Downhole multi-stage relay communication system and method

Abstract

This invention discloses a downhole multi-level relay communication system and method. The system includes: an oil and gas casing structure for installation in an open hole well, comprising a hollow casing embedded in the open hole and tubing arranged in the hollow casing along the casing's extension direction; a transmitter connected to the tubing and placed at a predetermined oil and gas producing layer location; multiple centralizers, each centralizer having two sides abutting against the inner wall of the casing, with one centralizer at each end of the transmitter; at least one repeater, with one centralizer at each end of each repeater, one repeater and two centralizers forming a unit, each unit sequentially connected to the tubing along the tubing's extension direction; and a surface receiver installed above the formation for communication connection with the repeaters. This invention solves the problem of inconsistent contact points encountered in traditional electromagnetic signal communication, enabling multi-level communication in the downhole communication system and improving transmission efficiency.

Description

Technical Field

[0001] This invention relates to the field of petrochemical technology, specifically to a downhole multi-level relay communication system and method. Background Technology

[0002] Historically, the confined space and stringent sealing requirements of downhole environments have limited the power supply of intelligent equipment supporting downhole wireless communication technology, necessitating battery power instead of cable power. Furthermore, with the development of deep wells, extending transmission distance using repeaters has become a research hotspot. Therefore, effectively extending the operating time of battery-powered downhole repeater transmission systems has become a crucial issue for the petroleum industry.

[0003] Currently, the mainstream research trend focuses on improving battery structural capacity, safety, and temperature resistance, or increasing device efficiency within the limited space of downhole wells. However, the following problems remain unresolved:

[0004] 1. In oil and gas extraction, there are occasions that require long-term monitoring. The downhole wireless transmission equipment needs to meet the needs of long-term operation for several years. The downhole transmission system has high requirements for working duration and real-time communication. Therefore, the system needs to be able to ensure long-term synchronous operation.

[0005] 2. In the current mainstream downhole electromagnetic wave communication technology, when electromagnetic waves are transmitted directly along the pipeline, problems such as low driving efficiency will occur due to the low impedance of the pipeline in the casing well. At the same time, due to the swaying of the pipeline, the contact point between the tubing and the casing in the casing structure is not fixed. When the electrical signal is transmitted along a single pipeline, there is uncertain contact with the casing, which greatly affects the transmission efficiency. Summary of the Invention

[0006] The purpose of this invention is to overcome the shortcomings of the above-mentioned background technology and provide a multi-level relay communication system and method for underground wells, which solves the problem of non-fixed contact points encountered in traditional electromagnetic signal communication, realizes multi-level communication in underground communication systems, and improves transmission efficiency.

[0007] Firstly, a multi-level relay communication system for underground mining is provided, comprising:

[0008] Oil and gas casing structure for use in open-hole wells in formations, including a hollow casing embedded in the open-hole well in the formation, and an oil pipe provided in the hollow casing and along the extension direction of the casing;

[0009] The transmitter is connected to the oil pipeline and placed at a predetermined oil and gas producing layer location;

[0010] Multiple centralizers, each with its two sides pressed against the inner wall of the sleeve, and one centralizer at each end of the transmitter;

[0011] At least one repeater, with a centralizer at each end of each repeater, and one repeater and two centralizers constitute a unit, with each unit sequentially connected to the oil pipe along the extension direction of the oil pipe;

[0012] A ground receiver is positioned above the ground and communicates with the repeater.

[0013] According to the first aspect, in a first possible implementation of the first aspect, the centralizer includes a tubular body connected to the oil pipe, and two centralizing connectors disposed on the periphery of the tubular body, the two centralizing connectors correspondingly abutting against the inner wall of the casing.

[0014] According to the second possible implementation of the first aspect, in the third possible implementation of the first aspect, the repeater and the transmitter are configured as access pipes.

[0015] Secondly, a downhole multi-level relay communication method is provided, applied to the downhole multi-level relay communication system as described above, comprising the following steps:

[0016] In the initial state, the transmitter and all repeaters remain in a shutdown and sleep state. After a single shutdown and sleep period, the transmitter remains in the power-on state to collect downhole data and transmits it to the repeaters through the electrical signal channels established by the centralizer, casing and formation before remaining in the shutdown and sleep state.

[0017] After the repeater remains powered on and transmits downhole data to the ground receiver via an electrical signal channel, it remains powered off and in sleep mode.

