Built-in optical fiber sensor intelligent sucker rod and state monitoring system thereof

Abstract

The application discloses an intelligent sucker rod with a built-in optical fiber sensor and a state monitoring system thereof, and relates to the technical field of oil exploitation. The intelligent sucker rod comprises a rod body, an optical fiber sensing unit, a data transmission unit and a power management unit which are arranged in the rod body. The optical fiber sensing unit is integrated with distributed optical fiber and point optical fiber sensors, and is used for collecting temperature, strain, sound wave and pressure parameters. The rod body adopts a composite detachable structure of a rod core, an intermediate layer and an outer cylinder. The intermediate layer is provided with cavities for accommodating the units, and has high strength and maintenance convenience. The application further comprises a ground collecting system, an optical fiber monitoring data processing and analyzing system and a sucker rod life cycle management system, which can receive sensing data, and obtain fluid flow and sucker rod state through a multiphase flow inversion and an intelligent diagnosis module. The application realizes multi-dimensional in-situ sensing, intelligent diagnosis and asset whole life cycle management of the downhole sucker rod, and significantly improves the intelligent level and safe operation ability of the beam-pump oil production system.

Description

Technical Field

[0001] This invention belongs to the field of oil extraction operation technology, specifically relating to an intelligent sucker rod with a built-in fiber optic sensor and its condition monitoring system. Background Technology

[0002] Currently, in oilfield rod pump production systems, the sucker rod is the core component for power transmission, and its working status directly affects oil production efficiency and system safety. Traditional sucker rods are merely mechanical force-bearing components and cannot sense their own or the downhole environment. Patent publication (announcement) number CN101922288B discloses an intelligent monitoring sucker rod and its monitoring system, including a sucker rod, coupling, and an RF storage chip. The RF storage chip stores the original information and well history information of the sucker rod, establishing an independent electronic account for it. The monitoring system includes a monitoring center, a wireless remote communication system, a surface sucker rod motion detection and storage device, and an RF reader / writer. The monitoring center uses the wireless remote communication system to remotely query the sucker rod's motion status and issue alarms for abnormal conditions, allowing users to understand the working status of the sucker rod within the well. The surface sucker rod motion detection and storage device detects and stores the sucker rod's motion status. The RF reader / writer reads and writes sucker rod parameters. This system effectively records and monitors the downhole working status of the sucker rod, achieving the goal of intelligent monitoring and management of the sucker rod. The defects of the above-mentioned patented technical solutions are as follows: 1) The monitoring function is limited, and it can only measure single parameters such as temperature or strain, and cannot achieve the coordinated sensing of multiple physical fields (temperature, strain, sound waves, pressure); 2) The sensor packaging and protection are insufficient. In the harsh environment of downhole high pressure, high temperature, corrosion and complex stress, the sensor is easily damaged and the signal is easily drifted, resulting in poor long-term reliability; 3) The data processing capability of the monitoring system is weak. It can usually only display the raw sensor data and lacks the ability to intelligently interpret and diagnose key production information (such as fluid flow rate, water cut, sand / wax deposition location); 4) It lacks intelligent management of the entire life cycle of the sucker rod body and cannot achieve predictive maintenance. Summary of the Invention

[0003] The purpose of this invention is to overcome the shortcomings of the prior art and provide an intelligent sucker rod with a built-in fiber optic sensor and its condition monitoring system, thereby solving the technical problems mentioned in the background art.

[0004] The objective of this invention is achieved as follows: A smart sucker rod with an integrated fiber optic sensor includes a rod body and a fiber optic sensing unit, a data transmission unit, and a power management unit disposed inside the rod body. The fiber optic sensing unit includes distributed sensing fibers arranged along the axial direction of the rod body and at least one point fiber optic sensor for collecting at least one of the rod body's temperature, strain, acoustic vibration, and pressure parameters. The data transmission unit is electrically connected to the fiber optic sensing unit for uploading the collected data to a ground-based data acquisition system. The power management unit is electrically connected to the fiber optic sensing unit and the data transmission unit for providing power to the smart sucker rod. During manufacturing, the distributed sensing fibers, such as DTS / DSS fibers for temperature and strain sensing or DAS fibers for acoustic sensing, and the point fiber optic sensors, such as FBG sensors, are first arranged according to a designed circuit. These are then electrically and optically connected to a miniaturized data transmission module (including photoelectric conversion and signal modulation circuits and a power module), a high-temperature resistant battery, or an energy harvesting device, and packaged into a single sensing module. This module is then embedded inside the sucker rod body. Its working principle is to transform the traditional sucker rod from a purely mechanical transmission component into an intelligent node integrating sensing, transmission, and power supply. The fiber optic sensing unit acts as the nerve ending, using optical principles to sense changes in physical quantities such as temperature, strain, vibration, and pressure downhole. The data transmission unit acts as the nerve channel, responsible for uploading the sensing data. The power management unit acts as the heart, providing energy to the downhole electronic system. By integrating the fiber optic sensing unit, data transmission unit, and power management unit, the traditional purely mechanical sucker rod is upgraded into an intelligent device capable of self-sensing, self-powering, and self-communicating, achieving in-situ, real-time, and synchronous monitoring of multi-dimensional physical quantities such as downhole temperature, strain, sound waves, and pressure.

