Induction logging instrument launch drive module and method

Abstract

This invention belongs to the field of oil and gas exploration and development technology, and discloses an induction logging tool transmission drive module and driving method. The drive module includes a MOS full-bridge chip U1 mounted on a substrate. One end of the GND wire is connected to the common ground pin and the heat dissipation pad pin, and the other end of the GND wire is connected to the negative power supply. The two ends of the IN2 wire are connected to the second input pin and the controller, respectively. The two ends of the IN1 wire are connected to the first input pin and the controller, respectively. The two ends of the VCC wire are connected to the voltage monitoring pin and the positive power supply, respectively. The first output pin is connected to one end of the transmission coil, and the second output pin is connected to the other end of the transmission coil. This invention's drive module, through the MOS full-bridge chip U1, can be used in various scenarios with selected components. It requires fewer discrete components, reducing its size to less than 1 / 10 of the original, and can be installed in confined spaces.

Description

Technical Field

[0001] This invention belongs to the field of oil and gas exploration and development technology, and specifically relates to an induction logging tool transmission drive module and driving method. Background Technology

[0002] An induction logging tool is a tool used for underground geological exploration, primarily for measuring the electrical conductivity or resistivity of formations. The tool's transmitter module drives the transmitter coil, generating an alternating electromagnetic field in the space surrounding the instrument. This field penetrates the surrounding formation and induces eddy currents within it. The magnitude of these eddy currents depends on the formation's electrical conductivity (or resistivity); higher conductivity results in stronger eddy currents. The receiver coil detects the secondary magnetic field generated by these eddy currents. This secondary magnetic field induces an electromotive force (EMF) in the receiver coil. The magnitude of this EMF is related to the intensity of the eddy currents, and consequently, to the formation's electrical conductivity. The received EMF is recorded by the logging tool's acquisition module. Through data processing and plotting interpretation, a profile of the formation's electrical conductivity or resistivity can be obtained. Changes in the formation's electrical conductivity or resistivity can reflect different geological characteristics, such as rock type, porosity, and oil saturation.

[0003] Typical induction logging tool transmitter drive circuits do not support both single-frequency and multi-frequency operation. Single-frequency designs often use operational amplifier circuits plus analog signal linear power amplifier circuits (including transformers), resulting in low power efficiency and high heat dissipation. Transmitting multi-frequency power signals often employs dedicated DDS (Direct Digital Synthesis) chips plus analog signal linear power amplifier circuits, which is costly and involves more complex control methods.

[0004] For example, Chinese patent CN104453868A discloses a signal synthesis device and method for induction logging instruments, as well as an induction logging method. While the DDS chip is eliminated from the transmission drive circuit mentioned in this patent, its working principle remains the same: DDS signal synthesis plus analog signal linear power amplification. It simply replaces the dedicated DDS chip with a combination of FPGA and DA (digital-to-analog converter) chips, resulting in a complex control method. Similar to the single-frequency power amplifier circuit mentioned above, it suffers from low energy efficiency and high heat dissipation due to the use of a linear power amplifier circuit. Another type of drive module for transmitting multi-frequency power signals consists of a switching power module and its control signal generator. First, a low-voltage three-level signal is converted into four PWM control signals. The PWM control signals control the switching power module to drive the primary coil of the transformer, and then the energy is transferred from the secondary winding of the transformer to the transmitting coil of the induction logging instrument. This structure has the disadvantages of numerous discrete electronic components, large size (even after being made into a thick-film circuit, the discrete components are still relatively large, and the drive circuit contains large components such as inductors and transformers), and high heat dissipation. In addition, the circuit design lacks protection. Due to the driving voltage (exceeding ±48V voltage difference), the driving circuit is prone to short circuit when restarted multiple times, which can lead to the burning out of the driving module and failure of the transmitting circuit.

[0005] For example, Chinese patent CN113738341A discloses an H-bridge multi-frequency array induction logging tool transmitting circuit. Although it can transmit multi-frequency signals, it has problems such as a large number of discrete components, large size, lack of overcurrent protection, and low reliability.

[0006] In summary, existing induction logging tools have problems such as numerous discrete components, large size, high heat dissipation, lack of overcurrent protection, and low reliability. Summary of the Invention

[0007] To address the above problems, this invention provides an induction logging tool transmission drive module and driving method, employing the following technical solution:

[0008] A sensing logging tool transmitter drive module includes a MOS full-bridge chip U1 disposed on a substrate. The MOS full-bridge chip U1 includes a common ground pin, a second input pin, a first input pin, a voltage monitoring pin, a first output pin, a second output pin, and a heat dissipation pad pin.