[0018] When the ground receiver detects that the received data is downhole data, it determines that the system operation is normal; when it detects that the received data is not downhole data, it determines that the system operation is abnormal and generates a calibration signal.

[0019] The repeater remains powered on and receives and transmits the calibration signal via the electrical signal channel;

[0020] The transmitter remains powered on and receives the calibration signal through the electrical signal channel, generates a transmitter synchronization command, and sends it.

[0021] The ground receiver receives the synchronization command via an electrical signal channel and stops generating calibration signals;

[0022] When the transmitter and repeater do not receive a calibration signal, they reset to the initial state and remain in a power-off sleep state.

[0023] According to the second aspect, in the first possible implementation of the second aspect, the step of "the repeater maintains its powered-on state to send downhole data to the surface receiver and then remains powered-off and in sleep mode; when it detects that the received data is not downhole data, it determines that the system operation is abnormal and generates a calibration signal" includes the following steps:

[0024] When the repeater does not receive downhole data, a repeater synchronization command is generated;

[0025] When the ground receiver detects that the received data is a repeater synchronization command, it determines that the system operation is abnormal and generates a calibration signal.

[0026] According to the first possible implementation of the second aspect, in the second possible implementation of the second aspect, the relationship between the single power-off sleep time of the transmitter and the single power-off sleep time of all repeaters is as follows:

[0027] ;

[0028] The relationship between the single power-on operating time of the transmitter and the single power-on operating time of all repeaters is as follows:

[0029] ;

[0030] In the formula, This refers to the transmitter's single shutdown sleep time; ...... The single shutdown sleep time for each repeater sequentially set along the transmitter;

[0031] The single power-on operating time of the transmitter; ...... The single power-on operating time of each repeater set sequentially along the transmitter.

[0032] According to the second possible implementation of the second aspect, in the third possible implementation of the second aspect, in the initial state, the transmitter and all repeaters are in the first power-off sleep state;

[0033] The first-level repeater closest to the transmitter has a power-on time that is earlier than the transmitter's power-on time and later than the transmitter's (T+1)th power-off sleep time.

[0034] The Tth power-on time of the next-level repeater set sequentially along the transmitter is earlier than the Tth power-on time of the previous-level repeater, but later than the T+1th power-off sleep time of the previous-level repeater.

[0035] Where T is a natural number.

[0036] According to the third possible implementation of the second aspect, in the fourth possible implementation of the second aspect, the sum of the single power-off sleep time and the single power-on working time of each transmitter is equal to the sum of the single power-off sleep time and the single power-on working time of each repeater:

[0037] .

[0038] According to the fourth possible implementation of the second aspect, in the fifth possible implementation of the second aspect, in the first initial state of all repeaters, the first shutdown sleep time of each repeater is greater than the single shutdown sleep time of repeaters in other time periods.

[0039] Compared with existing technologies, the multi-stage relay communication system based on centralizers provided by this invention solves the problems of unstable contact points and low driving efficiency encountered in traditional electromagnetic signal communication. Furthermore, it designs the relay communication path based on the centralizer, effectively extending the communication distance across multiple stages. Simultaneously, for deep well communication requiring multi-stage repeaters, it provides a battery collaborative management scheme for the long-term operation of the repeater transmission system, offering a basis for judging the working status of each level of repeater in the well for surface control, and providing a means for long-term monitoring of deep wells based on relay technology. Attached Figure Description

[0040] Figure 1 This is a schematic diagram of the structure of a multi-level relay communication system for underground mining provided in an embodiment of the present invention;

[0041] Figure 2 This is a flowchart illustrating a downhole multi-level relay communication method provided in an embodiment of the present invention;

[0042] Figure 3 This is a schematic diagram of the calibration process for a downhole multi-level relay communication method provided in an embodiment of the present invention;

[0043] Figure 4 This is a schematic diagram of the working timing of a downhole multi-level relay communication method provided in an embodiment of the present invention;

[0044] Icon labels:

[0045] 100. Oil and gas casing structure; 110. Oil pipe; 200. Transmitter; 300. Centralizer; 400. Repeater; 500. Ground receiver; 600. Formation; 700. Oil and gas producing layer. Detailed Implementation

[0046] Referring now to specific embodiments of the invention, examples of which are illustrated in the accompanying drawings. Although the invention will be described in conjunction with specific embodiments, it will be understood that it is not intended to limit the invention to the described embodiments. Rather, it is intended to cover variations, modifications, and equivalents included within the spirit and scope of the invention as defined by the appended claims. It should be noted that the method steps described herein can be implemented by any functional block or functional arrangement, and any functional block or functional arrangement can be implemented as a physical entity or a logical entity, or a combination of both.