[0005] Furthermore, the rod body includes a core, an intermediate layer, and an outer cylinder. The intermediate layer is disposed between the core and the outer cylinder, and the core and the intermediate layer are integrally formed by pultrusion. The outer wall of the end periphery of the intermediate layer has external threads, and the inner wall of the end periphery of the outer cylinder has internal threads. The outer cylinder is detachably sleeved on the outside of the intermediate layer. The intermediate layer has a cavity, and the optical fiber sensing unit, data transmission unit, and power management unit are all fixedly disposed inside the cavity. The distributed sensing optical fiber is a single-mode optical fiber or a multimode optical fiber. The core is made of alloy steel, and the intermediate layer and the outer cylinder are both made of carbon fiber.

[0006] An alloy steel core provides the core's tensile strength; the carbon fiber interlayer is integrally formed with the core through pultrusion, achieving lightweighting while providing the foundation for the internal cavity; the carbon fiber outer cylinder, connected by threads, forms a robust, corrosion-resistant, and reusable outer shell, protecting the internal precision components and facilitating maintenance. During production, the alloy steel rod (core) is fed into a pultrusion mold, while carbon fiber tows are impregnated with resin and wrapped around the core. Heating and curing then integrally pultrudes to form a carbon fiber composite interlayer with an internal cavity. Then, external threads are machined on the outer wall of one end of the interlayer, and the sensor module is installed into and secured within the cavity of the interlayer. Finally, the pre-manufactured carbon fiber protective outer cylinder, with internal threads on its inner wall, is screwed onto the interlayer to complete the overall assembly. This process achieves lightweighting of the rod, reducing suspension point load and energy consumption; the carbon fiber outer cylinder, with its detachable threaded connection, forms a robust outer protective shell that resists well fluid corrosion and mechanical abrasion, while also being easily opened for maintenance, facilitating the installation, inspection, and replacement of the internal sensor unit, significantly improving the product's maintainability and service life.

[0007] Furthermore, the point-type fiber optic sensors are fiber Bragg grating pressure gauges or fiber Bragg grating thermometers, and multiple point-type fiber optic sensors are spaced apart along the axial direction of the rod and connected in series via fiber Bragg grating pressure measurement cables. The distributed sensing fiber and the fiber Bragg grating pressure measurement cables with connected point-type fiber optic sensors are both housed within the cavity of the intermediate layer, forming a sensing system. In use, the distributed sensing fiber acts like a continuous nerve, sensing temperature and strain / vibration changes at any location along the entire length of the rod. The series-connected point-type fiber Bragg grating sensors accurately measure pressure and temperature at preset key points, such as pump hangers and casing couplings. The distributed fiber can monitor the temperature / strain / vibration field of the entire wellbore, while the point-type fiber Bragg gratings can accurately measure pressure and temperature at specific depths. All sensing elements are integrated within the cavity, resulting in a compact structure. Furthermore, the fiber optic sensing method itself is resistant to electromagnetic interference, making it particularly suitable for complex electromagnetic environments downhole.

[0008] A condition monitoring system for intelligent sucker rods with built-in fiber optic sensors is disclosed. The system is connected to the intelligent sucker rod via an electrical signal. The system includes: a ground-based acquisition system for receiving sensor data from the intelligent sucker rod; a fiber optic monitoring data processing and analysis system, communicatively connected to the ground-based acquisition system, for processing, interpreting, and visualizing the received sensor data to derive status information; and a sucker rod lifecycle management system for establishing a unique electronic identification for each intelligent sucker rod. This identification stores information such as the raw material, manufacturer, manufacturing date, ID number, and number of working cycles of the sucker rod, records the number of reciprocating or rotating movements of the sucker rod, and issues an early warning when the number of movements approaches a preset safety threshold. In use, a ground-based acquisition system cabinet is installed at the well site, containing equipment such as a distributed temperature / acoustic demodulator and a fiber optic grating demodulator. Fiber optic monitoring data processing and analysis system software is deployed on a ground-based industrial control computer or server. The software communicates with the ground acquisition hardware via Ethernet to acquire data in real time and runs built-in data processing, interpretation, and diagnostic algorithms. The results are then displayed to the operator through a human-machine interface (HMI).

