Automatic gain control system and method based on casing coupling positioning signal

Abstract

The embodiment of the invention provides an automatic gain control system and method based on a casing coupling positioning signal. The system is applied to the field of petroleum perforation engineering and comprises an analog front end, a prediction module, a master control module and a bus, and the analog front end comprises an over-temperature protection circuit, an over-current protection circuit, a level translation circuit, a buffer, a programmable amplification circuit and a filter circuit; wherein the level translation circuit is used for converting a bipolar signal into a unipolar signal; the buffer is used for isolating front-stage and rear-stage circuits; the programmable amplification circuit is used for adjusting a gain coefficient; the filter circuit is used for suppressing noise signals; the prediction module is used for pre-judging the voltage amplitude of the casing coupling positioning signal according to the real-time falling speed of the perforating gun; and the main control module is used for processing the falling speed data of the perforating gun, calling the prediction module to output a pre-judgment voltage value, matching an optimal gain coefficient according to the pre-judgment voltage value, and outputting a control instruction to the programmable amplification circuit through a bus, so that the quality of perforating data is improved.

Description

Technical Field

[0001] This application relates to the field of oil perforation engineering, and in particular to an automatic gain control system and method based on casing coupling positioning signals. Background Technology

[0002] In the field of oil extraction, perforation is a crucial link connecting oil and gas reservoirs to the wellbore, and its operational accuracy directly determines the efficiency and production of subsequent oil and gas extraction. Among these, casing coupling positioning technology is the core support for ensuring the perforating gun accurately reaches the target reservoir location. This technology collects positioning signals generated by the downhole casing coupling, providing crucial data for depth calibration and work position confirmation of the perforating gun. Therefore, the accuracy and stability of the casing coupling positioning signal are important factors affecting the quality of perforation data and even the overall effectiveness of the extraction operation.

[0003] However, in actual downhole operations, the perforating gun is constantly in a dynamic descent state. Its descent speed is affected by various complex factors such as downhole fluid resistance, casing inner wall friction coefficient, and changes in the tubing structure, exhibiting non-uniform dynamic fluctuation characteristics. Most current mainstream casing coupling positioning signal processing systems employ fixed gain designs or rely on manual experience for staged gain adjustments, failing to adapt in real-time to the signal acquisition needs arising from the dynamic speed changes of the perforating gun. When the perforating gun's descent speed increases, the acquisition frequency and signal strength of the positioning signal change accordingly, easily leading to signal oversaturation or distortion under fixed gain. Conversely, when the speed decreases, insufficient gain may prevent the effective capture of weak signals, causing positioning deviations. This mismatch between gain adjustment and the dynamic state of the perforating gun directly results in a reduced signal-to-noise ratio and compromised data integrity of the casing coupling positioning signal, leading to perforation depth calibration errors. This not only affects the accurate perforation of oil and gas reservoirs but may also cause reservoir damage, casing failure, and other safety hazards, severely restricting the improvement of perforation operation quality and oil extraction efficiency.

[0004] Therefore, there is an urgent need for a control system that can adjust the signal gain in real time based on the dynamic state of the perforating gun, in order to solve the current problem of casing connection positioning signal processing and improve the quality of perforation data. Summary of the Invention

[0005] To address the aforementioned issues, this application provides an automatic gain control system and method based on sleeve coupling positioning signals.

[0006] In a first aspect, this application provides an automatic gain control system based on sleeve coupling positioning signals, comprising: an analog front end, a prediction module, a main control module, and a bus;

[0007] The prediction module is used to predict the voltage amplitude of the casing coupling positioning signal based on the real-time falling speed of the perforating gun.

[0008] The analog front end is used to receive the original magnetic positioning signal and process the signal;

[0009] The main control module analyzes and processes the falling speed data of the perforating gun based on the preset prediction module to obtain the predicted magnetic positioning signal voltage, determines the signal gain based on the magnetic positioning signal voltage, and feeds the signal gain back to the analog front end through the bus.