[0009] Specifically, one end of the GND wire is connected to the common ground pin and the heat sink pin, and the other end of the GND wire is connected to the negative power supply; one end of the IN2 wire is connected to the second input pin, and the other end of the IN2 wire is connected to the controller; one end of the IN1 wire is connected to the first input pin, and the other end of the IN1 wire is connected to the controller; one end of the VCC wire is connected to the voltage monitoring pin, and the other end of the VCC wire is connected to the positive power supply; the first output pin is connected to one end of the transmitting coil via the OUT+ wire, and the second output pin is connected to the other end of the transmitting coil via the OUT- wire.

[0010] Furthermore, the driving module also includes a current-limiting resistor R1 disposed on the substrate, and the MOS full-bridge chip U1 also includes a current-limiting pin, wherein one end of the current-limiting resistor R1 is connected to the current-limiting pin, and the other end of the current-limiting resistor R1 is connected to the common ground line.

[0011] Furthermore, the driving module also includes a frequency selective filter capacitor C3 disposed on the substrate, wherein one end of the frequency selective filter capacitor C3 is connected to the OUT+ wire, and the other end of the frequency selective filter capacitor C3 is connected to the OUT- wire.

[0012] Furthermore, the driving module also includes power filter capacitor C1 and power filter capacitor C2 disposed on the substrate, and the MOS full-bridge chip U1 also includes a power ground pin;

[0013] One end of the VCC wire is connected to one end of the power filter capacitor C1, one end of the power filter capacitor C2, and the voltage monitoring pin. The other end of the VCC wire is connected to the positive power supply. The other ends of the power filter capacitor C1 and the other ends of the power filter capacitor C2 are connected to the power ground line PGND. The power ground line PGND is also connected to the power ground pin and the heat dissipation pad pin.

[0014] Furthermore, the drive module is disposed in the wire-passing metal cavity of the coil system frame.

[0015] Furthermore, the substrate is a flexible board, an aluminum substrate, a copper substrate, or a ceramic substrate.

[0016] Furthermore, it also includes a resonant circuit, wherein the two ends of the input side of the resonant circuit are respectively connected to the first output pin and the second output pin, and the two ends of the output side of the resonant circuit are respectively connected to the two ends of the transmitting coil.

[0017] Furthermore, the resonant circuit includes a capacitor Cr, an inductor Lr, an inductor Lm, and a transformer;

[0018] Wherein, one end of the capacitor Cr is connected to the second output pin, the other end of the capacitor Cr is connected to one end of the inductor Lr, the other end of the inductor Lr is connected to one end of the inductor Lm and one end of the primary winding of the transformer, the other end of the inductor Lm and the other end of the primary winding of the transformer are connected to the first output pin, and the two ends of the secondary winding of the transformer are respectively connected to the two ends of the transmitting coil.

[0019] The present invention also provides a method for driving the transmission of an induction logging tool, which is based on the aforementioned induction logging tool transmission driving module and includes the following steps:

[0020] The controller sends control signals with a period of T to the first input pin and the second input pin of the MOS full-bridge chip U1 through the IN1 wire and the IN2 wire, respectively.

[0021] The high-level pulse width of the first input pin and the second input pin is T / 2. The first output pin and the second output pin of the MOS full-bridge chip U1 generate a sine wave signal with a frequency of F = 1 / T and its odd harmonics through the OUT+ wire and the OUT- wire, respectively.

[0022] The present invention also provides a method for driving the transmission of an induction logging tool, which is based on the aforementioned induction logging tool transmission driving module and includes the following steps:

[0023] The high-level pulse width of the first input pin and the second input pin is T / 3. The first output pin and the second output pin of the MOS full-bridge chip U1 generate a sine wave signal with a frequency of F = 1 / T and its even harmonics through the OUT+ wire and the OUT- wire, respectively.

[0024] The present invention also provides a method for driving the transmission of an induction logging tool, which is based on the aforementioned induction logging tool transmission driving module and includes the following steps:

[0025] The high-level pulse width of the first input pin is T / 3, and the high-level pulse width of the second input pin is T / 2. The first output pin and the second output pin of the MOS full-bridge chip U1 generate a sine wave signal with a frequency of F = 1 / T and its odd and even harmonics through the OUT+ and OUT- wires, respectively.

[0026] Furthermore, the aforementioned induction logging tool transmission driving method further includes the following steps:

[0027] The high-order harmonics are converted into low-order harmonics or a single-frequency sine wave signal with frequency F = 1 / T by the frequency-selective filter capacitor C3.

