A downhole self-powered closed-loop feedback type solid corrosion inhibitor long-acting controlled-release filling device

Abstract

The application discloses a downhole self-powered closed-loop feedback type solid corrosion inhibitor long-acting controlled-release filling device, and belongs to the technical field of downhole corrosion prevention and agent controlled-release filling. The device comprises a central pipe, a downhole power generation device, a controlled-release upper section, a controlled-release lower section, a tension spring mechanism, an hourglass-shaped controlled-release sleeve and a particle screen pipe. The downhole power generation device is powered by the kinetic energy of wellbore fluid, the controlled-release upper section and the controlled-release lower section cooperate to form a sealed and isolated liquid storage space for storing wellbore liquid. When released, the sealed movable piston moves under the action of the tension spring mechanism, so that the solid corrosion inhibitor particles pass through the hourglass-shaped controlled-release sleeve and enter the particle screen pipe. The central pipe, the downhole power generation device, the controlled-release upper section, the controlled-release lower section and the tension spring mechanism form a controlled-release unit, the controlled-release unit can be used alone, or can be connected in an axial direction along the central pipe to form a multi-section long-acting controlled-release filling system, so that the solid corrosion inhibitor is released in stages and for a long period, the utilization rate of the corrosion inhibitor is improved, and the waste of the agent and the corrosion risk are reduced.

Description

Technical Field

[0001] This invention relates to the field of downhole corrosion prevention and intelligent chemical injection equipment for oil and gas wells, specifically to a downhole self-powered closed-loop feedback type solid corrosion inhibitor long-term controlled release injection device, which is suitable for long-term corrosion prevention operations in oil wells, gas wells, water injection wells, and wells containing corrosive media such as carbon dioxide, hydrogen sulfide, and high-salinity water. Background Technology

[0002] During oil and gas well production, the wellbore and production tubing are subjected to high temperature, high pressure, high salinity, and complex corrosive media environments for extended periods. Wellbore fluids often contain corrosive components such as carbon dioxide, hydrogen sulfide, dissolved oxygen, chloride ions, and organic acids. These corrosive media cause continuous corrosion to tubing, casing, downhole tools, and related metal components, leading to thinning of the tubing wall, localized pitting corrosion, perforation, joint failure, and even wellbore integrity loss. Especially in the later stages of oil and gas field development, increased water cut, increased salinity of produced fluids, and changes in wellbore flow conditions further exacerbate downhole corrosion risks. Therefore, how to replenish corrosion inhibitors stably and effectively downhole is a crucial technical issue for ensuring safe oil and gas well production and extending the service life of downhole tubing.

[0003] Currently, corrosion prevention in oil and gas wells typically employs methods such as continuous surface injection of corrosion inhibitors, periodic batch injection of corrosion inhibitors, and passive release of downhole solid corrosion inhibitors. Continuous surface injection delivers liquid corrosion inhibitors to the wellbore via surface pumps and pipelines, maintaining a certain level of inhibitor concentration. However, this method is heavily reliant on surface equipment, pipelines, and long-term maintenance, resulting in a complex system and high operating costs. While periodic batch injection is relatively simple to operate, the injection cycle and volume are largely determined by experience, making it difficult to reflect changes in the actual downhole corrosion environment and inhibitor concentration. Downhole solid corrosion inhibitor release reduces reliance on continuous surface injection equipment; however, existing solid corrosion inhibitors mostly rely on wellbore fluid scouring or self-dissolution for passive release. The release rate is significantly affected by temperature, pressure, flow rate, and inhibitor form, making active control difficult. Existing corrosion inhibitor injection and release technologies still have the following shortcomings:

[0004] 1. Existing methods of quantitative injection on the surface, periodic injection, or single-point concentration detection downhole mostly rely on preset time or a single concentration threshold to trigger injection, which makes it difficult to accurately reflect the concentration difference between the wellbore fluid and the controlled release chamber, and is prone to problems such as false triggering of release, over-injection, or under-injection.

[0005] 2. Existing downhole corrosion inhibitor release devices typically rely on surface cables, large-capacity batteries, or motor screws as drive mechanisms to release the agent. These devices are complex in structure and consume a lot of energy. In the confined space of downholes and under long-term service conditions, they suffer from problems such as insufficient power supply, decreased operational reliability, and maintenance difficulties.

[0006] 3. Existing solid corrosion inhibitors mostly adopt a single agent tank or passive dissolution and release method. The release rate is greatly affected by downhole temperature, pressure, flow rate and agent form. It is easy to have problems such as concentrated drop of particles, local accumulation or excessively rapid release in the early stage, making it difficult to achieve phased, long-term and uniform controlled release.

[0007] In summary, existing corrosion inhibitor application technologies cannot simultaneously meet the requirements of downhole self-powered operation, concentration feedback, active control, uniform release, and long-term corrosion protection. Therefore, there is an urgent need to develop a downhole self-powered closed-loop feedback solid corrosion inhibitor long-term controlled-release application device to achieve intelligent, low-power, phased, and long-cycle release of downhole corrosion inhibitors, thereby improving inhibitor utilization and reducing agent waste and the risk of under-application corrosion. Summary of the Invention

[0008] To address the aforementioned technical problems, a downhole self-powered closed-loop feedback type long-term controlled-release device for solid corrosion inhibitors has been invented. The device includes a central tube, a solid corrosion inhibitor controlled-release unit, an hourglass-shaped controlled-release sleeve, and a particle screen. The solid corrosion inhibitor controlled-release unit comprises a downhole power generation device, an upper section of the solid corrosion inhibitor controlled-release system, a lower section of the solid corrosion inhibitor controlled-release system, and a tension spring mechanism. The downhole power generation device utilizes the kinetic energy of the wellbore fluid to generate electrical energy, providing power for the operation of the solid corrosion inhibitor controlled-release unit. The upper and lower sections of the solid corrosion inhibitor controlled-release system work together to form a storage and release space for the solid corrosion inhibitor. During release, the sealed movable piston moves under the action of the tension spring mechanism, causing the solid corrosion inhibitor particles to enter the particle screen through the hourglass-shaped controlled-release sleeve and be dispersed and released into the wellbore fluid through the particle screen. The solid corrosion inhibitor controlled release unit can be used alone or connected sequentially along the central tube axis to form a multi-section long-term controlled release structure. When multiple single-section controlled release units are connected in series, an hourglass-shaped controlled release sleeve and a particle screen tube are connected below the lowest single-section controlled release unit, thereby realizing the phased and long-term release of the downhole solid corrosion inhibitor, improving the corrosion inhibitor utilization rate, and reducing agent waste and the risk of under-dosage corrosion.

[0009] The technical solution adopted by the present invention to solve its technical problem is as follows: a downhole self-powered closed-loop feedback solid corrosion inhibitor long-term controlled release injection device, including a downhole power generation device, a central tube, a solid corrosion inhibitor controlled release upper section, a solid corrosion inhibitor controlled release lower section, a tension spring mechanism, an hourglass-shaped controlled release sleeve, and a particle screen tube.

[0010] The components of the downhole power generation device are respectively installed in the central tube and the upper section of the solid corrosion inhibitor controlled release system. They are used to generate electrical energy using the kinetic energy of the well fluid in the central tube and to power the detection, control and execution components in the device. The lower end of the central tube is connected to a tension spring mechanism to form a well fluid flow channel. The upper and lower sections of the solid corrosion inhibitor controlled release system are connected axially along the central tube to form a sealed and isolated liquid storage space for storing the liquid in the well. The tension spring mechanism is installed in the lower section of the solid corrosion inhibitor controlled release system to control the release of solid corrosion inhibitor particles to the direction of the hourglass-shaped controlled release sleeve. The hourglass-shaped controlled release sleeve is installed between the lower section of the solid corrosion inhibitor controlled release system and the particle screen tube to limit the amount of solid corrosion inhibitor particles passing through per unit time. The particle screen tube is connected to the hourglass-shaped controlled release sleeve and has multiple release holes to disperse and release the solid corrosion inhibitor particles after flow restriction by the hourglass-shaped controlled release sleeve into the well fluid.

[0011] The downhole power generation device includes a sealing cover, a control module, a power transmission ring, and a power generation turbine; the control module is installed inside the power transmission ring, the sealing cover is installed on the upper end of the power transmission ring and forms a seal, and the power generation turbine is located in the fluid flow area inside the central tube and is electrically connected to the power transmission ring.

