MWD Pulser Control System Based on Modular Low-Power Drive

Abstract

The present application discloses a control system for an MWD pulser based on modular low-power drive, which relates to the field of mud pulse generators. The system includes a power management module, a pulse generation and adaptive control module, and a reconfigurable drive module. The power management module is used to regulate the input voltage to a stable operating voltage. The pulse generation and adaptive control module includes an algorithm controller and an adaptive pulse generator. The algorithm controller is used to calculate the target pulse width matching the input trigger data according to the adaptive control algorithm. The adaptive pulse generator is used to generate a target pulse control signal corresponding to the target pulse width. The reconfigurable drive module adopts a parallel MOSFET array structure including multiple drive channels, and is used to generate the number of channel drives corresponding to the target pulse control signal, and activate at least one target MOSFET channel of the corresponding number of channel drives to synchronously drive the solenoid valve coil. Thus, the downhole working duration of the MWD pulser system can be effectively extended.

Description

Technical Field

[0001] This application relates to the field of mud pulse generators, and particularly to a control system for an MWD pulser based on modular low-power drive. Background Art

[0002] As oil and gas exploration extends to deeper and more complex formations, higher requirements are put forward for downhole measurement and real-time transmission technologies. The Measurement While Drilling (MWD) technology can install a series of sensors near the drill bit to measure key parameters such as well inclination, azimuth, formation pressure, and bottom hole temperature, and in the process of drilling, these data are transmitted to the ground in real time through mud pulses to provide support for ground decision-making. Specifically, by opening or closing the solenoid valve in the downhole pulser, periodic pressure pulses are generated in the mud pipeline by the drilling fluid, and after these pulses are captured by the ground data processing center, demodulation is carried out. During the drilling measurement process, downhole equipment needs to work stably in extremely high temperature, high pressure, and high vibration environments, and the downhole power supply often relies on batteries or limited power generation devices, which puts extremely high requirements on the energy utilization efficiency of the system, which is directly related to the working duration of the MWD system.

[0003] In traditional designs, the driving of the solenoid valve coil generally uses a single MOSFET or a few driving devices to directly switch. This method is prone to low driving efficiency and high static loss under high-frequency pulses or large load conditions. Especially when the driving circuit works for a long time, the device is in a non-ideal state, and continuous leakage current and driving loss will occur, making the overall power consumption of the system remain high.

[0004] In addition, most of the existing pulsers adopt a control scheme with fixed pulse width and amplitude, and fail to make adaptive adjustments according to changes in the downhole environment. In the downhole working environment, the actual requirements for the suction and release of the solenoid valve coil are affected by various factors such as temperature, pressure, and fluid characteristics. Fixed control parameters will lead to energy surplus or deficiency in many cases, further causing power consumption mismatch and energy waste.

[0005] In response to the above problems, the industry has not yet proposed a better technical solution. Summary of the Invention

[0006] This application provides a control system for an MWD pulser based on modular low-power drive, so as to at least solve the problems of mismatched energy supply and energy waste of the pulser in the current related technologies.

[0007] An MWD pulser control system based on modular low-power drive provided by an embodiment of the present application includes a power management module, a pulse generation and adaptive control module, and a reconfigurable drive module; the power management module uses a three-terminal adjustable positive voltage regulator to adjust the input voltage to a stable operating voltage; the pulse generation and adaptive control module includes an algorithm controller and an adaptive pulse generator, the algorithm controller is used to calculate a target pulse width matching the input trigger data according to an adaptive control algorithm, and the input trigger data includes well inclination measurement parameters, downhole environment parameters, and the working state of the solenoid valve coil; the adaptive pulse generator includes a basic pulse generator and a digital control unit for generating a target pulse control signal corresponding to the target pulse width; the reconfigurable drive module uses a parallel MOSFET array structure including multiple drive channels to generate the number of channel drives corresponding to the target pulse control signal and activate at least one target MOSFET channel corresponding to the number of channel drives to synchronously drive the solenoid valve coil.

[0008] Through an MWD pulser control system based on modular low-power drive provided by the present application, through the collaborative work of multiple modules, the energy utilization rate and working stability of the MWD pulser in extreme downhole environments are significantly improved, and the following technical effects can be specifically achieved:

[0009] (1) The power management module uses a three-terminal adjustable positive voltage regulator to adjust the fluctuating input voltage to a stable operating voltage, effectively isolating the instability of downhole power supply and reducing the energy loss caused by voltage fluctuations.

