Downhole sound wave variable density data processing module

Abstract

The utility model provides an underground sound wave variable density data processing module, which belongs to the field of petroleum logging equipment and mainly comprises an MCU (Microprogrammed Control Unit) circuit, an input buffer circuit, a voltage reference circuit, a CAN (Controller Area Network) driving circuit and a power supply circuit, according to the voltage reference circuit, the power supply voltage of U3 is + 15V, the output end VOUT of the U3 is connected to a fifth pin of U2, and a sixth pin of the U2 is connected with a seventh pin of the U2; the three operational amplifiers are connected with the in-phase ends of the operational amplifiers, the three operational amplifiers are all used as voltage followers, and the output ends of the operational amplifiers are output by an ADC0, an ADC1 and an ADC2 respectively. The device is provided with two paths of 16-bit high-speed analog-digital signal conversion channels DMA for acquiring and processing acoustic variable density signals, and one path of low-speed analog-digital signal conversion channel for acquiring and processing magnetic positioning signals; and the controller local area network bus is adopted to transmit data, so that high-speed data transmission and high reliability are realized.

Description

Technical Field

[0001] The utility model relates to the technical field of petroleum well logging equipment, in particular to a downhole acoustic wave variable density data processing module. Background Art

[0002] Acoustic logging is a key geophysical logging method. It uses the differences in acoustic properties, such as velocity, amplitude, and frequency, of sound waves propagating through different rocks to analyze the geological profile of the well and assess cementing quality. It is a crucial tool for oil and gas field exploration and development. Acoustic variable density logging, a type of acoustic logging, uses the large difference in acoustic impedance between cement and mud (or water) to attenuate sound waves propagating along the casing axis, thereby reflecting the quality of the cement-casing and casing-formation bonds.

[0003] Acoustic variable density can evaluate the bonding condition of the first and second interfaces, namely the casing-cement and cement-formation interfaces. Acoustic amplitude logging requires two trips down the well, while acoustic variable density logging uses a combined logging method, which shortens operation time, reduces labor intensity, shortens completion cycle, and improves cementing quality to a certain extent. Acoustic amplitude can only evaluate the first interface, while acoustic variable density logging can evaluate both interfaces, which promotes the requirements of cementing work and the improvement of cementing technology.

[0004] Traditional acoustic variable density instruments use analog signal transmission, which has large interference, large errors and low transmission efficiency during long-distance transmission. It is not conducive to the ground system to process acoustic signals. It is no longer suitable for the development of contemporary logging technology and has seriously restricted the digital development of logging equipment. Utility Model Content

[0005] In view of the deficiencies in the prior art, the utility model provides a downhole acoustic wave variable density data processing module.

[0006] The embodiment of the present utility model provides a downhole acoustic wave variable density data processing module, comprising:

[0007] The processing module is mainly composed of MCU circuit, input buffer circuit, voltage reference circuit, CAN drive circuit and power supply circuit;

[0008] The voltage reference circuit: U3's power supply voltage is +15V, U3's output terminal VOUT is connected to U2's 5-pin, U2's 6-pin and 7-pin are connected, and as a voltage follower connected to REF to output a 3.0V voltage reference signal, the voltage reference circuit provides an external reference voltage for U4's analog-to-digital conversion circuit;

[0009] The input buffer circuit: two sound wave density signals are input from the AIN0 and AIN1 input terminals respectively, and one magnetic positioning signal is input from the CCL input terminal; they are connected to the non-inverting terminal of the operational amplifier, and the three operational amplifiers are all used as voltage followers. The output terminals of the operational amplifiers are output by ADC0, ADC1, and ADC2 respectively;

[0010] CAN drive circuit: The CAN controller of U4 is connected to the D and R pins of the transceiver U5 of the CAN drive circuit through CANTX and CANRX. CANTX serves as the data transmission port, and CANRX serves as the data reception port. Pins 7 and 6 of U5 are connected to CANH and CANL and the CAN bus respectively. The two ends of the transient voltage suppressor D1 are connected to the CAN bus respectively, and the other end is grounded.

[0011] MCU Circuit: The input buffer circuit output signal is connected to the MCU circuit's analog-to-digital converter (ADC) interface via ADC0, ADC1, and ADC2. The voltage reference circuit is connected to the MCU's external voltage reference terminal via REF. An external crystal oscillator is connected to the MCU's internal crystal oscillator circuit via the X1 pin, providing the MCU with a clock signal. The MCU outputs a total of 14 GPIO signals that can be used to control external devices. The MCU circuit's CAN controller is connected to the CAN driver circuit via CANTX and CANRX.