[0028] The beneficial effects of this invention are:

[0029] 1. The driving module of the present invention can realize various applications by using the MOS full-bridge chip U1 and selecting resistors and capacitors. It has fewer discrete components and its volume can be reduced to less than 1 / 10 of the original. It can be installed in a small space and is particularly suitable for logging instruments with limited space.

[0030] 2. The driving module of this invention uses a MOS full-bridge chip U1, which is low in cost, less than 1% of the cost of thick-film circuits. Since the closing resistance of the driving bridge switching circuit of the MOS full-bridge chip U1 is about 0.6Ω, the heat dissipation is no more than 0.25W when the driving current is 0.5A. Compared with the heat dissipation of several watts of a single thick-film module in the past, the heat dissipation is greatly reduced.

[0031] 3. The MOS full-bridge chip U1 in the drive module of this invention has built-in undervoltage lockout (UVLO), overcurrent protection (OCP) and overheat protection (TSD). After the fault is cleared, the device will automatically resume normal operation, which improves the reliability of the transmit drive module.

[0032] 4. The driving module of the present invention can accommodate both single-frequency and multi-frequency transmission. It can be used to transmit single-frequency electromagnetic signals or multi-frequency electromagnetic signals.

[0033] 5. In the non-emission waiting state, the MOS full-bridge chip U1 of the driving module of the present invention enters sleep mode, and the power supply output current is at the microampere level, with extremely low static power consumption.

[0034] Other features and advantages of the invention will be set forth in the following description, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention may be realized and obtained by means of the structures pointed out in the description and the drawings. Attached Figure Description

[0035] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0036] Figure 1 A schematic diagram of the structure of an induction logging tool according to an embodiment of the present invention is shown;

[0037] Figure 2 A schematic diagram of the principle structure of an induction logging tool transmission drive module according to an embodiment of the present invention is shown;

[0038] Figure 3 A schematic diagram of the device layout of a transmitting drive module for an induction logging tool according to an embodiment of the present invention is shown;

[0039] Figure 4 A schematic diagram of the transmission timing of the fundamental frequency signal and its odd harmonics according to an embodiment of the present invention is shown;

[0040] Figure 5 A schematic diagram of the transmission timing of the fundamental frequency signal and its even harmonics according to an embodiment of the present invention is shown;

[0041] Figure 6 A schematic diagram of the transmission timing of the fundamental frequency signal and its odd and even harmonics according to an embodiment of the present invention is shown.

[0042] Figure 7 A schematic diagram of a resonant circuit structure according to an embodiment of the present invention is shown.

[0043] In the diagram: 1. Electronic instrument frame; 2. Coil system; 3. Electronic instrument housing; 4. Coil system housing; 5. Intermediate connector; 6. Hydraulic balance short section; 7. Vibration damping rubber; 8. Coil system frame; 9. Transmitting coil; 10. Receiving coil; 11. Wire passage cavity; 12. Sealing plug with pin. Detailed Implementation

[0044] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0045] It should be noted that the terms "first," "second," etc., used in this application 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 for the embodiments of this application described herein.

[0046] As oil drilling deepens and wellbore sizes decrease, the size of instruments also decreases, and the space for installing instrument circuits becomes increasingly limited. Therefore, a small-sized, highly reliable transmitter drive circuit is needed to replace the current circuit and adapt to the needs of the instrument's working environment.

[0047] This invention provides a highly reliable single-frequency / multi-frequency transmission drive circuit for induction logging tools, featuring fewer discrete components, smaller size, lower cost, and overcurrent, overheat, and undervoltage protection functions.

[0048] like Figure 1As shown, the structure of an induction logging tool will be described first. An induction logging tool includes an electronic instrument frame 1, a coil system 2, an electronic instrument housing 3, a coil system housing 4, a central connector 5, an oil pressure balance sub 6, and a coil system frame 8.

[0049] Among them, the electronic instrument housing 3, the intermediate connector 5, the coil system housing 4, and the hydraulic balance short section 6 are connected in sequence. For example, the coil system housing 4 can be made of fiberglass. The electronic instrument frame 1 is set inside the electronic instrument housing 3, and the coil system frame 8 is set inside the coil system housing 4. One end of the coil system frame 8 passes through the intermediate connector 5 and extends into the electronic instrument frame 1, and is connected to the electronic instrument frame 1.

[0050] The coil system 2 is set on the coil system frame 8. The coil system 2 includes a transmitting coil 9 and a receiving coil 10 arranged at intervals. The coil system frame 8 has a wire passage cavity 11 (a cavity formed by hollowing out the metal rod along the axis) arranged axially inside. A sealing plug 12 with a pin is provided at one end of the coil system frame 8 near the oil pressure balance short section 6.

