invention, when there are multiple throttling units 3, the fluid entering the multiple throttling units 3 is throttled and expands to absorb heat, so that a temperature difference is formed between the throttling mechanism and the geothermal energy of the mining well. The thermoelectric power generation mechanism 1 uses this temperature difference to generate electricity to obtain electrical energy. The negative pole of the thermoelectric power generation mechanism 1 is connected to the corresponding throttling unit 3 through multiple anode mechanisms 4, and the positive pole is connected to the cathode protection mechanism 2 to form a circuit. That is, in the formed circuit, multiple anode mechanisms 4 are connected in parallel, and the protection current I0 of different anode mechanisms 4 is different.

[0082] In order to achieve the effect of automatically replacing the gas nozzle 32 with a large inner diameter according to the change in the production capacity of the mining well, preferably, when the material of the anode mechanism 4 is the same, along the flow direction of the fluid, the volume of the anode mechanism 4 located at the front end is smaller than the volume of the anode mechanism 4 located at the rear end; or, when the volume of the anode mechanism 4 is the same, along the flow direction of the fluid, the standard electrode potential of the anode mechanism 4 located at the front end is smaller than the standard electrode potential of the anode mechanism 4 located at the rear end; or, a control circuit is provided on the thermoelectric power generation mechanism 1, and the control circuit can adjust the current I passing through the anode mechanism 4.

[0083] In the present invention, as a specific embodiment of the throttling mechanism, the number of throttling units 3 is 2, and the two throttling units 3 are connected in series. When the current I passing through the first anode mechanism 4 is greater than or equal to its protection current I0, and the current I passing through the second anode mechanism 4 is greater than or equal to its protection current I0, the first anode mechanism 4 and the second anode mechanism 4 are not corroded. After the fluid enters the throttling mechanism, it continues to pass through the throttling unit 3 corresponding to the first anode mechanism 4 and the throttling unit 3 corresponding to the second anode mechanism 4 in sequence to enter the thermoelectric power generation mechanism 1; when the current I passing through the first anode mechanism 4 is less than the protection current of the anode mechanism 4 I0, and when the current I passing through the second anode mechanism 4 is greater than or equal to its protection current I0, the first anode mechanism 4 corrodes and melts, and the convex throttling seat 31 where it is located falls downward, and the second anode mechanism 4 is not corroded, and the fluid enters the thermoelectric power generation mechanism 1 through the throttling unit 3 corresponding to the second anode mechanism 4; as the production capacity of the mining well continues to decrease, the current I passing through the second anode mechanism 4 decreases until it is less than the protection current I0 of the anode mechanism 4, the second anode mechanism 4 corrodes and melts, and the convex throttling seat 31 where it is located falls downward, that is, the production channel A is opened, and the fluid enters the production channel A directly from the input channel B.

[0084] It should be noted that, along the flow direction of the fluid, the first anode mechanism 4 that contacts the fluid is the first anode mechanism 4, and its corresponding gas nozzle 32 in the throttling unit 3 is the first gas nozzle 32; the second anode mechanism 4 that contacts the fluid is the second anode mechanism 4, and its corresponding gas nozzle 32 in the throttling unit 3 is the second gas nozzle 32, and so on.

[0085] In the present invention, as a preferred embodiment of the thermoelectric power generation mechanism 1, the thermoelectric power generation mechanism 1 is further provided with a rechargeable battery. When the thermoelectric power generation mechanism 1 is provided with a rechargeable battery, the current I passing through the anode mechanism 4 can be controlled by the control circuit. When the production well needs to be shut down for maintenance, the power of the rechargeable battery can be used to protect the anode mechanism 4 from corrosion. When the production well is operating normally, the rechargeable battery can be properly charged.

[0086] In the present invention, in order to prevent the anode mechanism 4 from prematurely fusing in the early stages of mining, as a preferred embodiment of the anode mechanism 4, an anode material layer is provided on the outside of the anode mechanism 4. The standard electrode potential of the anode material layer is greater than the standard electrode potential of the anode mechanism 4, effectively increasing the corrosion fusing time of the anode mechanism. Exemplarily, the material of the anode material layer can be lithium, magnesium, sodium, aluminum, zinc, manganese, indium, or chromium, and can also be an alloy of at least two of the aforementioned metals. There is no limitation on the method of providing the anode material layer on the anode mechanism 4. For example, the anode material layer can be provided on the outer layer of the anode mechanism 4 by electroplating.

[0087] In the present invention, there is no limitation on the overall structure of the anode mechanism 4 and the anode material layer. As a preferred embodiment of the overall structure of the anode mechanism 4 and the anode material layer, referring to FIG5 , the overall structure of the anode mechanism 4 and the anode material layer is a semicircular ring of a semicircular ring structure, and the sector angle of the semicircular ring is ≤180°.

[0088] In the present invention, the thermoelectric power generation mechanism 1 utilizes semiconductor materials to achieve semiconductor power generation. As a preferred embodiment of the thermoelectric power generation mechanism 1, the thermoelectric power generation mechanism 1 includes a heat-conducting layer and a thermoelectric power generation layer disposed outside the heat-conducting layer. The thermoelectric power generation layer contains a semiconductor material. The semiconductor material can be a conventional semiconductor selected in the art, such as silicon, germanium, and gallium. The heat-conducting layer can be made of steel to meet the strength requirements for downhole throttling gas production and the thermal conductivity requirements of the thermoelectric power generation mechanism 1, further improving the power generation efficiency of the thermoelectric power generation mechanism 1.

[0089] In the present invention, as a specific embodiment of the thermoelectric power generation mechanism 1, the thermoelectric power generation mechanism 1 also includes a protective layer arranged on the outside of the thermoelectric power generation layer. The protective layer can be made of a material with high strength and good thermal conductivity, which can avoid damaging the thermoelectric power generation layer, ensure the thermal conductivity of the thermoelectric power generation mechanism 1, and further improve the power generation efficiency of the thermoelectric power generation mechanism 1.

[0090] In the present invention, as a preferred embodiment of connecting the heat-conducting layer, the thermoelectric power generation layer, and the protective layer, the heat-conducting layer, the thermoelectric power generation layer, and the protective layer are connected by nesting and fixing, thereby improving the sealing and power generation efficiency of the thermoelectric power generation mechanism 1. The nesting and fixing can adopt a nesting and fixing method conventionally selected in the art, for example, adhesive fixing with high-strength, heat-resistant, thermally conductive glue, thread fixing, or soldering fixing.

