Water injection well control system and method for calibrating underground water distributor through system

Abstract

The invention relates to a water injection well control system and a method for calibrating underground water distributors through the system.The method comprises the steps that S1, the water injection well control system is assembled, specifically, firstly, a ground controller is connected with a water injection well oil pipe column, then a plurality of intelligent water distributors are arranged in the water injection well oil pipe column, and packers are located among the intelligent water distributors; and finally, connecting a double-acting valve and a screwed plug at the lowest end of the oil pipe column of the water injection well to finish assembly. And S2, an instruction is sent to the underground intelligent water distributor through a wave code sending device in the ground controller, a sensor in the underground intelligent water distributor is calibrated, and full-well flow rapid testing and allocation and layered flow automatic testing and allocation are conducted after calibration. By means of the method, calibration and control over the underground intelligent water distributor are effectively achieved, and the technical problems that after the underground intelligent water distributor works for a long time, the sensor measurement is inaccurate, and the control precision of the intelligent water distributor is insufficient can be solved.

Description

Technical Field

[0001] This invention belongs to the field of oilfield stratified water injection technology, and particularly relates to a water injection well control system and a method for calibrating downhole water distributors through the system. Background Technology

[0002] Water injection is a crucial method for improving oilfield recovery, and precise stratified water injection is essential for the sustained high production of low-permeability oilfields. Currently, wavecode communication-based stratified water injection technology is widely used in oilfields both domestically and internationally. Intelligent water distributors, through their included pressure and flow sensors, can measure the pressure and flow values ​​of their respective formations in real time. However, because intelligent water distributors operate continuously downhole, the pressure and flow sensors are prone to drift in the high-temperature and highly corrosive downhole environment, affecting measurement accuracy and requiring periodic calibration.

[0003] Currently, there is no method for calibrating the pressure sensors in downhole intelligent water distributors. Pressure sensor drift not only affects the accuracy of pressure measurement but also the detection of pressure waves in wavecode communication. Calibration of the flow sensors in intelligent water distributors involves making corrections after data is transmitted back to the surface; it does not allow for calibration of the flow sensors themselves. The main problem is that this affects the accuracy of the intelligent water distributor's constant flow control within its layer. Control relies primarily on commands sent from the surface controller, lacking automated autonomous control methods.

[0004] The invention disclosed in Publication No. CN110847868A provides a remote calibration method for intelligent downhole stratified flow rate, comprising the following steps: Step 1) Install two pressure sensors on each downhole intelligent water distributor to simultaneously measure the pressure before and after the adjustable nozzle of each downhole intelligent water distributor; Step 2) Calculate the flow rate at the adjustable nozzle of each downhole intelligent water distributor according to the throttling formula; Step 3) Deploy all downhole intelligent water distributors, calculate the flow rate using the throttling formula in Step 2), and establish an artificial intelligence three-dimensional metering model; Step 4) After manual calibration, during long-term normal water injection, periodically return a large number of adjustable nozzle opening, pressure before and after the nozzle to the artificial intelligence three-dimensional metering model to obtain the corresponding flow rate, compare and correct this corresponding flow rate with the standard flow rate obtained from the surface standard flow meter to complete the remote calibration. This method involves transmitting the pressure and flow rate data recorded by the downhole intelligent water distributor back to the surface for revision, which introduces significant errors.

[0005] In summary, currently only surface flow meters can be calibrated, and there is no method to calibrate and control the pressure sensors in downhole intelligent water distributors. Therefore, existing technologies cannot solve the problems of inaccurate sensor measurements and insufficient control precision of the water distributor after long-term operation of intelligent injection downhole water distributors. Summary of the Invention

[0006] To address the shortcomings of the existing technology, the present invention aims to provide a water injection well control system and a method for calibrating the downhole water distributor through the system. This method includes stratified pressure sensor calibration, stratified flow sensor calibration, rapid testing and adjustment of the whole well flow rate, and automatic testing and adjustment of the stratified flow rate.