[0047] To enable those skilled in the art to better understand the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0048] Note: The examples described below are merely specific examples and are not intended to limit the embodiments of the present invention to the specific steps, values, conditions, data, order, etc. Those skilled in the art can utilize the concept of the present invention to construct more embodiments not mentioned herein by reading this specification.

[0049] See Figure 1 As shown, an embodiment of the present invention provides a downhole multi-level relay communication system, comprising:

[0050] Oil and gas casing structure 100 is used in an open hole well in formation 600, including a hollow casing embedded in the open hole well in formation 600, and an oil pipe 110 provided in the hollow casing and along the extension direction of the casing.

[0051] The transmitter 200 is connected to the oil pipe 110 and placed at a preset oil and gas production layer location 700;

[0052] Multiple stabilizers 300, each stabilizer 300 having its two sides pressed against the inner wall of the sleeve, with one stabilizer 300 at each end of the transmitter 200;

[0053] At least one repeater 400, with a centralizer 300 at each end of each repeater 400. One repeater 400 and two centralizers 300 constitute a unit, and each unit is sequentially connected to the oil pipe 110 along the extension direction of the oil pipe 110.

[0054] A ground receiver 500 is positioned above the ground stratum 600 and is communicatively connected to the repeater 400.

[0055] In the oil and gas industry, a well that has not been casingd after drilling is called an open-hole well.

[0056] Specifically, in this embodiment, during initial operation, the transmitter 200 and each level of repeater 400 simultaneously enter sleep mode, and after the configured sleep duration, they are powered on. The transmitter 200 remains powered on to collect downhole data and transmits it to the repeater 400 through the electrical signal channel established by the centralizer 300, casing, and formation 600, after which it remains powered off and in sleep mode. The repeater 400 remains powered on to transmit downhole data to the surface receiver 500 through the electrical signal channel, after which it remains powered off and in sleep mode. When the surface receiver 500 detects that the received data is downhole data, it determines that the system is... The system operation is normal. When the received data is not downhole data, the system operation is judged to be abnormal, and a calibration signal is generated. The repeater 400 remains powered on and receives and sends the calibration signal through the electrical signal channel. The transmitter 200 remains powered on and receives the calibration signal through the electrical signal channel, generates a transmitter 200 synchronization command, and sends it. The ground receiver 500 receives the synchronization command through the electrical signal channel and stops generating calibration signals. When the transmitter 200 and repeater 400 do not receive a calibration signal, they are reset to the initial state and remain powered off and in sleep mode.

[0057] The metal centralizer 300 is in direct contact with the oil and gas casing structure 100 to establish a current path. The communication system uses a current field to achieve communication. Specifically, the transmitter 200 encodes the collected data and then injects current into the oil and gas casing structure 100 through the centralizer 300. Figure 1 (In the direction indicated by the middle arrow); the current flows upward along the casing and tubing 110 of the oil and gas casing structure 100 into the next centralizer 300, and then through the tubing 110 into the repeater 400. The repeater 400 demodulates and processes the data, and then injects it into the oil and gas casing structure 100 through the next centralizer 300 to continue upward transmission; each level of repeater 400 receives the data sent by the previous level repeater 400 using the same principle, and sends it to the next level repeater 400; after receiving the signal, the Nth level repeater 400 sends the data to the ground receiver 500; the ground receiver 500 obtains the data by collecting the potential difference formed by the current signal sent by the Nth level repeater 400.

[0058] Therefore, the multi-level relay communication system based on the centralizer 300 provided by this invention solves the problems of unstable contact points and low driving efficiency encountered in traditional electromagnetic signal communication. Furthermore, it designs a communication path for the repeater 400 based on the centralizer 300, effectively extending the communication distance across multiple levels. Simultaneously, for deep well communication requiring multi-level repeaters 400, it provides a battery collaborative management scheme for the long-term operation of the repeater 400 transmission system, and provides a basis for judging the working status of each level of the downhole repeater 400 for surface control, thus providing a pathway for long-term monitoring of deep wells based on relay technology.

[0059] Optionally, the centralizer 300 includes a tubular body connected to the oil pipe 110, and two centralizing connectors disposed on the periphery of the tubular body, the two centralizing connectors being respectively pressed against the inner wall of the casing.

