Automatic control system for production increasing operation of coiled tubing

Abstract

The invention relates to the technical field of oil and gas extraction and yield increase, in particular to an automatic control system for continuous oil pipe yield increase operation. A pulse modulation unit, a waveform acquisition unit, an impedance analysis unit, a state discrimination unit and an adaptive adjustment unit are included; the system obtains pressure fluctuation data by superposing micro-perturbation excitation on the reference displacement; the core of the method is that terminal acoustic impedance parameters are obtained through frequency domain reflection solution, and load characteristic quantitative matching analysis is carried out; when a high-impedance locking state or a low-impedance conducting state is identified, the system adaptively adjusts the excitation frequency or switches to a stable injection mode; according to the method, an active closed-loop control mechanism capable of detecting and adjusting at the same time is constructed, on-way interference can be eliminated without an underground instrument, and accurate ground recognition and regulation of the well bottom state are achieved.

Description

Technical Field

[0001] This invention relates to the field of oil and gas extraction and production enhancement technology, specifically to an automated control system for coiled tubing production enhancement operations. Background Technology

[0002] In coiled tubing production enhancement operations, fluids need to be transported through thousands of meters of wellbore to the bottom reservoir, and the operating conditions are complex and variable. Existing operational solutions generally employ a constant displacement of ground high-pressure pump sets or an open-loop mode with simple pressure monitoring. Due to the severe signal attenuation and distortion caused by long-distance fluid transmission, and the inability to eliminate interference from frictional resistance and fluid compressibility by relying solely on pressure amplitude, it is difficult to accurately distinguish between formation blockage and open state. This blind operation not only causes control lag and misjudgment, but also often forces operators to blindly increase pump pressure, which can easily lead to fatigue damage or even rupture of the tubing. Furthermore, it is inefficient in clearing blockages or increasing production from micro-cracks. Therefore, how to eliminate signal interference over long distances to achieve accurate quantitative perception of well bottom conditions and make adaptive closed-loop adjustment of pumping parameters accordingly has become an urgent technical problem to be solved. Summary of the Invention

[0003] To solve the above-mentioned technical problems, the present invention provides an automated control system for coiled tubing production enhancement operations. Specifically, the technical solution of the present invention includes: The system comprises a pulse modulation execution unit, a response waveform acquisition unit, an impedance spectrum analysis unit, a state mapping discrimination unit, and an adaptive feedback adjustment unit. The pulse modulation execution unit controls the reference displacement of the fluid delivery equipment and, according to modulation commands, superimposes a micro-perturbation excitation of a preset frequency onto the reference displacement to generate a composite injected fluid. The response waveform acquisition unit acquires real-time pressure fluctuation data at the wellhead and sends this data to the impedance spectrum analysis unit for frequency domain reflection analysis to obtain the incident and reflected wave components. The phase difference and amplitude ratio between the reflected and incident wave components are processed to obtain the terminal acoustic impedance. The parameters; the state mapping discrimination unit is used to perform load characteristic quantization matching analysis on the terminal acoustic impedance parameters generated by the impedance spectrum analysis unit, and compares the obtained terminal acoustic impedance parameters with the preset impedance threshold to obtain a high impedance blocking signal or a low impedance conduction signal; when a high impedance blocking signal is generated, the adaptive feedback adjustment unit is used to generate a resonance optimization command, and controls the pulse modulation execution unit to adjust the frequency of micro-disturbance excitation to match the resonance point of the system; when a low impedance conduction signal is generated, the adaptive feedback adjustment unit is used to generate a smooth injection command, and controls the pulse modulation execution unit to eliminate micro-disturbance excitation and increase the reference displacement.

[0004] Preferably, the frequency domain reflection calculation and analysis process is as follows: pressure fluctuation data within a preset sampling period is collected, and the pressure fluctuation data is set as a time-domain waveform sequence. The time-domain waveform sequence is processed by fast Fourier transform to obtain the frequency domain response spectrum. Based on the distributed parameter transmission line model, the forward-transmitting incident wave component and the reverse-transmitting reflected wave component are separated from the frequency domain response spectrum. The complex reflection coefficient of the reflected wave component relative to the incident wave component is calculated, and the complex reflection coefficient is converted into the terminal acoustic impedance parameter.

[0005] Preferably, the terminal acoustic impedance parameter includes a real part of impedance and an imaginary part of impedance; the load characteristic quantification and matching analysis process is as follows: the real part of the terminal acoustic impedance parameter is obtained, which characterizes the fluid absorption capacity of the terminal load, and is set as a permeability characterization index; simultaneously, the imaginary part of the terminal acoustic impedance parameter is obtained, which characterizes the energy storage effect at the end of the transmission channel, and is set as a capacitive load index; the permeability characterization index is processed for discrimination; if the permeability characterization index is greater than a preset blockage threshold, a high impedance blocking signal is generated; if the permeability characterization index is less than or equal to the preset blockage threshold, a low impedance conduction signal is generated.

[0006] Preferably, when generating the resonance optimization command, the adaptive feedback adjustment unit performs the following frequency scanning operation: acquiring the preset frequency scanning range and step value, controlling the pulse modulation execution unit to sequentially output micro-perturbation excitations of different frequencies within the frequency scanning range, while monitoring the pressure fluctuation amplitude fed back by the response waveform acquisition unit, setting the frequency corresponding to when the pressure fluctuation amplitude reaches its maximum value as the system resonance frequency, and locking the system resonance frequency as the current working frequency, so as to generate water hammer resonance energy to physically break the terminal load.

