Downhole sound wave variable density signal conditioning module

Abstract

The utility model discloses an underground sound wave variable density signal conditioning module which comprises two unit circuits, and the two unit circuits are respectively two channels of sound wave variable density signal conditioning circuits and a magnetic positioning signal conditioning circuit. The two-channel sound wave variable density signal conditioning circuit comprises two signal attenuation circuits and two biasing circuits. The magnetic positioning signal conditioning circuit comprises a magnetic positioning signal pre-amplification circuit, a low-pass filter circuit, a gain control circuit and an output circuit, and through digital processing, interference and errors in the analog signal transmission process are reduced, and the stability and accuracy of signal transmission are improved; the module carries out attenuation and bias processing on sound wave variable density signals to enable the amplitude of the sound wave variable density signals to be suitable for subsequent digital processing, and carries out pre-amplification and low-pass filtering on magnetic positioning signals to effectively remove high-frequency noise.

Description

Technical Field

[0001] The utility model relates to the technical field of acoustic logging, in particular to a downhole acoustic variable density signal conditioning module. Background Technique

[0002] Acoustic logging is an important logging method in geophysical logging. It uses the differences in acoustic characteristics such as the speed, amplitude, and frequency of sound waves when propagating in different rocks to study the geological profile of the well, judge the cementing quality, and is an important means for exploring and developing oil and gas fields. Acoustic variable density logging belongs to a type of acoustic logging. Its principle is to use the large difference in acoustic impedance between cement and mud (or water) to reflect the bonding quality between cement and casing, and between casing and formation by the attenuation effect of sound waves propagating along the axial direction of the casing.

[0003] However, due to the analog signal transmission method of traditional acoustic variable density instruments, there are large interference, large errors, and low transmission efficiency during long-distance transmission, which is not conducive to the ground system to process acoustic signals, and it no longer adapts to the development of contemporary logging technology, seriously restricting the digital development of logging equipment. Content of the Utility Model

[0004] In order to solve the above problems, the utility model provides a downhole acoustic variable density signal conditioning module to solve this problem.

[0005] To achieve the above object, the present application provides the following technical solutions:

[0006] A downhole acoustic variable density signal conditioning module includes two unit circuits, namely a two-channel acoustic variable density signal conditioning circuit and a magnetic positioning signal conditioning circuit.

[0007] Further set as: the two-channel acoustic variable density signal conditioning circuit includes two signal attenuation circuits and two bias circuits.

[0008] Further set as: the magnetic positioning signal conditioning circuit includes a magnetic positioning signal preamplification circuit, a low-pass filter circuit, a gain control circuit, and an output circuit.

[0009] Further set as: the signal attenuation circuit is composed of a reference voltage, resistor R1, and resistor R2.

[0010] Further set as: the bias circuit includes a non-inverting adder composed of operational amplifier U1, resistor R1, resistor R2, and resistor R3. The output of the reference voltage is connected to the non-inverting terminal of operational amplifier U1, and the inverting terminal of operational amplifier U1 is connected to its own output terminal.

[0011] Further set as: The magnetic positioning signal conditioning circuit is provided with inputs from the CCL+ pin and the CCL- pin, the CCL- pin is connected to the ground, and the magnetic positioning signal pre-amplification circuit includes an inverting amplifier composed of a capacitor C3 connected between CCL+ and CCL-, an operational amplifier U2.1, a resistor R7, a resistor R8, and a resistor R9.

[0012] Further set as: The low-pass filter circuit includes a resistor R10, a resistor R11, a capacitor C6, a capacitor C7, and an operational amplifier U2.2, and the output of the operational amplifier U2.2 is connected to the CCL-A pin.