[0060] Optionally, the straightening connector is semi-circular.

[0061] Specifically, in this embodiment, by directly contacting the centralizer 300 with the oil and gas casing structure 100 (with the two centralizer connectors correspondingly pressed against the inner wall of the casing of the oil and gas casing structure 100), a current channel can be established for current data transmission.

[0062] Optionally, the repeater 400 and the transmitter 200 are configured as access pipes.

[0063] Specifically, in this embodiment, the transmitter 200 device is in the shape of a pipe and is connected to the oil pipe 110 in the oil and gas casing structure 100. It is powered by a battery and has a centralizer 300 installed at each end. The transmitter 200 is located at the target oil and gas production layer 700 at the lowest end and is used to collect production layer data and send it to the ground.

[0064] The repeater 400 device is designed as a pipe and is connected to the oil pipe 110 in the oil and gas casing structure 100. It is powered by a battery and has a centralizer 300 set installed at each end. The first-stage repeater 400 device is located at the near-ground end of the transmitter 200 and is used to receive the signal sent by the downhole transmitter 200 and send the signal to the next-stage repeater 400.

[0065] See Figure 2 As shown, this embodiment of the invention provides a downhole multi-level relay communication method, applied to the downhole multi-level relay communication system as described above, including the following steps:

[0066] S100: In the initial state, the transmitter and all repeaters remain in a shutdown and sleep state. After a single shutdown and sleep time, the transmitter remains in the power-on working state to collect downhole data and sends it to the repeaters through the electrical signal channels established by the centralizer, casing and formation before remaining in the shutdown and sleep state.

[0067] S200: After the repeater is powered on and transmits downhole data to the ground receiver via an electrical signal channel, it is powered off and put into sleep mode.

[0068] S300: When the ground receiver detects that the received data is downhole data, the system operation is considered normal; when the received data is not downhole data, the system operation is considered abnormal, and a calibration signal is generated.

[0069] S400, the repeater remains powered on and receives and sends the calibration signal through the electrical signal channel;

[0070] S500: The transmitter remains powered on and receives the calibration signal through the electrical signal channel, generates a transmitter synchronization command, and sends it.

[0071] S600, the ground receiver receives the synchronization command through the electrical signal channel and stops generating the calibration signal;

[0072] When the transmitter and repeater do not receive a calibration signal, the S700 resets to the initial state and remains in a power-off sleep state.

[0073] Specifically, in this embodiment, traditional serial relay communication systems rely on the timing of each device to achieve coordinated operation. Under the high temperatures and long-term operating conditions underground, timing inaccuracies are highly likely. Furthermore, circuit switching actions also cause time errors, and the accumulation of these errors over time leads to the relay communication system entering a state of synchronization loss. Once the system loses synchronization, it is extremely difficult to restore it. Therefore, to address these problems, this invention provides a solution to the synchronization problem inherent in traditional systems that rely on the timing switching of individual devices to save energy. This avoids the need to return all devices to the surface for adjustment after synchronization loss, while effectively saving underground power. It also solves the problems of inconsistent contact points and low drive efficiency encountered in traditional electromagnetic signal communication, and designs the relay communication path based on a centralizer, effectively extending the distance of multi-level communication. Furthermore, for deep well communication requiring multi-level repeaters, it provides a battery collaborative management scheme for the long-term operation of the repeater transmission system, providing a basis for judging the working status of each level of underground repeater for surface control, and providing a means for long-term monitoring of deep wells based on relay technology.

[0074] Optionally, in another embodiment of the present invention, the step of "the repeater maintains its powered-on state to send downhole data to the surface receiver and then remains powered-off and in sleep mode; when the received data is detected to be non-downhole data, the system process is determined to be abnormal, and a calibration signal is generated" includes the following steps:

[0075] When the repeater does not receive downhole data, a repeater synchronization command is generated;

[0076] When the ground receiver detects that the received data is a repeater synchronization command, it determines that the system operation is abnormal and generates a calibration signal.

[0077] Specifically, in this embodiment, there are two repeaters. Because the transmitter has been working for a long time, its power-on time is different from that of the first-level repeater, which causes the first-level repeater to be unable to receive production layer data during its power-on time.