[0007] Preferably, when a smooth injection command is generated, the adaptive feedback adjustment unit performs the following rheological characteristic optimization operation: obtains the non-Newtonian fluid characteristic parameters of the current fluid, calculates the apparent viscosity value of the fluid at different shear rates based on the shear dilution principle, compares and analyzes the apparent viscosity value with a preset microcrack entry resistance threshold, calculates the optimal reference displacement that minimizes the apparent viscosity value, and sends the optimal reference displacement to the pulse modulation execution unit for constant displacement pumping to achieve deep diffusion of chemical agents.

[0008] Preferably, the response waveform acquisition unit further includes a background noise filtering module; the background noise filtering module is used to acquire the background pressure fluctuation data of the fluid conveying equipment when no micro-disturbance excitation is applied, set the background pressure fluctuation data as the environmental noise reference, set the value obtained by subtracting the environmental noise reference from the real-time acquired pressure fluctuation data as the net response signal, and send the net response signal to the impedance spectrum analysis unit.

[0009] Preferably, the adaptive feedback adjustment unit further includes a safety fuse verification module; the safety fuse verification module is used to monitor the total pressure value at the wellhead in real time, compare the total pressure value with a preset pipe yield pressure threshold, and if the total pressure value is greater than or equal to the preset pipe yield pressure threshold, an emergency stop command is forcibly generated to block the output of the pulse modulation execution unit; if the total pressure value is less than the preset pipe yield pressure threshold, a resonance optimization command or a smooth injection command is allowed to be output.

[0010] Preferably, the pulse modulation execution unit generates the composite injection fluid as follows: It obtains the reference displacement instruction code. And micro-perturbation excitation instruction code, the micro-perturbation excitation instruction code contains frequency and amplitude Constructing fluid control equations The fluid control equations are converted into frequency conversion drive signals, which are then sent to the controller of the high-pressure pump unit to drive the high-pressure pump unit to output fluid medium with periodic pressure pulsation.

[0011] Compared with the prior art, the present invention has the following beneficial effects: 1. This system constructs an active closed-loop control system that simultaneously detects, operates, and adjusts. By superimposing micro-perturbation excitation on a benchmark displacement, the incident and reflected waves are separated using an impedance spectrum analysis unit based on a transmission line model, thereby resolving the terminal acoustic impedance parameters in the frequency domain. This method can effectively eliminate interference caused by frictional resistance and fluid compressibility during long-distance fluid transmission. It can accurately quantify and identify whether the well bottom is in a high-impedance locked state or a low-impedance conducting state on the surface without the need for downhole electronic instruments, overcoming the problem of misjudgment caused by existing technologies that rely solely on pressure amplitude for judgment. 2. For high-impedance blocking signals, this system automatically executes resonance optimization commands; it automatically locks the acoustic resonance frequency of the tubing-fluid system through frequency scanning, and drives the pulse modulation execution unit to generate high-intensity water hammer resonance energy; this mechanism can produce a physical fracturing effect similar to percussion drilling at the bottom of the well, and physically breaks up hard blockages or establishes initial fracture channels before chemical dissolution takes effect, which greatly improves the success rate of operations in difficult-to-access reservoirs; 3. For low-impedance conduction signals, this system uses the rheological properties of non-Newtonian fluids for adaptive adjustment; by calculating and executing the optimal reference displacement that minimizes the apparent viscosity of the fluid, the flow resistance of the fluid entering the micro-fractures of the formation is significantly reduced by utilizing the shear dilution principle; this enables chemical agents to be deeply transported to the fracture ends that are difficult to reach by traditional constant displacement methods, achieving deep sweep and uniform transformation, and significantly improving the production increase effect. 4. This system integrates background noise filtering and safety fuse verification functions. On the one hand, by collecting and subtracting environmental noise benchmarks, it eliminates on-site environmental interference such as pump truck vibration, significantly improving the signal-to-noise ratio and resolution accuracy of weak feedback signals. On the other hand, by monitoring the total pressure value in real time and comparing it with the pipe yield pressure threshold, a mandatory electronic fence is constructed. Once the pressure exceeds the limit, an emergency stop is triggered, effectively preventing pipe fatigue failure or rupture accidents caused by blindly pursuing increased production. Attached Figure Description

[0012] The present invention will be further explained below with reference to the accompanying drawings and embodiments: Figure 1 This is a structural diagram of the system of the present invention. Detailed Implementation

[0013] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments.

[0014] Example 1: Please see Figure 1 An automated control system for coiled tubing production enhancement operations includes a pulse modulation execution unit, a response waveform acquisition unit, an impedance spectrum analysis unit, a state mapping discrimination unit, and an adaptive feedback adjustment unit. The pulse modulation execution unit controls the reference displacement of the fluid delivery equipment and, according to modulation commands, superimposes a micro-perturbation excitation of a preset frequency onto the reference displacement to generate a composite injection fluid. The response waveform acquisition unit acquires pressure fluctuation data at the wellhead in real time and sends the pressure fluctuation data to the impedance spectrum analysis unit for frequency domain reflection analysis to obtain the incident wave component and the reflected wave component. The phase difference and amplitude ratio between the reflected wave component and the incident wave component are then analyzed. The system processes and obtains the terminal acoustic impedance parameters. The state mapping discrimination unit performs load characteristic quantization matching analysis on the terminal acoustic impedance parameters generated by the impedance spectrum analysis unit, compares the obtained terminal acoustic impedance parameters with the preset impedance threshold, and obtains a high-impedance blocking signal or a low-impedance conducting signal. When a high-impedance blocking signal is generated, the adaptive feedback adjustment unit generates a resonance optimization command to control the pulse modulation execution unit to adjust the frequency of the micro-disturbance excitation to match the resonance point of the system. When a low-impedance conducting signal is generated, the adaptive feedback adjustment unit generates a smooth injection command to control the pulse modulation execution unit to eliminate the micro-disturbance excitation and increase the reference displacement.