[0007] To achieve the above objectives, the present invention adopts the following technical solution: A method for calibrating a downhole water distributor through a water injection well control system includes the following steps: S1. Assemble the water injection well control system The water injection well control system includes a surface controller located at the wellhead, multiple intelligent water distributors located downhole, and a matching packer. When installing the water injection well control system, the surface controller is first connected to the wellhead tree, then multiple intelligent water distributors are placed in the water injection well tubing string, and the packer is located between the multiple intelligent water distributors. Finally, the upper end of the water injection well tubing string is connected to the wellhead tree, and a double-acting valve and a plug are connected to the bottom of the water injection well tubing string, thus completing the assembly of the water injection well control system. S2. Send commands to the downhole intelligent water distributor through the wavecode transmitter in the ground controller to calibrate the sensors in the downhole intelligent water distributor, and perform rapid testing and adjustment of the whole well flow rate and automatic testing and adjustment of the stratified flow rate after calibration.

[0008] Furthermore, step S2 sends commands to the downhole intelligent water distributor via the wavecode transmitting device in the ground controller to calibrate the sensors in the downhole intelligent water distributor. After calibration, it performs rapid testing and adjustment of the whole-well flow rate and automatic testing and adjustment of the stratified flow rate, including at least one of steps A, B, C, and D. Step A involves the downhole intelligent water distributor receiving the downhole pressure correction command sent by the wavecode transmitting device in the surface controller and then performing stratified pressure sensor calibration. Step B involves the downhole intelligent water distributor receiving the downhole flow correction command sent by the wavecode transmitting device in the ground controller and then performing stratified flow sensor calibration. Step C involves the downhole intelligent water distributor receiving the full well flow rate rapid test and allocation command sent by the wavecode transmitting device in the ground controller, and then performing the full well flow rate rapid test and allocation. Step D involves the intelligent water distributor in the well receiving the automatic test and allocation command for stratified flow from the wavecode transmitting device in the ground controller, and then performing automatic test and allocation of stratified flow.

[0009] Furthermore, after receiving the downhole pressure correction command sent by the wavecode transmitting device in the surface controller, the intelligent water distributor in step A performs stratified pressure sensor calibration, including the following steps: A1. All intelligent water distributors receive downhole pressure correction commands sent by the wavecode transmitter; A2. First, calibrate the pressure sensor of the top-level intelligent water distributor; A3. Then, perform pressure sensor calibration on all smart water distributors in a top-to-bottom order to complete the calibration of pressure sensors on each smart water distributor.

[0010] As a further optimization of the present invention, the calibration process of the pressure sensor is as follows: the flow control device of the intelligent water distributor being calibrated is controlled to the maximum opening position, and the flow control devices of other intelligent water distributors are controlled to the closed position. The intelligent water distributor controls the pressure in the tubing string of the water injection well to rise to a certain pressure value. Under three different pressure values, the pressure value remains stable within a set time. During the pressure stabilization period, the intelligent water distributor uses an interpolation method to calibrate its own pressure sensor.

[0011] Furthermore, after receiving the downhole flow correction command from the wavecode transmitting device in the surface controller, the intelligent water distributor in step B performs stratified flow sensor calibration, including the following steps: B1. All intelligent water distributors receive downhole flow correction commands sent by the wavecode transmitter; B2. First, the flow sensor of the top-level intelligent water distributor is calibrated. B3. Then, perform flow sensor calibration on all smart water distributors in a top-down order to complete the flow sensor calibration for each layer of smart water distributors.

[0012] As a further optimization of the present invention, the process of calibrating the flow sensor is as follows: first, the intelligent water distributor to be calibrated controls its own flow control device to the maximum opening position, and other intelligent water distributors control their own flow control devices to the closed position, so that the intelligent water distributor to be calibrated enters the flow calibration mode. Then, according to the flow calibration value preset by the ground controller, the flow rate of the injected water well is controlled by the flow control device of the ground controller to stabilize at three different proportions of the preset calibration value and remain stable for a specified time. During the flow stabilization period, three flow values ​​are collected from the intelligent water distributor being calibrated and compared with the flow calibration value preset by the ground controller to complete the three-point flow calibration of the standard meter method.