[0012] The solid corrosion inhibitor controlled-release upper section includes a controlled-release upper section sleeve, an electrically controlled needle valve I, an in-well corrosion inhibitor concentration meter, an in-sleeve corrosion inhibitor concentration meter, an electrically controlled needle valve II, an inclined sleeve, an upper liquid storage sleeve, and a lower liquid storage sleeve. The controlled-release upper section sleeve is sleeved on the outside of the central tube. The electrically controlled needle valve I, the in-well corrosion inhibitor concentration meter, the in-sleeve corrosion inhibitor concentration meter, and the electrically controlled needle valve II are installed on the controlled-release upper section sleeve. The inclined sleeve, the upper liquid storage sleeve, and the lower liquid storage sleeve are located inside the controlled-release upper section sleeve, and the upper liquid storage sleeve and the lower liquid storage sleeve are axially fitted to form a sealed and isolated liquid storage space for storing liquid in the wellbore.

[0013] The controlled-release lower section of the solid corrosion inhibitor includes a piston top cover, sealing ring I, piston body, sealing ring II, piston bottom cover, controlled-release lower section sleeve, electrically controlled telescopic pin I, high-energy battery I, electrically controlled telescopic pin II, and high-energy battery II. The piston top cover, piston body, and piston bottom cover are sequentially connected along the axial direction to form a sealed movable piston. The sealing ring I is used to achieve sealing isolation between the wellbore and the sleeve. The sealing ring I is placed on the controlled-release lower section sleeve. The sealing ring II is set in the sealing groove on the outer periphery of the piston body and slides and seals with the sealing surface. The electrically controlled telescopic pin I, high-energy battery I, electrically controlled telescopic pin II, and high-energy battery II are installed on the piston body.

[0014] The tension spring mechanism includes a tension spring, a spring retaining ring, and a spring support. The upper end of the tension spring is connected to the lower cover of the piston, and the other end is installed inside the spring support. The lower end of the tension spring is restricted within the spring support by the spring retaining ring. One end of the spring support is connected to the central tube, and the other end is connected to the lower section of the solid corrosion inhibitor control.

[0015] The upper end of the hourglass-shaped controlled-release sleeve is connected to the lower controlled-release sleeve, and the lower end is connected to the particle sieve tube.

[0016] The particle sieve tube is located at the lower end of the hourglass-shaped controlled-release sleeve and is connected to the hourglass-shaped controlled-release sleeve.

[0017] In the downhole power generation device, the sealing cover plate and the power transmission ring cooperate to form a sealed installation space for the control module. The control module controls the operation of the corrosion inhibitor concentration meter in the wellbore, the corrosion inhibitor concentration meter in the sleeve, the electrically controlled needle valve I, the electrically controlled needle valve II, the electrically controlled telescopic pin I, and the electrically controlled telescopic pin II, respectively.

[0018] The power transmission ring is electrically connected to the power generation turbine and is used to transmit the electrical energy generated by the power generation turbine to the control module and the electrical actuators.

[0019] The power transmission ring is provided with an external thread I, an internal thread I, and four circumferentially evenly distributed mounting holes I. The external thread I is threadedly connected to the internal area of ​​the upper control sleeve, the internal thread I is threadedly connected to the central tube, and the mounting holes I are used to install the control module and the sealing cover plate. The power transmission ring and the generator turbine form an electrical energy transmission path.

[0020] In the controlled-release upper section of the solid corrosion inhibitor, the upper section sleeve is connected to the upper end device adjacent to the bottom of the well via tapered thread I, and is connected to the inclined sleeve via internal thread II; the inclined sleeve, the upper liquid storage sleeve, and the lower liquid storage sleeve are assembled and connected sequentially along the axial direction;

[0021] The inclined hole I and inclined hole II on the upper sleeve of the controlled release section are connected to each other, so that the well fluid can enter the internal cavity of the upper sleeve of the solid corrosion inhibitor controlled release section through the electrically controlled needle valve I or the electrically controlled needle valve II; the electrically controlled needle valve I and the electrically controlled needle valve II are connected to the internal flow channel formed by the upper sleeve of the liquid storage and the lower sleeve of the liquid storage, and are used to control whether the inside of the upper sleeve of the solid corrosion inhibitor controlled release section is connected to the external well fluid.

[0022] The corrosion inhibitor concentration meter inside the wellbore is located at the position where the controlled-release upper sleeve is in fluid communication with the wellbore, and the corrosion inhibitor concentration meter inside the sleeve is located in the internal cavity of the controlled-release upper sleeve. Both are electrically connected to the control module.

[0023] The inclined sleeve is positioned above the upper and lower liquid storage sleeves. The inclined surface I on the inclined sleeve is used to guide the solid corrosion inhibitor particles downward. The through holes I on the inclined sleeve are used to install the electrically controlled needle valve I, the corrosion inhibitor concentration meter inside the wellbore, the corrosion inhibitor concentration meter inside the sleeve, and the electrically controlled needle valve II, respectively.

[0024] The flow channel groove I on the upper sleeve of the liquid storage is used to introduce the fluid flowing from the electrically controlled needle valve I into the corrosion inhibitor containing space. The mounting hole II on the upper sleeve of the liquid storage is used to install the corrosion inhibitor concentration meter inside the sleeve. The flow channel groove II on the upper sleeve of the liquid storage is used to introduce the fluid flowing from the electrically controlled needle valve II into the corrosion inhibitor containing space. The liquid storage chamber on the upper sleeve of the liquid storage is used to store the liquid in the wellbore.

[0025] The flow channel groove Ⅲ on the lower sleeve and the storage cavity on the upper sleeve cooperate to form a storage cavity for wellbore fluid to enter. The lower sleeve is connected to the external thread Ⅳ of the controlled release lower sleeve through the internal thread Ⅲ.

[0026] In the controlled release section of the solid corrosion inhibitor, the piston upper cover is connected to the piston body's internal thread IV via external thread II, and the piston lower cover is connected to the piston body's internal thread V via external thread III, so that the piston upper cover, piston body, and piston lower cover form a sealed movable piston.

[0027] The arc-shaped working surface I on the piston cover contacts the solid corrosion inhibitor particles, which is used to guide the solid corrosion inhibitor particles to fall when the sealed moving piston moves, preventing the particles from accumulating.

[0028] The sealing groove I on the piston body mates with the sealing ring II, and the sealing ring II forms a sliding seal fit with the inner diameter of the control release lower sleeve;

[0029] Mounting holes III and IV on the piston body are used to install electrically controlled telescopic pin I and high-energy battery I, respectively; mounting holes V and VI are used to install electrically controlled telescopic pin II and high-energy battery II, respectively.

[0030] The wire groove I on the piston body is located between the electrically controlled telescopic pin I and the high-energy battery I, and the wire groove II is located between the electrically controlled telescopic pin II and the high-energy battery II, for arranging electrical wiring;

[0031] The electrically controlled telescopic pin I and electrically controlled telescopic pin II can cooperate with the stop groove on the control and release lower sleeve to limit or release the axial movement of the sealing piston;

[0032] The controlled-release lower sleeve is connected to the liquid storage lower sleeve via external thread IV, to the controlled-release upper sleeve via external thread V, and to the hourglass-shaped controlled-release sleeve via tapered thread II.

[0033] In the tension spring mechanism, the tension spring is sleeved on the outside of the central tube. The upper end of the tension spring is connected to the lower cover of the piston, and the lower end extends into the spring support. The spring support is provided with a spring stop groove and a threaded hole. The lower end of the tension spring is placed in the spring stop groove. The spring retaining ring is connected to the threaded hole by a screw and limits the lower end of the tension spring to be located in the spring support. The tension spring is used to drive the sealing piston to move axially along the control release lower sleeve after the sealing piston is released from its limit position.

[0034] In the hourglass-shaped controlled-release sleeve, tapered thread Ⅲ is provided at the upper end of the hourglass-shaped controlled-release sleeve and is sealed to the tapered thread Ⅱ of the lower controlled-release sleeve;

[0035] The hourglass-shaped controlled-release sleeve is provided with an arc-shaped working surface II inside. The arc-shaped working surface II is used to guide the solid corrosion inhibitor particles to smoothly enter the hourglass-shaped controlled-release sleeve from the lower section of the solid corrosion inhibitor controlled-release.

[0036] The internal channel of the hourglass-shaped controlled-release sleeve is formed from top to bottom into a contraction section, a flow-limiting section, and a diffusion section, so that the solid corrosion inhibitor particles are subject to flow restriction and controlled release when passing through the hourglass-shaped controlled-release sleeve.

[0037] The external thread VI is located at the lower end of the hourglass-shaped controlled-release sleeve and is threadedly connected to the internal thread VI of the particle sieve tube, so that the hourglass-shaped controlled-release sleeve is connected to the particle sieve tube.

[0038] In the particle sieve tube, the internal thread VI is provided at the upper end of the particle sieve tube and is connected to the external thread VI of the hourglass-shaped controlled release sleeve;

[0039] The particle sieve tube is connected to the internal channel of the hourglass-shaped controlled-release sleeve, and is used to receive solid corrosion inhibitor particles after the flow is limited by the hourglass-shaped controlled-release sleeve.