[0091] In another preferred embodiment of the thermoelectric power generation mechanism 1 of the present invention, the thermoelectric power generation mechanism 1 is connected to a rechargeable battery and a thermoelectric power generation controller. During well maintenance and shut-in, the rechargeable battery and the thermoelectric power generation controller ensure that a continuous current I flows through the anode mechanism 4, and that the current I is greater than or equal to the protection current I0, thereby protecting the anode mechanism 4 from corrosion.

[0092] In the present invention, sand may be produced during the mining process of the mining well, which may easily clog the throttling mechanism, thereby affecting the throttling effect and service life of the downhole throttling device. In order to further improve the throttling effect and service life of the throttling device, preferably, as shown in Figures 1 to 3, a sand prevention mechanism 5 is provided in the fluid inflow direction of the throttling mechanism.

[0093] In the present invention, as a preferred embodiment of the cathodic protection mechanism 2, the cathodic protection mechanism 2 is a molded part made of high-silicon cast iron material.

[0094] In the present invention, to improve the applicability of the downhole throttling device, preferably, as shown in Figures 1 and 2 , the downhole throttling device further includes a rubber cartridge sealing mechanism 6, a slip anchoring mechanism 7, and a fishing head 8, which are sequentially connected to the thermoelectric generator 1. The rubber cartridge sealing mechanism 6, the slip anchoring mechanism 7, the fishing head 8, and the thermoelectric generator 1 are in communication. The fishing head 8 lowers the downhole throttling device to a predetermined depth in the wellbore of the production well, secures the downhole throttling device using the slip anchoring mechanism 7, and radially expands the rubber cartridge sealing mechanism 6 to form a seal with the wellbore, thereby improving the throttling effect of the downhole throttling device.

[0095] In the present invention, the position of the rubber cartridge sealing mechanism 6 is not particularly limited. Referring to Figures 1-4 , the rubber cartridge sealing mechanism 6 can be located above the throttling mechanism. There is also no particular limitation on the number of rubber cartridge sealing mechanisms 6 ; the number can be one or more. As a specific embodiment of the rubber cartridge sealing mechanism 6 , referring to Figure 4 , there are two rubber cartridge sealing mechanisms 6 , with a spacer ring 9 disposed between the two rubber cartridge sealing mechanisms 6 to further enhance the sealing effect of the rubber cartridge sealing mechanisms 6 .

[0096] In the present invention, the rubber cartridge sealing mechanism 6, the slip anchoring mechanism 7, and the fishing head 8 are all hollow structures, and the inner cavities of the rubber cartridge sealing mechanism 6, the slip anchoring mechanism 7, and the fishing head 8 are connected. The inner cavities of the rubber cartridge sealing mechanism 6, the slip anchoring mechanism 7, and the fishing head 8 can be part of the production channel A.

[0097] In the present invention, the cathodic protection mechanism 2 can be located between the rubber cartridge sealing mechanism 6 and the thermoelectric power generation mechanism 1. Alternatively, the cathodic protection mechanism 2 can be combined with the sand control mechanism 5 to avoid structural redundancy and reduce production costs. When adjusting the position of the cathodic protection mechanism 2, the size of the inner cavity of the cathodic protection mechanism 2 needs to be adjusted accordingly, so that the inner cavity of the cathodic protection mechanism 2 serves as part of the production channel A or the input channel B.

[0098] In the present invention, as a preferred embodiment of the cava anchoring mechanism 7, referring to Figure 1, the cava anchoring mechanism 7 includes a cava 71, an upper cava seat 72 and a lower cava seat 73. One end of the cava 71 is connected to the upper cava seat 72 and the other end is connected to the lower cava seat 73. The upper cava seat 72 and the lower cava seat 73 are provided to fix and protect the cava 71.

[0099] A third aspect of the present invention provides a method for controlling a downhole throttling device for full life cycle mining, the method comprising the following steps:

[0100] The fluid in the production well enters the thermoelectric power generation mechanism 1 through the throttling mechanism to enable the thermoelectric power generation mechanism 1 to generate electricity. When the current I passing through the anode mechanism 4 is greater than or equal to the protection current I0 of the anode mechanism 4, the anode mechanism 4 does not corrode, and the fluid continues to enter the thermoelectric power generation mechanism 1 through the throttling mechanism; when the current I passing through the anode mechanism 4 is less than the protection current I0 of the anode mechanism 4, the anode mechanism 4 corrodes and melts, and finally the fluid directly enters the thermoelectric power generation mechanism 1, so that the input channel B and the production channel A are directly connected, avoiding the need to salvage and replace the throttling device, and also avoiding the treatment method of lifting the pipe string to repair the well. In addition, it can realize automatic control without the need for human intervention, meeting the gas production requirements of the production well throughout its life cycle.

[0101] In the present invention, as a preferred embodiment of the control method of the downhole throttling device, the throttling mechanism includes a plurality of throttling units 3 and an anode mechanism 4 corresponding to each throttling unit 3, and the plurality of throttling units 3 are connected in series; wherein,

[0102] When the materials of the anode mechanism 4 are the same, along the flow direction of the fluid, the volume of the anode mechanism 4 at the front end is smaller than that of the anode mechanism 4 at the rear end; or, when the volumes of the anode mechanism 4 are the same, along the flow direction of the fluid, the standard electrode potential of the anode mechanism 4 at the front end is smaller than that of the anode mechanism 4 at the rear end; or, the thermoelectric power generation mechanism 1 is provided with a control circuit, and the control circuit is capable of adjusting the magnitude of the current I passing through the anode mechanism 4;

[0103] The fluid enters the thermoelectric power generation mechanism 1 through multiple throttling units 3 to enable the thermoelectric power generation mechanism 1 to generate electricity. When the current I passing through the first anode mechanism 4 is greater than or equal to the protection current I0 of the anode mechanism 4, the anode mechanism 4 does not corrode, and the fluid continues to enter the thermoelectric power generation mechanism 1 through the multiple throttling units 3; when the current I passing through the first anode mechanism 4 is less than the protection current I0 of the anode mechanism 4, the anode mechanism 4 corrodes and melts, and the fluid enters the thermoelectric power generation mechanism 1 through the remaining throttling units 3; when the current I passing through the second anode mechanism 4 is less than the protection current I0 of the anode mechanism 4, the anode mechanism 4 corrodes and melts, until all the anode mechanisms 4 corrode and melt, so that the input channel B and the production channel A are directly connected. This downhole throttling device can meet the gas production needs of the production well throughout its entire life cycle, not only avoiding the need to salvage and replace the downhole throttling device, but also avoiding the treatment method of lifting the tubing string for well repair, so that a downhole throttling device can meet the lifelong application of the production well without affecting the plunger gas lift drainage and gas production in the later stage of the production well.