[0009] Furthermore, the ground acquisition system includes a distributed temperature sensing unit, a distributed acoustic wave sensing unit, and a fiber optic grating pressure measurement unit, used to receive and process temperature, acoustic vibration, and pressure signals, respectively. Its working principle is to split and professionally demodulate different types of optical signals to obtain the highest signal-to-noise ratio and measurement accuracy. The distributed temperature sensing unit (DTS) inverts temperature by analyzing backscattered Raman light. The distributed acoustic wave sensing unit (DAS) senses vibration by analyzing the phase change of backscattered Rayleigh light. The fiber optic grating pressure measurement unit measures pressure and temperature by demodulating the drift of the reflected wavelength of the FBG. In practice, the composite sensing optical signal from downhole first enters an optical splitter and is split into three paths. One path is sent to the DTS demodulator to analyze its Raman scattering spectrum and generate a temperature distribution curve along the entire length of the fiber. Another path is sent to the DAS demodulator to detect the phase interference change of the Rayleigh scattering light and generate an acoustic intensity waterfall plot that varies with time and well depth. The third input is sent to the FBG demodulator, which scans and locks the reflected wavelength of each FBG sensor, and calculates the precise pressure and temperature values ​​at each sensor location.

[0010] Furthermore, the fiber optic monitoring data processing and analysis system includes: a data interpretation module, used to invert and calculate the fluid flow rate by using multiphase flow calculation methods and two-dimensional Fourier transform to obtain the collected temperature field, acoustic field, and pressure field information that varies with time along the depth direction; and a working condition diagnosis module, used to perform Butterworth filtering and spectrum analysis on the acoustic information, extract characteristic frequencies, and compare them with a pre-established database of typical working condition characteristics to determine the working status of the sucker rod. The working principle of the data interpretation module is multiphysics coupling inversion. By substituting the spatiotemporally synchronized temperature, pressure, and acoustic field data into the wellbore multiphase flow thermodynamic model, and using the two-dimensional Fourier transform method to analyze its spatiotemporal variation law, key production parameters that cannot be directly measured, such as production profile and water cut, are inverted. The working principle of the operating condition diagnostic module is feature extraction and pattern recognition. By performing Butterworth filtering on the DAS acoustic signal to remove noise, and then performing spectrum analysis to extract characteristic frequencies, such as specific frequency bands of sand impact and characteristic frequencies of pump and valve opening and closing, it is compared with a pre-established "typical operating condition feature database" to achieve automatic fault identification and location.

[0011] Within the software system, the data interpretation module invokes the computational engine to read temperature and pressure matrix data along well depth and over time. It then runs the built-in multiphase flow model, solving energy and mass conservation equations and combining this with two-dimensional FFT analysis of temperature and pressure wave propagation characteristics. Finally, it outputs the flow rate and water cut for each depth segment. The operating condition diagnostic module reads the DAS acoustic data stream in real time, performs bandpass filtering, and then performs a Fast Fourier Transform (FFT) on the signal at each depth point. The resulting spectrum is then compared with characteristic spectrum templates stored in the database for normal pump operating conditions, sand production, and wax deposition. When the matching degree exceeds a threshold, the corresponding alarm is triggered and the location is determined.

[0012] Furthermore, the fiber optic monitoring data processing and analysis system is also used to visualize the processed temperature, sound wave, and pressure information in the form of waterfall charts and curves, displaying the temperature distribution, sound intensity distribution, and pressure distribution along the wellbore depth. In use, the software system creates multiple views in the graphical user interface. One view dynamically displays the sound wave field in waterfall chart form, using color depth to represent sound intensity, with abnormal events (such as sand production) presented as a bright line. Another view overlays the current wellbore temperature and pressure profiles in curve chart form, with all data updating over time. This lowers the professional threshold for data interpretation, enabling field engineers to quickly, intuitively, and comprehensively grasp the production dynamics and anomalies of the entire wellbore, significantly improving human-machine interaction efficiency and the speed of anomaly detection.