[0013] Further set as: The gain control circuit includes an analog switch U3 and a resistor network composed of a resistor R12, a resistor R13, a resistor R14, and a resistor R15 connected in series in sequence. One end of the resistor R12 is connected to the CCL-A pin, and the CCL-A pin is simultaneously connected to the S4 end of the analog switch U3. The connection points of the resistor R13, the resistor R14, and the resistor R15 are respectively connected to the S3 end, the S2 end, and the S1 end of the analog switch U3; the A1 end and the A0 end of the analog switch U3 are respectively connected to C0 and C1 as the input control ends of the analog switch U3 to control the connection of the OUT end of the analog switch U3 to the S1 end, the S2 end, the S3 end, and the S4 end; the S5-S8 ends of the analog switch U3 are grounded.

[0014] Further set as: The OUT end of the analog switch U3 is connected to an inverting amplifier composed of a resistor R18, a resistor R19, a resistor R20, and an operational amplifier U4.1.

[0015] Further set as: The output circuit includes a resistor R21, a resistor R22, a resistor R23, and an operational amplifier U4.2 connected in series in sequence, and the output of the operational amplifier U4.2 is connected to the CCL pin.

[0016] Compared with the prior art, the beneficial technical effects of the present utility model are:

[0017] 1. High anti-interference ability: Through digital processing, interference and errors in the analog signal transmission process are reduced, and the stability and accuracy of signal transmission are improved.

[0018] 2. Signal conditioning ability: The module attenuates and biases the acoustic variable density signal to make its amplitude suitable for subsequent digital processing, and simultaneously pre-amplifies and low-pass filters the magnetic positioning signal, effectively removing high-frequency noise.

[0019] 3. Precise gain control: By using an AD7501 analog switch and a resistor network, precise gain control of the magnetic positioning signal is achieved, and the signal depth calibration accuracy is improved.

[0020] In summary, the design of this module conforms to the trend of the digital transformation of modern logging technology, which helps to improve the technical level of the entire logging industry. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for the description of the specific embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0022] Figure 1 is the circuit functional block diagram of the present invention;

[0023] Figure 2 is the schematic diagram of the acoustic variable density signal conditioning circuit of the present invention;

[0024] Figure 3 is the schematic diagram of the magnetic positioning signal conditioning circuit of the present invention;

[0025] Figure 4 is the schematic diagram of the gain control and output circuit of the present invention;

[0026] Figure 5 is the schematic diagram of the external shape of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0027] The following will clearly and completely describe the technical solutions of the present invention with reference to the drawings. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art without creative efforts based on the embodiments of the present invention belong to the scope of protection of the present invention.

[0028] In the description of the present invention, it should be noted that unless otherwise clearly defined and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0029] Embodiment

[0030] Refer to Figures 1-5, a downhole acoustic variable density signal conditioning module disclosed by the present utility model, includes two unit circuits, namely a two-channel acoustic variable density signal conditioning circuit and a magnetic positioning signal conditioning circuit. Among them, the two-channel acoustic variable density signal conditioning circuit includes two signal attenuation circuits and two bias circuits; the magnetic positioning signal conditioning circuit includes a magnetic positioning (CCL) signal pre-amplification circuit, a low-pass filter circuit, a gain control circuit, and an output circuit.

[0031] The two-channel acoustic variable density signal conditioning circuit is provided with INA and INB terminals as inputs and AINA and AINB terminals as outputs. The signals of the two signal attenuation circuits are attenuated, and the amplitude is attenuated from -15V to +15V to -1.25V to +1.25V. The attenuated acoustic variable density signal is subjected to bias processing through the two bias circuits, and the conditioned acoustic variable density signal of 0-2.5V is output from the two output terminals of AINA and AINB.

[0032] In the magnetic positioning signal conditioning circuit, CCL+ and CCL- terminals are provided as the magnetic positioning signal input terminals. The magnetic positioning signal enters the magnetic positioning signal pre-amplification circuit, and then passes through the low-pass filter circuit. The signal is output from the CCL-A output terminal of the low-pass filter circuit and enters the gain control circuit. The gain control circuit is provided with CO and C1 as the gain control signal input terminals, and the four-stage gain can be adjusted by the microcontroller. The magnetic positioning signal after gain adjustment finally enters the output buffer circuit for conditioning, and finally the output circuit outputs a magnetic positioning signal of 0-3V.