[0010] (2) The algorithm controller in the pulse generation and adaptive control module intelligently calculates the target pulse width based on the well inclination, environmental parameters, and solenoid valve state received in real time, and then the adaptive pulse generator generates a precise pulse signal. Thus, the pulse parameters can be dynamically adjusted according to various changeable factors such as downhole temperature, pressure, and fluid characteristics, effectively avoiding energy surplus or deficiency in the traditional fixed-parameter scheme, ensuring the matching of energy supply for the suction and release of the solenoid valve coil, and improving the system energy efficiency.

[0011] (3) Compared with the traditional single MOSFET direct drive scheme, the reconfigurable drive module uses a parallel MOSFET array structure with multiple drive channels, which can flexibly activate multiple drive channels according to the target pulse control signal, sharing the drive load under high-frequency pulses or large loads, significantly reducing the device leakage current and static loss problems, thereby reducing the energy consumption accumulation during long-term operation and improving the overall drive efficiency and system reliability.

[0012] Through this technical solution, by means of a stable power supply, intelligent adaptive control, and an efficient parallel drive architecture, it is possible to achieve precise and low-power pulse signal generation and transmission in extreme downhole environments of high temperature, high pressure, and high vibration. On the premise of ensuring the timeliness and accuracy of logging-while-drilling data, the system energy consumption is significantly reduced, and the downhole working duration of the MWD pulser system is extended. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] To more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present application. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0014] Figure 1 FIG. shows a schematic structural diagram of an example of an MWD pulser control system based on modular low-power drive according to an embodiment of the present application;

[0015] Figure 2 FIG. shows a schematic circuit connection diagram of an example of a power management module according to an embodiment of the present application;

[0016] Figure 3 FIG. shows an example operation flowchart of a reconfigurable drive module for performing PWM control on each MOSFET channel according to an embodiment of the present application. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0017] To make the objectives, technical solutions, and advantages of the embodiments of the present application clearer, the following will clearly and completely describe the technical solutions in the embodiments of the present application with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are some, but not all, of the embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of the present application.

[0018] Figure 1 FIG. shows a schematic structural diagram of an example of an MWD pulser control system based on modular low-power drive according to an embodiment of the present application.

[0019] As Figure 1 shown, the MWD pulser control system 100 based on modular low-power drive includes a power management module 110, a pulse generation and adaptive control module 120, and a reconfigurable drive module 130.

[0020] Specifically, the power management module 110 uses a three-terminal adjustable positive voltage regulator to regulate the input voltage to a stable operating voltage. By using a three-terminal adjustable positive voltage regulator, the input voltage is regulated through precise resistor voltage division or digital control methods to output a stable voltage value suitable for the subsequent modules to work.

[0021] It should be noted that compared with other types of voltage regulators, the three-terminal adjustable positive voltage regulator has the characteristics of simple structure, few peripheral components and flexible adjustment, and can quickly adapt to the voltage fluctuations underground; at the same time, the three-terminal adjustable positive voltage regulator has built-in temperature compensation and overcurrent and short-circuit protection functions to ensure stable power supply in extremely high temperature and high pressure environments. It should be understood that the models of the three-terminal adjustable positive voltage regulator can be diversified, such as LM117, LM217, LM317, etc., and can be adjusted according to the requirements of the operating temperature range and output voltage range. In some embodiments, it is also possible to improve on the basis of the original circuit design to further enhance the requirements for low-power operation underground. More details will be elaborated in combination with other examples below.

[0022] The pulse generation and adaptive control module 120 includes an algorithm controller 121 and an adaptive pulse generator 122. The algorithm controller 121 is used to calculate the target pulse width matching the input trigger data according to the adaptive control algorithm, and the input trigger data includes well inclination measurement parameters, downhole environment parameters, and the working state of the solenoid valve coil.

[0023] Specifically, the algorithm controller 121 uses a high-precision digital signal processor (DSP) or a dedicated microcontroller platform to collect and process the input trigger data in real time based on the adaptive control algorithm. By performing fusion analysis on multi-dimensional data such as well inclination measurement parameters, downhole environment parameters, and the working state of the solenoid valve coil, the target pulse width matching the current actual downhole working conditions can be quickly calculated. The well inclination measurement parameters are the core parameters measured by the MWD instrument, which can include well inclination angle, azimuth angle, or tool face angle, etc., trigger the encoding of the pulse, and convert it into corresponding mud pulse encoding information according to the preset encoding rules (for example, frequency modulation or amplitude modulation) for the ground decision center to decode the transmitted signal.

[0024] In addition, the downhole environment parameters can include temperature, pressure, mud flow rate, etc., and the working state of the solenoid valve coil can include coil current, solenoid valve response time, etc. By dynamically adjusting the pulse width based on such parameters, the coupling degree between the signal and the environment can be optimized.