[0013] Furthermore, the upper end of the intelligent sucker rod is detachably connected to a donkey head block, which is connected to a walking beam. The middle position of the walking beam is rotatably connected to the upper end of the support. The end of the walking beam away from the donkey head block is connected to a connecting rod, the lower end of which is connected to a balance block. The balance block is connected to a crank, which is connected to a drive motor. The drive motor is located on the upper end of the base; both the base and the support are fixed to the ground. In use, the upper end of the intelligent sucker rod is connected to the donkey head block using a conventional method (such as threads). The donkey head block is suspended from one end of the walking beam, and the middle of the walking beam is hinged to the support, forming a lever. The other end of the walking beam is connected to the drive motor (usually a geared motor) via a connecting rod and a crank. The motor drives the crank to rotate, which in turn drives the walking beam to swing up and down via the connecting rod, thereby driving the intelligent sucker rod to reciprocate. The intelligent sucker rod of this invention is fully compatible with the most common old-style beam pumping unit and can directly replace the traditional sucker rod without modifying the ground equipment, which greatly reduces the cost of promotion and application.

[0014] Furthermore, the lower end of the intelligent sucker rod is connected to a sucker piston. An oil pipe extending underground is installed outside the sucker piston, with the outer wall of the sucker piston slidably connected to the inner wall of the oil pipe. The sucker piston has a hollow chamber structure, with an inlet at the bottom, a sealing ball inside, and an outlet at the top. An oil drain pipe is connected to the upper end of the oil pipe. In operation, the sucker rod drives the sucker piston at its lower end to reciprocate within the oil pipe. When the piston moves upward, the inlet at its bottom opens, allowing well fluid to enter the piston chamber, while the outlet at the top is closed by the pressure of the liquid column lifted in the previous stroke. When the piston moves downward, the inlet is closed by the sealing ball (valve ball), and the liquid in the piston chamber is squeezed, opening the outlet and entering the upper part of the oil pipe. This cycle continues, lifting the well fluid to the surface. The outlet at the top of the piston is connected to the upper oil pipe. The drain pipe connected to the upper end of the oil pipeline transports the extracted liquid to the ground gathering and transportation system.

[0015] The beneficial effects of this invention are as follows: By integrating a built-in distributed optical fiber with a point-type fiber optic grating sensor, a single sucker rod can simultaneously acquire temperature, strain, acoustic vibration, and fixed-point pressure information distributed throughout the entire depth of the wellbore, achieving unprecedented comprehensive, continuous, and real-time sensing of downhole operating conditions. The pultruded integral molding structure of an alloy steel rod core and a carbon fiber composite layer ensures high strength and lightweight design of the rod body. The sensing unit is built into a sealed cavity within the carbon fiber intermediate layer and is double-protected by a detachable carbon fiber outer cylinder, enabling the fragile sensing system to withstand the harsh downhole environment and protecting the sensor. Simultaneously, the detachable outer cylinder design greatly facilitates installation and maintenance. Through the data interpretation module, based on a multiphase flow model and two-dimensional Fourier transform, fluid flow rate, water cut, sand production location, etc., are inverted. Through the operating condition diagnosis module, based on Butterworth filtering, spectrum analysis, and feature database comparison, the operating status of the sucker rod (pump) is intelligently diagnosed, achieving automated production analysis and fault early warning. By establishing a unique electronic file for each rod and recording its working cycle count in real time, and through cumulative load analysis, proactive warnings can be issued before it reaches the fatigue safety threshold, thus achieving intelligent lifecycle management of the sucker rod. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the overall structure of the present invention; Figure 2 This is the present invention. Figure 1 Enlarged view of A in the middle; Figure 3 This is the present invention. Figure 1 Enlarged view of B in the middle; Figure 4 This is a schematic diagram of the sucker rod structure of the present invention; Figure 5 This is a schematic diagram of the internal planing of the sucker rod of the present invention; Figure 6 This is the invention Figure 5 Enlarged view of C; Figure 7 This is the invention Figure 5 Enlarged view of D; Figure 8 This is a schematic diagram of the horizontal structure of the sucker rod of the present invention; Figure 9 This is the invention Figure 8 Enlarged view of the middle E.