[0040] The plurality of through holes II are spaced apart along the axial and circumferential directions of the particle screen tube, and are used to disperse and release solid corrosion inhibitor particles into the well fluid;

[0041] The through hole II is connected to the internal channel of the particle screen tube and to the well fluid space outside the central tube, so that the solid corrosion inhibitor particles can be released from the inside of the particle screen tube to the outside.

[0042] The downhole self-powered closed-loop feedback type long-term controlled release injection device for solid corrosion inhibitors is a single-section controlled release unit. Each single-section controlled release unit consists of a downhole power generation device, a central tube, an upper section of the solid corrosion inhibitor controlled release device, a lower section of the solid corrosion inhibitor controlled release device, and a tension spring mechanism. Multiple single-section controlled release units can be connected sequentially along the axial direction of the central tube. The bottommost single-section controlled release unit is connected to an hourglass-shaped controlled release sleeve and a particle screen tube to form a multi-section long-term controlled release injection system for solid corrosion inhibitors. Adjacent single-section controlled release units are connected by a tapered thread seal, and multiple single-section controlled release units release solid corrosion inhibitor particles sequentially from bottom to top.

[0043] The working process of the downhole self-powered closed-loop feedback solid corrosion inhibitor long-term controlled-release injection device includes the following steps:

[0044] SⅠ. The device is lowered into the wellbore:

[0045] The downhole self-powered closed-loop feedback solid corrosion inhibitor long-term controlled release injection device is lowered into the target position of the wellbore along with the tubing. Multiple single-section controlled release units are connected sequentially along the central tube axis and arranged together with the tubing inside the wellbore.

[0046] SⅡ, Downhole Self-Powered Start-up:

[0047] The fluid in the wellbore flows through the central pipe and the area where the downhole power generation device is located, driving the power generation turbine to rotate and generate electricity. The generated electrical energy is transmitted to the control module through the transmission ring and supplies power to the electrically controlled needle valve I, the corrosion inhibitor concentration meter in the wellbore, the corrosion inhibitor concentration meter in the sleeve, and the electrically controlled needle valve II.

[0048] SⅢ, Corrosion Inhibitor Concentration Detection:

[0049] After the control module is powered on, the corrosion inhibitor concentration meter inside the wellbore in the currently monitored single-section controlled release unit periodically detects the corrosion inhibitor concentration in the wellbore fluid, and the corrosion inhibitor concentration meter inside the sleeve periodically detects the corrosion inhibitor concentration inside the upper section of the solid corrosion inhibitor controlled release unit, and transmits the detection signals to the control module respectively; the control module calculates the concentration difference between the two based on the detection results of the corrosion inhibitor concentration meters inside the wellbore and the sleeve, and when the concentration difference does not reach the set difference threshold, the device maintains the detection state;

[0050] SⅣ, Pressure Balance and Flow Channel Opening:

[0051] When the concentration difference detected by the corrosion inhibitor concentration gauge inside the wellbore and the corrosion inhibitor concentration gauge inside the sleeve reaches the set difference threshold, the control module does not immediately execute the release action, but continues to wait for a preset detection cycle. After the preset detection cycle ends, the control module compares the detection values ​​of the corrosion inhibitor concentration gauge inside the wellbore and the corrosion inhibitor concentration gauge inside the sleeve again. If the concentration difference between the two still reaches or exceeds the set difference threshold, the control module controls the electrically controlled needle valve I and electrically controlled needle valve II in the currently released single-section controlled release unit to open, so that the wellbore fluid is connected to the corrosion inhibitor containing space, balancing the internal and external pressure difference between the upper and lower sections of the solid corrosion inhibitor controlled release unit. If the concentration difference value after verification is lower than the set difference threshold, the device continues to maintain the detection state.

[0052] S₅₅, Piston limit released:

[0053] The control module controls the retraction of the electrically controlled telescopic pin I and electrically controlled telescopic pin II, causing them to disengage from the stop groove on the lower control sleeve, thereby releasing the axial restriction on the sealed movable piston composed of the piston upper cover, piston body and piston lower cover;

[0054] SVI, Spring-driven release:

[0055] The tension spring releases elastic potential energy and drives the piston lower cover and sealing piston to move through its upper end. The sealing piston drives the solid corrosion inhibitor particles to move toward the hourglass-shaped controlled release sleeve.

[0056] SⅦ, Flow-limited controlled release:

[0057] After the solid corrosion inhibitor particles enter the hourglass-shaped controlled-release sleeve, they are subject to flow restriction control under the action of the contraction section, flow restriction section and diffusion section inside the hourglass-shaped controlled-release sleeve, thus avoiding the instantaneous concentrated release of the solid corrosion inhibitor particles;

[0058] SⅧ, Sieve tube dispersion and release:

[0059] After being restricted by the hourglass-shaped controlled-release sleeve, the solid corrosion inhibitor particles enter the particle screen tube and are dispersed and released into the well fluid through the through hole II on the particle screen tube, so that the solid corrosion inhibitor particles diffuse with the well fluid and play a corrosion inhibition role.

[0060] SⅨ, Closed-loop feedback and cyclic controlled release:

[0061] After the current single-section controlled-release unit completes the release of solid corrosion inhibitor particles, the corrosion inhibitor concentration gauges in the wellbore and the sleeve continue to detect the concentration and transmit the detection signals to the control module. When the corrosion inhibitor concentration in the wellbore fluid returns to the set range, the control module no longer triggers the subsequent actions of the current single-section controlled-release unit and sends a signal to the control module in the adjacent single-section controlled-release unit above it to activate it. When the adjacent single-section controlled-release unit above it detects that the concentration difference has reached the set difference threshold again, and the release conditions are still met after a preset detection cycle, the adjacent single-section controlled-release unit above it controls the adjacent single-section controlled-release unit above it to repeat SⅣ to SⅧ, thereby realizing the phased, long-cycle, closed-loop feedback on-demand controlled release of downhole solid corrosion inhibitors.

[0062] Beneficial effects of the present invention

[0063] 1. This invention employs dual-point detection using both an in-wellbore corrosion inhibitor concentration meter and an in-sleeve corrosion inhibitor concentration meter. The control module determines whether to trigger release based on the concentration difference between the two meters, and performs a verification after a one-cycle delay once the set difference is reached. Compared to traditional quantitative injection, periodic injection, or single threshold judgment methods, this method can reduce false triggering of release, improve the accuracy of on-demand injection, and reduce agent waste and the risk of under-dosing corrosion.

[0064] 2. This invention utilizes a downhole power generation device to convert the kinetic energy of the wellbore fluid into electrical energy, which powers the control module and actuators. During release, an electrically controlled needle valve balances the pressure inside and outside the corrosion inhibitor containment space, and then an electrically controlled telescopic pin releases the piston limit, allowing the tension spring mechanism to drive the sealed movable piston to release the solid corrosion inhibitor particles. This structure differs from those relying on surface cables, high-capacity batteries, or motor screw drives, and has the advantages of compact structure, low power consumption, and reliable operation.

[0065] 3. This invention incorporates an hourglass-shaped controlled-release sleeve and a particle screen along the release path of the solid corrosion inhibitor. The hourglass-shaped sleeve limits the instantaneous flow of particles, while the particle screen disperses the corrosion inhibitor particles into the wellbore fluid, reducing the risk of localized accumulation. Simultaneously, multiple single-section controlled-release units can be connected in series along the central tube axis and release in stages. Unlike a single agent tank passively dissolving and releasing structure, this allows for long-term, staged, and uniform controlled-release injection. Attached Figure Description

[0066] Figure 1 This is a schematic diagram of the downhole operation of the present invention;

[0067] Figure 2 This is a schematic diagram of the downhole self-powered closed-loop feedback solid corrosion inhibitor long-term controlled release injection device of the present invention;

[0068] Figure 3 This is a schematic diagram of the overall structure of the single-section controlled-release unit of the present invention;

[0069] Figure 4 This is a schematic diagram of the structure of the controlled-release solid corrosion inhibitor of the present invention.