[0010] The analog front end includes: an over-temperature protection circuit, an over-current protection circuit, a level shifting circuit, a buffer, a programmable amplifier circuit, and a filter circuit;

[0011] The over-temperature protection circuit includes: a first resistor, a second resistor, a third resistor, a thermistor, a fourth resistor, a first operational amplifier, and a first MOSFET;

[0012] The overcurrent protection circuit includes: a fifth resistor, a sixth resistor, a seventh resistor, an eighth resistor, a twenty-first resistor, a twenty-second resistor, a twenty-third resistor, a second operational amplifier, a second MOSFET, and a first transistor;

[0013] The level shifting circuit includes: a ninth resistor, a tenth resistor, an eleventh resistor, and a third operational amplifier;

[0014] The buffer includes: a first capacitor, a twelfth resistor, a thirteenth resistor, a fourteenth resistor, and a fourth operational amplifier;

[0015] The programmable amplifier circuit includes: a fifteenth resistor, a sixteenth resistor, a twenty-fourth resistor, and a fifth operational amplifier;

[0016] The filter circuit includes: a second capacitor, a third capacitor, a seventeenth resistor, an eighteenth resistor, a nineteenth resistor, a twentieth resistor, and a sixth operational amplifier.

[0017] Optionally, the power supply terminal of the analog front end is connected to the first end of the first resistor and the second resistor; the second end of the first resistor is connected to the positive input terminal of the first operational amplifier and the first end of the thermistor; the second end of the second resistor is connected to the negative input terminal of the first operational amplifier and the first end of the third resistor; the first end of the fourth resistor is connected to the source of the first MOSFET and then to the power supply terminal of the analog front end; the output terminal of the first operational amplifier is connected to the second end of the fourth resistor and the gate of the first MOSFET; and the drain of the first MOSFET is connected to the source of the second MOSFET.

[0018] Optionally, the power supply terminal of the analog front end is connected to the first end of the fifth resistor, the second end of the fifth resistor is connected to the negative input terminal of the second operational amplifier and the first end of the sixth resistor, the first end of the eighth resistor is connected to the power supply terminal of the analog front end, the output terminal of the second operational amplifier is connected to the second end of the eighth resistor and the gate of the second MOS transistor, the first end of the twenty-second resistor and the first end of the twenty-third resistor are connected to the power supply, the second end of the fourth capacitor is connected to the second end of the twenty-second resistor and the base of the transistor, the second end of the twenty-third resistor is connected to the collector of the transistor, the first end of the seventh resistor and the negative input terminal of the second operational amplifier; the negative power supply terminals of the third operational amplifier, the fourth operational amplifier, the fifth operational amplifier and the sixth operational amplifier are connected to the first end of the twenty-first resistor and the first end of the fourth capacitor.

[0019] Optionally, the power supply terminal of the analog front end is connected to the first terminal of the ninth resistor, the second terminal of the ninth resistor is connected to the first terminal of the tenth resistor and the positive input terminal of the third operational amplifier, the negative input terminal of the third operational amplifier is connected to the first terminal of the eleventh resistor, and the output terminal of the third operational amplifier is connected to the second terminal of the eleventh resistor, the first terminal of the thirteenth resistor, the first terminal of the twenty-fourth resistor, the first terminal of the twentieth resistor and the first terminal of the second capacitor.

[0020] Optionally, the signal input terminal of the analog front end is connected to the first terminal of the first capacitor, the second terminal of the first capacitor is connected to the first terminal of the twelfth resistor, the second terminal of the twelfth resistor is connected to the second terminal of the thirteenth resistor and the positive input of the fourth operational amplifier, the negative input terminal of the fourth operational amplifier is connected to the first terminal of the fourteenth resistor, and the output terminal of the fourth operational amplifier is connected to the second terminal of the fourteenth resistor and the first terminal of the fifteenth resistor.

[0021] Optionally, the negative input terminal of the fifth operational amplifier is connected to the second terminal of the fifteenth resistor and the first terminal of the sixteenth resistor, the positive input terminal of the fifth operational amplifier is connected to the second terminal of the thirteenth resistor, and the output terminal of the fifth operational amplifier is connected to the second terminal of the sixteenth resistor.

[0022] Optionally, the second terminal of the seventeenth resistor is connected to the first terminal of the eighteenth resistor, the first terminal of the nineteenth resistor, and the second terminal of the second capacitor; the negative input terminal of the sixth operational amplifier is connected to the second terminal of the nineteenth resistor and the first terminal of the third capacitor; the positive input terminal of the sixth operational amplifier is connected to the second terminal of the twentieth resistor; and the second terminal of the eighteenth resistor is connected to the second terminal of the third capacitor and the output terminal of the sixth operational amplifier.