[0017] In the diagram: 1. Sucker rod, 2. Distributed sensing fiber optic, 3. Point fiber optic sensor, 4. Data transmission unit, 5. Power management unit, 6. Rod core, 7. Intermediate layer, 8. Outer cylinder, 9. Cavity, 10. Ground acquisition system, 11. Fiber optic monitoring data processing and analysis system, 12. Sucker rod lifecycle management system, 13. Donkey head block, 14. Walking beam, 15. Support, 16. Connecting rod, 17. Balance weight, 18. Crank, 19. Drive motor, 20. Base, 21. Sucker piston, 22. Oil tubing, 23. Oil inlet, 24. Oil outlet, 25. Sealing ball, 26. Oil drain pipe. Detailed Implementation

[0018] The invention will now be described in further detail with reference to the accompanying drawings. It should be noted that all directional terms such as up, down, front, back, left, and right appearing in this invention are... Figure 1 The diagram is for reference only, and all directional terms are not intended to limit the invention, but are merely for clearer explanation and interpretation. Example 1

[0019] like Figure 1-9As shown, this embodiment discloses a smart sucker rod with a built-in fiber optic sensor, including a rod body and a fiber optic sensing unit, a data transmission unit 4, and a power management unit 5 disposed inside the rod body. The fiber optic sensing unit includes a distributed sensing fiber 2 arranged along the axial direction of the rod body and at least one point fiber optic sensor 3, used to collect at least one of the rod body's temperature, strain, acoustic vibration, and pressure parameters. The data transmission unit 4 is electrically connected to the fiber optic sensing unit and is used to upload the collected data to a ground acquisition system 12. The power management unit 5 is electrically connected to the fiber optic sensing unit and the data transmission unit 4 and is used to provide power to the smart sucker rod 1. During manufacturing, the distributed sensing fiber 2, such as DTS / DSS fiber for temperature and strain sensing or DAS fiber for acoustic sensing, and the point fiber optic sensor 3, such as an FBG sensor, are first arranged according to the design circuit, and electrically and optically connected to a miniaturized data transmission module, including photoelectric conversion and signal modulation circuits and a power module, a high-temperature resistant battery or energy harvesting device, and packaged into an integrated sensing module, which is then built into the inside of the sucker rod 1. Its working principle is to transform the traditional sucker rod 1 from a purely mechanical transmission component into an intelligent node integrating sensing, transmission, and power supply. The fiber optic sensing unit acts as a nerve ending, using optical principles to sense changes in physical quantities such as temperature, strain, vibration, and pressure downhole. The data transmission unit 4 acts as a nerve channel, responsible for uploading the sensing data. The power management unit 5 acts as the heart, providing energy to the downhole electronic system. By integrating the fiber optic sensing unit, data transmission unit 4, and power management unit 5, the traditional purely mechanical sucker rod 1 is upgraded into an intelligent device capable of self-sensing, self-powering, and self-communication, achieving in-situ, real-time, and synchronous monitoring of multi-dimensional physical quantities such as downhole temperature, strain, sound waves, and pressure.

[0020] For better performance, the pole body includes a core 6, an intermediate layer 7, and an outer cylinder 8. The intermediate layer 7 is located between the core 6 and the outer cylinder 8. The core 6 and the intermediate layer 7 are integrally formed by pultrusion. The outer wall of the end periphery of the intermediate layer 7 has external threads, and the inner wall of the end periphery of the outer cylinder 8 has internal threads. The outer cylinder 8 is detachably fitted onto the outside of the intermediate layer 7. The intermediate layer 7 has a cavity 9, and the fiber optic sensing unit, data transmission unit 4, and power management unit 5 are all fixedly installed inside the cavity 9. The distributed sensing fiber 2 is a single-mode fiber or a multimode fiber. The core 6 is made of alloy steel, and the intermediate layer 7 and the outer cylinder 8 are both made of carbon fiber.

[0021] The alloy steel core 6 provides the core's tensile strength; the carbon fiber interlayer 7 is integrally formed with the core 6 through pultrusion, achieving lightweighting while providing the foundation for the internal cavity 9; the carbon fiber outer cylinder 8, connected by threads, forms a robust, corrosion-resistant, and reusable outer shell, protecting the internal precision components and facilitating maintenance. During production, the alloy steel rod (core 6) is fed into the pultrusion mold, while carbon fiber tows are impregnated with resin and wrapped around the core 6. Heating and curing then integrally pultrudes to form the carbon fiber composite interlayer 7 with an internal cavity. Then, external threads are machined on the outer wall of one end of the interlayer 7. Next, the sensing module is installed into the cavity 9 of the interlayer 7 and secured. Finally, the pre-manufactured carbon fiber protective outer cylinder 8, with internal threads on its inner wall, is screwed onto the interlayer 7 to complete the overall assembly. The rod body is lightweight, reducing suspension point load and energy consumption; the carbon fiber outer cylinder 8 is detachably connected by threads, forming a robust outer protective shell that can resist well fluid corrosion and mechanical scratches, and is easy to open during maintenance, facilitating the installation, inspection and replacement of the internal sensing unit, greatly improving the maintainability and service life of the product.