[0070] Figure 5 This is a schematic diagram of the lower section of the structure of the solid corrosion inhibitor controlled release method of the present invention;

[0071] Figure 6 This is a schematic diagram of the tension spring mechanism of the present invention;

[0072] Figure 7 This is a schematic diagram of the hourglass-shaped controlled-release sleeve structure of the present invention;

[0073] Figure 8 This is a schematic diagram of the particle sieve tube structure of the present invention;

[0074] Figure 9 This is a schematic diagram of the current-carrying ring structure of the present invention;

[0075] Figure 10 This is a schematic diagram of the controlled-release upper sleeve structure of the present invention;

[0076] Figure 11 This is a schematic diagram of the inclined sleeve structure of the present invention;

[0077] Figure 12This is a schematic diagram of the liquid storage upper sleeve structure of the present invention;

[0078] Figure 13 This is a schematic diagram of the liquid storage lower sleeve structure of the present invention;

[0079] Figure 14 This is a schematic diagram of the piston cover structure of the present invention;

[0080] Figure 15 This is a schematic diagram of the piston body structure of the present invention;

[0081] Figure 16 This is a schematic diagram of the piston lower cover structure of the present invention;

[0082] Figure 17 This is a schematic diagram of the controlled-release lower sleeve structure of the present invention;

[0083] Figure 18 This is a schematic diagram of the spring support structure of the present invention;

[0084] Figure 19 This is a flowchart of the controlled release operation of the self-powered closed-loop feedback solid corrosion inhibitor in downhole according to the present invention.

[0085] In the diagram, 1. Downhole power generation device; 101. Sealing cover plate; 102. Control module; 103. Power transmission ring; 1031. External thread I; 1032. Internal thread I; 1033. Mounting hole I; 104. Generator turbine; 2. Center tube; 3. Controlled release upper section of solid corrosion inhibitor; 301. Controlled release upper section sleeve; 3011. Tapered thread I; 3012. Inclined hole I; 3013. Internal thread II; 302. Electrically controlled needle valve I; 303. Corrosion inhibitor concentration meter inside the wellbore; 304. Corrosion inhibitor concentration meter inside the sleeve; 305. 1. Electrically controlled needle valve II; 306. Inclined sleeve; 3061. Inclined surface I; 3062. Through hole I; 307. Upper reservoir sleeve; 3071. Flow channel groove I; 3072. Mounting hole II; 3073. Flow channel groove II; 3074. Reservoir chamber; 308. Lower reservoir sleeve; 3081. Inclined hole II; 3082. Flow channel groove III; 3083. Internal thread III; 4. Lower section of solid corrosion inhibitor controlled release; 401. Piston cover; 4011. External thread II; 4012. Circular arc working surface I; 402. Sealing ring I; 40 3. Piston body; 4031, Internal thread IV; 4032, Sealing groove I; 4033, Internal thread V; 4034, Mounting hole III; 4035, Wire passage groove I; 4036, Mounting hole IV; 4037, Mounting hole V; 4038, Wire passage groove II; 4039, Mounting hole VI; 404, Sealing ring II; 405, Piston lower cover; 4051, External thread III; 406, Controlled release lower sleeve; 4061, External thread IV; 4062, Sealing surface; 4063, External thread V; 4064, Stop groove; 40 65. Tapered thread II; 407. Electrically controlled telescopic pin I; 408. High-energy battery I; 409. Electrically controlled telescopic pin II; 410. High-energy battery II; 5. Tension spring mechanism; 501. Tension spring; 502. Spring retaining ring; 503. Spring support; 5031. Spring stop groove; 5032. Threaded hole; 6. Hourglass-shaped controlled release sleeve; 6001. Tapered thread III; 6002. Arc working surface II; 6003. External thread VI; 7. Granule screen tube; 7001. Internal thread VI; 7002. Through hole II. Detailed Implementation

[0086] The present invention will be further described below with reference to the accompanying drawings. The scope of protection of the present invention is not limited to the following description:

[0087] like Figures 1-19 As shown, this embodiment is a downhole self-powered closed-loop feedback solid corrosion inhibitor long-term controlled release injection device, including a downhole power generation device 1, a central pipe 2, a solid corrosion inhibitor controlled release upper section 3, a solid corrosion inhibitor controlled release lower section 4, a tension spring mechanism 5, an hourglass-shaped controlled release sleeve 6, and a particle screen pipe 7.

[0088] In this embodiment, the downhole self-powered closed-loop feedback solid corrosion inhibitor long-term controlled release injection device, such as... Figure 2As shown, the device includes a downhole power generation unit 1, a central pipe 2, a solid corrosion inhibitor controlled-release upper section 3, a solid corrosion inhibitor controlled-release lower section 4, a tension spring mechanism 5, an hourglass-shaped controlled-release sleeve 6, and a particle screen pipe 7. The components of the downhole power generation unit 1 are respectively housed within the central pipe 2 and the solid corrosion inhibitor controlled-release upper section 3. It is used to generate electrical energy from the kinetic energy of the wellbore fluid within the central pipe 2, and to power the detection, control, and execution components within the device. The lower end of the central pipe 2 is connected to the tension spring mechanism 5 to form a wellbore fluid flow channel. The solid corrosion inhibitor controlled-release upper section 3 and the solid corrosion inhibitor controlled-release lower section 4 are located along the axis of the central pipe 2. The system connects to form a sealed and isolated liquid storage space for storing liquid in the wellbore. The tension spring mechanism 5 is located inside the solid corrosion inhibitor controlled release lower section 4 and is used to control the release of solid corrosion inhibitor particles to the hourglass-shaped controlled release sleeve 6. The hourglass-shaped controlled release sleeve 6 is located between the solid corrosion inhibitor controlled release lower section 4 and the particle screen tube 7 and is used to limit the amount of solid corrosion inhibitor particles passing through per unit time. The particle screen tube 7 is connected to the hourglass-shaped controlled release sleeve 6 and is provided with multiple release holes for dispersing and releasing the solid corrosion inhibitor particles after flow restriction by the hourglass-shaped controlled release sleeve 6 into the wellbore fluid.

[0089] In this embodiment, the downhole power generation device 1, as shown... Figure 3 As shown, it includes a sealing cover plate 101, a control module 102, a power transmission ring 103, and a power generation turbine 104; the control module 102 is installed inside the power transmission ring 103, the sealing cover plate 101 is installed on the upper end of the power transmission ring 103 and forms a seal, and the power generation turbine 104 is located in the fluid flow area inside the central tube 2 and is electrically connected to the power transmission ring 103.

[0090] In this embodiment, the solid corrosion inhibitor is released in controlled manner as described in section 3, such as... Figure 4 As shown, the system includes a controlled-release upper sleeve 301, an electrically controlled needle valve I 302, a wellbore corrosion inhibitor concentration meter 303, a sleeve corrosion inhibitor concentration meter 304, an electrically controlled needle valve II 305, an inclined sleeve 306, a liquid storage upper sleeve 307, and a liquid storage lower sleeve 308. The controlled-release upper sleeve 301 is sleeved on the outside of the central tube 2. The electrically controlled needle valve I 302, the wellbore corrosion inhibitor concentration meter 303, the sleeve corrosion inhibitor concentration meter 304, and the electrically controlled needle valve II 305 are installed on the controlled-release upper sleeve 301. The inclined sleeve 306, the liquid storage upper sleeve 307, and the liquid storage lower sleeve 308 are disposed inside the controlled-release upper sleeve 301. The liquid storage upper sleeve 307 and the liquid storage lower sleeve 308 are axially fitted to form a sealed and isolated liquid storage space for storing liquid in the wellbore.

[0091] In this embodiment, the solid corrosion inhibitor is released under controlled conditions as described in section 4, such as... Figure 5As shown, the piston assembly includes an upper piston cover 401, a sealing ring I 402, a piston body 403, a sealing ring II 404, a lower piston cover 405, a controlled-release lower sleeve 406, an electrically controlled telescopic pin I 407, a high-energy battery I 408, an electrically controlled telescopic pin II 409, and a high-energy battery II 410. The upper piston cover 401, the piston body 403, and the lower piston cover 405 are sequentially connected axially to form a sealed movable piston. The sealing ring I 402 is used to achieve sealing isolation between the wellbore and the inner sleeve. The sealing ring II 404 is disposed in the sealing groove I 4032 and slides to seal with the inner diameter of the controlled-release lower sleeve 406. The sealed movable piston is disposed in the controlled-release lower sleeve 406. The electrically controlled telescopic pin I 407, the high-energy battery I 408, the electrically controlled telescopic pin II 409, and the high-energy battery II 410 are mounted on the piston body 403.

[0092] In this embodiment, the tension spring mechanism 5, as... Figure 6 As shown, it includes a tension spring 501, a spring retaining ring 502, and a spring support 503. The upper end of the tension spring 501 is connected to the piston lower cover 405, and the other end is installed inside the spring support 503. The lower end of the tension spring 501 is restricted inside the spring support 503 by the spring retaining ring 502. One end of the spring support 503 is connected to the central tube 2, and the other end is connected to the solid corrosion inhibitor controlled release lower section 4.

[0093] In this embodiment, the hourglass-shaped controlled-release sleeve 6, as... Figure 2 , 7 As shown in Figure 8, its upper end is connected to the controlled-release lower sleeve 406, and its lower end is connected to the particle sieve tube 7;

[0094] In this embodiment, the particle sieve tube 7, as shown... Figure 2 , 8 As shown, it is located at the lower end of the hourglass-shaped controlled-release sleeve 6 and is connected to the hourglass-shaped controlled-release sleeve 6.