[0025] Exemplarily, in a high-temperature environment, the resistance of the solenoid valve coil increases, resulting in a decrease in current and a slower response of the solenoid valve. At this time, the pulse width can be widened to compensate for the response delay of the solenoid valve and ensure that the coil delay is fully compensated. In the high-pressure well section environment, the mud resistance increases, causing a delay in the opening / closing time of the solenoid valve. At this time, the pulse width can be widened to ensure signal integrity. Additionally, if the current of the solenoid valve is too small, the solenoid valve may not open fully, resulting in an incomplete signal pulse. At this time, the pulse width should be widened to ensure that the solenoid valve still has sufficient response time under a weak current. If the current of the solenoid valve is too large, the pulse width can be appropriately shortened to save energy. Furthermore, when the response time of the solenoid valve indicates an increase in response time delay, the pulse width can be widened to ensure that the signal window covers the delay interval of the solenoid valve opening / closing.

[0026] It should be noted that compared with the traditional fixed-pulse control scheme, the adaptive control algorithm has the advantages of fast response speed, flexible adjustment, and higher energy efficiency. At the same time, the algorithm controller 121 can also have self-learning and dynamic optimization functions, and can continuously adjust the control strategy according to historical data and real-time feedback, so as to achieve precise pulse width control. In addition, the algorithm controller can be powered by an independent power supply to ensure the battery life of the system. In some embodiments, the model and algorithm details of the algorithm controller can be optimized and adjusted according to the actual downhole temperature, pressure, and solenoid valve state to further reduce the energy consumption of pulse generation and improve the response accuracy. More details will be elaborated in the subsequent examples.

[0027] The adaptive pulse generator 122 is used to generate a target pulse control signal corresponding to the target pulse width. Exemplarily, through the basic pulse generator 1221, the basic output of pulses within a fixed time interval is realized using a high-speed digital circuit. Furthermore, through the digital control unit 1222, the basic pulse is finely modulated so that the output pulse not only has the encoding information of the well inclination measurement parameter but also conforms to the target pulse width. In this way, through the target pulse control signal, the excitation duration and frequency of the solenoid valve coil are precisely defined, ensuring that each pulse can mechanically interact optimally with the mud, thereby forming an appropriate pressure pulse.

[0028] It should be noted that compared with the fixed-pulse signal generation method, the adaptive pulse generator has the characteristics of a wide adjustment range, sensitive response, and high energy consumption matching degree. Thus, the collaborative work of the algorithm controller 121 and the adaptive pulse generator 122 enables the MWD pulser to dynamically adjust the pulse width according to the real-time downhole working conditions, achieving precise control and energy consumption optimization.

[0029] The reconfigurable drive module 130 adopts a parallel MOSFET array structure including multiple drive channels, which is used to generate the number of channel drives corresponding to the target pulse control signal, and activate at least one target MOSFET channel with the corresponding number of channel drives to synchronously drive the solenoid valve coil.

[0030] Here, an array structure is formed by paralleling multiple MOSFET drive channels, and each channel can be independently controlled. After receiving the target pulse control signal, the reconfigurable drive module 130 will judge the current load and pulse requirements through the built-in digital control unit, and intelligently activate one or more target MOSFET channels to synchronously drive the solenoid valve coil. Specifically, according to the pulse signal requirements, the intelligent scheduling makes some or all of the MOSFET channels work together to share the heat and current impact brought by large loads and high-frequency switching. Preferably, a current sharing and balancing mechanism can also be introduced to ensure that each MOSFET channel operates within a safe range and avoid the accumulation of leakage current and static loss under long-term high load.

[0031] Specifically, a synchronous trigger design is adopted between the channels of the reconfigurable drive module to ensure that the activated MOSFET channels can respond to the pulse signal simultaneously, so as to accurately and synchronously drive the solenoid valve coil. Thus, the target pulse control signal is converted into the corresponding current switching operation to accurately activate the solenoid valve coil, so that it can quickly suck or release at a predetermined moment, and finally generate the required pulse through mechanical action with the mud.

[0032] Through the embodiments of the present application, the pulse generation and adaptive control module 120 can adjust the pulse width according to real-time downhole conditions, so that each action of the solenoid valve coil can reach the best state, and further ensure that the mechanical action with the mud reaches the ideal pulse effect. The reconfigurable drive module 130 converts the target pulse control signal into a high-power switching action to drive the solenoid valve coil. Through the collaborative action of the modules, it is ensured that high-efficiency, stable and low-power pulse generation can still be achieved in a harsh downhole environment, so that the mud pulse finally generated through mechanical action with the mud meets the actual working condition requirements.

[0033] Figure 2 Fig. shows an example circuit connection diagram of the power management module according to the embodiment of the present application.