[0023] Secondly, this application provides an automatic gain control method based on a sleeve coupling positioning signal, applied to the aforementioned automatic gain control system based on a sleeve coupling positioning signal, the method comprising:

[0024] The system receives magnetic positioning signals from the magnetic positioning device via a simulated front end and processes these signals.

[0025] The processed magnetic positioning signal is input into an analog-to-digital converter for analog-to-digital conversion to obtain the converted digital signal.

[0026] The coupling is identified based on the converted digital signal, and the identified coupling signal is obtained.

[0027] The average speed between the couplings is calculated based on the identified coupling signals to obtain the descent speed of the perforating gun;

[0028] The corresponding magnetic positioning signal voltage is determined based on the falling speed of the perforating gun, the signal gain is determined based on the magnetic positioning signal voltage, and the signal gain is fed back to the analog front end.

[0029] The analog front end adjusts the signal amplification factor based on the feedback signal gain.

[0030] This application provides an automatic gain control system and method based on casing coupling positioning signals. The automatic gain control system includes: a sensor module, a main control module, and a bus. The sensor module is used to acquire the original downhole magnetic positioning signal and the perforating gun descent velocity data. The analog front-end is used to receive the original magnetic positioning signal and process the signal. The main control module analyzes and processes the perforating gun descent velocity data based on a preset velocity-voltage linear fitting model to obtain the predicted magnetic positioning signal voltage, determines the signal gain based on the magnetic positioning signal voltage, and feeds the signal gain back to the analog front-end via the bus. The analog front-end includes: an over-temperature protection circuit, an over-current protection circuit, a level shifting circuit, a buffer, a programmable amplifier circuit, and a filter circuit. The over-temperature protection circuit is used to initiate temperature shutdown when the temperature exceeds a preset temperature threshold; the over-current protection circuit is used to initiate current shutdown when the current exceeds a preset current threshold; the level shifting circuit is used to convert bipolar signals to unipolar signals; the buffer is used to isolate the preceding and following circuits; the programmable amplifier circuit is used to adjust the gain coefficient; and the filter circuit is used to suppress noise signals. This automatic gain control system based on the casing coupling positioning signal can improve the quality of perforation data. Attached Figure Description

[0031] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0032] Figure 1 This is a schematic diagram of the analog front end of the automatic gain control system based on the sleeve coupling positioning signal provided in the embodiments of this application.

[0033] The accompanying drawings illustrate specific embodiments of this application, which will be described in more detail below. These drawings and descriptions are not intended to limit the scope of the concept in any way, but rather to illustrate the concept of this application to those skilled in the art through reference to particular embodiments. Detailed Implementation

[0034] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0035] The terms "first," "second," "third," "fourth," etc. (if present) in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein.

[0036] In this application, the terms "exemplary" or "for example" are used to indicate examples, illustrations, or descriptions. Any embodiment or design described as "exemplary" or "for example" in this application should not be construed as being more preferred or advantageous than other embodiments or designs. Specifically, the use of terms such as "exemplary" or "for example" is intended to present the relevant concepts in a specific manner.

[0037] The technical solution of this application and how the technical solution of this application solves the above-mentioned technical problems are described in detail below with specific embodiments. These specific embodiments can be combined with each other, and the same or similar concepts or processes may not be described again in some embodiments. The embodiments of this application will now be described with reference to the accompanying drawings.

[0038] The automatic gain control system based on the casing coupling positioning signal provided in this embodiment includes: an analog front end, a prediction module, a main control module, and a bus. The prediction module is used to predict the voltage amplitude of the casing coupling positioning signal based on the real-time falling speed of the perforating gun. The analog front end is used to receive the original magnetic positioning signal and process the signal. The main control module analyzes and processes the falling speed data of the perforating gun based on the preset prediction module to obtain the predicted magnetic positioning signal voltage, determines the signal gain based on the magnetic positioning signal voltage, and feeds back the signal gain to the analog front end through the bus.

[0039] Figure 1This is a schematic diagram of the analog front-end of an automatic gain control system based on a sleeve coupling positioning signal, provided in an embodiment of this application. The analog front-end includes: an over-temperature protection circuit, an over-current protection circuit, a level shifting circuit, a buffer, a programmable amplifier circuit, and a filter circuit.