[0051] The end of the oil pressure balance sub 6 away from the coil system housing 4 is equipped with shock-absorbing rubber. The shock-absorbing rubber 7 is an approximately hemispherical wear-resistant and corrosion-resistant rubber body that plays a protective role in guiding and damping vibrations downhole.

[0052] The electronic instrument housing 3 and the coil system housing 4 are for protecting the circuit and the coil system 2. The coil system frame 8 includes a metal rod, and a circular wire-passing cavity 11 is arranged axially along the inside of the metal rod. The inner diameter of the wire-passing cavity 11 is about 12.5 mm, which can pass wires. The electronic instrument's cable passes through the wire-passing cavity 11 and is connected to one end of the socket on the sealing plug. The other end of the pin leads the cable to the cavity between the coil system housing 4 and the coil system frame 8, and connects to the transmitting coil 9.

[0053] The cavity between the coil housing 4 and the coil frame 8 is filled with highly insulating and compressible oil. A pressure balancing sub is connected to the cavity, balancing the pressure inside and outside the cavity in the high-temperature and high-pressure environment downhole, making the coil housing 4 less susceptible to compression and deformation.

[0054] like Figure 2 and Figure 3 As shown, an induction logging tool transmitter drive module includes a MOS full-bridge chip U1 mounted on a substrate. The MOS full-bridge chip U1 includes a common ground pin (pin 1, GND), a second input pin (pin 2, IN2), a first input pin (pin 3, IN1), a current limiting pin (pin 4, ILIM), a voltage monitoring pin (pin 5, VM), a first output pin (pin 6, OUT1), a power ground pin (pin 7, PGND), a second output pin (pin 8, OUT2), and a heat dissipation pad pin (pin 9, EP).

[0055] One end of the GND wire is connected to the common ground pin and the heat sink pin, and the other end of the GND wire is connected to the negative power supply. One end of the IN2 wire is connected to the second input pin, and the other end of the IN2 wire is connected to the controller. One end of the IN1 wire is connected to the first input pin, and the other end of the IN1 wire is connected to the controller. One end of the VCC wire is connected to the voltage monitoring pin, and the other end of the VCC wire is connected to the positive power supply.

[0056] The first output pin is connected to one end of the transmitting coil 9 via the OUT+ wire, and the second output pin is connected to the other end of the transmitting coil 9 via the OUT- wire.

[0057] The driving module in this embodiment is suitable for power supplies with strong load-carrying capacity that power the transmitting driving module. When driving the coil, the power supply voltage fluctuates relatively little. In this application scenario, a power supply filter capacitor is not required.

[0058] In this embodiment, the drive module does not have a current-limiting resistor (the corresponding chip pin ILIM is connected to the common ground). In this case, the maximum emitter current of the drive module is approximately 3.6A, which is the maximum protection current limited by the MOS full-bridge chip U1.

[0059] In this embodiment, the driver module does not include a frequency selection / filtering capacitor. The transmitted byproduct—the high-frequency signal (such as high-frequency harmonics)—has an energy that decreases exponentially with increasing frequency, and the harmonic components become smaller and smaller. If the high-frequency harmonics (such as the 6th harmonic, whose energy is 1 / 256 of the fundamental frequency energy) and their response are introduced into the circuit as interference signals, the response generated by this signal can be filtered out using a low-pass filter in the signal conditioning and amplification circuit due to its small size. Therefore, it is not necessary to use capacitors to filter it at the first and second output pins of the driver module. In this case, by omitting C3 (the frequency selection / filtering capacitor), the circuit board can be reduced to 10x10mm.

[0060] The driving module of this embodiment is 21mm long and 11mm wide, wherein the MOS full-bridge chip U1 is a small HSOP package with dimensions of 4.9mm × 6mm.

[0061] The MOS full-bridge chip U1 features advanced current regulation circuitry that uses standard, low-cost, low-power resistors to set the current threshold, limiting the current to a known level. This significantly reduces system power consumption requirements and eliminates the need for large capacitors to maintain stable voltage, especially during startup and shutdown.

[0062] The driving module of this embodiment of the invention has a width of 11mm. Therefore, the driving module can be set on the electronic instrument frame 1 or in the wire passage cavity 11 of the coil system frame 8. Setting the driving module in the wire passage cavity 11 of the coil system frame 8 has the following advantages:

[0063] 1. Saves space for the electronic instrument frame 1, which helps to reduce the length of the electronic instrument;

[0064] 2. Reduce electromagnetic interference within the electronic instrument frame 1;

[0065] 3. It helps dissipate heat from the drive module.