[0022] For better performance, the point-type fiber optic sensors 3 are fiber optic pressure gauges or fiber optic thermometers, and multiple point-type fiber optic sensors 3 are spaced apart along the axial direction of the rod and connected in series via fiber optic pressure measurement cables. The distributed sensing fiber optic cable 2 and the fiber optic pressure measurement cable with series-connected point-type fiber optic sensors 3 are both located within the cavity 9 of the intermediate layer 7, forming a sensing system. In use, the distributed sensing fiber optic cable 2 acts like a continuous nerve, sensing temperature and strain / vibration changes at any location along the entire length of the rod. The series-connected point-type fiber optic sensors accurately measure pressure and temperature at preset key points, such as pump hangers and casing couplings. The distributed fiber optic cable can monitor the temperature / strain / vibration field of the entire wellbore, while the point-type fiber optic cables can accurately measure pressure and temperature at specific depths. All sensing elements are integrated within the cavity 9, resulting in a compact structure. Furthermore, the fiber optic sensing method itself is resistant to electromagnetic interference, making it particularly suitable for complex electromagnetic environments downhole. Example 2

[0023] like Figure 1-9As shown, Embodiment 2 discloses a status monitoring system for intelligent sucker rods with built-in fiber optic sensors, based on Embodiment 1. The status monitoring system is connected to the aforementioned intelligent sucker rod 1 with built-in fiber optic sensors via electrical signals. The status monitoring system includes: a ground acquisition system 12 for receiving sensor data from the intelligent sucker rod 1; a fiber optic monitoring data processing and analysis system, communicatively connected to the ground acquisition system 12, for processing, interpreting, and visualizing the received sensor data to derive status information; and a sucker rod 1 lifecycle management system for establishing a unique electronic identification for each intelligent sucker rod 1. This identification stores information such as the raw material, manufacturer, manufacturing date, ID number, and number of operations for the sucker rod 1, records the number of reciprocating or rotating movements of the sucker rod 1, and issues an early warning when the number of movements approaches a preset safety threshold. In use, a cabinet for the ground acquisition system 12 is installed at the well site, containing equipment such as a distributed temperature / acoustic demodulator and a fiber optic grating demodulator. Fiber optic monitoring data processing and analysis system software is deployed on a ground-based industrial control computer or server. The software communicates with the ground acquisition hardware via Ethernet to acquire data in real time and runs built-in data processing, interpretation, and diagnostic algorithms. The results are then displayed to the operator through a human-machine interface (HMI).

[0024] For better performance, the ground acquisition system 12 includes a distributed temperature sensing unit, a distributed acoustic wave sensing unit, and a fiber optic grating pressure measurement unit, used to receive and process temperature, acoustic vibration, and pressure signals, respectively. Its working principle is to split and professionally demodulate different types of optical signals to obtain the highest signal-to-noise ratio and measurement accuracy. The distributed temperature sensing unit (DTS) inverts temperature by analyzing backscattered Raman light. The distributed acoustic wave sensing unit (DAS) senses vibration by analyzing the phase change of backscattered Rayleigh light. The fiber optic grating pressure measurement unit measures pressure and temperature by demodulating the drift of the reflected wavelength of the FBG. In practice, the composite sensing optical signal from downhole first enters an optical splitter and is split into three paths. One path is sent to the DTS demodulator to analyze its Raman scattering spectrum and generate a temperature distribution curve along the entire length of the fiber. Another path is sent to the DAS demodulator to detect the phase interference change of the Rayleigh scattering light and generate an acoustic intensity waterfall plot that varies with time and well depth. The third input is sent to the FBG demodulator, which scans and locks the reflected wavelength of each FBG sensor, and calculates the precise pressure and temperature values ​​at each sensor location.

[0025] For better results, the fiber optic monitoring data processing and analysis system includes: a data interpretation module, used to invert and calculate the fluid flow rate by using multiphase flow calculation methods and two-dimensional Fourier transform to obtain the collected temperature field, acoustic field, and pressure field information that varies with time along the depth direction; and a working condition diagnosis module, used to perform Butterworth filtering and spectrum analysis on the acoustic information, extract characteristic frequencies, and compare them with a pre-established database of typical working condition characteristics to determine the working status of sucker rod 1. The working principle of the data interpretation module is multiphysics coupling inversion. By substituting the spatiotemporally synchronized temperature, pressure, and acoustic field data into the wellbore multiphase flow thermodynamic model, the spatiotemporal variation law is analyzed using the two-dimensional Fourier transform method, thereby inverting key production parameters that cannot be directly measured, such as production profile and water cut. The working principle of the operating condition diagnostic module is feature extraction and pattern recognition. By performing Butterworth filtering on the DAS acoustic signal to remove noise, and then performing spectrum analysis to extract characteristic frequencies, such as specific frequency bands of sand impact and characteristic frequencies of pump and valve opening and closing, it is compared with a pre-established "typical operating condition feature database" to achieve automatic fault identification and location.