[0040] Specifically, the over-temperature protection circuit includes: a first resistor R1, a second resistor R2, a third resistor R3, a thermistor Rt, a fourth resistor R4, a first operational amplifier AMP1, and a first MOSFET M1;

[0041] The power supply terminal VDD of the analog front end is connected to the first terminals of the first resistor R1 and the second resistor R2. The second terminal of the first resistor R1 is connected to the positive input terminal of the first operational amplifier AMP1 and the first terminal of the thermistor Rt. The second terminal of the second resistor R2 is connected to the negative input terminal of the first operational amplifier AMP1 and the first terminal of the third resistor R3. The first terminal of the fourth resistor R4 is connected to the source of the first MOSFET M1 and then to the power supply terminal VDD of the analog front end. The output terminal of the first operational amplifier AMP1 is connected to the second terminal of the fourth resistor R4 and the gate of the first MOSFET M1. The drain of the first MOSFET M1 is connected to the source of the second MOSFET M2.

[0042] The over-temperature protection circuit is used to activate temperature shutdown protection to prevent device damage when the temperature exceeds a preset temperature threshold. Understandably, the resistance of a thermistor Rt increases with temperature, according to the voltage divider formula... It can be seen that when the temperature rises... When the terminal voltage rises, it is greater than When the voltage at the terminal is VCC, the output of the first operational amplifier AMP1 is high, and after being pulled up by the fourth resistor R4, the output is VCC. At this time, the first MOSFET M1 is off, that is, the power supply is turned off, protecting the components; when End smaller than When the reference voltage is applied to the terminal, the output of the first operational amplifier AMP1 is low, and the first MOSFET M1 is turned on.

[0043] Specifically, the overcurrent protection circuit includes: fifth resistor R5, sixth resistor R6, seventh resistor R7, eighth resistor R8, twenty-first resistor R21, twenty-second resistor R22, twenty-third resistor R23, second operational amplifier AMP2, second MOSFET M2 and transistor Q1;

[0044] The analog front-end power supply VDD is connected to the first terminal of the fifth resistor R5. The second terminal of the fifth resistor R5 is connected to the negative input terminal of the second operational amplifier AMP2 and the first terminal of the sixth resistor R6. The first terminal of the eighth resistor R8 is connected to the analog front-end power supply VDD. The output terminal of the second operational amplifier AMP2 is connected to the second terminal of the eighth resistor R8 and the gate of the second MOSFET M2. The first terminals of the twenty-second resistor R22 and the twenty-third resistor R23 are connected to the analog front-end power supply VDD. The second terminal of the fourth capacitor C4 is connected to the second terminal of the twenty-second resistor R22 and the base of the first transistor Q1. The second terminal of the twenty-third resistor R23 is connected to the collector of the transistor Q1. The negative power supply terminals of the third operational amplifier AMP3, the fourth operational amplifier AMP4, the fifth operational amplifier AMP5, and the sixth operational amplifier AMP6 are connected to the first terminal of the twenty-first resistor R21 and the first terminal of the fourth capacitor C4.

[0045] The overcurrent protection circuit activates current shutdown protection to prevent device damage when the current exceeds a preset current threshold. Understandably, resistor R21 (the 21st resistor) is a sampling resistor. Current flowing through R21 generates a voltage drop. Since this voltage drop is too low to be directly compared, an amplifier circuit amplifies the voltage. The voltage amplification factor is... . Specifically, When the voltage across resistor R7 is greater than When the second operational amplifier AMP2 outputs a high level, the second MOSFET M2 is off. When the voltage across resistor R7 is less than... When the second operational amplifier AMP2 outputs a low level, the second MOSFET M2 is in the turned-on state.

[0046] A level shifting circuit is used to forward shift a bipolar signal into a unipolar signal within a certain range. Specifically, the level shifting circuit includes: a ninth resistor R9, a tenth resistor R10, an eleventh resistor R11, and a third operational amplifier AMP3.

[0047] The analog front-end power supply VDD is connected to the first terminal of the ninth resistor R9. The second terminal of the ninth resistor R9 is connected to the first terminal of the tenth resistor R10 and the positive input terminal of the third operational amplifier AMP3. The negative input terminal of the third operational amplifier AMP3 is connected to the first terminal of the eleventh resistor R11. The output terminal of the third operational amplifier AMP3 is connected to the second terminal of the eleventh resistor R11, the first terminal of the thirteenth resistor R13, and the first terminal of the twenty-fourth resistor R24. After voltage division by series resistors, the voltage is boosted to [value missing]. The operational amplifier is used to make the output voltage the same as the input voltage, thus boosting the input signal, which was originally based on 0V, to a value based on 0V. The baseline change.