[0104] In the present invention, as another preferred embodiment of the control method of the downhole throttling device, when the downhole throttling device is required to lose its throttling effect in advance or the throttling mechanism is blocked by scaling and cannot work normally, after the reagent is pumped into the downhole throttling device, the production well is closed, and after the reagent reacts and dissolves with the anode mechanism 4 or the scale, the production well is opened for blowout and then production is carried out to achieve a change in the inner diameter of the throttling path in the downhole throttling device, or all the throttling units 3 are dropped so that the production channel A and the input channel B can be directly connected.

[0105] In the present invention, there is no limitation on the type of reagent, and the reagent may be a descaling agent. Preferably, the reagent is an acidic reagent, which can both descaling and accelerate the corrosion of the anode mechanism 4, so that the throttling unit 3 can fall smoothly to open a throttling channel with a larger inner diameter, or all throttling units 3 can fall to directly connect the production channel A and the input channel B.

[0106] In the present invention, if the energy of the mining well itself is insufficient, after the reagent is pumped in, nitrogen or carbon dioxide can be pumped back into the wellbore through a compressor to replenish energy on the one hand, and on the other hand, ensure sufficient contact between the reagent and the downhole throttling device, thereby improving the descaling effect and further improving the throttling effect of the downhole throttling device.

[0107] The downhole throttling device provided by the aforementioned embodiment of the present invention has the function of dropping the throttling mechanism to directly connect the production channel A and the input channel B, without affecting the normal production of the production well and eliminating the need for salvaging and replacing the downhole throttling device. Furthermore, it can be automatically controlled without human intervention, meeting the full life cycle of gas production in the production well. This downhole throttling device has a simple structure, flexible installation methods, no human intervention, and low cost.

[0108] In addition, the fourth aspect of the present invention further provides a method for powering a downhole throttling device for full life cycle mining, wherein the method for powering a downhole throttling device comprises the following steps:

[0109] The downhole fluid expands after being depressurized by the throttling mechanism and enters the temperature difference power generation mechanism 1. The temperature difference power generation mechanism 1 can generate electricity by using the temperature difference between the low-temperature fluid after throttling and the surrounding environment, thereby supplying power to the downhole throttling device.

[0110] In addition, the downhole throttling device includes a throttling mechanism and a cathodic protection mechanism 2 for throttling the fluid entering the thermoelectric power generation mechanism 1. The throttling mechanism includes at least one throttling unit 3 and an anode mechanism 4 corresponding to the throttling unit 3. The power supply method further includes the following steps:

[0111] When the current I passing through the anode mechanism 4 is greater than or equal to the protection current I0 of the anode mechanism 4, the anode mechanism 4 does not corrode, and the fluid continues to enter the thermoelectric power generation mechanism 1 through the throttling mechanism; when the current I passing through the anode mechanism 4 is less than the protection current I0 of the anode mechanism 4, the anode mechanism 4 corrodes and melts, and finally the fluid directly enters the thermoelectric power generation mechanism 1.

[0112] In addition, the throttling mechanism includes a plurality of throttling units 3 and the anode mechanism 4 corresponding to each throttling unit 3, and the plurality of throttling units 3 are connected in series; wherein,

[0113] When the materials of the anode mechanism 4 are the same, along the flow direction of the fluid, the volume of the anode mechanism 4 at the front end is smaller than the volume of the anode mechanism 4 at the rear end;

[0114] Alternatively, when the volumes of the anode mechanisms 4 are the same, along the flow direction of the fluid, the standard electrode potential of the anode mechanism 4 at the front end is smaller than the standard electrode potential of the anode mechanism 4 at the rear end;

[0115] Alternatively, the thermoelectric power generation mechanism 1 is provided with a control circuit, and the control circuit is capable of adjusting the magnitude of the current I passing through the anode mechanism 4;

[0116] The fluid enters the thermoelectric power generation mechanism 1 through multiple throttling units 3 to enable the thermoelectric power generation mechanism 1 to generate electricity. When the current I passing through the first anode mechanism 4 is greater than or equal to the protection current I0 of the anode mechanism 4, the anode mechanism 4 is not corroded, and the fluid continues to enter the thermoelectric power generation mechanism 1 through multiple throttling units 3; when the current I of the first anode mechanism 4 is less than the protection current I0 of the anode mechanism 4, the anode mechanism 4 corrodes and melts, and the fluid enters the thermoelectric power generation mechanism 1 through the remaining throttling units 3; when the current I passing through the second anode mechanism 4 is less than the protection current I0 of the anode mechanism 4, the anode mechanism 4 corrodes and melts, until multiple anode mechanisms 4 are corroded and melted.

[0117] In addition, when the downhole throttling device needs to lose its throttling effect in advance or the throttling mechanism is blocked by scaling and cannot work normally, after the reagent is pumped into the downhole throttling device, the production well is closed, and after the reagent reacts and dissolves with the anode mechanism 4 or the scale, the production well is opened to release the fluid and then carry out production.