[0026] Within the software system, the data interpretation module invokes the computational engine to read temperature and pressure matrix data along well depth and over time. It then runs the built-in multiphase flow model, solving energy and mass conservation equations and combining this with two-dimensional FFT analysis of temperature and pressure wave propagation characteristics. Finally, it outputs the flow rate and water cut for each depth segment. The operating condition diagnostic module reads the DAS acoustic data stream in real time, performs bandpass filtering, and then performs a Fast Fourier Transform (FFT) on the signal at each depth point. The resulting spectrum is then compared with characteristic spectrum templates stored in the database for normal pump operating conditions, sand production, and wax deposition. When the matching degree exceeds a threshold, the corresponding alarm is triggered and the location is determined.

[0027] For better results, the fiber optic monitoring data processing and analysis system also visualizes the processed temperature, sound wave, and pressure information in the form of waterfall charts and curves, displaying the temperature, sound intensity, and pressure distributions along the wellbore depth. In use, the software system creates multiple views in the graphical user interface. One view dynamically displays the sound field in waterfall chart form, using color depth to represent sound intensity, with abnormal events (such as sand production) presented as a bright line. Another view overlays the current wellbore temperature and pressure profiles in curve chart form, with all data updating over time. This lowers the professional barrier to data interpretation, enabling field engineers to quickly, intuitively, and comprehensively grasp the production dynamics and anomalies of the entire wellbore, significantly improving human-machine interaction efficiency and the speed of anomaly detection.

[0028] For better performance, the upper end of the intelligent sucker rod 1 is detachably connected to a donkey head block 13. The donkey head block 13 is connected to a walking beam 14, which is rotatably connected to the upper end of a bracket 15 at its middle position. A connecting rod 16 is connected to the end of the walking beam 14 away from the donkey head block 13. A balance block 17 is connected to the lower end of the connecting rod 16. A crank 18 is connected to the balance block 17, and a drive motor 19 is connected to the crank 18. The drive motor 19 is located on the upper end of a base 20. Both the base 20 and the bracket 15 are fixed to the ground. In use, the upper end of the intelligent sucker rod 1 is connected to the donkey head block 13 using a conventional method (such as threads). The donkey head block 13 is suspended from one end of the walking beam 14, and the middle of the walking beam 14 is hinged to the bracket 15, forming a lever. The other end of the walking beam 14 is connected to the drive motor 19 (usually a geared motor) via the connecting rod 16 and the crank 18. The motor drives the crank 18 to rotate, which in turn drives the walking beam 14 to swing up and down via the connecting rod 16, thereby driving the intelligent sucker rod 1 to reciprocate. The intelligent sucker rod 1 of this invention is fully compatible with the most common walking beam 14 type pumping unit and can directly replace the traditional sucker rod 1 without modifying the ground equipment, greatly reducing the barriers and costs for promotion and application.

[0029] For better performance, the lower end of the intelligent sucker rod 1 is connected to a sucker piston 21. An oil pipe 22 extending underground is provided outside the sucker piston 21, and the outer wall of the sucker piston 21 is slidably connected to the inner wall of the oil pipe 22. The interior of the sucker piston 21 is a hollow structure, with an oil inlet 23 at the bottom, a sealing ball 25 inside, and an oil outlet 24 at the top. The upper end of the oil pipe 22 is connected to a drain pipe 2622. In use, the sucker rod 1 drives the sucker piston 21 at its lower end to reciprocate within the oil pipe 22. When the piston moves upward, the inlet 23 at its bottom opens, allowing well fluid to enter the piston chamber, while the outlet 24 at the top is closed by the pressure of the fluid column lifted in the previous stroke. When the piston moves downward, the inlet 23 is closed by the sealing ball 25 (valve ball), and the fluid in the piston chamber is squeezed, opening the outlet 24 and entering the upper part of the tubing 22. This cycle continues, lifting the well fluid to the surface. The outlet 24 at the top of the piston is connected to the upper tubing 22. The drain pipe 2622 connected to the upper end of the tubing 22 transports the produced fluid to the surface gathering and transportation system.