[0012] Power supply circuit: The power input ports of this module are VS+ (+15V), VCC (+3.3V) and GND. The positive power supply is connected from the VS+ input terminal to the resistor R3, and then to the capacitors C16 and C17 for filtering. The +15V is used to power the voltage reference circuit in the module. The positive power supply VCC input terminal is connected to the resistor R4, and then to the capacitors C18 and C19 for filtering. The +3.3V is used to power the digital part of the module. The +3.3V passes through the resistor R5 and is then connected to the capacitors C20 and C21 for filtering. The AV+ provides power for the analog circuit part of the MCU circuit.

[0013] Furthermore, the MCU circuit has a control LAN interface circuit, which can receive telemetry commands and upload acoustic wave density and magnetic positioning data at the same time, with a transmission rate of up to 1Mbit / s.

[0014] Furthermore, the processing module has a dual-channel acoustic wave variable density signal acquisition and data processing circuit and a magnetic positioning signal acquisition and data processing circuit.

[0015] Furthermore, the processing module is manufactured using a thick film process and is packaged in a QDIP-44 direct plug-in package.

[0016] Furthermore, the buffer circuit can receive a 0-3V acoustic wave density variation signal and a magnetic positioning signal.

[0017] Furthermore, the MCU circuit even provides 14 GPIO ports; 8 GPIOs can be used for gain control of the acoustic variable density signal preamplifier circuit, 2 GPIOs are used for gain control of the magnetic positioning signal, and 4 GPIOs are used for SPI serial communication to connect external E2PROM and watchdog circuit.

[0018] Furthermore, the voltage reference circuit mainly consists of an ultra-low noise XFET voltage reference ADR433 with compensation function and an AD8552 operational amplifier. The maximum temperature drift of the ADR433 is 3ppm / ℃, the maximum load adjustment is 15ppm / mA, and the maximum linear adjustment is 20ppm / V. An 82k resistor and a 10nF capacitor are connected in series between the COMP pin and the VOUT pin of the AD433 for temperature compensation.

[0019] Furthermore, the CAN driving circuit is mainly composed of a CAN transceiver and a bidirectional TVS chip.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] The utility model has two 16-bit high-speed analog-to-digital signal conversion channels DMA to collect and process acoustic variable density signals, and one low-speed analog-to-digital signal conversion channel to collect and process magnetic positioning signals; it improves the measurement accuracy of acoustic variable density, adopts a controller local area network bus to transmit data, and has high-speed data transmission and high reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a module diagram.

[0023] Figure 2 This is the application schematic diagram of the acoustic wave variable density data processing module.

[0024] Figure 3 This is the voltage reference circuit diagram.

[0025] Figure 4 This is the input buffer circuit diagram.

[0026] Figure 5 This is the MCU circuit diagram.

[0027] Figure 6 This is the CAN driver circuit diagram.

[0028] Figure 7 This is the power supply circuit diagram.

[0029] Figure 8 Defines a diagram for the pins.

[0030] Figure 9 This is the basic principle diagram of acoustic variable density logging. DETAILED DESCRIPTION

[0031] The technical solution of the present invention is further described below with reference to the accompanying drawings and embodiments.

[0032] like Figures 1-9 As shown, the embodiment of the present utility model proposes a downhole acoustic wave variable density data processing module, comprising:

[0033] The processing module is mainly composed of MCU circuit, input buffer circuit, voltage reference circuit, CAN drive circuit and power supply circuit;

[0034] The voltage reference circuit: U3's power supply voltage is +15V, U3's output terminal VOUT is connected to U2's 5-pin, U2's 6-pin and 7-pin are connected, and as a voltage follower connected to REF to output a 3.0V voltage reference signal, the voltage reference circuit provides an external reference voltage for U4's analog-to-digital conversion circuit;

[0035] The input buffer circuit: two sound wave density signals are input from the AIN0 and AIN1 input terminals respectively, and one magnetic positioning signal is input from the CCL input terminal; they are connected to the non-inverting terminal of the operational amplifier, and the three operational amplifiers are all used as voltage followers. The output terminals of the operational amplifiers are output by ADC0, ADC1, and ADC2 respectively;

[0036] CAN drive circuit: The CAN controller of U4 is connected to the D and R pins of the transceiver U5 of the CAN drive circuit through CANTX and CANRX. CANTX serves as the data transmission port, and CANRX serves as the data reception port. Pins 7 and 6 of U5 are connected to CANH and CANL and the CAN bus respectively. The two ends of the transient voltage suppressor D1 are connected to the CAN bus respectively, and the other end is grounded.