[0095] In this embodiment, the downhole power generation device 1, as shown... Figure 3 , 9As shown, the sealing cover plate 101 and the power transmission ring 103 cooperate to form a sealed installation space for the control module 102. The control module 102 controls the operation of the corrosion inhibitor concentration meter 303 in the wellbore, the corrosion inhibitor concentration meter 304 in the sleeve, the electrically controlled needle valve I 302, the electrically controlled needle valve II 305, the electrically controlled telescopic pin I 407, and the electrically controlled telescopic pin II 409. The power transmission ring 103 is electrically connected to the generator turbine 104 and is used to transmit the electrical energy generated by the generator turbine 104 to the control module 102 and... The electric actuator has an external thread I1031, an internal thread I1032, and four circumferentially distributed mounting holes I1033. The external thread I1031 is threaded to the internal area of ​​the upper control sleeve 301, the internal thread I1032 is threaded to the central tube 2, and the mounting holes I1033 are used to install the control module 102 and the sealing cover plate 101. The electric actuator 103 and the generator turbine 104 form an electrical energy transmission path.

[0096] In this embodiment, the solid corrosion inhibitor is released in controlled manner as described in section 3, such as... Figure 4 , 11 As shown in Figures 12 and 13, the controlled release upper sleeve 301 is connected to the upper end device adjacent to the bottom of the well via tapered thread I 3011, and is connected to the inclined sleeve 306, the liquid storage upper sleeve 307, the liquid storage lower sleeve 308, and the controlled release lower sleeve 406 via internal thread II 3013.

[0097] The inclined hole I 3012 and inclined hole II 3081 on the controlled-release upper sleeve 301 are connected, allowing wellbore fluid to enter the internal cavity of the solid corrosion inhibitor controlled-release upper section 3 via the electrically controlled needle valve I 302 or electrically controlled needle valve II 305. The electrically controlled needle valve I 302 and electrically controlled needle valve II 305 are connected to the internal flow channel formed by the liquid storage upper sleeve 307 and the liquid storage lower sleeve 308, and are used to control whether the internal cavity of the solid corrosion inhibitor controlled-release upper section 3 is connected to the external wellbore fluid. The corrosion inhibitor concentration meter 303 is installed in the wellbore where the controlled-release upper sleeve 301 is connected to the wellbore fluid. The sleeve internal corrosion inhibitor concentration meter 304 is located inside the cavity of the controlled-release upper sleeve 301, and both are electrically connected to the control module 102. The inclined sleeve 306 is located above the liquid storage upper sleeve 307 and the liquid storage lower sleeve 308. The inclined surface I 3061 on the inclined sleeve 306 is used to guide the solid corrosion inhibitor particles to move downward. The through hole I 3062 on the inclined sleeve 306 is used to install the electrically controlled needle valve I 302, the wellbore internal corrosion inhibitor concentration meter 303, the sleeve internal corrosion inhibitor concentration meter 304, and the electrically controlled needle valve II 305, respectively.

[0098] The flow channel groove I 3071 on the upper sleeve 307 is used to introduce the fluid flowing from the electrically controlled needle valve I 302 into the corrosion inhibitor containing space. The mounting hole II 3072 on the upper sleeve 307 is used to install the corrosion inhibitor concentration meter 304 inside the sleeve. The flow channel groove II 3073 on the upper sleeve 307 is used to introduce the fluid flowing from the electrically controlled needle valve II 305 into the corrosion inhibitor containing space. The liquid storage chamber 3074 on the upper sleeve 307 is used to store the liquid in the wellbore.

[0099] The flow channel groove Ⅲ3082 on the lower sleeve 308 and the storage cavity 3074 on the upper sleeve 307 cooperate to form a storage cavity for wellbore fluid to enter. The lower sleeve 308 is connected to the external thread Ⅳ4061 of the controlled release lower sleeve 406 through the internal thread Ⅲ3083.

[0100] In this embodiment, the solid corrosion inhibitor is released under controlled conditions as described in section 4, such as... Figure 5 , 14 As shown in 15, 16, and 17, the piston upper cover 401 is connected to the piston body 403 internally via external thread II 4011, and the piston lower cover 405 is connected to the piston body 403 internally via external thread III 4051, thereby forming a sealed movable piston with the piston upper cover 401, piston body 403, and piston lower cover 405.

[0101] The arc working surface I 4012 on the piston cover 401 contacts the solid corrosion inhibitor particles and is used to guide the solid corrosion inhibitor particles to fall when the sealed moving piston moves to prevent particle accumulation; the sealing groove I 4032 on the piston body 403 cooperates with the sealing ring II 404, and the sealing ring II 404 forms a sliding sealing cooperation with the inner diameter of the control release lower sleeve 406.

[0102] The mounting holes Ⅲ4034 and Ⅳ4036 on the piston body 403 are used to install the electrically controlled telescopic pin Ⅰ407 and the high-energy battery Ⅰ408, respectively; the mounting holes Ⅴ4037 and VI4039 are used to install the electrically controlled telescopic pin Ⅱ409 and the high-energy battery Ⅱ410, respectively.

[0103] The wire passage groove I 4035 on the piston body 403 is located between the electrically controlled telescopic pin I 407 and the high-energy battery I 408, and the wire passage groove II 4038 is located between the electrically controlled telescopic pin II 409 and the high-energy battery II 410, for arranging electrical wiring;

[0104] The electrically controlled telescopic pin I 407 and electrically controlled telescopic pin II 409 can cooperate with the stop groove 4064 on the control and release lower sleeve 406 to limit or release the axial movement of the sealing piston.

[0105] The controlled-release lower sleeve 406 is connected to the liquid storage lower sleeve 308 via external thread IV 4061, to the controlled-release upper sleeve 301 via external thread V 4063, and to the hourglass-shaped controlled-release sleeve 6 via tapered thread II 4065.

[0106] In this embodiment, the tension spring mechanism 5, as... Figure 6 , 18 As shown, the tension spring 501 is sleeved on the outside of the central tube 2. The upper end of the tension spring 501 is connected to the piston lower cover 405, and the lower end extends into the spring support 503. The spring support 503 is provided with a spring stop groove 5031 and a threaded hole 5032. The lower end of the tension spring 501 is placed in the spring stop groove 5031. The spring retaining ring 502 is connected to the threaded hole 5032 by a screw and limits the lower end of the tension spring 501 to be located in the spring support 503. The tension spring 501 is used to drive the sealing piston to move axially along the control release lower sleeve 406 after the sealing piston is released from its limit position.

[0107] In this embodiment, the hourglass-shaped controlled-release sleeve 6, as... Figure 7 As shown, tapered thread Ⅲ6001 is provided on the upper end of hourglass-shaped controlled release sleeve 6 and is sealed to tapered thread Ⅱ4065 of controlled release lower sleeve 406;

[0108] The hourglass-shaped controlled-release sleeve 6 is provided with an arc-shaped working surface II 6002 inside. The arc-shaped working surface II 6002 is used to guide the solid corrosion inhibitor particles from the solid corrosion inhibitor controlled-release lower section 4 into the hourglass-shaped controlled-release sleeve 6.

[0109] The internal channel of the hourglass-shaped controlled-release sleeve 6 forms a contraction section, a flow-limiting section, and a diffusion section from top to bottom, so that the solid corrosion inhibitor particles are subject to flow restriction and controlled release when passing through the hourglass-shaped controlled-release sleeve 6; the external thread VI6003 is provided at the lower end of the hourglass-shaped controlled-release sleeve 6 and is threadedly connected to the internal thread VI7001 of the particle sieve tube 7, so that the hourglass-shaped controlled-release sleeve 6 is connected to the particle sieve tube 7.

[0110] In this embodiment, the particle sieve tube 7, as shown... Figure 8 As shown, the internal thread VI7001 is provided at the upper end of the particle sieve tube 7 and is connected to the external thread VI6003 of the hourglass-shaped controlled release sleeve 6;

[0111] The particle sieve tube 7 is connected to the internal channel of the hourglass-shaped controlled-release sleeve 6, and is used to receive solid corrosion inhibitor particles after being restricted by the hourglass-shaped controlled-release sleeve 6.

[0112] The multiple through holes II 7002 are spaced apart along the axial and circumferential directions of the particle screen tube 7 to disperse and release solid corrosion inhibitor particles into the well fluid; the through holes II 7002 are connected to the internal channel of the particle screen tube 7 and to the well fluid space outside the central tube 2, so that the solid corrosion inhibitor particles can be released from the inside of the particle screen tube 7 to the outside.