[0118] Example 1

[0119] The underground throttling device for full life cycle mining includes a temperature difference power generation mechanism 1 for power generation, a cathode protection mechanism 2, a throttling mechanism for throttling the fluid entering the temperature difference power generation mechanism 1, a sand prevention mechanism 5, a rubber cylinder sealing mechanism 6, a slip anchoring mechanism 7 and a fishing head 8. The throttling mechanism includes two throttling units 3 and an anode mechanism 4 corresponding to each throttling unit 3. The anode mechanism 4 can corrode and fuse when the current I passing through the anode mechanism 4 is less than the protection current I0 of the anode mechanism 4. The anode mechanism 4 is a shear nail. The negative pole of the temperature difference power generation mechanism 1 is connected to the corresponding throttling unit 3 through the two anode mechanisms 4, and the positive pole is connected to the cathode protection mechanism 2. Each throttling unit 3 includes The convex throttle seat 31 is hollow inside, and the convex throttle seat 31 is connected to the thermoelectric power generation mechanism 1 through the anode mechanism 4. The inner cavity of the thermoelectric power generation mechanism 1 connected to the convex throttle seat 31 is set to a convex inner cavity that is embedded with the convex throttle seat 31. The inner cavity of the convex throttle seat 31 is provided with a gas nozzle 32. The outer diameter of the gas nozzle 32 is larger than the inner diameter of the outlet of the convex throttle seat 31. The inner cavity of the convex throttle seat 31 is also provided with a hollow fastening stud 33. The fluid is suitable for entering the gas nozzle 32 from the hollow fastening stud 33. The inner diameter of the hollow fastening stud 33 is larger than the inner diameter of the gas nozzle 32. The throttling unit 3 also includes a sealing structure and a prestressed mechanism 36. The sealing structure includes a sealing structure provided between the convex throttle seat 31 and the thermoelectric power generation mechanism 1 The sealing ring 34 between the two parts and the sealing gasket 35 arranged between the air nozzle 32 and the convex throttle seat 31, the prestressed mechanism 36 is arranged on the shoulder of the convex throttle seat 31, the two throttling units 3 are connected in series, along the flow direction of the fluid, the inner diameter of the air nozzle 32 at the front end (i.e., the first air nozzle 32) is smaller than the inner diameter of the air nozzle 32 at the rear end (i.e., the second air nozzle 32), the anode mechanism 4 at the front end (i.e., the first anode mechanism 4) and the anode mechanism 4 at the rear end (i.e., the second anode mechanism 4) are made of the same material, and the volume of the first anode mechanism 4 is smaller than the volume of the second anode mechanism 4, the thermoelectric power generation mechanism 1 includes a heat conductive layer and a thermoelectric power generation layer arranged outside the heat conductive layer. And a protective layer arranged on the outside of the thermoelectric power generation layer, the thermoelectric power generation layer contains semiconductor material, the heat conductive layer, the thermoelectric power generation layer and the protective layer are connected in a nested and fixed manner, a sand control mechanism 5 is provided in the fluid inflow direction of the throttling mechanism, the cathode protection mechanism 2 is a molded part of high-silicon cast iron material, the rubber cylinder sealing mechanism 6, the slip anchoring mechanism 7, the salvage head 8 and the thermoelectric power generation mechanism 1 are connected, the slip anchoring mechanism 7 includes a slip 71, an upper slip seat 72 and a lower slip seat 73, one end of the slip 71 is connected to the upper slip seat 72, and the other end is connected to the lower slip seat 73, the inner diameter of the cathode protection mechanism 2 and the sand control mechanism 5 is larger than the outer diameter of the throttling mechanism, and the cathode protection mechanism 2 and the sand control mechanism 5 are arranged together.

[0120] The control method of the downhole throttling device comprises the following steps:

[0121] The fishing head 8 lowers the downhole throttling device to a predetermined depth in the wellbore of the production well, and fixes the downhole throttling device using the slip anchoring mechanism 7. The rubber sleeve sealing mechanism 6 radially expands to form a seal with the wellbore, and the production well begins. The fluid in the downhole reservoir enters the throttling mechanism from the wellbore and is throttled through the first gas nozzle 32 and the second gas nozzle 32 in sequence before entering the thermoelectric power generation mechanism 1. The thermoelectric power generation mechanism 1 generates electricity by using the temperature difference formed between the throttling mechanism and the geothermal energy of the production well. The negative electrode of the thermoelectric power generation mechanism 1 is connected to the corresponding throttling unit 3 through two anode mechanisms 4, and the positive electrode is connected to the cathode protection mechanism 2 to form a circuit. The current I flowing through the first anode mechanism 4 and the second anode mechanism 4 is greater than or equal to its protection current I0, which can ensure that the two anode mechanisms 4 are not corroded. The fluid enters the throttling mechanism and enters the production channel A through the first gas nozzle 32 and the second gas nozzle 32 in sequence.

[0122] As the production capacity of the mining well decreases, the temperature difference between the throttling mechanism and the geothermal heat of the mining well decreases, and the electric energy obtained by the thermoelectric power generation mechanism 1 decreases. When the current I passing through the first anode mechanism 4 is less than its protection current I0, and the current I passing through the second anode mechanism 4 is greater than or equal to its protection current I0, the first anode mechanism 4 melts, and the prestressed mechanism 36 located on the shoulder of the convex throttling seat 31 corresponding to the first anode mechanism 4 pushes the convex throttling seat 31 to fall. The fluid enters the throttling mechanism, is throttled by the second gas nozzle 32, and then enters the thermoelectric power generation mechanism 1;

[0123] As the production capacity of the mining well continues to decrease, when the current I passing through the second anode mechanism 4 is less than its protection current I0, the second anode mechanism 4 melts and corrodes, and the prestressed mechanism 36 located on the shoulder of the convex throttle seat 31 corresponding to the second anode mechanism 4 pushes the convex throttle seat 31 to fall, so that the input channel B and the production channel A are directly connected and the next production step is carried out.

[0124] Example 2

[0125] The underground throttling device for full life cycle mining includes a temperature difference power generation mechanism 1 for power generation, a cathode protection mechanism 2, a throttling mechanism for throttling the fluid entering the temperature difference power generation mechanism 1, a sand control mechanism 5, a rubber cylinder sealing mechanism 6, a slip anchoring mechanism 7 and a fishing head 8. The throttling mechanism includes a throttling unit 3 and an anode mechanism 4 corresponding to the throttling unit 3. The anode mechanism 4 can be corroded and melted when the current I passing through the anode mechanism 4 is less than the protection current I0 of the anode mechanism 4. The anode mechanism 4 is a shear nail. The negative electrode of the temperature difference power generation mechanism 1 is connected to the anode mechanism 4 through the anode mechanism. The structure 4 is connected to the corresponding throttling unit 3, and the positive electrode is connected to the cathode protection mechanism 2. The throttling unit 3 includes a convex throttling seat 31 with a hollow interior. The convex throttling seat 31 is connected to the temperature difference power generation mechanism 1 through the anode mechanism 4. The inner cavity of the temperature difference power generation mechanism 1 connected to the convex throttling seat 31 is set to a convex inner cavity that is embedded with the convex throttling seat 31. The inner cavity of the convex throttling seat 31 is provided with a gas nozzle 32. The outer diameter of the gas nozzle 32 is larger than the inner diameter of the outlet of the convex throttling seat 31. The inner cavity of the convex throttling seat 31 is also provided with a hollow fastening stud 33. The fluid is suitable for flowing out of the hollow The fastening stud 33 enters the air nozzle 32. The inner diameter of the hollow fastening stud 33 is larger than the inner diameter of the air nozzle 32. The throttling unit 3 also includes a sealing structure and a prestressing mechanism 36. The sealing structure includes a sealing ring 34 arranged between the convex throttle seat 31 and the thermoelectric power generation mechanism 1 and a sealing gasket 35 arranged between the air nozzle 32 and the convex throttle seat 31. The prestressing mechanism 36 is arranged on the shoulder of the convex throttle seat 31. The thermoelectric power generation mechanism 1 includes a heat-conducting layer, a thermoelectric power generation layer arranged outside the heat-conducting layer, and a protective layer arranged outside the thermoelectric power generation layer. The thermoelectric power generation layer contains The semiconductor material, the heat-conducting layer, the thermoelectric power generation layer and the protective layer are connected in a nested and fixed manner. A sand-control mechanism 5 is provided in the fluid inflow direction of the throttling mechanism. The cathodic protection mechanism 2 is a molded part made of high-silicon cast iron. The rubber cylinder sealing mechanism 6, the slip anchoring mechanism 7, the fishing head 8 and the thermoelectric power generation mechanism 1 are connected. The slip anchoring mechanism 7 includes a slip 71, an upper slip seat 72 and a lower slip seat 73. One end of the slip 71 is connected to the upper slip seat 72 and the other end is connected to the lower slip seat 73. The inner diameter of the cathodic protection mechanism 2 and the sand-control mechanism 5 is larger than the outer diameter of the throttling mechanism.