[0078] See Figure 3As shown, the first-stage repeater sends a synchronization command to the second-stage repeater, and this signal is then transmitted to the ground receiver via the second-stage repeater. The ground receiver determines the received synchronization command. Not a synchronization command issued by the transmitter When real-time downhole data (formation data) is received, the system is deemed to be malfunctioning, and a calibration signal is generated. The surface receiver sends a calibration signal downhole. After their respective sleep periods, the transmitter, first-stage repeater, and second-stage repeater power on upon receiving the calibration signal and remain powered on. The transmitter then sends a synchronization command. Upon receiving the synchronization command from the transmitter, the surface receiver stops generating calibration signals, and the transmitter, first-stage repeater, and second-stage repeater reset to their initial states. , and The system enters hibernation mode, and the overall system timing and synchronization are restored.

[0079] See also Figure 4 As shown, in another embodiment of the present invention, the relationship between the single power-off sleep time of the transmitter and the single power-off sleep time of all repeaters is as follows:

[0080] ;

[0081] The relationship between the single power-on operating time of the transmitter and the single power-on operating time of all repeaters is as follows:

[0082] ;

[0083] In the formula, This refers to the transmitter's single shutdown sleep time; ...... The single shutdown sleep time for each repeater sequentially set along the transmitter;

[0084] The single power-on operating time of the transmitter; ...... The single power-on operating time of each repeater set sequentially along the transmitter.

[0085] See Figure 4 As shown, in another embodiment of the present invention, in the initial state, the transmitter and all repeaters are in the first power-off sleep state.

[0086] The first-level repeater closest to the transmitter has a power-on time that is earlier than the transmitter's power-on time and later than the transmitter's (T+1)th power-off sleep time.

[0087] The Tth power-on time of the next-level repeater sequentially set along the transmitter is earlier than the Tth power-on time of the previous-level repeater, but later than the T+1th power-off sleep time of the previous-level repeater;

[0088] Where T is a natural number.

[0089] See Figure 4 As shown, in another embodiment of the present invention, the sum of the single power-off sleep time and the single power-on working time of each transmitter is equal to the sum of the single power-off sleep time and the single power-on working time of each repeater:

[0090]

[0091] See Figure 4 As shown, in another embodiment of the present invention, in the first initial state of all repeaters, the first shutdown sleep time of each repeater is greater than the single shutdown sleep time of repeaters in other time periods.

[0092] When a repeater at each level enters sleep mode for the first time during initial operation, its sleep time is... … Greater than other time periods … Except for the first shutdown and sleep time of the repeater, the shutdown and sleep time is the same for all other time periods.

[0093] Based on the same inventive concept, embodiments of this application also provide a computer-readable storage medium storing a computer program thereon, which, when executed by a processor, implements all or part of the method steps of the above method.

[0094] The present invention can implement all or part of the processes in the above methods, or it can be accomplished by a computer program instructing related hardware. The computer program can be stored in a computer-readable storage medium, and when the computer program is executed by a processor, it can implement the steps of the various method embodiments described above. The computer program includes computer program code, which can be in the form of source code, object code, executable files, or certain intermediate forms. The computer-readable medium can include: any entity or device capable of carrying computer program code, recording media, USB flash drives, portable hard drives, magnetic disks, optical disks, computer memory, read-only memory (ROM), random access memory (RAM), electrical carrier signals, telecommunication signals, and software distribution media, etc. It should be noted that the content contained in the computer-readable medium can be appropriately added or removed according to the requirements of legislation and patent practice in the jurisdiction. For example, in some jurisdictions, according to legislation and patent practice, the computer-readable medium does not include electrical carrier signals and telecommunication signals.

[0095] Based on the same inventive concept, embodiments of this application also provide an electronic device, including a memory and a processor. The memory stores a computer program that runs on the processor. When the processor executes the computer program, it implements all or part of the method steps described above.

[0096] The processor can be a Central Processing Unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general-purpose processor can be a microprocessor or any conventional processor. The processor is the control center of the computer device, connecting all parts of the computer device through various interfaces and lines.

[0097] Memory can be used to store computer programs and / or modules. The processor performs various functions of the computer device by running or executing the computer programs and / or modules stored in the memory, and by accessing data stored in the memory. Memory can primarily include a program storage area and a data storage area. The program storage area can store the operating system and at least one application program required for a function (e.g., sound playback, image playback, etc.); the data storage area can store data created based on the use of the mobile phone (e.g., audio data, video data, etc.). Furthermore, memory can include high-speed random access memory, and can also include non-volatile memory, such as hard disks, RAM, plug-in hard disks, SmartMedia Cards (SMC), Secure Digital (SD) cards, Flash Cards, at least one disk storage device, flash memory device, or other volatile solid-state storage devices.