[0013] Furthermore, after receiving the full-well flow rate rapid test and allocation command sent by the wavecode transmitting device in the surface controller, the intelligent water distributor in step C performs a full-well flow rate rapid test and allocation, including the following steps: C1. All intelligent water distributors receive the full well flow rate rapid test and allocation command sent by the wavecode transmitting device and enter the full well flow rate rapid test and allocation state; C2. The topmost smart water distributor first uses a binary search method to quickly reach the target position of flow control, which is the pre-set dispensing volume in the smart water distributor. After a certain pre-set time interval, the next layer of smart water distributors uses the binary search method to quickly reach the target position of flow control. After the same pre-set time interval, the next layer of smart water distributors uses the binary search method to quickly reach the target position of flow control, and so on, until all smart water distributors have completed one round of operation. C3. Repeat the operation method described in C2 three times to achieve the pre-set injection volume in the intelligent water distributor while eliminating inter-layer interference, thus realizing rapid testing and adjustment of the whole well flow rate.

[0014] Furthermore, after receiving the stratified flow rate automatic test and allocation command sent by the wavecode transmitting device in the surface controller, the intelligent water distributor in step D performs stratified flow rate automatic test and allocation, including the following steps: D1. All intelligent water distributors receive the stratified flow automatic test and allocation command sent by the wavecode transmitting device and enter the flow automatic test and allocation state; D2. Flow control and allocation are performed on each intelligent water distributor in a top-down order, and the time interval between each intelligent water distributor entering the automatic flow test and allocation state is: a pre-set time in a certain intelligent water distributor, to ensure that each intelligent water distributor does not perform flow control at the same time, thereby eliminating inter-floor interference.

[0015] As a further optimization of the present invention, the specific method for flow control of each intelligent water distributor is as follows: according to the preset test and adjustment cycle in the intelligent water distributor, the injection flow of the layer is continuously measured by the flow sensor of the intelligent water distributor itself. When the flow error is greater than the preset value of flow error in the intelligent water distributor, the intelligent water distributor enters the flow control mode, that is, the target flow control is quickly obtained by using the binary search method, so that the injection flow reaches the control target under low energy consumption.

[0016] A water injection well control system for implementing the above-mentioned method of calibrating downhole water distributors through a water injection well control system, the water injection well control system comprising a surface controller located at the wellhead of the water injection well, multiple intelligent water distributors located downhole, and a matching packer, the surface controller being connected to the wellhead tree, the multiple intelligent water distributors being placed in the water injection well tubing string, the packer being located between the multiple intelligent water distributors, the upper end of the water injection well tubing string being connected to the wellhead tree, and the lower end of the water injection well tubing string being connected to a double-acting valve and a plug.

[0017] Compared with the prior art, the present invention has the following beneficial effects: This invention uses pressure and flow sensors in the ground controller as a reference, and combines them with the precise fluid control function of the flow control device in the ground controller. The proposed method effectively realizes the calibration and control of the downhole intelligent water distributor, and can solve the technical problems of inaccurate sensor measurements and insufficient control accuracy of the intelligent water distributor after long-term operation.

[0018] This invention provides a solution for calibrating sensors in a downhole intelligent water distributor using standard pressure and flow sensors in a surface controller. It also provides a method for rapid testing and adjustment of the whole-well flow rate after calibration and automatic testing and adjustment of the stratified flow rate during long-term operation. This can effectively solve the problems of inaccurate sensor measurements and insufficient control precision of the water distributor after long-term operation of the intelligent injection downhole water distributor, which are difficult to solve with existing technologies.