[0015] This embodiment details the physical architecture and closed-loop control logic of the system, aiming to address the technical pain points of blind spot and control lag in traditional operations. The system connects to the frequency converter of the high-pressure pump unit through a pulse modulation execution unit installed on the surface pump truck. This unit not only maintains the baseline displacement required for the operation, but more importantly, it superimposes a micro-perturbation excitation of a preset frequency on the baseline displacement according to the modulation command. This micro-perturbation excitation is set to a sine wave or square wave flow pulsation with an amplitude much smaller than the baseline displacement and a specific frequency, which is sent as a detection signal to the bottom of the well to generate a composite injection fluid containing DC and AC components. During this process, the system relies on a mathematical model... Waveform synthesis is performed, where, Based on the standard displacement, For the amplitude of the disturbance, The frequency ensures that the physical characteristics of the injected fluid strictly correspond to the control commands; the response waveform acquisition unit uses a high-frequency pressure transmitter with a sampling frequency of not less than 1kHz to capture transient pressure fluctuation data at the wellhead in real time and transmit it to the impedance spectrum analysis unit deployed in the industrial control computer. The impedance spectrum analysis unit, based on transmission line theory, treats the wellbore as an acoustic waveguide. It uses algorithms to separate the incident wave component propagating downwards from the surface and the reflected wave component reflected back from the bottom of the well, calculating their phase difference and amplitude ratio to determine the terminal acoustic impedance parameters. Based on this, the state mapping discrimination unit performs load characteristic quantification and matching analysis on these parameters, comparing the abstract impedance value with a preset impedance threshold. In response to extremely high impedance, the system determines that fluid cannot enter the formation, generating a high-impedance blocking signal. In response to low and matched impedance, the system determines that fluid is smoothly drawn in, generating a low-impedance conduction signal. The adaptive feedback adjustment unit, as the core decision-making center, dynamically adjusts the pumping strategy based on the discrimination results: in response to the high-impedance blocking signal, it generates a resonance optimization command to utilize the amplified pressure wave to break up the blockage; in response to the low-impedance conduction signal, it generates a smooth injection command to eliminate micro-disturbances and increase the flow rate, maximizing operational efficiency. This embodiment constructs an active closed-loop control system that simultaneously detects, operates, and adjusts. By introducing micro-disturbance excitation into the fluid and analyzing its frequency domain reflection characteristics, real-time acoustic sensing of the state at the bottom of a well several kilometers deep is achieved. The system uses a high-impedance blocking signal to trigger resonance optimization and a low-impedance conduction signal to trigger smooth injection. This adaptive mechanism not only avoids the risk of tubing fatigue caused by blind high-pressure pumping, but also significantly improves the success rate of unblocking tight reservoirs or blockage conditions and the swept volume of production-enhancing agents through the synergistic effect of physical resonance breakage and large-volume chemical injection. To further verify the overall performance of the system, a field implementation was conducted in a shale gas horizontal well at a depth of 4200m; such as Figure 1As shown in the diagram, the system uses a 2-inch continuous tubing string. Initially, the system detects a high-impedance blockage signal from the bottom of the well and immediately activates the resonant optimization mode. Within 5 minutes, it locks the resonant frequency at 3.2 Hz and generates a water hammer pulse with an amplitude of 8 MPa at the bottom of the well. After 20 minutes of continuous operation, the impedance parameter transitions to the low-impedance conduction range, and the system automatically switches to a stable injection mode, increasing the baseline flow rate to 300 L / min. Post-operation testing shows that the skin factor of this cluster decreased from 5.2 before operation to -1.5, confirming the system's automated production enhancement effect.

[0016] Example 2: The frequency domain reflection calculation and analysis process is as follows: pressure fluctuation data within a preset sampling period is collected and set as a time-domain waveform sequence. The time-domain waveform sequence is processed by fast Fourier transform to obtain the frequency domain response spectrum. Based on the distributed parameter transmission line model, the forward-propagating incident wave component and the reverse-propagating reflected wave component are separated from the frequency domain response spectrum. The complex reflection coefficient of the reflected wave component relative to the incident wave component is calculated and converted into the terminal acoustic impedance parameter.