[0066] Since the drive module is located in the narrow coil frame 8 through cavity 11 instead of inside the electronic instrument frame 1, the electronic instrument frame 1 does not need to consider the installation space of the drive module, thus saving space (the existing drive module is over 20 cm long and does not include the discrete, large inductors and transformers).

[0067] When the drive module is in operation, due to the high transmission voltage (up to ±50V) and large transmission current (which is AC), it greatly interferes with the signal amplification circuit of the receiving coil 10 on the electronic instrument frame 1. Therefore, it is necessary to take various shielding measures to reduce the interference, such as using shielded wires, shielded grounding, and adding metal shielded extension tubes.

[0068] Since the driving module of this embodiment is located in the wire cavity 11 of the hollow metal rod of the coil frame 8, far away from the signal amplification circuit of the receiving coil 10, and the driving module is input with DC power, the electromagnetic interference of the driving module to the receiving coil 10 is reduced.

[0069] like Figure 2 and Figure 3 As shown, for example, the driving module also includes a current-limiting resistor R1 disposed on the substrate. The current-limiting resistor R1 is disposed on the lower left side of the MOS full-bridge chip U1. One end of the current-limiting resistor R1 is connected to the current limiting pin, and the other end of the current-limiting resistor R1 is connected to the common ground line.

[0070] like Figure 2 and Figure 3 As shown, for example, the driving module also includes a frequency-selective filter capacitor C3 disposed on the substrate. The frequency-selective filter capacitor C3 resonates selectively when a single-frequency signal needs to be transmitted and filters when multiple-frequency signals need to be transmitted. The frequency-selective filter capacitor C3 is disposed to the right of the MOS full-bridge chip U1, with one end connected to the OUT- wire and the other end connected to the OUT+ wire.

[0071] like Figure 2 and Figure 3 As shown, for example, the driving module also includes a power supply filter capacitor C1 and a power supply filter capacitor C2 disposed on the substrate. The power supply filter capacitor C1 is disposed on the lower right side of the MOS full-bridge chip U1, and the power supply filter capacitor C2 is disposed between the current limiting resistor R1 and the power supply filter capacitor C1.

[0072] One end of the VCC wire is connected to one end of the power filter capacitor C1, one end of the power filter capacitor C2, and the voltage monitoring pin. The other end of the VCC wire is connected to the positive terminal of the power supply. The other ends of the power filter capacitors C1 and C2 are connected to the power ground wire PGND. The power ground wire PGND is also connected to the power ground pin and the heat sink pad pin.

[0073] The GND and VCC wires of this invention provide the energy required for the drive module and the transmitting coil 9 to transmit the electromagnetic field; the controller sends control signals to the first input pin and the second input pin of the drive module through the IN1 and IN2 wires, and drives the transmitting coil 9 to generate an electromagnetic field through the first output pin and the second output pin of the drive module.

[0074] The working principle of the induction logging tool transmission drive module of the present invention is as follows: the voltage difference between the GND wire and the VCC wire is Vo, and the IN1 wire and IN2 wire respectively control the conduction of the OUT+ wire / OUT- wire and the VCC wire / GND wire.

[0075] When IN1 is high and IN2 is low, the voltage difference between OUT+ and OUT- is approximately +Vo(VCC-GND); when IN1 is low and IN2 is high, the voltage difference between OUT+ and OUT- is approximately -Vo; when IN1 is high and IN2 is high, the voltage between OUT+ and OUT- is 0. When both IN1 and IN2 are low, OUT+ and OUT- are disconnected from the power supply VCC / GND lines. Furthermore, when IN1 and IN2 are low for an extended period (greater than 1ms), the MOS full-bridge chip U1 enters sleep mode, and the system supply current is in the microampere range, meaning extremely low static power consumption.

[0076] The substrate of the driving module in this embodiment of the invention is a single-layer board. The board material can be an aluminum substrate, a copper substrate, or a ceramic substrate (or an ordinary glass fiber board). It has good heat dissipation function, which is beneficial to the cooling of the MOS full-bridge chip U1.

[0077] Because the MOS full-bridge chip U1 has overheat protection, it will activate the thermal protection function when the temperature exceeds 175℃ (the thermal protection function activates between 175 and 195℃). The MOS full-bridge chip U1 itself generates heat during operation, and combined with the ambient temperature, the internal temperature of the MOS full-bridge chip U1 will be higher than the ambient temperature. Therefore, in high-temperature environments, it is essential to dissipate the heat inside the MOS full-bridge chip U1 to bring the internal temperature of the chip down to a level comparable to the ambient temperature.