[0019] To make the above description of the present invention more apparent and understandable, preferred embodiments are described below in detail with reference to the accompanying drawings. Attached Figure Description

[0020] Figure 1 This is a timing diagram showing the stratified pressure calibration of the downhole water distributor's stratified pressure sensors according to the pressure correction instructions sent by the wavecode transmitting device.

[0021] Figure 2 This is a timing diagram showing the stratified flow calibration of the downhole water distributor's stratified flow sensor according to the flow correction command sent by the wavecode transmitting device.

[0022] Figure 3 It is a timing diagram for automatic testing and allocation of tiered traffic.

[0023] Figure 4 This is a timing diagram for rapid testing and adjustment of the entire well's flow rate.

[0024] Figure 5 This is a schematic diagram of the water injection well control system.

[0025] Explanation of reference numerals in the attached figures 1. Wellhead Christmas tree; 2. Packer; 3. Intelligent water distributor; 4. Ground control valve; 3. Integrated controller; 4. Double-acting valve; 5. Plug; 6. Ground controller; 7. Water inlet flange. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. 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 described embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0027] This invention provides a method for calibrating and controlling a downhole intelligent water distributor using a ground controller. Based on the pressure and flow sensors in the ground controller, and with the precise fluid control function of the flow control device in the ground controller, the proposed method effectively achieves the calibration and control of the downhole intelligent water distributor. It can solve the technical problems of inaccurate sensor measurements and insufficient control precision of the intelligent water distributor after long-term operation.

[0028] In one typical embodiment of this application, a water injection well control system is provided, referring to... Figure 5 It includes a surface controller 6 located at the wellhead, multiple intelligent water distributors 3 located downhole, and their matching packers 2. The surface controller 6 is connected to the wellhead tree 1, the multiple intelligent water distributors 3 are placed in the water injection well tubing string, the packers 2 are located between the multiple intelligent water distributors 3, the upper end of the water injection well tubing string is connected to the wellhead tree 1, and the lower end of the water injection well tubing string is connected to a double-acting valve 4 and a plug 5.

[0029] It is worth mentioning that each intelligent water distributor includes a pressure sensor, a flow sensor, and a flow control device. The packer is used to effectively isolate the injection well sections, ensuring that each water distributor controls the injection volume of its assigned injection layer. The surface controller 6 includes a standard pressure sensor, a standard flow sensor, a flow control device, and a wavecode transmitter. The wavecode transmitter sends downhole pressure correction commands, flow correction commands, rapid well flow test and adjustment commands, and / or automatic stratified flow test and adjustment commands to the downhole intelligent water distributor. Furthermore, the surface controller 6 is also connected to an inlet flange 7 and a surface monitoring valve.

[0030] Commands are sent to the downhole intelligent water distributor via the wavecode transmitter in the ground controller to calibrate the sensors in the downhole intelligent water distributor. After calibration, rapid testing and allocation of the whole well flow rate and automatic testing and allocation of the stratified flow rate during long-term operation are carried out.

[0031] The above-mentioned water injection well control system is used to calibrate and control the target intelligent downhole water distributor. Based on the pressure and flow sensors in the surface controller, the fluid is precisely controlled through the flow control device in the surface controller; this includes the following steps: A. Layered pressure sensor calibration; the implementation method is as follows: A1. The ground controller sends downhole pressure correction commands to the downhole smart water distributors via a wavecode transmitter. All smart water distributors can receive the commands sent by the wavecode transmitter. A2. First, the pressure sensor of the top-level smart water distributor is calibrated. The calibration process is as follows: the flow control device of the smart water distributor being calibrated is controlled to the maximum opening position, and the flow control devices of other smart water distributors are controlled to the closed position. A3. The pressure in the tubing string of the water injection well is controlled to rise to a certain pressure value (1MPa, 2MPa, 3MPa) and remain stable at these three pressure values ​​for a set period of time (1 hour). During the pressure stabilization period, the intelligent water distributor uses interpolation to calibrate its own pressure sensor. A4. Then, control all the smart water distributors sequentially from top to bottom according to A2-A3 to complete the calibration of the pressure sensors of each smart water distributor.