[0017] This embodiment provides a detailed description of the internal calculation logic of the impedance spectroscopy analysis unit, aiming to extract bottom-hole feature information from mixed pressure signals. The impedance spectroscopy analysis unit performs data acquisition and sequence construction, collecting pressure fluctuation data within a preset sampling period and setting it as a time-domain waveform sequence. ; The source is the real-time output of the response waveform acquisition unit. When the system enables the background noise filtering module, this data corresponds to the net response signal. The physical meaning is the pressure value at the wellhead that changes over time, with the unit being MPa; the element performs frequency domain transformation, for Perform Fast Fourier Transform (FFT) processing to convert the discrete-time signal into a frequency domain response spectrum. ; Based on the distributed parameter transmission line model, real-time flow command data fed back by the pulse modulation execution unit is obtained, and its flow frequency domain spectrum is obtained by performing a fast Fourier transform on it. Combined with the obtained pressure frequency response spectrum Utilizing characteristic impedance The forward-propagating incident wave component is mathematically separated from the frequency domain response spectrum. and the reflected wave component that travels back in the opposite direction The specific formula for separation calculation is as follows: in, and Complex spectral values ​​at the same frequency point; characteristic impedance The calculation formula is Based on transmission line theory, and considering that the fluid inside the wellbore may be in a turbulent state during production enhancement operations, a turbulence correction factor is introduced. The propagation constant of sound waves inside the oil pipe The calculation formula is as follows: in, The source is a fluid property parameter table; its physical meaning is the average density of the fluid inside the wellbore, in units of... ; The source is acoustic measurement value; its physical meaning is the propagation speed of pressure waves in a fluid, and the unit is... ; The source is the tubing string structural parameters; its physical meaning is the cross-sectional area inside the coiled tubing for fluid flow, and the unit is... ; The source is a frequency domain transform variable, and its physical meaning is angular frequency. The unit is ; The source is a fluid property parameter, specifically the dynamic viscosity constant of a fluid in a static state, with units of... ; The source is tubing string parameters; its physical meaning is the inner radius of the tubing, and the unit is... ; The imaginary unit, ; This is the turbulence correction factor, when the Reynolds number... When, take 1, when Time to take Among them, the Reynolds number The calculation formula is Imaginary unit Here, the phase rotation characteristics of sound waves during propagation are physically characterized to describe the time delay effect of the wave; furthermore, the unit calculates the complex reflection coefficient. Its calculation formula is ,in, The complex spectral value of the reflected wave component. Let be the complex spectral value of the incident wave component, and use the formula... Convert the complex reflection coefficient into the terminal acoustic impedance parameter ; This embodiment effectively eliminates DC or low-frequency interference caused by friction along the well by using wave separation technology in the frequency domain, and constructs a virtual bottom hole pressure gauge. This method uses the phase information carried by the reflected wave to accurately restore the real load characteristics at the bottom of the well without the need to lower an electronic pressure gauge, and solves the problem of discrimination distortion caused by signal attenuation and distortion in long-distance fluid transmission. In practice, a 10-second period of pressure data with a sampling rate of 2kHz was selected for verification. As shown in the figure, the frequency domain response analysis diagram shows that the original time-domain signal contains a large amount of random noise. After FFT processing and transmission line model separation, the reflected wave component with a fundamental frequency of 5Hz was clearly extracted from the frequency domain spectrum. The complex reflection coefficient modulus at this frequency point was calculated to be 0.85, and the phase angle was -30 degrees. Substituting these values ​​into the formula, the terminal acoustic impedance parameters were calculated. The calculation results were compared with the playback data from the downhole storage pressure gauge, and the relative error was only 3.2%, which verified the high accuracy of the algorithm.

[0018] Example 3: The terminal acoustic impedance parameters include the real part and the imaginary part of the impedance. The load characteristic quantification and matching analysis process is as follows: The real part of the terminal acoustic impedance parameters is obtained, which represents the fluid absorption capacity of the terminal load and is set as the permeability characterization index. At the same time, the imaginary part of the terminal acoustic impedance parameters is obtained, which represents the energy storage effect at the end of the transmission channel and is set as the capacitive load index. The permeability characterization index is processed for discrimination. If the permeability characterization index is greater than the preset blockage threshold, a high impedance blocking signal is generated; if the permeability characterization index is less than or equal to the preset blockage threshold, a low impedance conduction signal is generated.

[0019] This embodiment further refines the physical meaning and discrimination logic of the terminal acoustic impedance parameters, aiming to transform the abstract complex impedance into a specific operating condition description; the state mapping discrimination unit processes the calculated terminal acoustic impedance parameters. Perform orthogonal decomposition to obtain the real part of the impedance. and the imaginary part of impedance Real part of impedance The source is the real part of the terminal acoustic impedance parameter, which physically represents the energy dissipation capacity, i.e., the ease with which the terminal load absorbs fluid, and is measured in acoustic ohms; this value is set as a permeability characterization index; the imaginary part of the impedance value... The source is the imaginary part of the terminal acoustic impedance parameter, which physically represents the energy storage effect and reflects the capacitive load characteristics at the end of the transmission channel. The unit is acoustic ohms. This value is set as the capacitive load index. The unit focuses on the real part for quantitative matching analysis of load characteristics to obtain the penetration rate characterization index. It also performs threshold discrimination; in response to a penetration rate indicator exceeding a preset clogging threshold... This indicates that most of the acoustic energy is reflected and very little fluid is absorbed by the formation. The system determines this as a hard connection or blockage, and thus generates a high-impedance blocking signal. When the permeability characterization index is less than or equal to the preset blockage threshold, it indicates that the acoustic energy is absorbed by the formation and converted into fluid flow. The system determines this as a formation opening, and thus generates a low-impedance conduction signal. This embodiment achieves both qualitative and quantitative diagnosis of well bottom conditions by introducing orthogonal analysis of the real and imaginary parts of complex impedance. By directly mapping the real part of impedance to the permeability index, a feedback variable with high linearity and clear physical meaning is provided for the control system. This effectively avoids the misjudgment caused by fluid compressibility when relying solely on pressure amplitude for judgment, enabling the system to accurately distinguish whether the formation is blocked or open. In practice, regarding the preset blockage threshold As shown in the figure, historical operational data from 30 wells within the target block were selected for statistical analysis. The results indicate that, based on historical test data from 50 similar injection wells in this block under the same fluid properties, with a confidence level of 95%, the real part of the wellhead acoustic impedance for effective formation communication is distributed as follows: The distribution of unconnected or blocked wells is within the range. The interval; accordingly, this embodiment defines the blocking threshold. Set as This setting follows the principles of statistical hypothesis testing, calculating the receiver operating characteristic curve of historical data and selecting the point with the maximum Youden index as the optimal cutoff value to balance the false negative and false positive rates; this threshold is selected from the upper limit of the effective communication interval. And the lower limit of the congestion range, The arithmetic mean of the values ​​is used to ensure a safety margin for classification; in a certain measurement, the calculated real part of the impedance is... Based on this, the system accurately determines that the system is in a blocked state and triggers the unblocking procedure.