[0033] Refer to Figure 2 , the acoustic variable density signal conditioning circuit further includes a 2.5V reference voltage as the voltage source input terminal for bias adjustment. Taking one of the signal conditioning circuits as an example, the acoustic variable density signal is input from INA and then connected to a signal attenuation circuit composed of a resistor R1 with a resistance value of 50kΩ and a resistor R2 with a resistance value of 10kΩ;

[0034] The bias circuit includes a non-inverting adder composed of an operational amplifier U1 of model OP2177, a resistor R1, a resistor R2, and a resistor R3. Among them, the output of the reference voltage is connected to the non-inverting terminal of the operational amplifier U1, the inverting terminal of the operational amplifier U1 is connected to its own output terminal, and the output of the operational amplifier U1 is connected to the AIN output terminal. The conditioned two-channel acoustic variable density signals are finally output from the AIN output terminal.

[0035] Refer to Figure 3, the magnetic positioning signal conditioning circuit has inputs from the CCL+ pin and the CCL- pin, where the CCL- pin is connected to ground. The magnetic positioning signal pre-amplification circuit includes a capacitor C3 with a capacitance value of 0.47 uF connected between CCL+ and CCL-, and an inverting amplifier composed of an operational amplifier U2.1 of model OP2177, a resistor R7 with a resistance value of 91 kΩ, a resistor R8 with a resistance value of 10 kΩ, and a resistor R9 with a resistance value of 80 kΩ;

[0036] The low-pass filter circuit includes a resistor R10 with a resistance value of 30 kΩ, a resistor R11 with a resistance value of 30 kΩ, a capacitor C6 with a capacitance value of 0.1 uF, a capacitor C7 with a capacitance value of 0.1 uF, and an operational amplifier U2.2 of model OP2177. The output of the operational amplifier U2.2 is connected to the CCL-A pin.

[0037] Refer to Figure 4 , the gain control circuit includes an analog switch U3 of model AD7501 and a resistor network composed of resistors R12, R13, R14, and R15 connected in series in sequence. One end of the resistor R12 is connected to the CCL-A pin, and the CCL-A pin is simultaneously connected to the S4 end of the analog switch U3. The connection points of the resistors R13, R14, and R15 are respectively connected to the S3 end, S2 end, and S1 end of the analog switch U3;

[0038] In this embodiment, the resistor network performs a resistor voltage division attenuation process on the magnetic positioning signal input to CCL-A. The A1 end and A0 end of the analog switch U3 are respectively connected to C0 and C1 as the input control terminals of the analog switch U3 to control the connection of the OUT end of the analog switch U3 to the S1 end, S2 end, S3 end, and S4 end; the S5 - S8 ends of the analog switch U3 are grounded.

[0039] The OUT end of the analog switch U3 is connected to an inverting amplifier composed of a resistor R18, a resistor R19, a resistor R20, and an operational amplifier U4.1 of model OP2177,

[0040] The output circuit includes a resistor R21, a resistor R22, a resistor R23, and an operational amplifier U4.2 of model OP2177 connected in series in sequence. The output of the operational amplifier U4.2 is connected to the CCL pin, and the CCL pin serves as the output terminal of the magnetic positioning signal conditioning circuit.

[0041] The working principle and beneficial effects of the present utility model are:

[0042] In this utility model, the operational amplifier of model OP2177 has characteristics such as extremely low offset voltage and drift, low input bias current, low noise and low power consumption. When using a capacitive load of more than 1000 pF, the output is stable and no external compensation is required. When the power supply voltage is 30V, the power supply current of each amplifier is less than 500 μA.