[0048] A buffer isolates the preceding and following circuits, eliminating mutual interference and improving signal quality. Specifically, the buffer includes: a first capacitor C1, a twelfth resistor R12, a thirteenth resistor R13, a fourteenth resistor R14, and a fourth operational amplifier AMP4;

[0049] The signal input terminal Vin of the analog front end is connected to the first terminal of the first capacitor C1. The second terminal of the first capacitor C1 is connected to the first terminal of the twelfth resistor R12. The second terminal of the twelfth resistor R12 is connected to the second terminal of the thirteenth resistor R13 and the positive input of the fourth operational amplifier AMP4. The negative input terminal of the fourth operational amplifier AMP4 is connected to the first terminal of the fourteenth resistor R14. The output terminal of the second operational amplifier AMP2 is connected to the second terminal of the sixth resistor R6 and the first terminal of the seventh resistor R7.

[0050] Understandably, the first capacitor C1 blocks DC and passes AC, the twelfth resistor R12 and the thirteenth resistor R13 form a voltage divider circuit, the output of the fourth operational amplifier AMP4 has the same voltage as the positive input of AMP4, and it also isolates the subsequent circuits from the previous circuits.

[0051] A programmable amplifier circuit is used to adjust the gain coefficient by modifying the resistance value according to a control signal. Specifically, the programmable amplifier circuit includes: a fifteenth resistor R15, a sixteenth resistor R16, a twenty-fourth resistor R24, and a fifth operational amplifier AMP5;

[0052] The negative input terminal of the fifth operational amplifier AMP5 is connected to the second terminal of the fifteenth resistor R15 and the first terminal of the sixteenth resistor R16, and the output terminal of the fifth operational amplifier AMP5 is connected to the second terminal of the sixteenth resistor R16.

[0053] The output of the fifth operational amplifier AMP5 is connected to the second terminal of resistor R16 as the output of the inverting amplifier circuit. The amplification factor of the analog front-end is changed by adjusting the value of the sixteenth resistor R16, satisfying the following formula: This enables the function of changing the magnification factor.

[0054] A filtering circuit is used to suppress noise signals. Specifically, the filtering circuit includes: a second capacitor C2, a third capacitor C3, a seventeenth resistor R17, an eighteenth resistor R18, a nineteenth resistor R19, a twentieth resistor R20, and a sixth operational amplifier AMP6;

[0055] The second terminal of the seventeenth resistor R17 is connected to the first terminal of the eighteenth resistor R18, the first terminal of the nineteenth resistor R19, and the second terminal of the second capacitor C2. The positive input terminal of the fifth operational amplifier AMP5 is connected to the second terminal of the eighteenth resistor R18. The negative input terminal of the sixth operational amplifier AMP6 is connected to the second terminal of the nineteenth resistor R19 and the first terminal of the third capacitor C3. The positive input terminal of the sixth operational amplifier AMP6 is connected to the second terminal of the twentieth resistor R20. The second terminal of the eighteenth resistor R18 is connected to the second terminal of the third capacitor C3 and the output terminal of the sixth operational amplifier AMP6 as the output Vout.

[0056] The above-described filter circuit is an infinite-gain multi-feedback filter circuit, using Butterworth approximation. After setting the specified cutoff frequency, refer to the capacitor selection table for a second-order infinite-gain multi-feedback Butterworth low-pass filter design to select the value of the second capacitor C2. Based on the actual value of the second capacitor C2, the resistance transposition factor K can be calculated. The resistance transposition factor K satisfies... , Here, the cutoff frequency is in Hz. Referring to the design table for a second-order infinite gain multiple feedback Butterworth low-pass filter, we can obtain r17, r18, and r19. Multiplying the normalized resistance values ​​by the resistance scaling factor respectively, we can obtain the actual resistance values, i.e., R17=K×r17, R18=K×r18, and R19=K×r19. From the design table for a second-order infinite gain multiple feedback Butterworth low-pass filter, we can obtain C3 / C2, thus obtaining the capacitance value of C3.