[0020] Example 4: When a resonance optimization command is generated, the adaptive feedback adjustment unit performs the following frequency scanning operation: it acquires the preset frequency scanning range and step value, controls the pulse modulation execution unit to output micro-perturbation excitations of different frequencies in sequence within the frequency scanning range, and monitors the pressure fluctuation amplitude fed back by the response waveform acquisition unit. It sets the frequency corresponding to the maximum value of the pressure fluctuation amplitude as the system resonance frequency and locks the system resonance frequency as the current working frequency to generate water hammer resonance energy to physically break the terminal load.

[0021] This embodiment details the active frequency optimization process under congestion conditions, aiming to solve the congestion problem by utilizing the principle of physical resonance. In response to the generation of a high-impedance blocking signal, the adaptive feedback adjustment unit initiates a frequency scanning operation to obtain a preset frequency scanning range. and step value Frequency scanning range: The source is preset parameters, and the physical meaning is the range of excitation frequencies allowed by the system, such as 0.5Hz to 10Hz; The unit-controlled pulse modulation execution unit sequentially outputs micro-perturbation excitations of different frequencies in step values ​​within the frequency scanning interval to perform frequency sweep testing on the downhole tubing fluid system. During this period, the unit simultaneously monitors the pressure fluctuation amplitude fed back by the response waveform acquisition unit. The specific amplitude calculation logic is as follows: the sliding variance of the pressure fluctuation data is calculated in real time, and the first... The variance of each period is , No. The variance of each period is Construct the rate of change of variance The calculation formula is as follows: When the variance change rate over three consecutive periods When the value is less than the preset steady-state threshold, the system is determined to have reached a steady-state response; When the rate of change of variance over three consecutive periods is less than a preset steady-state threshold, the system is deemed to have reached a steady-state response. A time-domain data segment of five complete periods, after low-pass filtering, is extracted, and the peak-to-peak value within this segment is calculated. This is used as the pressure fluctuation amplitude; the amplitude response at each frequency point is compared in real time; since the fluid string has an inherent acoustic resonant frequency, the pressure wave amplitude will increase significantly when the excitation frequency approaches this inherent frequency, and the system sets the frequency corresponding to the maximum pressure fluctuation amplitude as the system resonant frequency. The unit locks the system's resonant frequency to the current operating frequency, and drives the pulse modulation execution unit to continuously output excitation at that frequency, thereby generating water hammer resonant energy to physically break the terminal load. This embodiment utilizes the water hammer resonance principle in fluid mechanics to achieve high energy output under low power excitation by automatically optimizing and locking the resonance frequency. This method generates an extremely high amplitude pressure pulse at the bottom end of the well, producing a physical breaking effect on rocks or blockages similar to that of an impact drill, thereby establishing physical fracture channels before chemical dissolution, which greatly improves the unblocking efficiency for hard blockages. Experimental data verified the effectiveness of the optimization mechanism. On the 2000m simulated tubing test platform, the frequency scanning range was set from 1Hz to 8Hz, with a step value of 0.2Hz. As shown in the frequency sweep response curve, the system captured a significant peak in the pressure fluctuation amplitude at 3.4Hz during the scanning process, reaching 1.5MPa, while the amplitude at a frequency 0.5Hz away from this frequency rapidly decayed to below 0.3MPa. The system successfully locked onto 3.4Hz for resonant impact, and the experiment showed that the blockage breaking time was shortened by 65% ​​compared to fixed frequency operation.

[0022] Example 5: When a smooth injection command is generated, the adaptive feedback control unit performs the following rheological optimization operations: it acquires the non-Newtonian fluid characteristic parameters of the current fluid, calculates the apparent viscosity of the fluid at different shear rates based on the shear dilution principle, compares and analyzes the apparent viscosity with the preset microcrack entry resistance threshold, calculates the optimal reference displacement that minimizes the apparent viscosity, and sends the optimal reference displacement to the pulse modulation execution unit for constant displacement pumping to achieve deep penetration of the chemical agent.