[0113] In this embodiment, the downhole self-powered closed-loop feedback type long-term controlled release injection device for solid corrosion inhibitors is a single-section controlled release unit. The single-section controlled release unit consists of a downhole power generation device 1, a central tube 2, a solid corrosion inhibitor upper section 3, a solid corrosion inhibitor lower section 4, and a tension spring mechanism 5. Multiple single-section controlled release units can be connected sequentially along the axial direction of the central tube 2 to form a multi-section long-term controlled release injection system for solid corrosion inhibitors. Adjacent single-section controlled release units are connected by a tapered thread seal, and multiple single-section controlled release units release solid corrosion inhibitor particles sequentially from bottom to top.

[0114] In this embodiment, the working process of the downhole self-powered closed-loop feedback solid corrosion inhibitor long-term controlled release injection device is as follows: Figure 19 As shown, it includes the following process:

[0115] SⅠ. The device is lowered into the wellbore: The downhole self-powered closed-loop feedback solid corrosion inhibitor long-term controlled release injection device is lowered into the target position of the wellbore along with the tubing. Multiple single-section controlled release units are connected sequentially along the central tube 2 and arranged together with the tubing in the wellbore.

[0116] SⅡ, Downhole Self-Powered Start-up: The well fluid flows through the area where the central pipe 2 and the downhole power generation device 1 are located, driving the power generation turbine 104 to rotate and generate electricity. The generated electrical energy is transmitted to the control module 102 through the power transmission ring 103 and supplies power to the electrically controlled needle valve I 302, the corrosion inhibitor concentration meter 303 in the well, the corrosion inhibitor concentration meter 304 in the sleeve, and the electrically controlled needle valve II 305.

[0117] SⅢ, Corrosion Inhibitor Concentration Detection: After the control module 102 is powered on, the corrosion inhibitor concentration meter 303 in the wellbore of the currently monitored single-section controlled release unit periodically detects the corrosion inhibitor concentration in the wellbore fluid, and the corrosion inhibitor concentration meter 304 in the sleeve periodically detects the corrosion inhibitor concentration inside the solid corrosion inhibitor controlled release upper section 3, and transmits the detection signals to the control module 102 respectively; the control module 102 calculates the concentration difference between the two based on the detection results of the corrosion inhibitor concentration meter 303 in the wellbore and the corrosion inhibitor concentration meter 304 in the sleeve. When the concentration difference does not reach the set difference threshold, the device maintains the detection state;

[0118] SⅣ, Pressure Balance and Flow Channel Opening: When the concentration difference detected by the corrosion inhibitor concentration meter 303 in the wellbore and the corrosion inhibitor concentration meter 304 in the sleeve reaches the set difference threshold, the control module 102 does not immediately execute the release action, but continues to wait for a preset detection cycle; after the preset detection cycle ends, the control module 102 compares the detection values ​​of the corrosion inhibitor concentration meter 303 in the wellbore and the corrosion inhibitor concentration meter 304 in the sleeve again. If the concentration difference between the two still reaches or exceeds the set difference threshold, the control module 102 controls the opening of the electrically controlled needle valve I 302 and electrically controlled needle valve II 305 in the currently released single-section controlled release unit, so that the wellbore fluid is connected to the corrosion inhibitor containing space, balancing the internal and external pressure difference between the upper section 3 and the lower section 4 of the solid corrosion inhibitor controlled release; if the concentration difference value after verification is lower than the set difference threshold, the device continues to maintain the detection state;

[0119] SⅤ, Piston Limit Release: Control module 102 controls the retraction of electrically controlled telescopic pin I 407 and electrically controlled telescopic pin II 409, causing them to disengage from the stop groove 4064 on the control release lower sleeve 406, thereby releasing the axial limit on the sealed movable piston composed of piston upper cover 401, piston body 403 and piston lower cover 405.

[0120] SVI. Spring-driven release: The tension spring 501 releases elastic potential energy and drives the sealing piston to move axially along the lower control sleeve 406. The sealing piston drives the solid corrosion inhibitor particles to move toward the hourglass-shaped control sleeve 6.

[0121] SⅦ, Flow-limiting and controlled release: After the solid corrosion inhibitor particles enter the hourglass-shaped controlled release sleeve 6, they are subject to flow-limiting control under the action of the contraction section, flow-limiting section and diffusion section inside the hourglass-shaped controlled release sleeve 6, so as to avoid the instantaneous concentrated release of solid corrosion inhibitor particles;

[0122] SⅧ, Screen tube dispersion and release: After the solid corrosion inhibitor particles are restricted by the hourglass-shaped controlled release sleeve 6, they enter the particle screen tube 7 and are dispersed and released into the well fluid through the through hole II7002 on the particle screen tube 7, so that the solid corrosion inhibitor particles diffuse with the well fluid and play a corrosion inhibition role.

[0123] SⅨ, Closed-Loop Feedback and Cyclic Controlled Release: After the current single-section controlled release unit completes the release of solid corrosion inhibitor particles, the corrosion inhibitor concentration meter 303 in the wellbore and the corrosion inhibitor concentration meter 304 in the sleeve continue to detect the concentration and transmit the detection signal to the control module 102. When the corrosion inhibitor concentration in the wellbore fluid returns to the set range, the control module 102 no longer triggers the subsequent actions of the current single-section controlled release unit and sends a signal to the control module 102 of the adjacent single-section controlled release unit above it to make it work. When the adjacent single-section controlled release unit above it detects that the concentration difference value reaches the set difference threshold again, and after a preset detection cycle, the release conditions are still met, the adjacent single-section controlled release unit 102 above it controls the adjacent single-section controlled release unit above it to repeat SⅣ to SⅧ, thereby realizing the phased, long-cycle, closed-loop feedback on-demand controlled release of downhole solid corrosion inhibitors.

[0124] Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0125] In the description of this invention, it should be noted that the directions or positional relationships indicated by terms such as "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer" are based on the directions or positional relationships shown in the accompanying drawings and are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0126] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0127] Furthermore, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0128] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art can make other variations or modifications based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A downhole self-powered closed-loop feedback type long-term controlled-release injection device for solid corrosion inhibitors, characterized in that: Includes downhole power generation device (1), central pipe (2), upper section of solid corrosion inhibitor controlled release (3), lower section of solid corrosion inhibitor controlled release (4), tension spring mechanism (5), hourglass-shaped controlled release sleeve (6), and particle screen pipe (7). The components of the downhole power generation device (1) are respectively installed in the central tube (2) and the upper section (3) of the solid corrosion inhibitor controlled release mechanism. They are used to generate electrical energy from the kinetic energy of the wellbore fluid within the central tube (2) and to power the detection, control, and execution components in the device. The lower end of the central tube (2) is connected to a tension spring mechanism (5) to form a wellbore fluid flow channel. The upper section (3) and the lower section (4) of the solid corrosion inhibitor controlled release mechanism are axially connected along the central tube (2) to form a sealed and isolated liquid storage space for storing the liquid in the wellbore. The tension spring... The spring mechanism (5) is located inside the lower section (4) of the solid corrosion inhibitor controlled release and is used to control the release of solid corrosion inhibitor particles to the direction of the hourglass-shaped controlled release sleeve (6). The hourglass-shaped controlled release sleeve (6) is located between the lower section (4) of the solid corrosion inhibitor controlled release and the particle screen (7) and is used to limit the amount of solid corrosion inhibitor particles passing through per unit time. The particle screen (7) is connected to the hourglass-shaped controlled release sleeve (6) and is provided with multiple release holes for dispersing and releasing the solid corrosion inhibitor particles after flow restriction by the hourglass-shaped controlled release sleeve (6) into the well fluid.