[0078] For example, the outer shell 4 of the coil system is made of fiberglass, which has a lower thermal conductivity than the metal shell of the electronic instrument. Under high-temperature conditions, external heat enters the coil system 2 more slowly. In addition, the coil system 2 is immersed in transformer oil, and the coil system frame 8 is also in contact with the transformer oil. The transformer oil has the function of absorbing and storing heat. In actual use under high-temperature conditions downhole, the maximum temperature difference between the coil system frame 8 in the transformer oil and the electronic instrument is more than 30°C. The temperature rise inside the metal tube is more than one hour slower than the temperature rise of the electronic instrument frame 1.

[0079] Therefore, in this embodiment of the invention, the drive module is disposed inside the hollow metal rod passage cavity of the coil system skeleton 8 immersed in transformer oil, which is beneficial for cooling and heat dissipation of the drive module.

[0080] For example, the drive module is located inside the wire passage cavity 11 at one end (left end) near the electronic instrument frame 1. Metal shielding or solder sealing can be added at the outlet of the wire passage cavity 11 to reduce interference from the drive module.

[0081] For example, the drive module is located inside the wire cavity 11 at one end (right end) near the electronic instrument frame 1, and the OUT+ and OUT- wires are connected to the left end of the pin, so that they can be isolated from the transformer oil.

[0082] The control signals for the MOS full-bridge chip U1 are issued by the controller, which can be an embedded chip such as a microcontroller, DSP, CPLD, FPGA, or ARM core controller. For example, the controller integrates PWM functionality and output pins, and by setting the modulation pulse width and phase angle, the output control signal can be easily generated.

[0083] For example, using a flexible substrate allows it to be bent, enabling the drive module to be placed in a more confined space. Simultaneously, the substrate can fit more tightly against the metal surface of the cavity 11, which is beneficial for heat dissipation.

[0084] For example, the substrate adopts a double-sided board, in which the MOS full-bridge chip U1, power supply filter capacitor C1, power supply filter capacitor C2, current limiting resistor R1 and frequency selection filter capacitor C3 are set on one side of the flexible board, and the other side of the flexible board exposes the metal surface and is attached to the metal surface of the through-line cavity 11 for heat conduction.

[0085] For example, the induction logging tool's transmission drive module can also be used as a driver for a resonant circuit. The two ends of the input side of the resonant circuit are connected to the first output pin and the second output pin, respectively, and the two ends of the output side of the resonant circuit are connected to the two ends of the transmission coil 9, respectively.

[0086] like Figure 7As shown, for example, the resonant circuit includes a capacitor Cr, an inductor Lr, an inductor Lm, and a transformer. One end of the capacitor Cr is connected to the second output pin, the other end of the capacitor Cr is connected to one end of the inductor Lr, the other end of the inductor Lr is connected to one end of the inductor Lm and one end of the primary winding of the transformer, the other end of the inductor Lm and the other end of the primary winding of the transformer are connected to the first output pin, and the two ends of the secondary winding of the transformer are respectively connected to the two ends of the transmitting coil 9.

[0087] The driving module of this invention serves as the driver for the LLC resonant circuit, enabling zero-voltage switching, reducing switching losses, and achieving high efficiency over a wide input voltage and load range. Compared to traditional hard-switching converters, it also exhibits less electromagnetic interference (EMI).

[0088] This invention also provides a method for driving the transmission of an induction logging tool, based on the aforementioned induction logging tool transmission driving module, comprising the following steps:

[0089] The first method: The controller sends control signals with a period of T to the first and second input pins of the MOS full-bridge chip U1 via the IN1 and IN2 wires, respectively. Figure 4 As shown, the high-level pulse width of the first input pin and the second input pin is T / 2. The first output pin and the second output pin of the MOS full-bridge chip U1 transmit signals with frequency F = 1 / T and their odd harmonics to the transmitting coil 9 through the OUT- wire and the OUT+ wire, respectively.

[0090] For example, in one transmission timing, the controller sends a control signal with a period of T. The high-level pulse width of the first input pin and the second input pin is T / 2, and the phase difference is 180 degrees. In this way, a signal with a frequency of F = 1 / T and its odd harmonics are obtained on the OUT+ and OUT- wires.

[0091] Optionally, a frequency-selective filter capacitor C3 can be used to convert high-order odd harmonics into low-order harmonics or a single-frequency signal with frequency F = 1 / T. The frequency-selective filter capacitor C3 has an absorption and conversion effect on high-order harmonics; the higher the signal frequency, the stronger the absorption effect, thus suppressing high-frequency signals.