[0023] This embodiment details the displacement optimization logic under formation open conditions, aiming to improve the agent sweep range by utilizing non-Newtonian fluid characteristics. In response to the generation of a low-impedance conduction signal, the adaptive feedback control unit performs rheological characteristic optimization operations to obtain the non-Newtonian fluid characteristic parameters of the currently injected fluid. These non-Newtonian fluid characteristic parameters are sourced from laboratory measurements or preset databases, including the consistency coefficient. and rheological index ; and The fluid samples were scanned at varying shear rates in the laboratory using a six-speed rotational viscometer according to API RP 13B-1 standards, and the data were obtained through double logarithmic regression fitting. Based on the shear dilution principle, that is, the apparent viscosity of non-Newtonian fluids decreases with increasing shear rate, the unit utilizes the formula... The apparent viscosity of the calculated fluid is determined at different base displacements and corresponding shear rates; where... The source is a calculation output; its physical meaning is the apparent viscosity of a non-Newtonian fluid under specific shear conditions, and the unit is... ; The source is from fluid dynamics calculations. To distinguish it from the aforementioned sound wave propagation constant, a dotted symbol is used here to represent the fluid shear rate, with units of 1. For power-law fluids, the correction formula is as follows: in, To convert the flow rate to International Units (SI), i.e. The value is the current instantaneous setpoint. The inner radius of the coiled tubing, in units of ; The unit compares the calculated apparent viscosity value with the preset microcrack entry resistance threshold. Simultaneously, to ensure operational safety, the adaptive feedback control unit introduces a pressure prediction model to calculate the current baseline displacement using the following formula. Predicted wellhead circulating pressure : in, The inner diameter of the tubular column is the same as the aforementioned radius. The relationship is ; For the effective measurement length of the tubing; The formula for calculating the pure hydrostatic pressure after deducting the effect of friction is as follows: ,in, Let be the acceleration due to gravity, and take . , The vertical depth at the bottom of the well; This is the consistency coefficient; The rheological index; To convert flow rate to International System of Units (SI) ,Right now coefficient here To be Convert to Unit conversion constant; For traffic; The unit executes iterative optimization logic: within a preset displacement adjustment range, it searches for the apparent viscosity value. Minimize, and satisfy ,in, The displacement value of the equipment's safe pressure limit is set as the optimal reference displacement; the unit sends this optimal reference displacement to the pulse modulation execution unit, at which point pulsation is eliminated and constant displacement pumping is performed. This embodiment fully utilizes the shear dilution characteristics of the production-enhancing fluid. The algorithm calculates the optimal flow rate that dilutes the fluid, significantly reducing the flow resistance of the fluid entering the micro-cracks. This strategy enables chemical agents to penetrate deep into the ends of micro-cracks that are difficult to reach by traditional methods, achieving deep penetration of chemical agents and thus significantly expanding the effective production-enhancing radius. Taking the use of guar gum fracturing fluid as an example, the rheological parameters were measured. for rheological index for The preset microfracture entry resistance threshold is set to 20 mPa·s; this threshold is based on the critical apparent viscosity value determined by rheological experiments on the target reservoir core, representing the minimum fluidity index required for fluid to effectively enter the microfracture; based on the current tubing geometry, i.e., an inner diameter of 30 mm, the system calculates that when the baseline flow rate is adjusted to 280 L / min, the shear rate at the tubing wall reaches 1500 s⁻¹. - ¹, at this point the apparent viscosity of the fluid is reduced to 18 mPa·s, which meets the threshold requirement; compared with the apparent viscosity of 45 mPa·s under the traditional fixed displacement of 150 L / min, the optimization strategy of this embodiment reduces the fluid flow resistance by 60%, effectively realizing the filling of deep microcracks.

[0024] Example 6: The response waveform acquisition unit also includes a background noise filtering module; the background noise filtering module is used to acquire the background pressure fluctuation data of the fluid transport equipment when no micro-disturbance excitation is applied, set the background pressure fluctuation data as the environmental noise reference, subtract the environmental noise reference from the real-time acquired pressure fluctuation data as the net response signal, and send the net response signal to the impedance spectrum analysis unit.

[0025] This embodiment supplements the signal preprocessing stage to eliminate interference from the on-site environment on weak detection signals. Before operation or during intervals, the background noise filtering module acquires the background pressure fluctuation data of the fluid transport equipment when no micro-disturbance excitation is applied, i.e., when there is only the baseline displacement or the equipment is stationary. The module performs statistical averaging on this data and sets it as the environmental noise baseline. Environmental noise standards The source is on-site measured statistics; the physical meaning is non-signal pressure fluctuations caused by engine vibration and pump / valve opening / closing, with units of MPa; during operation, net pressure Raw pressure collected in real time Subtracting the background noise baseline yields: in, Data collected in a static state before the water pump is turned on. A continuous background noise pressure sample point, where the subscript is... This represents the index value of the discrete sampling sequence, with a value range of 1. arrive The term to be subtracted in the formula is the arithmetic mean of the background noise. The number of sample points for sampling the background noise is determined by the sampling frequency. With sampling duration Decision, that is The net response signal is sent to the impedance spectroscopy analysis unit for further processing. This embodiment eliminates environmental pressure zero-point drift and static system deviation through differential processing; while for periodic dynamic noise such as pump truck vibration, it relies on frequency domain filtering in the subsequent impedance spectrum analysis unit for separation, thereby significantly improving the signal-to-noise ratio; ensuring that the fluctuations processed by the impedance spectrum analysis unit are indeed system responses caused by micro-perturbation excitation; this preprocessing mechanism effectively shields external interference such as pump truck vibration, ensuring the accuracy of impedance calculation and the reliability of control commands in complex construction environments; In a field test, the measured root mean square value of the background noise caused by the pump truck idling speed and pipeline vibration was 0.15 MPa. As shown in the figure, the original acquired signal was mixed with a large amount of clutter, and the signal-to-noise ratio was only 3 dB. After processing by this module, the environmental noise benchmark was subtracted, and the micro-perturbation characteristics of the obtained net response signal were clearly visible, and the signal-to-noise ratio was improved to 18 dB, ensuring the accuracy of phase extraction in subsequent impedance calculation.