[0126] The control method of the downhole throttling device comprises the following steps:

[0127] The fishing head 8 lowers the downhole throttling device into the predetermined depth of the wellbore of the production well, and the downhole throttling device is fixed by the slip anchoring mechanism 7. The rubber sleeve sealing mechanism 6 radially expands to form a seal with the wellbore, and the production well begins. The fluid in the downhole reservoir enters the throttling mechanism from the wellbore, and after being throttled by the gas nozzle 32, enters the thermoelectric power generation mechanism 1. The thermoelectric power generation mechanism 1 generates electricity by using the temperature difference formed by the throttling mechanism and the geothermal energy of the production well. The negative electrode of the thermoelectric power generation mechanism 1 is connected to the corresponding throttling unit 3 through the anode mechanism 4, and the positive electrode is connected to the cathode protection mechanism 2 to form a circuit. The current I flowing through the anode mechanism 4 is greater than or equal to its protection current I0, which can ensure that the anode mechanism 4 is not corroded. The fluid enters the throttling mechanism and enters the production channel A through the gas nozzle 32;

[0128] As the production capacity of the mining well decreases, the temperature difference between the throttling mechanism and the geothermal heat of the mining well decreases, and the electric energy obtained by the thermoelectric power generation mechanism 1 decreases. When the current I flowing through the anode mechanism 4 is less than its protection current I0, the anode mechanism 4 melts, and the prestressed mechanism 36 located on the shoulder of the convex throttling seat 31 pushes the convex throttling seat 31 to fall, so that the input channel B and the production channel A are directly connected and the next production step is carried out.

[0129] Example 3

[0130] The underground throttling device for full life cycle mining is different from Example 2 in that, as shown in FIG5 , the overall structure of the anode mechanism 4 and the anode material layer is set to a semicircular ring structure with a fan angle of 150°.

[0131] Example 4

[0132] The underground throttling device for full life cycle mining includes a thermoelectric power generation mechanism 1 for power generation, a cathode protection mechanism 2 and a throttling mechanism for throttling the fluid entering the thermoelectric power generation mechanism 1. The throttling mechanism includes a throttling unit 3 and an anode mechanism 4 corresponding to the throttling unit 3. The anode mechanism 4 can be corroded and melted when the current I passing through the anode mechanism 4 is less than the protection current I0 of the anode mechanism 4. The anode mechanism 4 is a shear nail. The negative pole of the thermoelectric power generation mechanism 1 is connected to the corresponding throttling unit 3 through the anode mechanism 4, and the positive pole is connected to the cathode protection mechanism 2. The throttling unit 3 includes a convex throttling seat 31 with a hollow interior. The convex throttling seat 31 is connected to the thermoelectric power generation mechanism 1 through the anode mechanism 4. The inner cavity where the thermoelectric power generation mechanism 1 is connected to the convex throttling seat 31 is set as a convex inner cavity that is embedded with the convex throttling seat 31. The inner cavity of the convex throttling seat 31 is provided with a gas nozzle 32. The outer diameter of the air nozzle 32 is larger than the inner diameter of the outlet of the convex throttle seat 31. The inner cavity of the convex throttle seat 31 is also provided with a hollow fastening stud 33. The fluid is suitable for entering the air nozzle 32 from the hollow fastening stud 33. The inner diameter of the hollow fastening stud 33 is larger than the inner diameter of the air nozzle 32. The throttling unit 3 also includes a sealing structure and a prestressed mechanism 36. The sealing structure includes a sealing ring 34 arranged between the convex throttle seat 31 and the thermoelectric power generation mechanism 1 and a sealing gasket 35 arranged between the air nozzle 32 and the convex throttle seat 31. The prestressed mechanism 36 is arranged on the shoulder of the convex throttle seat 31. The thermoelectric power generation mechanism 1 includes a heat-conducting layer, a thermoelectric power generation layer arranged outside the heat-conducting layer, and a protective layer arranged outside the thermoelectric power generation layer. The thermoelectric power generation layer contains semiconductor material. The heat-conducting layer, the thermoelectric power generation layer and the protective layer are connected in a nested and fixed manner. The inner diameter of the cathode protection mechanism 2 is larger than the outer diameter of the throttling mechanism.

[0133] The control method of the downhole throttling device comprises the following steps:

[0134] The downhole throttling device is directly connected to the production tubing. The fluid in the tubing enters the throttling mechanism, is throttled by the gas nozzle 32, and then enters the thermoelectric generator 1. The thermoelectric generator 1 generates electricity by utilizing the temperature difference between the throttling mechanism and the geothermal energy of the production well. The negative electrode of the thermoelectric generator 1 is connected to the corresponding throttling unit 3 through the anode mechanism 4, and the positive electrode is connected to the cathode protection mechanism 2 to form a circuit. The current I flowing through the anode mechanism 4 is greater than or equal to its protection current I0, which can ensure that the anode mechanism 4 is not corroded. The fluid enters the throttling mechanism and enters the production channel A through the gas nozzle 32.

[0135] As the production capacity of the mining well decreases, the temperature difference between the throttling mechanism and the geothermal heat of the mining well decreases, and the electric energy obtained by the thermoelectric power generation mechanism 1 decreases. When the current I flowing through the anode mechanism 4 is less than its protection current I0, the anode mechanism 4 melts, and the prestressed mechanism 36 located on the shoulder of the convex throttling seat 31 pushes the convex throttling seat 31 to fall, so that the input channel B and the production channel A are directly connected and the next production step is carried out.