[0034] As Figure 2 shown, the power management module adopts an improved circuit design based on the LM117 three-terminal adjustable positive voltage regulator. Specifically, the three-terminal adjustable positive voltage regulator includes an adjustment terminal adj, an input terminal Vin, and an output terminal Vout.

[0035] Specifically, a first capacitor C4 is connected in parallel to the output terminal Vout, and the capacitance of the first capacitor C4 is greater than or equal to 10 µF. The output terminal Vout is connected in series with a first external resistor R4 and a second external resistor R6 to set the output voltage, where the first external resistor R4 is connected to the adjustment terminal adj and connected to the ground terminal via the second external resistor R6. The second external resistor R6 is also connected in parallel with a fixed resistor R5, one end of the fixed resistor R5 is connected to the adjustment terminal adj, and the other end is connected to the ground terminal. The resistor R3 and the capacitor C3 provide a simple RC filtering function at the input terminal.

[0036] Through the power management module, it is possible to stabilize the output at around 5V based on the LM117 linear voltage regulator at an input voltage of up to 28V and provide a certain load current. In addition, when the adjustment terminal is shorted to the ground, the output terminal can directly output according to the internal reference voltage of the three-terminal adjustable positive voltage regulator (for example, 1.25V) to achieve a low-power mode.

[0037] Specifically, on the one hand, a capacitor C4 with a large capacitance (greater than 10 µF) is connected in parallel at the output of the LM117, which can store energy and quickly respond to the current demand during load mutations, reducing the transient fluctuation of the output voltage. Thus, when the load switches from light load to heavy load (or from heavy load to light load), the output capacitor can provide / absorb transient current, keep the output voltage stable, and improve the transient response. In addition, the capacitor C4 is also beneficial for filtering high-frequency noise and fluctuations, reducing the output ripple.

[0038] On the other hand, by additionally connecting a fixed resistor R5 between the adjustment pin and the output, the LM117 series can also be used as a high-precision current regulator. Specifically, an accurate resistor R5 is connected between the adj pin and Vout of the LM117, and the load is placed between the output terminal of the voltage regulator and the ground, so that the load can be placed between adj and the ground in specific situations. Exemplarily, the internal reference voltage of the LM117 is about 1.25V. After clamping the adjustment terminal to the ground, the output is set to 1.25V to achieve a low-power mode. In particular, during the standby or sleep phase of the downhole system, the energy consumption can be significantly reduced. If a high voltage is required for the subsequent load, the normal external resistor voltage division can be restored to reset to the desired voltage, and the transition process is safe and smooth.

[0039] Through the embodiments of the present application, based on the output capacitance and the regulator terminal bypass design, not only the transient response is strengthened, but also the ripple rejection ability is improved. In addition, the LM117 can be used as both a linear voltage regulator and a high-precision constant current source on the same hardware platform to meet different load requirements. Additionally, by connecting the fixed resistor R5, it is possible to short the regulator terminal to ground to achieve a 1.25V low-power output. Combining the overcurrent, thermal overload, and safe area protection of the LM117 itself, the system is both energy-saving and reliable.

[0040] In some examples of the embodiments of the present application, low-resistance shunt resistors are connected in series in each MOSFET channel to monitor the current waveforms of each MOSFET channel. The reconfigurable drive module 130 can monitor the current waveforms of each MOSFET channel to perform PWM control on each drive channel.

[0041] Specifically, each channel includes one or a group of MOSFETs connected in parallel, which can independently provide controllable driving capabilities for the solenoid valve coil. When the load is low or the valve is easy to suck in, only a small number of channels can be enabled through PWM directional control to reduce power consumption; in addition, when the load increases or the sucking is slow, more channels can be quickly enabled through PWM directional control to increase the driving current.

[0042] In some embodiments, the drive PWM duty cycle for the MOSFET channels can also be adjusted according to the current of each MOSFET channel.

[0043] Figure 3 The operation flowchart of an example of the reconfigurable drive module performing PWM control on each MOSFET channel according to the embodiments of the present application is shown.

[0044] As Figure 3 shown, in step S310, the current flowing through each MOSFET channel is obtained by measuring the voltage drop across the low-resistance shunt resistor, and the load status of the MOSFET channel is determined according to each measured current.

[0045] In some embodiments, multiple current thresholds can be preset in the system to divide the load levels into multiple intervals such as low, medium, and high. Exemplarily, when the current detected in a certain channel is lower than the threshold value A, the load is considered to be at a low level; when the current is between the threshold value A and the threshold value B, the load is considered to be at a medium level; and when it exceeds the threshold value B, it is determined to be in a high-load state. In this way, by detecting the current through the shunt resistor, the load status of each MOSFET channel can be accurately identified.