[0026] Example 7: The adaptive feedback adjustment unit also includes a safety fuse verification module. The safety fuse verification module is used to monitor the total pressure value at the wellhead in real time, compare the total pressure value with the preset pipe yield pressure threshold, and if the total pressure value is greater than or equal to the preset pipe yield pressure threshold, an emergency stop command is forcibly generated to block the output of the pulse modulation execution unit; if the total pressure value is less than the preset pipe yield pressure threshold, a resonance optimization command or a smooth injection command is allowed to be output.

[0027] This embodiment introduces the highest priority safety monitoring logic to prevent overpressure accidents during the automated optimization process; the safety fuse verification module is independent of the impedance analysis loop and monitors the total pressure value at the wellhead in real time at an extremely high frequency. The module will With respect to the preset pipe yield pressure threshold Comparative analysis was conducted; yield pressure threshold of pipe materials. The source is the material parameter table of coiled tubing. Its physical meaning is the maximum pressure that the tubing can withstand before plastic deformation. It is usually set to 80% of the yield strength, and the unit is MPa. This proportional coefficient is based on the tubing strength design specifications of the oil and gas industry and has reserved a safety margin for the fatigue effect of the tubing caused by downhole high temperature and long-term alternating load. Execution logic judgment: In response to the total pressure value being greater than or equal to the preset pipe yield pressure threshold, the system triggers hard safety logic, forcibly generates an emergency stop command, and physically cuts off the output of the pulse modulation execution unit or opens the pressure relief valve; In response to the total pressure value being less than the preset pipe yield pressure threshold, the system determines that it is currently within the safety window and allows the output of the resonance optimization command or the smooth injection command. This embodiment constructs an electronic fence for the system, ensuring that no matter how the algorithm optimizes resonance, the system always operates within the physical safety boundary of the pipe. This module, as the last line of defense, effectively prevents the risk of pipe overpressure rupture caused by excessive pursuit of resonance-enhanced production, thus ensuring the inherent safety of engineering operations. To verify the response speed of the safety module, a simulated overpressure test was conducted. The yield pressure threshold of the pipe was set to 60 MPa. During the test, the pump pressure was artificially and rapidly increased. When the pressure sensor reading reached 60.1 MPa, the module generated an emergency stop command within 15 ms, the pressure relief valve opened, and the pressure dropped back to the safe range within 0.5 seconds. No plastic deformation of the pipe occurred, verifying the reliability of the fuse mechanism.

[0028] Example 8: The process of generating composite injected fluid by the pulse modulation execution unit is as follows: Obtaining the baseline displacement command code. And micro-perturbation excitation instruction code, the micro-perturbation excitation instruction code contains frequency and amplitude Constructing fluid control equations The fluid control equations are converted into frequency conversion drive signals, which are then sent to the controller of the high-pressure pump unit to drive the high-pressure pump unit to output fluid medium with periodic pressure pulsation.

[0029] This embodiment details the digital generation algorithm for composite injected fluid, aiming to achieve precise control of the fluid waveform; the pulse modulation execution unit receives the reference displacement instruction code from the upper-level controller. and micro-perturbation excitation instruction code, wherein the micro-perturbation instruction contains the target frequency. and amplitude To generate a continuous and smooth control signal, for the ideal flow response model of the reciprocating piston pump, neglecting mechanical transmission delay and fluid compressibility, its flow control equation is expressed as: ;in, The source is calculated and the physical meaning is the target instantaneous displacement at time t, with the unit being L / min; The source is the system clock, and its physical meaning is the time variable in the process of generating micro-perturbation excitation, with the unit being seconds (s). The source is the baseline displacement command, and its physical meaning is the DC baseline quantity, which determines the overall delivery speed of the drug. The source is a micro-perturbation command, which physically represents the AC amplitude and determines the strength of the detection or excitation signal; the processor will calculate... The signal is converted into a corresponding variable frequency drive signal in real time, such as a 4-20mA analog signal or a CAN bus message, and sent to the variable frequency controller of the high-pressure pump set. The high-pressure pump set adjusts the plunger stroke according to the change signal, thereby outputting a fluid medium with periodic pressure pulsation. This embodiment uses mathematical equations to accurately construct the driving signal, realizing the digital synthesis and stepless adjustment of fluid waveforms. Compared with mechanical pulse generators, this electronic control method can switch between detection mode, attack mode and resonance mode instantly, giving the system extremely high flexibility and enabling it to adapt to the needs of refined operations under different geological conditions. The output accuracy of the pulse modulation execution unit was tested and verified; a reference displacement was set. 200 L / min, micro-perturbation frequency 5Hz, amplitude The flow rate is 20 L / min. As shown in the figure, the output waveform measured by the high-frequency flow meter is superimposed and compared with the waveform generated by the theoretical control equation. The phase deviation between the two is less than 5 degrees and the amplitude deviation is less than 1.5%, which proves that the digital control equation generates high fidelity of composite injected fluid and meets the requirements of precision acoustic detection for the purity of the signal source.

[0030] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention.