2. The downhole self-powered closed-loop feedback solid corrosion inhibitor long-term controlled release injection device according to claim 1, characterized in that: The downhole power generation device (1) includes a sealing cover plate (101), a control module (102), a power transmission ring (103), and a power generation turbine (104); the control module (102) is installed inside the power transmission ring (103), the sealing cover plate (101) is installed on the upper end of the power transmission ring (103) and forms a seal, and the power generation turbine (104) is located in the fluid flow area inside the central tube (2) and is electrically connected to the power transmission ring (103); The controlled-release upper section (3) of the solid corrosion inhibitor includes a controlled-release upper section sleeve (301), an electrically controlled needle valve I (302), an in-wellbore corrosion inhibitor concentration meter (303), an in-sleeve corrosion inhibitor concentration meter (304), an electrically controlled needle valve II (305), an inclined sleeve (306), a liquid storage upper sleeve (307), and a liquid storage lower sleeve (308). The controlled-release upper section sleeve (301) is sleeved on the outside of the central tube (2). The electrically controlled needle valve I (302), the in-wellbore corrosion inhibitor concentration meter (303), the sleeve corrosion inhibitor concentration meter (304), the electrically controlled needle valve II (305), the inclined sleeve (306), the liquid storage upper sleeve (307), and the liquid storage lower sleeve (308). The corrosion inhibitor concentration meter (303), the internal corrosion inhibitor concentration meter (304), and the electrically controlled needle valve II (305) are installed on the upper control sleeve (301). The inclined sleeve (306), the upper liquid storage sleeve (307), and the lower liquid storage sleeve (308) are located inside the upper control sleeve (301). The upper liquid storage sleeve (307) and the lower liquid storage sleeve (308) are axially fitted to form a sealed and isolated liquid storage space for storing liquid in the wellbore. The controlled-release lower section (4) of the solid corrosion inhibitor includes a piston top cover (401), sealing ring I (402), piston body (403), sealing ring II (404), piston bottom cover (405), controlled-release lower section sleeve (406), electrically controlled telescopic pin I (407), high-energy battery I (408), electrically controlled telescopic pin II (409), and high-energy battery II (410). The piston top cover (401), piston body (403), and piston bottom cover (405) are connected axially to form a sealed movable piston. The sealing ring I (402) is used to achieve sealing isolation between the wellbore and the sleeve. The sealing ring II (404) is used to seal the outer periphery of the movable piston. The sealed movable piston is set inside the controlled-release lower section sleeve (406). The electrically controlled telescopic pin I (407), high-energy battery I (408), electrically controlled telescopic pin II (409), and high-energy battery II (410) are installed on the piston body (403). The tension spring mechanism (5) includes a tension spring (501), a spring retaining ring (502) and a spring support (503). The upper end of the tension spring (501) is connected to the piston lower cover (405), and the other end is installed inside the spring support (503). The lower end of the tension spring (501) is restricted inside the spring support (503) by the spring retaining ring (502). One end of the spring support (503) is connected to the central tube (2), and the other end is connected to the solid corrosion inhibitor controlled release lower section (4). The upper end of the hourglass-shaped controlled-release sleeve (6) is connected to the lower controlled-release sleeve (406), and the lower end is connected to the particle sieve tube (7); The particle sieve tube (7) is located at the lower end of the hourglass-shaped controlled-release sleeve (6) and is connected to the hourglass-shaped controlled-release sleeve (6).

3. The downhole self-powered closed-loop feedback solid corrosion inhibitor long-term controlled release injection device according to claim 2, characterized in that: In the downhole power generation device (1), the sealing cover plate (101) and the power transmission ring (103) cooperate to form a sealed installation space for the control module (102). The control module (102) controls the operation of the corrosion inhibitor concentration meter (303) in the wellbore, the corrosion inhibitor concentration meter (304) in the sleeve, the electrically controlled needle valve I (302), the electrically controlled needle valve II (305), the electrically controlled telescopic pin I (407), and the electrically controlled telescopic pin II (409). The power transmission ring (103) is electrically connected to the power generation turbine (104) and is used to transmit the electrical energy generated by the power generation turbine (104) to the control module (102) and the electrical actuator. The power transmission ring (103) is provided with an external thread I (1031), an internal thread I (1032) and four circumferentially evenly distributed mounting holes I (1033). The external thread I (1031) is threaded to the inner wall of the control release upper sleeve (301), and the internal thread I (1032) is threaded to the central tube (2). The mounting holes I (1033) are used to install the control module (102) and the sealing cover plate (101). The power transmission ring (103) and the power generation turbine (104) form an electrical energy transmission path.

4. The downhole self-powered closed-loop feedback solid corrosion inhibitor long-term controlled release injection device according to claim 2, characterized in that: In the solid corrosion inhibitor controlled release upper section (3), the controlled release upper section sleeve (301) is connected to the upper end device adjacent to the bottom of the well through tapered thread I (3011), and is connected to the inclined sleeve (306) through internal thread II (3013); the inclined sleeve (306), the liquid storage upper sleeve (307) and the liquid storage lower sleeve (308) are assembled sequentially along the axial direction; The inclined hole I (3012) and inclined hole II (3081) on the upper sleeve (301) of the controlled release section are connected to each other, so that the well fluid can enter the internal cavity of the upper section (3) of the solid corrosion inhibitor controlled release section through the electrically controlled needle valve I (302) or the electrically controlled needle valve II (305); the electrically controlled needle valve I (302) and the electrically controlled needle valve II (305) are connected to the internal flow channel formed by the upper sleeve (307) of the liquid storage and the lower sleeve (308) of the liquid storage, and are used to control whether the internal of the upper section (3) of the solid corrosion inhibitor controlled release section (3) is connected to the external well fluid; The corrosion inhibitor concentration meter (303) inside the wellbore is located at the position where the controlled release upper sleeve (301) is in fluid communication with the wellbore, and the corrosion inhibitor concentration meter (304) inside the sleeve is located in the internal cavity of the controlled release upper sleeve (301). Both are electrically connected to the control module (102). The inclined sleeve (306) is positioned above the upper sleeve (307) and the lower sleeve (308) of the liquid storage. The inclined surface I (3061) on the inclined sleeve (306) is used to guide the solid corrosion inhibitor particles to move downward. The inclined sleeve (306) has four circumferentially evenly arranged through holes I (3062) for installing the electrically controlled needle valve I (302), the corrosion inhibitor concentration meter (303) in the wellbore, the corrosion inhibitor concentration meter (304) in the sleeve, and the electrically controlled needle valve II (305), respectively. The flow channel groove I (3071) on the upper sleeve of the liquid storage (307) is used to introduce the fluid flowing from the electrically controlled needle valve I (302) into the corrosion inhibitor containing space. The mounting hole II (3072) on the upper sleeve of the liquid storage (307) is used to install the corrosion inhibitor concentration meter (304) inside the sleeve. The flow channel groove II (3073) on the upper sleeve of the liquid storage (307) is used to introduce the fluid flowing from the electrically controlled needle valve II (305) into the corrosion inhibitor containing space. The liquid storage chamber (3074) on the upper sleeve of the liquid storage (307) is used to store the liquid in the wellbore. The flow channel groove Ⅲ (3082) on the lower sleeve (308) and the storage cavity (3074) on the upper sleeve (307) cooperate to form a storage cavity for well fluid to enter. The lower sleeve (308) is connected to the external thread Ⅳ (4061) of the controlled release lower sleeve (406) through the internal thread Ⅲ (3083).

5. The downhole self-powered closed-loop feedback solid corrosion inhibitor long-term controlled release injection device according to claim 2, characterized in that: In the controlled release section (4) of the solid corrosion inhibitor, the piston upper cover (401) is connected to the piston body (403) internal thread (4031) through external thread II (4011), and the piston lower cover (405) is connected to the piston body (403) internal thread V (4033) through external thread III (4051), so that the piston upper cover (401), piston body (403) and piston lower cover (405) form a sealed movable piston; The arc working surface I (4012) on the piston cover (401) is in contact with the solid corrosion inhibitor particles, which is used to guide the solid corrosion inhibitor particles to fall when the sealed moving piston moves, and prevent the particles from accumulating. The sealing ring I (402) is placed on the controlled release lower sleeve (406) to achieve sealing isolation between the wellbore and the sleeve; the sealing ring II (404) is set in the sealing groove I (4032) on the outer periphery of the piston body (403) and slides and seals with the sealing surface of the controlled release lower sleeve. The mounting holes Ⅲ (4034) and Ⅳ (4036) on the piston body (403) are used to install the electrically controlled telescopic pin Ⅰ (407) and the high-energy battery Ⅰ (408), respectively. The mounting holes Ⅴ (4037) and Ⅵ (4039) are used to install the electrically controlled telescopic pin Ⅱ (409) and the high-energy battery Ⅱ (410), respectively. The wire groove I (4035) on the piston body (403) is located between the electrically controlled telescopic pin I (407) and the high-energy battery I (408), and the wire groove II (4038) is located between the electrically controlled telescopic pin II (409) and the high-energy battery II (410) for arranging electrical wiring; The electrically controlled telescopic pin I (407) and electrically controlled telescopic pin II (409) can cooperate with the stop groove (4064) on the control release lower sleeve (406) to limit or release the axial movement of the sealing piston; The controlled-release lower sleeve (406) is connected to the internal thread (3083) of the liquid storage lower sleeve (308) via the external thread (4061), to the controlled-release upper sleeve (301) via the external thread (4063), and to the tapered thread (6001) of the hourglass-shaped controlled-release sleeve (6) via the tapered thread (4065).