[0046] In step S320, a PWM duty cycle matching the load state of the MOSFET channel is determined, and each target MOSFET channel is activated to synchronously drive the solenoid valve coil according to the PWM duty cycle. The PWM duty cycle corresponding to the high load state is greater than the PWM duty cycle corresponding to the low load state.

[0047] In some embodiments, in the low load state, the PWM duty cycle is reduced to reduce static power consumption and maintain high energy efficiency. In the medium load state, the PWM duty cycle is appropriately increased to meet the load demand while avoiding sudden large current surges. In the high load state, the PWM duty cycle is adjusted to a higher level to ensure sufficient driving ability and avoid channel overload.

[0048] Through the embodiments of the present application, a segmented threshold strategy is adopted to perform multi-level partitioning of the load of the MOSFET channel, so as to adopt a differential driving strategy for different load states. It can not only minimize power consumption when the MOSFET channel is in low load, improve the endurance of the MWD system, but also provide sufficient driving ability when the MOSFET channel is in high load, ultimately achieving the best balance between energy consumption and performance.

[0049] In some examples of the embodiments of the present application, during the process of synchronously driving the solenoid valve by using at least one MOSFET channel, the solenoid valve response data can also be collected in real time to adjust the driving state of the MOSFET channel and achieve more refined driving reconstruction.

[0050] Specifically, the algorithm controller 121 is further configured to receive the solenoid valve response data and generate pulse driving deviation information according to the solenoid valve response data. The solenoid valve response data includes the pull-in time, release time, and peak current of the solenoid valve.

[0051] , Equation (1)

[0052] , Equation (2)

[0053] , Equation (3)

[0054] In the formula, represents the pull-in time deviation, represents the release time deviation, represents the peak current deviation; , and respectively represent the actual pull-in time, actual release time, and actual peak current in the obtained solenoid valve response data; , and respectively represent the expected pull-in time, expected release time, and expected peak current.

[0055] It should be noted that if , it indicates that the actual closing speed is slower than expected; if , it indicates that the closing speed is too fast (there may be over-driving or favorable environmental conditions). Characterize the difference between the valve release speed and the expected value. If , it indicates that the peak current is insufficient, which may lead to insufficient suction force; if , it indicates that the actual current exceeds the expectation, and there may be risks of over-driving, energy waste or coil heating. Through the above items, when the solenoid valve operates too slowly ( ), fails to release in time ( ) or has insufficient driving force ( ), the comprehensive deviation will increase.

[0056] In addition, the expected closing time, expected release time and expected peak current can be pre-set target parameters, which can represent the standard working indicators that the system should achieve under ideal conditions. Exemplarily, according to the design specifications of the solenoid valve and the coil, and the data provided by the manufacturer (such as the typical values of the closing time, release time and peak current), the preliminary expected parameters are determined. Under laboratory conditions, a large number of test data are used to determine the optimal working parameters, and statistical analysis is carried out, and an average value or an optimized and adjusted value is selected as the expected value.

[0057] The reconfigurable drive module 130 is used to update the number of channel drives according to the pulse drive deviation information:

[0058] , Equation (4)

[0059] , Equation (5)

[0060] In the formula, represents the number of enabled drive channels, represents the number of MOSFET channels to be updated; represents rounding the calculation result in the parentheses to obtain an integer value; represents the proportionality constant, represents the comprehensive deviation index, is a preset weight used to balance the importance of the closing time, release time and peak current; is the expected comprehensive deviation index; represents the minimum allowable number of drive channels, represents the maximum allowable number of drive channels; represents not exceeding , represents not less than 。

[0061] Here, when there is a deviation between the actual solenoid valve response and the expectation (i.e., ), the number of drive channels is increased positively through Equation (5) to increase the drive current, improve the closing speed, or reach the expected peak current. Additionally, when the actual response exceeds the expectation ( ), the number of channels is reduced through Equation (5), thereby reducing the drive power consumption and avoiding over-driving.

[0062] Furthermore, by adopting the proportionality constant and the rounding function, the update of the number of channels can be carried out in discrete steps, avoiding excessive jumps. Combined with the closed-loop feedback, it is updated once per pulse period (or preset sampling period), thereby achieving dynamic adjustment and continuous optimization, which helps the system to operate stably.

[0063] Through the embodiments of the present application, if the valve closing speed is too slow or the peak current is too low, the system automatically increases the number of MOSFET channels to improve the driving force; if there are signs of over-driving or energy waste, the number of channels is reduced to save energy consumption. Thus, the adaptive update of the number of drive channels is achieved, which can effectively adjust the pulse driving ability, ensure that the response of the solenoid valve meets the expectation, and at the same time take into account energy consumption optimization. In an environment where the downhole power supply is limited, it can effectively extend the downhole operation time of the MWD system.