[0057] This embodiment proposes an automatic gain control system based on the casing coupling positioning signal, including: an analog front-end, a prediction module, a main control module, and a bus; the prediction module is used to predict the voltage amplitude of the casing coupling positioning signal based on the real-time falling speed of the perforating gun; the analog front-end is used to receive the original magnetic positioning signal and process the signal; the main control module analyzes and processes the falling speed data of the perforating gun based on the preset prediction module to obtain the predicted magnetic positioning signal voltage, determines the signal gain based on the magnetic positioning signal voltage, and feeds back the signal gain to the analog front-end through the bus; the analog front-end includes: an over-temperature protection circuit, an over-current protection circuit, a level shifting circuit, a buffer, a programmable amplifier circuit, and a filter circuit; wherein, the over-temperature protection circuit is used to activate temperature shutdown when the temperature exceeds a preset temperature threshold; the over-current protection circuit is used to activate current shutdown when the current exceeds a preset current threshold; the level shifting circuit is used to convert bipolar signals into unipolar signals; the buffer is used to isolate the preceding and following circuits; the programmable amplifier circuit is used to adjust the gain coefficient; and the filter circuit is used to suppress noise signals. This automatic gain control system based on the casing coupling positioning signal can improve the quality of perforation data.

[0058] The automatic gain control method based on casing coupling positioning signals provided in this embodiment is applied to the aforementioned automatic gain control system based on casing coupling positioning signals. The method includes: receiving a magnetic positioning signal from a magnetic locator via an analog front-end and processing the magnetic positioning signal; inputting the processed magnetic positioning signal into an analog-to-digital converter for analog-to-digital conversion to obtain a converted digital signal; identifying the coupling based on the converted digital signal to obtain the identified coupling signal; calculating the average velocity between the couplings based on the identified coupling signal to obtain the perforation gun drop velocity; determining the corresponding magnetic positioning signal voltage based on the perforation gun drop velocity; determining the signal gain based on the magnetic positioning signal voltage and feeding the signal gain back to the analog front-end; and adjusting the signal amplification factor based on the feedback signal gain. This method can improve the quality of perforation data.

[0059] Other embodiments of this application will readily occur to those skilled in the art upon consideration of the specification and practice of the invention disclosed herein. This application is intended to cover any variations, uses, or adaptations of this application that follow the general principles of this application and include common knowledge or customary techniques in the art not disclosed herein. The specification and examples are to be considered exemplary only, and the true scope and spirit of this application are indicated by the following claims.

[0060] It should be understood that this application is not limited to the precise structure described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of this application is limited only by the appended claims.

Claims

1. An automatic gain control system based on sleeve coupling positioning signals, characterized in that, The automatic gain control system based on the sleeve coupling positioning signal includes: an analog front end, a prediction module, a main control module, and a bus; The prediction module is used to predict the voltage amplitude of the casing coupling positioning signal based on the real-time falling speed of the perforating gun. The analog front end is used to receive the original magnetic positioning signal and process the signal; The main control module analyzes and processes the falling speed data of the perforating gun based on the preset prediction module to obtain the predicted magnetic positioning signal voltage, determines the signal gain based on the magnetic positioning signal voltage, and feeds the signal gain back to the analog front end through the bus. The analog front end includes: an over-temperature protection circuit, an over-current protection circuit, a level shifting circuit, a buffer, a programmable amplifier circuit, and a filter circuit; The over-temperature protection circuit includes: a first resistor, a second resistor, a third resistor, a thermistor, a fourth resistor, a first operational amplifier, and a first MOSFET; The overcurrent protection circuit includes: a fifth resistor, a sixth resistor, a seventh resistor, an eighth resistor, a twenty-first resistor, a twenty-second resistor, a twenty-third resistor, a fourth capacitor, a second operational amplifier, a second MOSFET, and a first transistor; The level shifting circuit includes: a ninth resistor, a tenth resistor, an eleventh resistor, and a third operational amplifier; The buffer includes: a first capacitor, a twelfth resistor, a thirteenth resistor, a fourteenth resistor, and a fourth operational amplifier; The programmable amplifier circuit includes: a fifteenth resistor, a sixteenth resistor, a twenty-fourth resistor, and a fifth operational amplifier; The filter circuit includes: a second capacitor, a third capacitor, a seventeenth resistor, an eighteenth resistor, a nineteenth resistor, a twentieth resistor, and a sixth operational amplifier.