[0032] B. The method for calibrating the stratified flow sensor is as follows: B1. The ground controller sends flow correction instructions to the downhole smart water distributors via the wavecode transmitter. All smart water distributors can receive the instructions sent by the wavecode transmitter. B2. First, the top-level smart water distributor calibrates its flow sensor. The calibration process is as follows: the smart water distributor being calibrated controls its own flow control device to the maximum opening position, while other smart water distributors control their own flow control devices to the closed position. The smart water distributor being calibrated then enters the flow calibration mode. B3. According to the preset flow calibration value of the ground controller, the flow rate of the injection well is controlled by the flow control device of the ground controller to stabilize at three different proportions of the preset calibration value (such as 50%, 100% and 150%), and the flow rate remains stable for the specified time. During the flow stabilization period, three flow values ​​are collected from the intelligent water distributor being calibrated and compared with the standard value to complete the three-point flow calibration of the standard meter method. B4. Then, operate all the smart water distributors sequentially from top to bottom, and complete the calibration of the flow sensors of each smart water distributor according to B2-B3.

[0033] C. The method for rapid testing and allocation of full well flow rate is as follows: C1. The ground controller sends a full well flow rate rapid test and allocation command to the downhole intelligent water distributor via a wavecode transmitter. All intelligent water distributors can receive the command sent by the wavecode transmitter and enter the full well flow rate rapid test and allocation state. C2. The topmost smart water distributor first uses a binary search method to quickly obtain the target position for flow control. After a certain preset time interval, the next layer of smart water distributors uses the same binary search method to quickly obtain the target position for flow control. After the same preset time interval, this process continues until all smart water distributors have completed one round of operation. C3. Performing three rounds consecutively according to the operation method described in C2 can achieve the injection volume while eliminating inter-layer interference, thus realizing rapid testing and adjustment of the whole well flow rate.

[0034] D. The method for implementing automatic testing and allocation of tiered traffic is as follows: D1. The ground controller sends a layered flow automatic test and allocation command to the intelligent water distributor downhole via a wavecode transmitter; D2. All intelligent water distributors can receive the instructions sent by the wavecode transmitting device and enter the automatic flow test and adjustment state. The interval between each intelligent water distributor entering the automatic flow test and adjustment state from top to bottom is a certain time. Preferably, the interval is a certain preset time to ensure that each intelligent water distributor does not perform flow control at the same time, so as to eliminate inter-layer interference. D3. The specific flow control of each intelligent water distributor is as follows: according to the preset test and adjustment cycle, the flow rate of the layer is continuously measured by the flow sensor of the intelligent water distributor itself. When the flow error is greater than the preset value of flow error, the intelligent water distributor enters the flow control mode, that is, the binary optimization method is used to quickly obtain the target flow control, so that the injection flow rate reaches the control target under low energy consumption.

[0035] By following the steps above, the intelligent water distributor in the well can be calibrated and controlled via a ground controller.

[0036] The following embodiments include stratified pressure correction, stratified flow correction, automatic stratified flow test and adjustment, and one-click automatic measurement and adjustment of full well flow implemented using the method of the present invention.

[0037] Example 1: (Layered Pressure Calibration Example) The ground controller sends a downhole pressure calibration command to the downhole intelligent water distributor via a wavecode transmitter. Upon receiving the command, the intelligent water distributor automatically stops other ongoing operations.

[0038] A 4-hour injection cycle was performed, starting from layer 1. The injection was performed on the corrected layers, with the remaining layers closed. The surface controller was completely shut off. The pressure was stabilized for 1 hour, then increased by 1 MPa, stabilized for 1 hour, and so on, up to 3 MPa. Corresponding pressure changes were made within the 4-hour injection cycle, controlling the wellbore pressure to increase by 1 MPa, 2 MPa, and 3 MPa respectively. The pressure sensor before the nozzle was calibrated using three 1 MPa pressure changes.