[0037] MCU Circuit: The input buffer circuit output signal is connected to the MCU circuit's analog-to-digital converter (ADC) interface via ADC0, ADC1, and ADC2. The voltage reference circuit is connected to the MCU's external voltage reference terminal via REF. An external crystal oscillator is connected to the MCU's internal crystal oscillator circuit via the X1 pin, providing the MCU with a clock signal. The MCU outputs a total of 14 GPIO signals that can be used to control external devices. The MCU circuit's CAN controller is connected to the CAN driver circuit via CANTX and CANRX.

[0038] Power supply circuit: The power input ports of this module are VS+ (+15V), VCC (+3.3V) and GND. The positive power supply is connected from the VS+ input terminal to the resistor R3, and then to the capacitors C16 and C17 for filtering. The +15V is used to power the voltage reference circuit in the module. The positive power supply VCC input terminal is connected to the resistor R4, and then to the capacitors C18 and C19 for filtering. The +3.3V is used to power the digital part of the module. The +3.3V passes through the resistor R5 and is then connected to the capacitors C20 and C21 for filtering. The AV+ provides power for the analog circuit part of the MCU circuit.

[0039] Further explanation is given that the MCU circuit has a control LAN interface circuit, which can receive telemetry short section commands and upload acoustic wave density and magnetic positioning data at the same time, with a transmission rate of up to 1Mbit / s.

[0040] Further explanation: the processing module has a dual-channel acoustic wave variable density signal acquisition and data processing circuit and a magnetic positioning signal acquisition and data processing circuit.

[0041] Further explanation is given, the processing module is manufactured using thick film technology and QDIP-44 through-hole packaging.

[0042] To further explain, the buffer circuit can receive 0~3V sound wave density variable signal and magnetic positioning signal.

[0043] To further explain, the MCU circuit even provides 14 GPIO ports; 8 GPIOs can be used for gain control of the acoustic variable density signal preamplifier circuit, 2 GPIOs are used for gain control of the magnetic positioning signal, and 4 GPIOs are used for SPI serial communication to connect external E2PROM and watchdog circuit.

[0044] Further explanation: the voltage reference circuit mainly consists of an ultra-low noise XFET voltage reference ADR433 with compensation function and the AD8552 op amp. The maximum temperature drift of the ADR433 is 3ppm / ℃, the maximum load adjustment is 15ppm / mA, and the maximum linear adjustment is 20ppm / V. An 82k resistor and a 10nF capacitor are connected in series between the COMP pin and the VOUT pin of the AD433 for temperature compensation.

[0045] To further explain, the CAN driving circuit is mainly composed of a CAN transceiver and a bidirectional TVS chip.

[0046] Further detailed explanation:

[0047] The acoustic variable density logging tool converts five channels of acoustic variable density signals downhole for analog-to-digital conversion. These signals are transmitted to a telemetry sub via the control area network bus (CAN2.0B). The sub then transmits the received acoustic variable density signal data to the surface. This prevents cable noise interference during acoustic signal transmission. The dynamic range of the acoustic variable density signal is significantly improved, enhancing acoustic detection accuracy. Commands sent from the surface control the sampling interval (1us / 2us / 4us), number of sampling points (256 / 512 / 1024 points), gain adjustment, noise gate, and operating mode (send five and receive two).

[0048] At the beginning of a working cycle, the teletransmission sub sends a remote frame (ID: 001 1000 1100) to the acoustic density instrument via the CAN bus, initiating data transmission. After data transmission is complete, if the teletransmission receives a ground acoustic control command, it will send an acoustic command word (ID: 001 1000 1100). If the data exceeds 1024 words, it must be transmitted in several parts. After completing data acquisition, the acoustic density instrument begins transmitting data to the data transmission system after receiving the remote frame from the teletransmission sub for data upload. As data upload cannot exceed 1K words at a time, it may not be able to transmit all the acquired data at once. In this case, the acoustic instrument will wait for the next remote frame and continue uploading data until data upload is complete. Only when all data transmission is complete (the frame end flag is asserted) can the acoustic instrument start operating and collect data, waiting for the teletransmission to send an RTR remote frame to begin the next cycle.