2. The automatic gain control system based on the sleeve coupling positioning signal according to claim 1, characterized in that, The power supply terminal of the analog front end is connected to the first end of the first resistor and the first end of the second resistor. The second end of the first resistor is connected to the positive input terminal of the first operational amplifier and the first end of the thermistor. The second end of the second resistor is connected to the negative input terminal of the first operational amplifier and the first end of the third resistor. The first end of the fourth resistor is connected to the source of the first MOS transistor and then to the power supply terminal of the analog front end. The output terminal of the first operational amplifier is connected to the second end of the fourth resistor and the gate of the first MOS transistor. The drain of the first MOS transistor is connected to the source of the second MOS transistor.

3. The automatic gain control system based on the sleeve coupling positioning signal according to claim 1, characterized in that, The power supply terminal of the analog front end is connected to the first end of the fifth resistor. The second end of the fifth resistor is connected to the negative input terminal of the second operational amplifier and the first end of the sixth resistor. The first end of the eighth resistor is connected to the power supply terminal of the analog front end. The output terminal of the second operational amplifier is connected to the second end of the eighth resistor and the gate of the second MOS transistor. The first ends of the twenty-second and twenty-third resistors are connected to the power supply. The second end of the fourth capacitor is connected to the second end of the twenty-second resistor and the base of the transistor. The second end of the twenty-third resistor is connected to the collector of the transistor, the first end of the seventh resistor, and the negative input terminal of the second operational amplifier. The negative power supply terminals of the third, fourth, fifth, and sixth operational amplifiers are connected to the first end of the twenty-first resistor and the first end of the fourth capacitor.

4. The automatic gain control system based on the sleeve coupling positioning signal according to claim 1, characterized in that, The power supply terminal of the analog front end is connected to the first terminal of the ninth resistor, the second terminal of the ninth resistor is connected to the first terminal of the tenth resistor and the positive input terminal of the third operational amplifier, the negative input terminal of the third operational amplifier is connected to the first terminal of the eleventh resistor, and the output terminal of the third operational amplifier is connected to the second terminal of the eleventh resistor, the first terminal of the thirteenth resistor, the first terminal of the twenty-fourth resistor, the first terminal of the twentieth resistor and the first terminal of the second capacitor.

5. The automatic gain control system based on the sleeve coupling positioning signal according to claim 1, characterized in that, The signal input terminal of the analog front end is connected to the first terminal of the first capacitor, the second terminal of the first capacitor is connected to the first terminal of the twelfth resistor, the second terminal of the twelfth resistor is connected to the second terminal of the thirteenth resistor and the positive input of the fourth operational amplifier, the negative input terminal of the fourth operational amplifier is connected to the first terminal of the fourteenth resistor, and the output terminal of the fourth operational amplifier is connected to the second terminal of the fourteenth resistor and the first terminal of the fifteenth resistor.

6. The automatic gain control system based on the sleeve coupling positioning signal according to claim 1, characterized in that, The negative input terminal of the fifth operational amplifier is connected to the second terminal of the fifteenth resistor and the first terminal of the sixteenth resistor. The positive input terminal of the fifth operational amplifier is connected to the second terminal of the thirteenth resistor. The output terminal of the fifth operational amplifier is connected to the second terminal of the sixteenth resistor.

7. The automatic gain control system based on the sleeve coupling positioning signal according to claim 1, characterized in that, The second terminal of the seventeenth resistor is connected to the first terminal of the eighteenth resistor, the first terminal of the nineteenth resistor, and the second terminal of the second capacitor. The negative input terminal of the sixth operational amplifier is connected to the second terminal of the nineteenth resistor and the first terminal of the third capacitor. The positive input terminal of the sixth operational amplifier is connected to the second terminal of the twentieth resistor. The second terminal of the eighteenth resistor is connected to the second terminal of the third capacitor and the output terminal of the sixth operational amplifier.

8. An automatic gain control method based on sleeve coupling positioning signals, characterized in that, The method, applied to the automatic gain control system based on the sleeve coupling positioning signal as described in any one of claims 1-7, comprises: The system receives magnetic positioning signals from the magnetic positioning device via a simulated front end and processes these signals. The processed magnetic positioning signal is input into an analog-to-digital converter for analog-to-digital conversion to obtain the converted digital signal. The coupling is identified based on the converted digital signal, and the identified coupling signal is obtained. The average speed between the couplings is calculated based on the identified coupling signals to obtain the descent speed of the perforating gun; The corresponding magnetic positioning signal voltage is determined based on the falling speed of the perforating gun, the signal gain is determined based on the magnetic positioning signal voltage, and the signal gain is fed back to the analog front end. The analog front end adjusts the signal amplification factor based on the feedback signal gain.

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