[0136] Example 5

[0137] The underground throttling device for full life cycle mining includes a thermoelectric power generation mechanism 1 for power generation, a cathode protection mechanism 2, a throttling mechanism for throttling the fluid entering the thermoelectric power generation mechanism 1, a sand prevention mechanism 5, a rubber cylinder sealing mechanism 6, a slip anchoring mechanism 7 and a fishing head 8. The throttling mechanism includes a throttling unit 3 and an anode mechanism 4 corresponding to the throttling unit 3. The anode mechanism 4 can be corroded and melted when the current I passing through the anode mechanism 4 is less than the protection current I0 of the anode mechanism 4. The anode mechanism 4 is a shear nail. The negative pole of the thermoelectric power generation mechanism 1 is connected to the corresponding throttling unit 3 through the anode mechanism 4, and the positive pole is connected to the cathode protection mechanism 2. The thermoelectric power generation mechanism 1 includes a heat conductive layer, a thermoelectric power generation layer arranged on the outside of the heat conducting layer, and a protective layer arranged on the outside of the thermoelectric power generation layer, the thermoelectric power generation layer contains semiconductor material, the heat conducting layer, the thermoelectric power generation layer and the protective layer are connected in a nested and fixed manner, a sand control mechanism 5 is provided in the fluid inflow direction of the throttling mechanism, the cathodic protection mechanism 2 is a molded part made of high silicon cast iron material, the rubber cylinder sealing mechanism 6, the slip anchoring mechanism 7, the salvage head 8 are connected to the thermoelectric power generation mechanism 1, the slip anchoring mechanism 7 includes a slip 71, an upper slip seat 72 and a lower slip seat 73, one end of the slip 71 is connected to the upper slip seat 72, and the other end is connected to the lower slip seat 73, the inner diameter of the cathodic protection mechanism 2 and the sand control mechanism 5 is larger than the outer diameter of the throttling mechanism.

[0138] The control method of the downhole throttling device comprises the following steps:

[0139] The fishing head 8 lowers the downhole throttling device to a predetermined depth in the wellbore of the production well. The downhole throttling device is fixed by the slip anchoring mechanism 7. The rubber sleeve sealing mechanism 6 radially expands to form a seal with the wellbore. The production of the production well begins. The fluid in the production well enters the throttling mechanism from the wellbore, is throttled, and then enters the thermoelectric power generation mechanism 1. The thermoelectric power generation mechanism 1 generates electricity by using the temperature difference formed by the throttling mechanism and the geothermal heat of the production well. The negative electrode of the thermoelectric power generation mechanism 1 is connected to the corresponding throttling unit 3 through the anode mechanism 4, and the positive electrode is connected to the cathode protection mechanism 2 to form a circuit. The current I flowing through the anode mechanism 4 is greater than or equal to its protection current I0, which can ensure that the anode mechanism 4 is not corroded. The fluid enters the throttling mechanism and enters the production channel A through the throttling unit 3.

[0140] As the production capacity of the mining well decreases, the temperature difference between the throttling mechanism and the geothermal heat of the mining well decreases, and the electric energy obtained by the thermoelectric power generation mechanism 1 decreases. When the current I flowing through the anode mechanism 4 is less than its protection current I0, the anode mechanism 4 melts, and the throttling unit 3 falls, so that the input channel B and the production channel A are directly connected and the next production step is carried out.

[0141] Example 6

[0142] The underground throttling device for full life cycle mining includes a thermoelectric power generation mechanism 1 for generating electricity, a cathode protection mechanism 2 and a throttling mechanism for throttling the fluid entering the thermoelectric power generation mechanism 1. The throttling mechanism includes a throttling unit 3 and an anode mechanism 4 arranged corresponding to the throttling unit 3. The negative pole of the thermoelectric power generation mechanism 1 is connected to the corresponding throttling unit 3 through two anode mechanisms 4, and the positive pole is connected to the cathode protection mechanism 2. The thermoelectric power generation mechanism 1 includes a heat conductive layer, a thermoelectric power generation layer arranged outside the heat conductive layer, and a protective layer arranged outside the thermoelectric power generation layer. The thermoelectric power generation layer contains semiconductor material. The heat conductive layer, the thermoelectric power generation layer and the protective layer are connected in a nested and fixed manner. The inner diameter of the cathode protection mechanism 2 is larger than the outer diameter of the throttling mechanism.

[0143] The control method of the downhole throttling device comprises the following steps:

[0144] The downhole throttling device is directly connected to the production tubing. The fluid in the tubing enters the throttling mechanism and then enters the thermoelectric power generation mechanism 1. The thermoelectric power generation mechanism 1 generates electricity by utilizing the temperature difference between the throttling mechanism and the geothermal energy of the production well. The negative electrode of the thermoelectric power generation mechanism 1 is connected to the corresponding throttling unit 3 through the anode mechanism 4, and the positive electrode is connected to the cathode protection mechanism 2 to form a circuit. The current I flowing through the anode mechanism 4 is greater than or equal to its protection current I0, which can ensure that the anode mechanism 4 is not corroded. The fluid enters the throttling mechanism and enters the production channel A through the throttling unit 3.

[0145] As the production capacity of the mining well decreases, the temperature difference between the throttling mechanism and the geothermal energy of the mining well decreases, and the electric energy obtained by the thermoelectric power generation mechanism 1 decreases. When the current I flowing through the anode mechanism 4 is less than its protection current I0, the anode mechanism 4 melts, and then the throttling unit 3 falls, so that the input channel B and the production channel A are directly connected and the next production step is carried out.

[0146] Example 7

[0147] The underground throttling device for full life cycle mining is different from Example 2 in that the thermoelectric power generation mechanism 1 includes a heat-conducting layer and a thermoelectric power generation layer arranged outside the heat-conducting layer.

[0148] Example 8

[0149] The underground throttling tool used for full life cycle mining is different from Example 2 in that the cathodic protection mechanism 2 is a copper molded part.

[0150] Example 9

[0151] The underground throttling device for full life cycle mining is different from that in Example 2 in that the throttling unit 3 does not have a sealing structure.

[0152] Example 10

[0153] The underground throttling device for full life cycle mining is different from that in Example 2 in that the temperature difference power generation mechanism 1 is further provided with a rechargeable battery and a control circuit.