[0039] There are several layers of injection in rotation. After each layer is injected, the surface controller at the wellhead automatically maintains a constant flow to the total injection volume of the entire well, with the timing as follows: Figure 1 As shown.

[0040] Example 2: (Layered Flow Calibration Example) Sending a wavecode command activates the kinetic energy, automatically stopping other ongoing operations (except for seal verification). If in automatic control mode, automatic control is stopped.

[0041] First, a 30-minute zero-point calibration is performed. During this period, the ground controller remains fully open after the code is transmitted and does not perform any control actions.

[0042] Then, a 6-hour rotation injection is performed, starting from layer 1. Correction is performed layer by layer, using the layered injection volume set before well entry. Three flow correction points are set at 50%, 100%, and 150% of the injection volume, with each point requiring 2 hours for correction. The surface flow is then kept constant to the corresponding injection volume (which should be consistent with the injection volume configured on the distributor before well entry).

[0043] After the injection cycle is completed, the surface controller automatically maintains constant flow control to the total injection volume of the well, and the stratified flow calibration sequence is as follows: Figure 2 As shown.

[0044] Example 3: (Hierarchical Flow Automatic Testing and Allocation Example) After the function is activated by sending a wavecode command, it analyzes every 10 days whether the difference between the stratified flow rate and the injection volume exceeds 10% of the injection volume. If it does, corresponding control measures are taken.

[0045] The control time for adjacent layers differs by 12 hours. After automatic control of the first layer, it stabilizes for 2 hours, then switches from constant flow to open-end mode. The surface controller maintains the open end, and waits another hour. The flow rate value for the first layer is then transmitted back from the wellbore. After transmission, the surface controller switches back to constant flow mode and applies constant flow according to the total well injection rate. This process repeats for 12 hours. The second layer is then controlled, stabilizes for 2 hours, switches from constant flow to open-end mode, and the surface controller maintains the open end. After another hour, the flow rate value for the second layer is transmitted back from the wellbore. After transmission, the surface controller switches back to constant flow mode and applies constant flow according to the total well injection rate. This process repeats for another 12 hours. The third layer is controlled, stabilizes for 2 hours, switches from constant flow to open-end mode, and the surface controller maintains the open end. After another hour, the flow rate value for the third layer is transmitted back from the wellbore. After transmission, the surface controller switches back to constant flow mode and applies constant flow according to the total well injection rate. This cycle continues until automatic control is stopped. (The wellhead controller needs to synchronize its time.) The returned stratified flow rate updates the stratified flow rate value of the surface controller system. The automatic testing and adjustment sequence of the stratified flow rate is as follows: Figure 3 As shown.

[0046] Example 4: (Example of rapid testing and adjustment of full well flow rate) Sending a wavecode command initiates the kinetic energy. After sending the command, the surface controller maintains constant flow to the sum of all injection volumes (or constant pressure to the set pressure). The constant flow (or constant pressure) is maintained for (N layers × 5 hours + 2 hours). Then, the surface controller switches to the opening mode. One hour later, the water distributor of the first layer in the well begins to transmit the layer flow rate value. The transmission interval for each layer flow rate value is 2 hours until all water distributor data transmission is completed. That is, after the water distributor of the first layer begins to transmit data, the surface controller switches back to the constant flow mode on the (N layers × 2 hours)th, maintaining constant flow to the sum of all injection volumes.

[0047] The surface controller needs to automatically identify the returned flow rate and update the hierarchical flow rate values ​​of the surface controller system. The sequence for rapid testing and commissioning of the full well flow rate is as follows: Figure 4 As shown.

[0048] It should be noted that the purpose of disclosing the embodiments is to help further understand the present invention. However, those skilled in the art will understand that various substitutions and modifications are possible without departing from the scope of the present invention and the appended claims. Therefore, the present invention should not be limited to the content disclosed in the embodiments, and the scope of protection of the present invention is defined by the scope of the claims.