[0092] For example, when the capacitance of the selective frequency filter capacitor C3 is large enough, the resonant frequency f = 1 / [2π√(LC)] (where L and C are the inductance and capacitance, respectively) of the selective frequency filter capacitor C3 and the transmitting coil 9 is close to F. The odd harmonics will be converted into the fundamental wave, thus obtaining a single-frequency signal with frequency F = 1 / T.

[0093] The second type: such as Figure 5As shown, the high-level pulse width of the first input pin and the second input pin is T / 3. The first output pin and the second output pin of the MOS full-bridge chip U1 transmit a signal with frequency F = 1 / T and its even harmonics to the transmitting coil 9 through the OUT- wire and the OUT+ wire, respectively.

[0094] For example, in another transmission timing sequence, the high-level pulse width of IN1 and IN2 is T / 3, and the phase difference is 120 degrees. In this way, the frequency F = 1 / T and its even harmonics are obtained in OUT+ and OUT-.

[0095] Optionally, the high-order even harmonics can be converted into low-order harmonics or a single-frequency signal with frequency F = 1 / T by using the frequency-selective filter capacitor C3.

[0096] Similarly, when the capacitance of the selective frequency filter capacitor C3 is large enough, the resonant frequency f = 1 / [2π√(LC)] (where L and C are the inductance and capacitance, respectively) of the selective frequency filter capacitor C3 and the transmitting coil 9 is close to F. The even harmonics will be converted into the fundamental wave, thus obtaining a single-frequency signal with frequency F = 1 / T.

[0097] The third type: such as Figure 6 As shown, the high-level pulse width of the first input pin is T / 3, and the high-level pulse width of the second input pin is T / 2. The first output pin and the second output pin of the MOS full-bridge chip U1 transmit a signal with frequency F = 1 / T and its odd and even harmonics to the transmitting coil 9 through the OUT+ and OUT- wires, respectively.

[0098] For example, in another transmission timing sequence, the high-level pulse width of the IN1 conductor is T / 3 and the high-level pulse width of the IN2 conductor is T / 2. In this way, the frequency F = 1 / T and its odd and even harmonics are obtained in the OUT+ and OUT- conductors.

[0099] Optionally, the higher harmonics can be converted into lower harmonics or a single-frequency signal with frequency F = 1 / T by using the frequency-selective filter capacitor C3.

[0100] For example, when the capacitance of the selective frequency filter capacitor C3 is large enough, the resonant frequency f = 1 / [2π√(LC)] (where L and C are the inductance and capacitance, respectively) of the selective frequency filter capacitor C3 and the transmitting coil 9 is close to F. All harmonics will be converted into the fundamental frequency, thus obtaining a single-frequency signal with frequency F = 1 / T.

[0101] Therefore, by using the driving module of this embodiment of the invention, the fundamental wave of a 1-200KHz sine wave, as well as its odd and even harmonics, can be obtained.

[0102] Because the drive module of this invention has fewer discrete components, its volume can be reduced to less than 1 / 10 of the original, allowing it to be installed in a small space, making it particularly suitable for well logging instruments with limited space.

[0103] The driving module of this invention can accommodate both single-frequency and multi-frequency transmission; it can be used to transmit both single-frequency and multi-frequency electromagnetic signals.

[0104] The MOS full-bridge chip U1 in the drive module of this invention has built-in undervoltage lockout (UVLO), overcurrent protection (OCP), and overheat protection (TSD). After the fault is cleared, the device will automatically resume normal operation, which improves the reliability of the transmit drive module.

[0105] The driving module of this invention uses a MOS full-bridge chip U1, which is low in cost, less than 1% of the cost of a thick-film circuit. Since the closing resistance of the driving bridge switching circuit of the MOS full-bridge chip U1 is about 0.6Ω, the heat dissipation is no more than 0.25W when the driving current is 0.5A. Compared with the heat dissipation of several watts of a single thick-film module in the past, the heat dissipation is greatly reduced.

[0106] In this embodiment of the invention, the driving module enters sleep mode when the MOS full-bridge chip U1 is in a standby state without transmitting. The power supply output current is at the microampere level, and the static power consumption is extremely low and can be basically ignored.

[0107] Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A transmitting drive module for an induction logging tool, characterized in that, It includes a MOS full-bridge chip U1 disposed on a substrate, the MOS full-bridge chip U1 including a common ground pin, a second input pin, a first input pin, a voltage monitoring pin, a first output pin, a second output pin, and a heat dissipation pad pin; Specifically, one end of the GND wire is connected to the common ground pin and the heat sink pin, and the other end of the GND wire is connected to the negative power supply; one end of the IN2 wire is connected to the second input pin, and the other end of the IN2 wire is connected to the controller; one end of the IN1 wire is connected to the first input pin, and the other end of the IN1 wire is connected to the controller; one end of the VCC wire is connected to the voltage monitoring pin, and the other end of the VCC wire is connected to the positive power supply; the first output pin is connected to one end of the transmitting coil via the OUT+ wire, and the second output pin is connected to the other end of the transmitting coil via the OUT- wire.