[0154] The control method of the above-mentioned downhole throttling device is different from that of Example 2 in that: when the mining well needs to be shut down for maintenance, the rechargeable battery can provide electrical energy to the anode mechanism 4, and through the control circuit, the current I flowing through the anode mechanism 4 is made greater than or equal to its protection current I0, thereby protecting the anode mechanism 4 from corrosion and effectively ensuring that the throttling mechanism does not lose its throttling function during the shutdown of the mining well; when the mining well is in normal production, the rechargeable battery uses the electrical energy provided by the temperature difference power generation mechanism 1 to achieve normal charging.

[0155] The preferred embodiments of the present invention are described in detail above in conjunction with the accompanying drawings. However, the present invention is not limited to the specific details in the above embodiments. Within the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the scope of protection of the present invention.

[0156] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any appropriate manner without contradiction. In order to avoid unnecessary repetition, the present invention will not further describe various possible combinations. In addition, the various different embodiments of the present invention can also be arbitrarily combined, as long as they do not violate the concept of the present invention, they should also be regarded as the content disclosed by the present invention.

Claims

1. An underground throttling device for full life cycle mining, characterized in that: The downhole throttling device comprises a temperature difference power generation mechanism (1) for generating electricity and a throttling mechanism for throttling a fluid entering the temperature difference power generation mechanism (1), wherein the throttling mechanism comprises at least one throttling unit (3), and the temperature difference power generation mechanism (1) can generate electrical energy to supply the downhole throttling device through the temperature difference between the low-temperature fluid after throttling expansion and the surrounding environment.

2. The downhole throttling device according to claim 1, characterized in that: The downhole throttling device comprises a control mechanism electrically connected to the temperature difference power generation mechanism (1), and the control mechanism is capable of adjusting the flow area of ​​the throttling unit (3).

3. The downhole throttling device according to claim 2, characterized in that: The throttling unit (3) comprises an air nozzle (32) and a conical valve core (37) arranged at the inlet of the temperature difference power generation mechanism (1); the valve core (37) is coaxially arranged with the air nozzle (32); and the control mechanism is capable of driving the valve core (37) to move axially relative to the air nozzle (32) to adjust the flow area of ​​the air nozzle (32).

4. The downhole throttling device according to claim 3, characterized in that: The control mechanism comprises a motor (12) electrically connected to the temperature difference power generation mechanism (1) and a controller (10); the motor (12) is connected to the valve core (37) via a screw mechanism; and the controller (10) is capable of controlling the operation of the motor (12) to adjust the flow area of ​​the throttling unit (3).

5. The downhole throttling device according to claim 1, characterized in that: It also comprises a cathode protection mechanism (2), the throttling mechanism comprising an anode mechanism (4) arranged corresponding to the throttling unit (3), the negative pole of the temperature difference power generation mechanism (1) being connected to the throttling unit (3) through the anode mechanism (4), and the positive pole being connected to the cathode protection mechanism (2); the anode mechanism (4) being capable of being corroded and melted when the current I passing through the anode mechanism (4) is less than the protection current I0 of the anode mechanism (4).

6. The downhole throttling device according to claim 5, characterized in that: The throttling unit (3) comprises a convex throttling seat (31) with a hollow interior. The convex throttling seat (31) is connected to the temperature difference power generation mechanism (1) via the anode mechanism (4). The inner cavity of the convex throttling seat (31) is provided with a gas nozzle (32).

7. The downhole throttling device according to claim 6, characterized in that: The outer diameter of the gas nozzle (32) is greater than the inner diameter of the outlet of the convex throttle seat (31).

8. The downhole throttling device according to claim 6, characterized in that: The inner cavity of the convex throttle seat (31) is also provided with a hollow fastening stud (33), and the fluid is suitable for entering the air nozzle (32) from the hollow fastening stud (33).

9. The downhole throttling device according to claim 8, characterized in that: The inner diameter of the hollow fastening stud (33) is greater than the inner diameter of the air nozzle (32).

10. The downhole throttling device according to claim 6, characterized in that: The throttling unit (3) also includes a sealing structure, which includes a sealing ring (34) arranged between the convex throttling seat (31) and the temperature difference power generation mechanism (1) and a sealing gasket (35) arranged between the air nozzle (32) and the convex throttling seat (31).

11. The downhole throttling device according to claim 6, characterized in that: The throttling unit (3) further comprises a prestressing mechanism (36) arranged on the shoulder of the convex throttling seat (31).

12. The downhole throttling device according to any one of claims 6 to 11, characterized in that: The number of the throttling units (3) is multiple, and the multiple throttling units (3) are connected in series. Along the flow direction of the fluid, the inner diameter of the air nozzle (32) located at the front end is smaller than the inner diameter of the air nozzle (32) located at the rear end.

13. The downhole throttling device according to claim 12, characterized in that: When the material of the anode mechanism (4) is the same, along the flow direction of the fluid, the volume of the anode mechanism (4) located at the front end is smaller than the volume of the anode mechanism (4) located at the rear end; Alternatively, when the volumes of the anode mechanisms (4) are the same, along the flow direction of the fluid, the standard electrode potential of the anode mechanism (4) located at the front end is smaller than the standard electrode potential of the anode mechanism (4) located at the rear end; Alternatively, the temperature difference power generation mechanism (1) is provided with a control circuit, and the control circuit is capable of adjusting the magnitude of the current I passing through the anode mechanism (4).

14. The downhole throttling device according to claim 13, characterized in that: The temperature difference power generation mechanism (1) is also provided with a rechargeable battery.

15. The downhole throttling device according to any one of claims 5 to 11, characterized in that: An anode material layer is arranged outside the anode mechanism (4), and the standard electrode potential of the anode material layer is greater than the standard electrode potential of the anode mechanism (4).

16. The downhole throttling device according to any one of claims 5 to 11, characterized in that: The thermoelectric power generation mechanism (1) comprises a heat conducting layer and a thermoelectric power generation layer arranged outside the heat conducting layer, wherein the thermoelectric power generation layer contains a semiconductor material.

17. The downhole throttling device according to claim 16, characterized in that: The thermoelectric power generation mechanism (1) further comprises a protective layer arranged outside the thermoelectric power generation layer.

18. The downhole throttling device according to any one of claims 5 to 11, characterized in that: A sand prevention mechanism (5) is provided in the fluid inflow direction of the throttling mechanism.

19. The downhole throttling device according to any one of claims 5 to 11, characterized in that: The cathode protection mechanism (2) is a molded part made of high-silicon cast iron material.