6. The downhole self-powered closed-loop feedback solid corrosion inhibitor long-term controlled release injection device according to claim 2, characterized in that: In the tension spring mechanism (5), the tension spring (501) is sleeved on the outside of the central tube (2). The upper end of the tension spring (501) is connected to the piston lower cover (405), and the lower end extends into the spring support (503). The spring support (503) is provided with a spring stop groove (5031) and a threaded hole (5032). The lower end of the tension spring (501) is placed in the spring stop groove (5031). The spring retaining ring (502) is connected to the threaded hole (5032) by a screw and limits the lower end of the tension spring (501) to be located in the spring support (503). The tension spring (501) is used to drive the sealing piston to move axially along the control release lower sleeve (406) after the sealing piston is released from its limit.

7. The downhole self-powered closed-loop feedback solid corrosion inhibitor long-term controlled release injection device according to claim 2, characterized in that: In the hourglass-shaped controlled release sleeve (6), the tapered thread III (6001) is provided at the upper end of the hourglass-shaped controlled release sleeve (6) and is sealed to the tapered thread II (4065) of the controlled release lower sleeve (406); The hourglass-shaped controlled-release sleeve (6) is provided with an arc working surface II (6002) inside. The arc working surface II (6002) is used to guide the solid corrosion inhibitor particles from the solid corrosion inhibitor controlled-release lower section (4) into the hourglass-shaped controlled-release sleeve (6). The internal channel of the hourglass-shaped controlled-release sleeve (6) is formed from top to bottom into a contraction section, a flow-limiting section and a diffusion section, so that the solid corrosion inhibitor particles are subject to flow restriction and controlled release when passing through the hourglass-shaped controlled-release sleeve (6); The external thread VI (6003) is located at the lower end of the hourglass-shaped controlled-release sleeve (6) and is threadedly connected to the internal thread VI (7001) of the particle sieve tube (7), so that the hourglass-shaped controlled-release sleeve (6) is connected to the particle sieve tube (7).

8. The downhole self-powered closed-loop feedback solid corrosion inhibitor long-term controlled release injection device according to claim 2, characterized in that: In the particle sieve tube (7), the internal thread VI (7001) is provided at the upper end of the particle sieve tube (7) and is connected to the external thread VI (6003) of the hourglass-shaped controlled release sleeve (6); The particle sieve tube (7) is connected to the internal channel of the hourglass-shaped controlled-release sleeve (6) and is used to receive solid corrosion inhibitor particles after being restricted by the hourglass-shaped controlled-release sleeve (6). The plurality of through holes II (7002) are arranged at intervals along the axial and circumferential directions of the particle screen tube (7) to disperse and release solid corrosion inhibitor particles into the well fluid; The through hole II (7002) is connected to the internal channel of the particle screen tube (7) and to the well fluid space outside the central tube (2), so that the solid corrosion inhibitor particles can be released from the inside of the particle screen tube (7) to the outside.

9. The downhole self-powered closed-loop feedback solid corrosion inhibitor long-term controlled release injection device according to claim 1, characterized in that: The downhole self-powered closed-loop feedback solid corrosion inhibitor long-term controlled release injection device is a single-section controlled release unit. The single-section controlled release unit consists of a downhole power generation device (1), a central pipe (2), a solid corrosion inhibitor upper section (3), a solid corrosion inhibitor lower section (4), and a tension spring mechanism (5). Multiple single-section controlled release units can be connected sequentially along the central pipe (2) to form a multi-section long-term controlled release injection system. Adjacent single-section controlled release units are connected by a tapered thread seal. Multiple single-section controlled release units are connected along the central pipe (2) axially. The bottom single-section controlled release unit is connected to an hourglass-shaped controlled release sleeve (6) and a particle screen (7) to release solid corrosion inhibitor particles sequentially from bottom to top.

10. A downhole self-powered closed-loop feedback solid corrosion inhibitor long-term controlled-release injection device according to claim 9, characterized in that: The working process of the downhole self-powered closed-loop feedback solid corrosion inhibitor long-term controlled-release injection device includes the following steps: SⅠ. The device is lowered into the wellbore: The downhole self-powered closed-loop feedback solid corrosion inhibitor long-term controlled release injection device is lowered into the target position of the wellbore along the tubing. Multiple single-section controlled release units are connected sequentially along the central pipe (2) and arranged together in the wellbore along with the tubing. SⅡ, Downhole Self-Powered Start-up: The fluid in the wellbore flows through the area where the central pipe (2) and the downhole power generation device (1) are located, driving the power generation turbine (104) to rotate and generate electricity. The generated electrical energy is transmitted to the control module (102) through the power transmission ring (103) and supplies power to the electrically controlled needle valve I (302), the corrosion inhibitor concentration meter in the wellbore (303), the corrosion inhibitor concentration meter in the sleeve (304), and the electrically controlled needle valve II (305). SⅢ, Corrosion Inhibitor Concentration Detection: After the control module (102) is powered on, the in-well corrosion inhibitor concentration meter (303) in the currently monitored single-section controlled release unit periodically detects the corrosion inhibitor concentration in the well fluid, and the in-sleeve corrosion inhibitor concentration meter (304) periodically detects the corrosion inhibitor concentration inside the solid corrosion inhibitor controlled release upper section (3), and transmits the detection signals to the control module (102) respectively; the control module (102) calculates the concentration difference between the in-well corrosion inhibitor concentration meter (303) and the in-sleeve corrosion inhibitor concentration meter (304) based on the detection results of the in-well corrosion inhibitor concentration meter (303) and the in-sleeve corrosion inhibitor concentration meter (304). When the concentration difference does not reach the set difference threshold, the device maintains the detection state; SⅣ, Pressure Balance and Flow Channel Opening: When the concentration difference detected by the corrosion inhibitor concentration meter (303) in the wellbore and the corrosion inhibitor concentration meter (304) in the sleeve reaches the set difference threshold, the control module (102) does not immediately perform the release action, but continues to wait for a preset detection cycle; after the preset detection cycle ends, the control module (102) compares the detection values ​​of the corrosion inhibitor concentration meter (303) in the wellbore and the corrosion inhibitor concentration meter (304) in the sleeve again. If the concentration difference between the two still reaches or exceeds the set difference threshold, the control module (102) controls the opening of the electrically controlled needle valve I (302) and electrically controlled needle valve II (305) in the current single-section controlled release unit to be released, so that the wellbore fluid is connected to the corrosion inhibitor containment space, and the internal and external pressure difference between the upper section (3) and the lower section (4) of the solid corrosion inhibitor controlled release is balanced; if the concentration difference value after verification is lower than the set difference threshold, the device continues to maintain the detection state; S₅₅, Piston limit released: The control module (102) controls the retraction of the electrically controlled telescopic pin I (407) and the electrically controlled telescopic pin II (409), so that they are disengaged from the stop groove (4064) on the control release lower sleeve (406), thereby releasing the axial limit on the sealed movable piston composed of piston upper cover (401), piston body (403) and piston lower cover (405); SVI, Spring-driven release: The tension spring (501) releases elastic potential energy and drives the piston lower cover (405) and the sealing movable piston to move axially along the control release lower sleeve (406) through its upper end. The sealing movable piston drives the solid corrosion inhibitor particles to move towards the hourglass-shaped control release sleeve (6). SⅦ, Flow-limited controlled release: After the solid corrosion inhibitor particles enter the hourglass-shaped controlled-release sleeve (6), they are subject to flow restriction control under the action of the contraction section, flow restriction section and diffusion section inside the hourglass-shaped controlled-release sleeve (6), so as to avoid the instantaneous concentrated release of solid corrosion inhibitor particles; SⅧ, Sieve tube dispersion and release: After being restricted by the hourglass-shaped controlled release sleeve (6), the solid corrosion inhibitor particles enter the particle screen tube (7) and are dispersed and released into the well fluid through the through hole II (7002) on the particle screen tube (7), so that the solid corrosion inhibitor particles diffuse with the well fluid and play a corrosion inhibition role. SⅨ, Closed-loop feedback and cyclic controlled release: After the current single-section controlled release unit completes the release of solid corrosion inhibitor particles, the corrosion inhibitor concentration meter (303) in the wellbore and the corrosion inhibitor concentration meter (304) in the sleeve continue to detect the concentration and transmit the detection signal to the control module (102). When the corrosion inhibitor concentration in the wellbore fluid returns to the set range, the control module (102) no longer triggers the subsequent actions of the current single-section controlled release unit and sends a signal to the control module (102) in the adjacent single-section controlled release unit above it to make it work. When the adjacent single-section controlled release unit above it detects that the concentration difference value reaches the set difference threshold again, and after a preset detection cycle, it still meets the release conditions, the adjacent single-section controlled release unit above it (102) controls the adjacent single-section controlled release unit above it to repeatedly execute SⅣ to SⅧ, thereby realizing the phased, long-cycle, closed-loop feedback on-demand controlled release of downhole solid corrosion inhibitor.

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