[0064] Regarding the details of the adaptive pulse generator 122, in some embodiments, the basic pulse generator 1221 employs a monostable multivibrator, and the digital control unit 1222 is used to generate a variable threshold voltage corresponding to the target pulse width through a digital-to-analog converter and adjust the equivalent impedance of the RC network in the monostable multivibrator according to the variable threshold voltage to adjust the pulse width of the output pulse of the monostable multivibrator.

[0065] Specifically, the variable threshold voltage generated by the digital-to-analog converter is applied to the comparator input terminal of the monostable multivibrator, resulting in a change in the time required for the RC charging to reach the trigger level, and then triggering an adjustment of the pulse width of the output pulse:

[0066] , Equation (6)

[0067] In the formula, represents the new pulse width of the output pulse of the monostable multivibrator under the action of the variable threshold voltage , with the unit of millisecond; represents the equivalent resistance of the RC network in the monostable multivibrator, represents the capacitance in the RC network; It is the supply voltage used by the monostable multivibrator, representing the highest potential reference that the RC network can reach during charging.

[0068] It should be noted that in the RC network, based on the principle of RC exponential charging: when the capacitor starts charging from 0V to a certain threshold voltage The time required is the width of the monostable output pulse. By dynamically setting the threshold voltage ( ) by the digital control unit, it is possible to adaptively adjust the pulse width without changing the and in the hardware. Specifically, the digital control unit (such as an MCU or FPGA) supports the real-time generation of a variable threshold voltage through a built-in or external digital-to-analog converter according to the deviation between the target pulse control signal and the current pulse control signal, thereby directly affecting the charging cut-off point of the RC network in the monostable multivibrator, that is, determining how long it takes for the capacitor to reach the trigger level.

[0069] Preferably, a closed-loop feedback regulator can also be introduced into the digital control unit to measure the actual width of each pulse, compare it with the expected value, and then correct the variable threshold voltage to gradually converge the control pulse to the target range.

[0070] Through the embodiments of the present application, by changing the threshold voltage at any time through the digital control unit, the pulse width of the pulse control signal can be adjusted online in real time to meet the diverse requirements for different times or different loads. In addition, the monostable multivibrator itself is a circuit form with a simple structure and low power consumption. The digital control unit only consumes limited power when updating the threshold voltage, and the overall energy usage efficiency is high.

[0071] Regarding the implementation details of the adaptive control algorithm, in some examples of the embodiments of the present application, the adaptive control algorithm adopts the ANFIS model. There are fuzzy rules preset for the ANFIS model, and each fuzzy rule adopts the Takagi-Sugeno type rule. Using the ANFIS algorithm, these input variables are mapped to the target pulse width. ANFIS combines the robustness of fuzzy logic and the local linear functions of each input variable to establish a non-linear mapping model, and continuously corrects the model parameters through online learning on-site to make the output more in line with actual requirements. ANFIS has the ability of non-linear mapping, is suitable for implementation in embedded systems, and the computational resources occupied are moderate, meeting the low-power requirements.

[0072] For each input variable, the Gaussian membership function is used to describe its membership degree in the fuzzy set:

[0073] , Equation (7)

[0074] wherein, represents the th input variable, , and respectively represent the normalized values of the well deviation measurement parameters, downhole environment parameters, and the working state of the solenoid valve coil; represents the fuzzy set corresponding to the th input variable in the th fuzzy rule; represents the membership degree of the input variable in the fuzzy set to which it belongs in the th rule; represents the central value of the membership function of the input in the th rule, represents the standard deviation of the membership function of the input in the th rule.

[0075] It should be noted that each input variable (such as downhole temperature, downhole pressure, working state of the solenoid valve coil) is usually divided into several fuzzy sets (such as "low", "medium", "high"). By describing the fuzzy set that represents the value range of the th input under the th rule, this set is determined by the membership function parameters (central value) and (width), and the Gaussian function is used as the membership function. Through the membership function, the system can characterize the non - linear distribution and fuzzy interval of the input variable, making the subsequent rule activation degree closer to the actual working conditions.

[0076] , Equation (8)

[0077] , Equation (9)

[0078] wherein, represents the original activation degree of the th fuzzy rule, represents the activation normalized weight of the th fuzzy rule; represents the sum of the original activation degrees of all fuzzy rules, which is used for normalization processing.

[0079] It should be noted that if the membership degree of a certain input in the fuzzy set corresponding to this rule is high, the product value is also relatively large, indicating that this rule has a high matching degree to the current input state. Here, the original activation degrees of all rules are summed and normalized to obtain the The weight of each rule in the subsequent output calculation.