[0049] The digital acoustic variable density logging tool mainly consists of three parts: upper electronic circuit, acoustic system and lower electronic circuit.

[0050] The upper electronic circuit consists of an AC-DC power supply module and three acquisition and control circuit boards.

[0051] Each acquisition control circuit board provides two channels of acoustic wave signal processing and acquisition circuits, among which the acquisition control board A is responsible for the acquisition and processing of the first and second channels of acoustic wave signals, the acquisition control board B is responsible for the acquisition and processing of the third and fourth channels of acoustic wave signals, and the acquisition control board C is responsible for the acquisition and processing of the fifth channel of acoustic wave signals; and a CCL signal acquisition and processing circuit is added to the acquisition control board A.

[0052] The downhole acoustic wave variable density data processing module is the core component of the digital acoustic wave variable density logging instrument. It mainly consists of an MCU circuit, an input buffer circuit, a voltage reference circuit, a CAN driver circuit, and a power supply circuit.

[0053] Two acoustic wave density signals and one magnetic positioning signal undergo amplification, bandpass filtering, and signal shifting and attenuation processing in the preamplifier circuit and signal conditioning module. Three 0-3V output signals are fed into the input buffer circuit of the downhole acoustic wave density data processing module via the AIN1, AIN2, and CCL pins. The input buffer circuit primarily protects the analog-to-digital converter (ADC) in the subsequent MUC circuit by preventing damage from excessively high input voltages. The input buffer circuit comprises three high-precision, low-noise rail-to-rail operational amplifiers (AD8552).

[0054] The MCU (C8051F061) is a fully integrated mixed-signal system-on-chip (SoC) featuring a high-speed, pipelined, 8051-compatible CIP-51 core and a rich set of peripherals. It includes two 16-bit, 1Msps ADCs with DMA controllers, a 10-bit, 200ksps 8-channel ADC, a Controller Area Network (CAN) 2.0B controller with 32 message objects and a maximum communication rate of 1Mbps, 64KB of in-system programmable FLASH memory, 4KB of on-chip RAM, five general-purpose 16-bit timers, a programmable timer array, and 24 GPIO pins.

[0055] The three analog signals from the input buffer circuit enter the analog-to-digital converter of the MCU circuit. Under the control of the internal program, the analog signals are converted into 16-bit wide data of 256 points, 512 points or 1024 points at a sampling interval of 1uS, 2uS or 4uS and cached in the on-chip RAM. The digital filtering algorithm is used to process the collected waveform data to remove noise and other interference in the digital signal. When the MCU receives the command to upload data through the CAN controller, the CAN controller sends the processed data to the CAN bus via the CAN driver circuit, and the telemetry short section receives this data.

[0056] The MCU circuit even provides 14 GPIO ports; 8 GPIOs can be used for gain control of the acoustic variable density signal preamplifier circuit, 2 GPIOs are used for gain control of the magnetic positioning signal, and 4 GPIOs are used for SPI serial communication to connect to an external E2PROM and watchdog circuit.

[0057] The voltage reference circuit provides an external 3.0V voltage reference for the MCU's analog-to-digital converter (ADC). It primarily consists of an ultra-low-noise, compensated ADR433 XFET voltage reference and an AD8552 op amp. The ADR433 has a maximum temperature drift of 3ppm / °C, a maximum load adjustment of 15ppm / mA, and a maximum linear adjustment of 20ppm / V. An 82kΩ resistor and a 10nF capacitor are connected in series between the AD433's COMP and VOUT pins for temperature compensation.

[0058] The CAN driver circuit primarily consists of a CAN transceiver (SN65HVD233S) and a bidirectional TVS IC (NUP2105L). The SN65HVD233S, designed by Texas Instruments (TI), is specifically designed for applications requiring high-speed data transmission and high reliability. This transceiver supports the ISO 11898 standard, operates from a single 3.3V power supply, and can achieve data rates up to 1Mbps. The NUP2105L is a high-performance bidirectional TVS IC with fast response time and high surge current capability, protecting the CAN transceiver from transient voltage damage.

[0059] In summary, the beneficial effects of the present invention are:

[0060] It has two 16-bit high-speed analog-to-digital signal conversion channels DMA to collect and process acoustic wave variable density signals, and one low-speed analog-to-digital signal conversion channel to collect and process magnetic positioning signals, which improves the accuracy of acoustic wave variable density measurement.