Claims

1. An automated control system for coiled tubing production enhancement operations, characterized in that, It includes a pulse modulation execution unit, a response waveform acquisition unit, an impedance spectrum analysis unit, a state mapping discrimination unit, and an adaptive feedback adjustment unit; the pulse modulation execution unit is used to control the reference displacement of the fluid conveying equipment, and to superimpose a micro-perturbation excitation of a preset frequency on the reference displacement according to the modulation command to generate a composite injection fluid; The response waveform acquisition unit is used to acquire pressure fluctuation data at the wellhead in real time and send the pressure fluctuation data to the impedance spectrum analysis unit for frequency domain reflection calculation and analysis to obtain the incident wave component and the reflected wave component. The phase difference and amplitude ratio between the reflected wave component and the incident wave component are processed to obtain the terminal acoustic impedance parameters. The state mapping discrimination unit is used to perform load characteristic quantization matching analysis on the terminal acoustic impedance parameters generated by the impedance spectrum analysis unit. The obtained terminal acoustic impedance parameters are compared and analyzed with the preset impedance threshold to obtain a high impedance blocking signal or a low impedance conduction signal. When a high impedance blocking signal is generated, the adaptive feedback adjustment unit is used to generate a resonance optimization command to control the pulse modulation execution unit to adjust the frequency of micro-disturbance excitation to match the resonance point of the system. When a low impedance conduction signal is generated, the adaptive feedback adjustment unit is used to generate a smooth injection command to control the pulse modulation execution unit to eliminate micro-disturbance excitation and increase the reference flow rate.

2. The automated control system for coiled tubing production enhancement operations according to claim 1, characterized in that, The frequency domain reflection calculation and analysis process is as follows: pressure fluctuation data within a preset sampling period is collected, and the pressure fluctuation data is set as a time-domain waveform sequence. The time-domain waveform sequence is processed by fast Fourier transform to obtain the frequency domain response spectrum. Based on the distributed parameter transmission line model, the forward-transmitting incident wave component and the reverse-transmitting reflected wave component are separated from the frequency domain response spectrum. The complex reflection coefficient of the reflected wave component relative to the incident wave component is calculated, and the complex reflection coefficient is converted into the terminal acoustic impedance parameter.

3. The automated control system for coiled tubing production enhancement operations according to claim 2, characterized in that, The terminal acoustic impedance parameter includes a real part and an imaginary part of impedance. The load characteristic quantitative matching analysis process is as follows: the real part of the terminal acoustic impedance parameter is obtained, which represents the fluid absorption capacity of the terminal load and is set as the permeability characterization index; at the same time, the imaginary part of the terminal acoustic impedance parameter is obtained, which represents the energy storage effect at the end of the transmission channel and is set as the capacitive load index. The permeability characterization index is processed for discrimination. If the permeability characterization index is greater than the preset blockage threshold, a high impedance blocking signal is generated. If the permeability indicator is less than or equal to the preset blockage threshold, a low-impedance conduction signal is generated.

4. The automated control system for coiled tubing production enhancement operations according to claim 1, characterized in that, When a resonance optimization command is generated, the adaptive feedback adjustment unit performs the following frequency scanning operation: it acquires a preset frequency scanning range and step value, controls the pulse modulation execution unit to output micro-perturbation excitations of different frequencies in sequence within the frequency scanning range, monitors the pressure fluctuation amplitude fed back by the response waveform acquisition unit, sets the frequency corresponding to when the pressure fluctuation amplitude reaches its maximum value as the system resonance frequency, and locks the system resonance frequency as the current working frequency to generate water hammer resonance energy to physically break the terminal load.

5. The automated control system for coiled tubing production enhancement operations according to claim 1, characterized in that, When a smooth injection command is generated, the adaptive feedback adjustment unit performs the following rheological characteristic optimization operations: acquiring the non-Newtonian fluid characteristic parameters of the current fluid, calculating the apparent viscosity value of the fluid at different shear rates based on the shear dilution principle, comparing and analyzing the apparent viscosity value with the preset microcrack entry resistance threshold, calculating the optimal reference displacement that minimizes the apparent viscosity value, and sending the optimal reference displacement to the pulse modulation execution unit for constant displacement pumping to achieve deep diffusion of chemical agents.

6. The automated control system for coiled tubing production enhancement operations according to claim 1, characterized in that, The response waveform acquisition unit also includes a background noise filtering module; The background noise filtering module is used to acquire the background pressure fluctuation data of the fluid transport equipment when no micro-disturbance excitation is applied, set the background pressure fluctuation data as the environmental noise reference, subtract the environmental noise reference from the real-time acquired pressure fluctuation data and set the value as the net response signal, and send the net response signal to the impedance spectrum analysis unit.

7. The automated control system for coiled tubing production enhancement operations according to claim 1, characterized in that, The adaptive feedback adjustment unit also includes a safety fuse verification module; the safety fuse verification module is used to monitor the total pressure value at the wellhead in real time, compare the total pressure value with the preset pipe yield pressure threshold, and if the total pressure value is greater than or equal to the preset pipe yield pressure threshold, an emergency stop command is forcibly generated to block the output of the pulse modulation execution unit; if the total pressure value is less than the preset pipe yield pressure threshold, a resonance optimization command or a smooth injection command is allowed to be output.

8. The automated control system for coiled tubing production enhancement operations according to claim 1, characterized in that, The pulse modulation execution unit generates the composite injection fluid as follows: It obtains the baseline displacement command code. And micro-perturbation excitation instruction code, the micro-perturbation excitation instruction code contains frequency and amplitude Constructing fluid control equations The fluid control equations are converted into frequency conversion drive signals, which are then sent to the controller of the high-pressure pump unit to drive the high-pressure pump unit to output fluid medium with periodic pressure pulsation.

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