[0080] According to the local linear function corresponding to each fuzzy rule, the output of the corresponding local linear model is calculated as:

[0081] , Equation (10)

[0082] Where is the output of the local linear model corresponding to the th rule, representing the predicted value of the pulse width calculated according to the input parameters under this rule; , and respectively represent the linear calibration values of the input variables in the and th rule, with the unit of millisecond; is the bias term in the th rule, representing the basic output value of this rule when there is no input, and its unit is millisecond.

[0083] According to the characteristics of the Takagi - Sugeno model, different linear equations are used in different fuzzy rule intervals to capture the overall non - linear relationship. Each rule has a set of local linear parameters, so different linear equations are used in different fuzzy intervals to describe the influence of the input on the output. The combination of fuzzy rules and local linear models enables the system to flexibly switch the mapping method in different intervals and has good robustness to environmental fluctuations (such as temperature increase, pressure change, etc.).

[0084] An exemplary description of the fuzzy rules is as follows:

[0085] If the temperature is "HighTemp" and the pressure is "LowPress" and the coil state is "WeakCoil", and are normalized to [0, 1];

[0086] Then the local linear function is .

[0087] The fuzzy sets are defined as follows:

[0088] For the temperature : "HighTemp" corresponds to the normalized center (i.e., about 120 °C), and the standard deviation (10 °C / 150 °C).

[0089] For the pressure : "LowPress" corresponds to the normalized center (about 5 MPa), standard deviation (2 MPa / 30 MPa).

[0090] For the coil state : "WeakCoil" corresponds to the center , standard deviation .

[0091] Set or learn the linear calibration values , and , and obtain the local linear function as .

[0092] Perform a weighted average on the output of the local linear model of each fuzzy rule and the corresponding activation normalization weight to obtain the final target pulse width:

[0093] , Equation (11)

[0094] In the formula, represents the target pulse width.

[0095] Through the embodiments of the present application, ANFIS combines the rule expression ability of fuzzy logic and local linear functions, can capture the complex non - linear relationship between input variables and pulse width, avoid the inapplicability problems brought by simple linear models, and can perform more accurate non - linear mapping and prediction of the target pulse width under multiple inputs and multiple working conditions, improving the control accuracy. In addition, although it is a non - linear model, the core operations are membership degree calculation, product, and weighted linear output, which can be relatively easily implemented in downhole terminals without significantly increasing power consumption. In addition, the fuzzy rule base and local linear functions make the system have a certain interpretability, can view the contribution of each rule to the output, and can add, delete, or modify fuzzy rules, facilitating the debugging and management of the system.

[0096] It should be noted that for the foregoing system embodiments, for the sake of simple description, they are all expressed as a combination of a series of actions. However, those skilled in the art should know that the present application is not limited by the described action sequence, because according to the present application, certain steps can be performed in other sequences or simultaneously. Secondly, those skilled in the art should also know that the embodiments described in the specification are all preferred embodiments, and the actions and modules involved are not necessarily essential to the present application. In the above embodiments, the descriptions of each embodiment have their own emphases. For the parts not detailed in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0097] The system embodiments described above are merely illustrative. The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed to multiple network units. Some or all of the modules can be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0098] Through the description of the above embodiments, those skilled in the art can clearly understand that each embodiment can be implemented by means of software plus a general hardware platform, and of course, it can also be implemented by hardware. Based on this understanding, the essence of the above technical solution, or the part that contributes to the related technology, can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes several instructions for causing a computer device (which can be a personal computer, a server, or a network device, etc.) to execute the systems described in each embodiment or some parts of the embodiments.