[0098] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, systems, servers, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention can take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage and optical storage) containing computer-usable program code.

[0099] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), servers, and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart... Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0100] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0101] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0102] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A downhole multi-stage relay communication method applied to a downhole multi-stage relay communication system, characterized by, The downhole multi-level relay communication system includes: Oil and gas casing structure for use in open-hole wells in formations, including a hollow casing embedded in the open-hole well in the formation, and an oil pipe provided in the hollow casing and along the extension direction of the casing; The transmitter is connected to the oil pipeline and placed at a predetermined oil and gas producing layer location; Multiple centralizers, each with its two sides pressed against the inner wall of the sleeve, and one centralizer at each end of the transmitter; At least one repeater, with a centralizer at each end of each repeater, and one repeater and two centralizers constitute a unit, with each unit sequentially connected to the oil pipe along the extension direction of the oil pipe; A ground receiver is installed above the ground and communicates with the repeater. The downhole multi-level relay communication method includes the following steps: In the initial state, the transmitter and all repeaters remain in a shutdown and sleep state. After a single shutdown and sleep period, the transmitter remains in the power-on state to collect downhole data and transmits it to the repeaters through the electrical signal channels established by the centralizer, casing and formation before remaining in the shutdown and sleep state. After the repeater remains powered on and transmits downhole data to the ground receiver via an electrical signal channel, it remains powered off and in sleep mode. When the ground receiver detects that the received data is downhole data, it determines that the system operation is normal; when it detects that the received data is not downhole data, it determines that the system operation is abnormal and generates a calibration signal. The repeater remains powered on and receives and transmits the calibration signal via the electrical signal channel; The transmitter remains powered on and receives the calibration signal through the electrical signal channel, generates a transmitter synchronization command, and sends it. The ground receiver receives the synchronization command via an electrical signal channel and stops generating calibration signals; When the transmitter and repeater do not receive a calibration signal, they will reset to the initial state and remain in a power-off sleep state. The relationship between the single-time shutdown sleep time of the transmitter and the single-time shutdown sleep time of all repeaters is as follows: ； The relationship between the single power-on operating time of the transmitter and the single power-on operating time of all repeaters is as follows: ； In the formula, single shutdown sleep time for the transmitter; ... single shutdown sleep time for each repeater arranged in sequence along the transmitter; The single-time power-on operating time of the transmitter; ...... The single power-on operating time of each repeater sequentially set along the transmitter; In the initial state, the transmitter and all repeaters are in the first power-off sleep state; The first-level repeater closest to the transmitter has a power-on time that is earlier than the transmitter's power-on time and later than the transmitter's (T+1)th power-off sleep time. The Tth power-on time of the next-level repeater set sequentially along the transmitter is earlier than the Tth power-on time of the previous-level repeater, but later than the T+1th power-off sleep time of the previous-level repeater. Where T is a natural number.

2. The downhole multi-level relay communication method as described in claim 1, characterized in that, The centralizer includes a tubular body connected to the oil pipe, and two centralizing connectors disposed on the periphery of the tubular body, the two centralizing connectors being respectively pressed against the inner wall of the casing.

3. The downhole multi-level relay communication method as described in claim 1, characterized in that, The repeater and the transmitter are configured as access pipes.

4. The downhole multi-level relay communication method as described in claim 1, characterized in that, The process of "the repeater maintaining its powered-on state to send downhole data to the surface receiver, and then remaining powered-off and in sleep mode; if the received data is not downhole data, the system is deemed to be malfunctioning, and a calibration signal is generated" includes the following steps: When the repeater does not receive downhole data, a repeater synchronization command is generated; When the ground receiver detects that the received data is a repeater synchronization command, it determines that the system operation is abnormal and generates a calibration signal.

5. The downhole multi-level relay communication method as described in claim 1, characterized in that, The sum of the single-time shutdown sleep time and single-time power-on working time of each transmitter is equal to the sum of the single-time shutdown sleep time and single-time power-on working time of each repeater: 。 6. The downhole multi-level relay communication method as described in claim 1, characterized in that, In the initial state of all repeaters, the first shutdown sleep time of each repeater is longer than the single shutdown sleep time of repeaters in other time periods.

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