[0061] It uses the controller area network (CAN2.0B) bus to transmit data, with high-speed data transmission and high reliability.

[0062] Computer-aided design (CAD) was used to optimize the device's circuit and structural design, improving module reliability. Computer-aided design (CAD) and circuit simulation were used to optimize the device's circuit and structural design. During the circuit simulation process, a parameter model for the circuit in a high-temperature environment was established, and some circuit parameter redundancy was adjusted, improving module reliability.

[0063] It adopts thick film manufacturing process and has a maximum operating temperature of 175℃.

[0064] This module is described as follows: This module consists of an analog signal input buffer circuit, an MCU circuit, a voltage reference circuit, a CAN drive circuit, and a power supply circuit.

[0065] The three analog signals are connected to the input buffer circuit via the AIN0, AIN1, and CCL input terminals, respectively. This buffer circuit buffers and limits the input analog signals to protect the downstream MCU circuitry. The output signals from the input buffer circuit are connected to the MCU's analog-to-digital converter (ADC) interface via ADC0, ADC1, and ADC2. The voltage reference circuit then connects the REF pin to the MCU's external voltage reference terminals (VREF0, VREF1, and VREF2). An external crystal oscillator is connected to the MCU's internal crystal oscillator circuit via the X1 pin, providing the MCU with a clock signal. The MCU outputs a total of 14 GPIO signals for controlling external devices. The MCU's CAN controller connects to the CAN driver circuit via CANTX and CANRX. Serial communication data is transmitted to the external CAN bus via the CAN transceiver via CANH and CANL.

[0066] The power input ports of this module are VS+ (+15V), VCC (+3.3V) and GND.

[0067] Voltage reference circuit: U3 (ADR433AR) is powered by a +15V supply. U3's output, VOUT, is connected to pin 5 of U2 (AD8552). Pins 6 and 7 of U2 are connected to REF, acting as a voltage follower to output a 3.0V voltage reference signal. The voltage reference circuit provides an external reference voltage for the analog-to-digital conversion circuit in U4 (C8051F061).

[0068] Input buffer circuit: Two acoustic wave density signals are input from the AIN0 and AIN1 input terminals respectively, and one magnetic positioning signal is input from the CCL input terminal; they are connected to the non-inverting terminal of the operational amplifier. The three operational amplifiers are all used as voltage followers, and the output terminals of the operational amplifiers are output by ADC0, ADC1, and ADC2 respectively.

[0069] MCU Circuit: The output signal of the input buffer circuit is connected to the MCU's analog-to-digital converter (ADC) interface via ADC0, ADC1, and ADC2. The voltage reference circuit then connects REF to the MCU's external voltage reference. An external crystal oscillator is connected to the MCU's internal crystal oscillator circuit via the X1 pin, providing the MCU with a clock signal. The MCU outputs a total of 14 GPIO signals for controlling external devices. The MCU's CAN controller connects to the CAN driver circuit via CANTX and CANRX.

[0070] CAN driver circuit: The CAN controller in U4 (C8051F061) connects to the D and R pins of the CAN driver circuit's transceiver, U5 (SN65HVD233S), via CANTX and CANRX. CANTX serves as the data transmit port, and CANRX as the data receive port. U5's pins 7 and 6 connect to the CAN bus, CANH and CANL, respectively. Transient voltage suppressor D1 (NUP2105L) has its two ends connected to the CAN bus, with the other end connected to ground.

[0071] Power supply circuit: This module's power input ports are VS+ (+15V), VCC (+3.3V), and GND. The positive power supply is connected from the VS+ input to resistor R3, then to capacitors C16 and C17 for filtering. The +15V voltage provides power to the module's voltage reference circuit. The positive power supply VCC input is connected to resistor R4, then to capacitors C18 and C19 for filtering. The +3.3V voltage provides power to the module's digital circuits. The +3.3V voltage passes through resistor R5 and is then connected to capacitors C20 and C21 for filtering. The AV+ voltage provides power to the analog circuitry within the MCU.

[0072]

[0073] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the utility model and are not limiting. Although the utility model is described in detail with reference to the preferred embodiments, ordinary technicians in this field should understand that the technical solution of the utility model can be modified or replaced by equivalents without departing from the purpose and scope of the technical solution of the utility model, which should be included in the scope of the claims of the utility model.