[0099] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them; although the present application 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 for some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A MWD pulser control system based on modular low-power drive, characterized in that: It includes a power management module, a pulse generation and adaptive control module, and a reconfigurable drive module; The power management module adopts a three-terminal adjustable positive voltage regulator to adjust the input voltage to a stable operating voltage; The pulse generation and adaptive control module includes an algorithm controller and an adaptive pulse generator. The algorithm controller is used to calculate the target pulse width matching the input trigger data according to the adaptive control algorithm. The input trigger data includes the well deviation measurement parameters, the downhole environment parameters, and the working state of the solenoid valve coil. The adaptive pulse generator includes a basic pulse generator and a digital control unit to generate a target pulse control signal corresponding to the target pulse width. The reconfigurable driving module adopts a parallel MOSFET array structure including multiple driving channels, and is used to generate a channel driving quantity corresponding to the target pulse control signal, and activate at least one target MOSFET channel corresponding to the channel driving quantity to synchronously drive the solenoid valve coil; Wherein, the three-terminal adjustable positive voltage regulator comprises an adjustment terminal, an input terminal and an output terminal; A first capacitor is connected in parallel to the output terminal, wherein the capacitance of the first capacitor is greater than or equal to 10 μF; The output terminal is connected in series with a first external resistor and a second external resistor to set an output voltage, wherein the first external resistor is connected to the adjustment terminal and connected to the ground terminal via the second external resistor; The second external resistor is also connected in parallel with a fixed resistor, one end of the fixed resistor is connected to the adjustment terminal, and the other end of the fixed resistor is connected to the ground terminal; Wherein, when the adjustment terminal is short-circuited with the ground, the output terminal can directly output according to the internal reference voltage of the three-terminal adjustable positive voltage regulator to achieve a low power consumption mode; Wherein, each of the MOSFET channels is connected in series with a low-resistance shunt resistor; and the reconfigurable drive module is further used to perform the following operations: Obtaining the current flowing through each MOSFET channel by measuring the voltage drop of the low-resistance shunt resistor, and determining the load state of the MOSFET channel according to each measured current; Determine a PWM duty cycle that matches the load state of the MOSFET channel, and activate each of the target MOSFET channels to synchronously drive the solenoid valve coil according to the PWM duty cycle; wherein the PWM duty cycle corresponding to the high load state is greater than the PWM duty cycle corresponding to the low load state; The algorithm controller is also used to receive solenoid valve response data and generate pulse drive deviation information according to the solenoid valve response data; the solenoid valve response data includes the solenoid valve's pull-in time, release time and peak current: ， ， ， In the formula, Indicates the pull-in time deviation, Indicates the release time deviation, Indicates the peak current deviation; , and Respectively represent the actual pull-in time, actual release time and actual peak current in the acquired solenoid valve response data; , and They represent the expected value of the pull-in time, the expected value of the release time and the expected value of the peak current respectively; The reconfigurable driving module is used to update the channel driving quantity according to the pulse driving deviation information: ， ， In the formula, Indicates the number of enabled drive channels. Indicates the number of MOSFET channels to be updated; Indicates that the calculation result in the brackets is rounded to obtain an integer value; represents the proportionality constant, represents the comprehensive deviation index, Preset weights to balance the importance of pull-in time, release time and peak current; is the expected comprehensive deviation index; Indicates the minimum allowed number of drive channels, Indicates the maximum allowed number of drive channels; Indicates no more than , Indicates not less than ; Wherein, the basic pulse generator adopts a monostable multivibrator, and the digital control unit is used to generate a variable threshold voltage corresponding to the target pulse width through a digital-to-analog converter, and adjust the equivalent impedance of the RC network in the monostable multivibrator according to the variable threshold voltage to adjust the pulse width of the output pulse of the monostable multivibrator; Variable threshold voltage generated by a digital-to-analog converter Applied to the comparator input of the monostable multivibrator, it causes a change in the time required for the RC charge to reach the trigger level, which in turn triggers an adjustment in the pulse width of the output pulse: ， In the formula, Indicates the variable threshold voltage Under the action, the new pulse width of the output pulse of the monostable multivibrator is in milliseconds; represents the equivalent resistance of the RC network in the monostable multivibrator, Represents the capacitance in the RC network; It is the supply voltage used by the monostable multivibrator, representing the highest potential reference that the RC network can reach when charging; The adaptive control algorithm adopts the ANFIS model, and the ANFIS model is preset with fuzzy rules, each fuzzy rule adopts Takagi-Sugeno type rule; For each input variable, a Gaussian membership function is used to describe its membership in the fuzzy set: ， In the formula, Indicates input variables, , and They represent the normalized values ​​of downhole temperature, downhole pressure and the working state of the solenoid valve coil. Through normalization, various input parameters can be fuzzy operated at the same level to avoid high-value variables from dominating the results when calculating the membership function. Indicated in Among the fuzzy rules, The fuzzy sets corresponding to the input variables; Represents input variables In the The fuzzy set of the rules The degree of membership; Indicates Enter the rule The central value of the membership function, Indicates Enter the rule Standard deviation of membership functions; ， ， In the formula, Indicates The original activation degree of the fuzzy rules, Indicates The activation normalized weights of the fuzzy rules; Represents the sum of the original activation levels of all fuzzy rules, which is used for normalization; According to the local linear function corresponding to each fuzzy rule, the corresponding local linear model output is calculated as: ， In the formula, It is The local linear model output corresponding to the rule represents the pulse width prediction value calculated according to the input parameters under the rule; , and Respectively represent Input variables in rules and The linear calibration value of is in milliseconds; For the The bias term in a rule indicates the basic output value of the rule when there is no input, and its unit is milliseconds; The local linear model outputs of the fuzzy rules and the corresponding activation normalized weights are weighted averaged to obtain the final target pulse width: ， In the formula, Indicates the target pulse width.

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