[0043] The downhole acoustic variable density signal conditioning module receives and conditions a magnetic positioning signal. The magnetic positioning signal first enters the magnetic positioning signal pre-amplification circuit, which amplifies the magnetic positioning signal by 9 times, and then passes through a low-pass filter circuit to remove the high-frequency noise signal of the friction between the downhole instrument and the wellbore in the magnetic positioning signal. This utility model designs an adjustable magnetic positioning gain adjustment circuit, and the gain adjustment is mainly composed of an AD7501 analog switch U3 of a certain model and a resistor network. The analog switch U3 is a single-chip CMOS, 8-channel analog multiplexer, which switches one of the eight inputs to a common output according to the states of three binary address lines and an "enable" input. All digital inputs are TTL / DTL and CMOS logic compatible. The magnetic positioning signal after gain adjustment is then buffered and output by the CCL output circuit after signal attenuation and bias processing.

[0044] This utility model preprocesses two-way acoustic variable density signals and one-way magnetic positioning, which is easy for digital processing by a microcontroller, can remove the high-frequency interference noise in the magnetic positioning signal, and performs precise gain control on it, improving the instrument depth calibration accuracy.

[0045] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present utility model and are not intended to limit them; although the present utility model has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present utility model.

Claims

1. An underground acoustic variable density signal conditioning module, characterized in that It includes two unit circuits, namely a two-channel acoustic wave variable density signal conditioning circuit and a magnetic positioning signal conditioning circuit; the two-channel acoustic wave variable density signal conditioning circuit includes two signal attenuation circuits and two bias circuits; the magnetic positioning signal conditioning circuit includes a magnetic positioning signal pre-amplification circuit, a low-pass filter circuit, a gain control circuit and an output circuit.

2. The downhole acoustic variable density signal conditioning module according to claim 1, characterized in that The signal attenuation circuit consists of a reference voltage, resistor R1, and resistor R2.

3. The downhole acoustic variable density signal conditioning module according to claim 2, wherein The bias circuit includes a non-inverting adder composed of operational amplifier U1, resistor R1, resistor R2, and resistor R3. The output of the reference voltage is connected to the non-inverting terminal of operational amplifier U1, and the inverting terminal of operational amplifier U1 is connected to its own output terminal.

4. The downhole acoustic variable density signal conditioning module according to claim 3, characterized in that, The magnetic positioning signal conditioning circuit is provided with inputs through CCL+ pin and CCL- pin. The CCL- pin is connected to ground. The magnetic positioning signal pre-amplification circuit includes an inverting amplifier composed of capacitor C3 connected between CCL+ and CCL-, operational amplifier U2.1, resistor R7, resistor R8, and resistor R9.

5. The downhole acoustic variable density signal conditioning module according to claim 4, characterized in that, The low-pass filter circuit includes resistor R10, resistor R11, capacitor C6, capacitor C7, and operational amplifier U2.

2. The output of operational amplifier U2.2 is connected to CCL-A pin.

6. The downhole acoustic variable density signal conditioning module according to claim 5, wherein The gain control circuit includes analog switch U3 and a resistor network composed of resistor R12, resistor R13, resistor R14, and resistor R15 connected in series in sequence. One end of resistor R12 is connected to CCL-A pin, and CCL-A pin is also connected to the S4 terminal of analog switch U3. The connection points of resistor R13, resistor R14, and resistor R15 are respectively connected to the S3 terminal, S2 terminal, and S1 terminal of analog switch U3; the A1 terminal and A0 terminal of analog switch U3 are respectively connected to C0 and C1 as the input control terminals of analog switch U3 to control the connection between the OUT terminal of analog switch U3 and the S1 terminal, S2 terminal, S3 terminal, and S4 terminal; the S5-S8 terminals of analog switch U3 are grounded.

7. The downhole acoustic variable density signal conditioning module according to claim 6, characterized in that, The OUT terminal of analog switch U3 is connected to an inverting amplifier composed of resistor R18, resistor R19, resistor R20, and operational amplifier U4.

1.

8. The downhole acoustic variable density signal conditioning module according to claim 7, characterized in that The output circuit includes resistor R21, resistor R22, resistor R23, and operational amplifier U4.2 connected in series in sequence. The output of operational amplifier U4.2 is connected to CCL pin.

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