[0049] Those skilled in the art will understand that the above embodiments are specific examples of implementing the present invention, and in practical applications, various changes in form and detail may be made without departing from the spirit and scope of the present invention.

Claims

1. A method for calibrating a downhole water distributor using a water injection well control system, characterized in that, Includes the following steps: S1. Assemble the water injection well control system The water injection well control system includes a surface controller located at the wellhead, multiple intelligent water distributors located downhole, and a matching packer. When installing the water injection well control system, the surface controller is first connected to the wellhead tree, then multiple intelligent water distributors are placed in the water injection well tubing string, and the packer is located between the multiple intelligent water distributors. Finally, the upper end of the water injection well tubing string is connected to the wellhead tree, and a double-acting valve and a plug are connected to the bottom of the water injection well tubing string, thus completing the assembly of the water injection well control system. S2. Send commands to the intelligent water distributor in the well through the wavecode transmitting device in the ground controller to calibrate the sensors in the intelligent water distributor in the well, and perform rapid testing and adjustment of the whole well flow rate and automatic testing and adjustment of the stratified flow rate after calibration; The commands sent by the wavecode transmitting device include downhole pressure correction commands, flow rate correction commands, whole-well flow rate rapid test and allocation commands, and / or stratified flow rate automatic test and allocation commands.

2. The method for calibrating a downhole water distributor via a water injection well control system according to claim 1, characterized in that, S2 sends commands to the downhole intelligent water distributor via the wavecode transmitter in the ground controller to calibrate the sensors in the downhole intelligent water distributor. After calibration, it performs rapid testing and adjustment of the whole-well flow rate and automatic testing and adjustment of the stratified flow rate, including at least one of steps A, B, C, and D. Step A involves the downhole intelligent water distributor receiving the downhole pressure correction command sent by the wavecode transmitting device in the surface controller and then performing stratified pressure sensor calibration. Step B involves the downhole intelligent water distributor receiving the downhole flow correction command sent by the wavecode transmitting device in the ground controller and then performing stratified flow sensor calibration. Step C involves the downhole intelligent water distributor receiving the full well flow rate rapid test and allocation command sent by the wavecode transmitting device in the ground controller, and then performing the full well flow rate rapid test and allocation. Step D involves the intelligent water distributor in the well receiving the automatic test and allocation command for stratified flow from the wavecode transmitting device in the ground controller, and then performing automatic test and allocation of stratified flow.

3. The method for calibrating a downhole water distributor via a water injection well control system according to claim 2, characterized in that, After receiving the downhole pressure correction command from the wavecode transmitting device in the surface controller, the intelligent water distributor in step A performs stratified pressure sensor calibration, including the following steps: A1. All intelligent water distributors receive downhole pressure correction commands sent by the wavecode transmitter; A2. First, calibrate the pressure sensor of the top-level intelligent water distributor; A3. Then, perform pressure sensor calibration on all smart water distributors in a top-to-bottom order to complete the calibration of pressure sensors on each smart water distributor.

4. The method for calibrating a downhole water distributor via a water injection well control system according to claim 3, characterized in that, The calibration process of the pressure sensor is as follows: the flow control device of the intelligent water distributor being calibrated is controlled to the maximum opening position, and the flow control devices of other intelligent water distributors are controlled to the closed position. The intelligent water distributor controls the pressure in the tubing string of the water injection well to rise to a certain pressure value. Under three different pressure values, the pressure value remains stable within a set time. During the pressure stabilization period, the intelligent water distributor uses an interpolation method to calibrate its own pressure sensor.