2. The induction logging tool transmission drive module according to claim 1, characterized in that, The driving module further includes a current-limiting resistor R1 disposed on the substrate, and the MOS full-bridge chip U1 further includes a current-limiting pin, wherein one end of the current-limiting resistor R1 is connected to the current-limiting pin, and the other end of the current-limiting resistor R1 is connected to the common ground line.

3. The induction logging tool transmission drive module according to claim 1, characterized in that, The driving module further includes a frequency selective filter capacitor C3 disposed on the substrate, wherein one end of the frequency selective filter capacitor C3 is connected to the OUT+ wire, and the other end of the frequency selective filter capacitor C3 is connected to the OUT- wire.

4. The induction logging tool transmission drive module according to claim 1, characterized in that, The driving module also includes power filter capacitors C1 and C2 disposed on the substrate, and the MOS full-bridge chip U1 also includes a power ground pin. One end of the VCC wire is connected to one end of the power filter capacitor C1, one end of the power filter capacitor C2, and the voltage monitoring pin. The other end of the VCC wire is connected to the positive power supply. The other ends of the power filter capacitor C1 and the other ends of the power filter capacitor C2 are connected to the power ground line PGND. The power ground line PGND is also connected to the power ground pin and the heat dissipation pad pin.

5. The induction logging tool transmission drive module according to claim 1, characterized in that, The drive module is located in the wire-passing metal cavity of the coil system frame.

6. The induction logging tool transmission drive module according to claim 1, characterized in that, The substrate is a flexible board, an aluminum substrate, a copper substrate, or a ceramic substrate.

7. The induction logging tool transmission drive module according to any one of claims 1-6, characterized in that, It also includes a resonant circuit, the two ends of the input side of the resonant circuit being connected to the first output pin and the second output pin respectively, and the two ends of the output side of the resonant circuit being connected to the two ends of the transmitting coil respectively.

8. The induction logging tool transmission drive module according to claim 7, characterized in that, The resonant circuit includes a capacitor Cr, an inductor Lr, an inductor Lm, and a transformer; Wherein, one end of the capacitor Cr is connected to the second output pin, the other end of the capacitor Cr is connected to one end of the inductor Lr, the other end of the inductor Lr is connected to one end of the inductor Lm and one end of the primary winding of the transformer, the other end of the inductor Lm and the other end of the primary winding of the transformer are connected to the first output pin, and the two ends of the secondary winding of the transformer are respectively connected to the two ends of the transmitting coil.

9. A method for driving the transmission of an induction logging tool, characterized in that, Based on the induction logging tool transmission drive module according to any one of claims 1-8, the implementation includes the following steps: The controller sends control signals with a period of T to the first input pin and the second input pin of the MOS full-bridge chip U1 through the IN1 wire and the IN2 wire, respectively. The high-level pulse width of the first input pin and the second input pin is T / 2. The first output pin and the second output pin of the MOS full-bridge chip U1 generate a sine wave signal with a frequency of F = 1 / T and its odd harmonics through the OUT+ wire and the OUT- wire, respectively.

10. A method for driving the transmission of an induction logging tool, characterized in that, Based on the induction logging tool transmission drive module according to any one of claims 1-8, the implementation includes the following steps: The high-level pulse width of the first input pin and the second input pin is T / 3. The first output pin and the second output pin of the MOS full-bridge chip U1 generate a sine wave signal with a frequency of F = 1 / T and its even harmonics through the OUT+ wire and the OUT- wire, respectively.

11. A method for driving the transmission of an induction logging tool, characterized in that, Based on the induction logging tool transmission drive module according to any one of claims 1-8, the implementation includes the following steps: The high-level pulse width of the first input pin is T / 3, and the high-level pulse width of the second input pin is T / 2. The first output pin and the second output pin of the MOS full-bridge chip U1 generate a sine wave signal with a frequency of F = 1 / T and its odd and even harmonics through the OUT+ and OUT- wires, respectively.

12. The induction logging tool transmission driving method according to any one of claims 9, 10, and 11, characterized in that, It also includes the following steps: The high-order harmonics are converted into low-order harmonics or a single-frequency sine wave signal with frequency F = 1 / T by the frequency-selective filter capacitor C3.

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