Claims

1. A downhole acoustic wave variable density data processing module, characterized by: The processing module is mainly composed of MCU circuit, input buffer circuit, voltage reference circuit, CAN drive circuit and power supply circuit; The voltage reference circuit: U3's power supply voltage is +15V, U3's output terminal VOUT is connected to U2's 5-pin, U2's 6-pin and 7-pin are connected, and as a voltage follower connected to REF to output a 3.0V voltage reference signal, the voltage reference circuit provides an external reference voltage for U4's analog-to-digital conversion circuit; The input buffer circuit: two sound wave density signals are input from the AIN0 and AIN1 input terminals respectively, and one magnetic positioning signal is input from the CCL input terminal; they are connected to the non-inverting terminal of the operational amplifier, and the three operational amplifiers are all used as voltage followers. The output terminals of the operational amplifiers are output by ADC0, ADC1, and ADC2 respectively; CAN drive circuit: The CAN controller of U4 is connected to the D and R pins of the transceiver U5 of the CAN drive circuit through CANTX and CANRX. CANTX serves as the data transmission port, and CANRX serves as the data reception port. Pins 7 and 6 of U5 are connected to CANH and CANL and the CAN bus respectively. The two ends of the transient voltage suppressor D1 are connected to the CAN bus respectively, and the other end is grounded. MCU circuit: The output signal of the input buffer circuit is connected to the analog-to-digital conversion interface of the MCU circuit via ADC0, ADC1, and ADC2. The voltage reference circuit is connected to the MCU external voltage reference terminal via REF. The external crystal oscillator is connected to the internal crystal oscillator circuit of the MCU via the X1 pin to provide a clock signal for the MCU. The MCU outputs a total of 14 GPIO signals that can be used to control external devices. The CAN controller of the MCU circuit is connected to the CAN driver circuit via CANTX and CANRX. Power supply circuit: The power input ports of this module are VS+, VCC and GND. The positive power supply is connected from the VS+ input terminal to the resistor R3, and then to the capacitors C16 and C17 for filtering. +15V is used to power the voltage reference circuit in the module. The positive power supply VCC input terminal is connected to the resistor R4, and then to the capacitors C18 and C19 for filtering. +3.3V is used to power the digital part of the module. +3.3V passes through the resistor R5 and is then connected to the capacitors C20 and C21 for filtering. AV+ provides power for the analog circuit part in the MCU circuit.

2. A downhole acoustic wave variable density data processing module according to claim 1, characterized in that: in: The MCU circuit has a control LAN interface circuit, which can receive telemetry commands and upload acoustic wave density and magnetic positioning data at the same time, with a transmission rate of up to 1Mbit / s.

3. The downhole acoustic wave variable density data processing module according to claim 1, characterized in that: in: The processing module has a dual-channel acoustic wave variable density signal acquisition and data processing circuit and a one-channel magnetic positioning signal acquisition and data processing circuit.

4. The downhole acoustic wave variable density data processing module according to claim 1, characterized in that: in: The processing module is manufactured using a thick film process and is packaged in a QDIP-44 direct plug-in package.

5. The downhole acoustic wave variable density data processing module according to claim 1, characterized in that: in: The buffer circuit can receive a 0-3V acoustic wave density change signal and a magnetic positioning signal.

6. The downhole acoustic wave variable density data processing module according to claim 1, characterized in that: in: The MCU circuit even provides 14 GPIO ports; 8 GPIOs can be used for gain control of the acoustic variable density signal preamplifier circuit, 2 GPIOs are used for gain control of the magnetic positioning signal, and 4 GPIOs are used for SPI serial communication to connect an external E2PROM and a watchdog circuit.

7. The downhole acoustic wave variable density data processing module according to claim 1, characterized in that: in: The voltage reference circuit is mainly composed of an ultra-low noise, compensation-capable XFET voltage reference ADR433 and an AD8552 op amp. The maximum temperature drift of the ADR433 is 3ppm / °C, the maximum load adjustment is 15ppm / mA, and the maximum linear adjustment is 20ppm / V. An 82k resistor and a 10nF capacitor are connected in series between the COMP pin and VOUT pin of the AD433 for temperature compensation.

8. The downhole acoustic wave variable density data processing module according to claim 1, characterized in that: in: The CAN drive circuit is mainly composed of a CAN transceiver and a bidirectional TVS chip.

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