5. The method for calibrating a downhole water distributor via a water injection well control system according to claim 2, characterized in that, After receiving the downhole flow correction command from the wavecode transmitting device in the surface controller, the intelligent water distributor in step B performs stratified flow sensor calibration, including the following steps: B1. All intelligent water distributors receive downhole flow correction commands sent by the wavecode transmitter; B2. First, the flow sensor of the top-level intelligent water distributor is calibrated. B3. Then, perform flow sensor calibration on all smart water distributors in a top-down order to complete the flow sensor calibration for each layer of smart water distributors.

6. The method for calibrating a downhole water distributor via a water injection well control system according to claim 5, characterized in that, The process of calibrating the flow sensor is as follows: First, the smart water distributor to be calibrated controls its own flow control device to the maximum opening position, and other smart water distributors control their own flow control devices to the closed position, so that the smart water distributor to be calibrated enters the flow calibration mode. Then, according to the flow calibration value preset by the ground controller, the flow rate of the injected water well is controlled by the flow control device of the ground controller to stabilize at three different proportions of the preset calibration value and remain stable for a specified time. During the flow stabilization period, three flow values ​​are collected from the intelligent water distributor being calibrated and compared with the flow calibration value preset by the ground controller to complete the three-point flow calibration of the standard meter method.

7. The method for calibrating a downhole water distributor via a water injection well control system according to claim 2, characterized in that, After receiving the full-well flow rate rapid test and allocation command sent by the wavecode transmitting device in the ground controller, the intelligent water distributor in step C performs the full-well flow rate rapid test and allocation, including the following steps: C1. All intelligent water distributors receive the full well flow rate rapid test and allocation command sent by the wavecode transmitting device and enter the full well flow rate rapid test and allocation state; C2. The topmost smart water distributor first uses a binary search method to quickly reach the target position of flow control, which is the pre-set dispensing volume in the smart water distributor. After a certain pre-set time interval, the next layer of smart water distributors uses the binary search method to quickly reach the target position of flow control. After the same pre-set time interval, the next layer of smart water distributors uses the binary search method to quickly reach the target position of flow control, and so on, until all smart water distributors have completed one round of operation. C3. Repeat the operation method described in C2 three times to achieve the pre-set injection volume in the intelligent water distributor while eliminating inter-layer interference, thus realizing rapid testing and adjustment of the whole well flow rate.

8. The method for calibrating a downhole water distributor via a water injection well control system according to claim 2, characterized in that, After receiving the stratified flow automatic test and allocation command sent by the wavecode transmitting device in the surface controller, the intelligent water distributor in step D performs the stratified flow automatic test and allocation, including the following steps: D1. All intelligent water distributors receive the stratified flow automatic test and allocation command sent by the wavecode transmitting device and enter the flow automatic test and allocation state; D2. Flow control and allocation are performed on each intelligent water distributor in a top-down order, and the intelligent water distributors enter the automatic flow test and allocation state at certain intervals. The interval is a pre-set time to ensure that each intelligent water distributor does not perform flow control at the same time, thereby eliminating inter-floor interference.

9. The method for calibrating a downhole water distributor via a water injection well control system according to claim 8, characterized in that, The specific method for flow control of each intelligent water distributor is as follows: according to the preset test and adjustment cycle in the intelligent water distributor, the injection flow of the layer is continuously measured by the flow sensor of the intelligent water distributor itself. When the flow error is greater than the preset value of flow error in the intelligent water distributor, the intelligent water distributor enters the flow control mode, that is, the binary optimization method is used to quickly obtain the target flow control, so that the injection flow reaches the control target under low energy consumption.

10. A water injection well control system for implementing the method of calibrating a downhole water distributor via a water injection well control system as described in any one of claims 1-9, characterized in that: The water injection well control system includes a surface controller located at the wellhead, multiple intelligent water distributors located downhole, and a matching packer. The surface controller is connected to the wellhead tree, the multiple intelligent water distributors are placed in the water injection well tubing string, and the packer is located between the multiple intelligent water distributors. The upper end of the water injection well tubing string is connected to the wellhead tree, and the lower end of the water injection well tubing string is connected to a double-acting valve and a plug.

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