20. The downhole throttling device according to any one of claims 5 to 11, characterized in that: The downhole throttling device further comprises a rubber cartridge sealing mechanism (6), a slip anchoring mechanism (7) and a fishing head (8) which are sequentially connected to the temperature difference power generation mechanism (1); the rubber cartridge sealing mechanism (6), the slip anchoring mechanism (7), the fishing head (8) and the temperature difference power generation mechanism (1) are in communication.

21. The downhole throttling device according to claim 20, characterized in that: The slip anchoring mechanism (7) comprises a slip (71), an upper slip seat (72) and a lower slip seat (73); one end of the slip (71) is connected to the upper slip seat (72) and the other end is connected to the lower slip seat (73).

22. The downhole throttling device according to claim 5, characterized in that: The downhole throttling device is configured as follows: The fluid in the extraction well enters the temperature difference power generation mechanism (1) via the throttling mechanism so that the temperature difference power generation mechanism (1) generates electricity. When the current I passing through the anode mechanism (4) is greater than or equal to the protection current I0 of the anode mechanism (4), the anode mechanism (4) is not corroded, and the fluid continues to enter the temperature difference power generation mechanism (1) via the throttling mechanism; when the current I passing through the anode mechanism (4) is less than the protection current I0 of the anode mechanism (4), the anode mechanism (4) corrodes and melts, and finally the fluid directly enters the temperature difference power generation mechanism (1).

23. The downhole throttling device according to claim 22, characterized in that: The throttling mechanism comprises a plurality of throttling units (3) and an anode mechanism (4) arranged corresponding to each of the throttling units (3), wherein the plurality of throttling units (3) are connected in series; When the material of the anode mechanism (4) is the same, along the flow direction of the fluid, the volume of the anode mechanism (4) located at the front end is smaller than the volume of the anode mechanism (4) located at the rear end; Alternatively, when the volumes of the anode mechanisms (4) are the same, along the flow direction of the fluid, the standard electrode potential of the anode mechanism (4) located at the front end is smaller than the standard electrode potential of the anode mechanism (4) located at the rear end; Alternatively, the temperature difference power generation mechanism (1) is provided with a control circuit, and the control circuit is capable of adjusting the magnitude of the current I passing through the anode mechanism (4); The fluid enters the temperature difference power generation mechanism (1) through the plurality of throttling units (3) so that the temperature difference power generation mechanism (1) generates electricity. When the current I passing through the first anode mechanism (4) is greater than or equal to the protection current I0 of the anode mechanism (4), the anode mechanism (4) does not corrode, and the fluid continues to enter the temperature difference power generation mechanism (1) through the plurality of throttling units (3); when the current I of the first anode mechanism (4) is less than the protection current I0 of the anode mechanism (4), the anode mechanism (4) corrodes and melts, and the fluid enters the temperature difference power generation mechanism (1) through the remaining throttling units (3); when the current I passing through the second anode mechanism (4) is less than the protection current I0 of the anode mechanism (4), the anode mechanism (4) corrodes and melts, until all the anode mechanisms (4) are corroded and melted.

24. The downhole throttling device according to claim 22 or 23, characterized in that: When the downhole throttling device is required to lose its throttling function prematurely or the throttling mechanism is blocked by scaling and cannot work normally, the reagent is pumped into the downhole throttling device, the production well is closed, and after the reagent reacts with the anode mechanism (4) or the scale to dissolve, the production well is opened to release the fluid and then carry out production.

25. A power supply method for an underground throttling device for full life cycle mining, characterized in that: The power supply method of the underground throttling device comprises the following steps: After the downhole fluid is depressurized by the throttling mechanism, it expands and enters the temperature difference power generation mechanism (1). The temperature difference power generation mechanism (1) can generate electricity by using the temperature difference between the low-temperature fluid after throttling and expansion and the surrounding environment, thereby supplying power to the downhole throttling device.

26. The power supply method according to claim 25, characterized in that: The downhole throttling device comprises a throttling mechanism and a cathode protection mechanism (2) for throttling the fluid entering the temperature difference power generation mechanism (1), the throttling mechanism comprises at least one throttling unit (3) and an anode mechanism (4) arranged corresponding to the throttling unit (3), and the power supply method further comprises the following steps: When the current I passing through the anode mechanism (4) is greater than or equal to the protection current I0 of the anode mechanism (4), the anode mechanism (4) does not corrode, and the fluid continues to enter the temperature difference power generation mechanism (1) through the throttling mechanism; when the current I passing through the anode mechanism (4) is less than the protection current I0 of the anode mechanism (4), the anode mechanism (4) corrodes and melts, and finally the fluid directly enters the temperature difference power generation mechanism (1).

27. The power supply method according to claim 26, characterized in that: The throttling mechanism comprises a plurality of throttling units (3) and an anode mechanism (4) arranged corresponding to each of the throttling units (3), wherein the plurality of throttling units (3) are connected in series; When the material of the anode mechanism (4) is the same, along the flow direction of the fluid, the volume of the anode mechanism (4) located at the front end is smaller than the volume of the anode mechanism (4) located at the rear end; Alternatively, when the volumes of the anode mechanisms (4) are the same, along the flow direction of the fluid, the standard electrode potential of the anode mechanism (4) located at the front end is smaller than the standard electrode potential of the anode mechanism (4) located at the rear end; Alternatively, the temperature difference power generation mechanism (1) is provided with a control circuit, and the control circuit is capable of adjusting the magnitude of the current I passing through the anode mechanism (4); The fluid enters the temperature difference power generation mechanism (1) through the plurality of throttling units (3) so that the temperature difference power generation mechanism (1) generates electricity. When the current I passing through the first anode mechanism (4) is greater than or equal to the protection current I0 of the anode mechanism (4), the anode mechanism (4) does not corrode, and the fluid continues to enter the temperature difference power generation mechanism (1) through the plurality of throttling units (3); when the current I of the first anode mechanism (4) is less than the protection current I0 of the anode mechanism (4), the anode mechanism (4) corrodes and melts, and the fluid enters the temperature difference power generation mechanism (1) through the remaining throttling units (3); when the current I passing through the second anode mechanism (4) is less than the protection current I0 of the anode mechanism (4), the anode mechanism (4) corrodes and melts, until all the anode mechanisms (4) are corroded and melted.

28. The power supply method according to claim 26 or 27, characterized in that: When the downhole throttling device is required to lose its throttling function prematurely or the throttling mechanism is blocked by scaling and cannot work normally, the reagent is pumped into the downhole throttling device, the production well is closed, and after the reagent reacts with the anode mechanism (4) or the scale to dissolve, the production well is opened to release the fluid and then carry out production.

Images