[0030] The above are merely preferred embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A smart sucker rod with a built-in fiber optic sensor, characterized in that, It includes a pole body and an optical fiber sensing unit, a data transmission unit, and a power management unit disposed inside the pole body; The fiber optic sensing unit includes a distributed sensing fiber optic cable arranged along the axial direction of the pole and at least one point fiber optic sensor, used to collect at least one of the pole's temperature, strain, acoustic vibration and pressure parameters. The data transmission unit is electrically connected to the optical fiber sensing unit and is used to upload the collected data to the ground acquisition system. The power management unit is electrically connected to the fiber optic sensing unit and the data transmission unit, and is used to provide power to the intelligent sucker rod.

2. The intelligent sucker rod with built-in fiber optic sensor according to claim 1, characterized in that, The rod body includes a rod core, an intermediate layer, and an outer cylinder. The intermediate layer is located between the rod core and the outer cylinder. The rod core and the intermediate layer are integrally formed by pultrusion. The outer wall of the end periphery of the intermediate layer is provided with external threads, and the inner wall of the end periphery of the outer cylinder is provided with internal threads. The outer cylinder is detachably sleeved on the outside of the intermediate layer.

3. The intelligent sucker rod with built-in fiber optic sensor according to claim 2, characterized in that, The intermediate layer has a cavity, and the optical fiber sensing unit, data transmission unit, and power management unit are all fixedly installed inside the cavity; the distributed sensing optical fiber is a single-mode optical fiber or a multi-mode optical fiber; the core is made of alloy steel, and the intermediate layer and outer cylinder are both made of carbon fiber.

4. The intelligent sucker rod with built-in fiber optic sensor according to claim 3, characterized in that, The point-type fiber optic sensor is a fiber optic pressure gauge or a fiber optic thermometer, and multiple point-type fiber optic sensors are spaced apart along the axial direction of the rod and connected in series by a fiber optic pressure measuring cable; the distributed sensing fiber and the fiber optic pressure measuring cable with the point-type fiber optic sensor connected in series are both set in the cavity of the middle layer to form a sensing system.

5. A condition monitoring system for intelligent sucker rods with built-in fiber optic sensors, characterized in that, The condition monitoring system is connected to the intelligent sucker rod with a built-in fiber optic sensor as described in any one of claims 1-4 via an electrical signal; the condition monitoring system includes: A ground-based data acquisition system is used to receive sensor data from the intelligent sucker rod; The fiber optic monitoring data processing and analysis system is communicatively connected to the ground acquisition system and is used to process, interpret, and visualize the received sensor data to derive status information. The sucker rod lifecycle management system is used to establish a unique electronic identity for each of the aforementioned smart sucker rods. The identity stores information such as the raw materials, manufacturer, production date, ID number, and number of times the sucker rod has been used. It records the number of reciprocating or rotating movements of the sucker rod and issues an early warning when the number of movements approaches a preset safety threshold.

6. The condition monitoring system for intelligent sucker rods with built-in fiber optic sensors according to claim 5, characterized in that, The ground acquisition system includes a distributed temperature sensing unit, a distributed acoustic wave sensing unit, and a fiber optic pressure measurement unit, which are used to receive and process temperature, acoustic vibration, and pressure signals, respectively.

7. The condition monitoring system for intelligent sucker rods with built-in fiber optic sensors according to claim 6, characterized in that, The fiber optic monitoring data processing and analysis system includes: The data interpretation module is used to invert the collected temperature field, sound field, and pressure field information that varies with time in the depth direction using multiphase flow calculation methods and two-dimensional Fourier transform to obtain the fluid flow rate. The operating condition diagnostic module is used to perform Butterworth filtering and spectrum analysis on the acoustic information, extract characteristic frequencies, and compare them with a pre-established database of typical operating condition characteristics to determine the working status of the sucker rod.

8. The condition monitoring system for intelligent sucker rods with built-in fiber optic sensors according to claim 5, characterized in that, The fiber optic monitoring data processing and analysis system is also used to visualize the processed temperature, sound wave, and pressure information in the form of waterfall plots and curves, showing the temperature distribution, sound intensity distribution, and pressure distribution along the well depth direction.

9. The condition monitoring system for intelligent sucker rods with built-in fiber optic sensors according to claim 5, characterized in that, The upper end of the intelligent sucker rod is detachably connected to a donkey head block, which is connected to a walking beam. The middle position of the walking beam is rotatably connected to the upper end of the bracket. The end of the walking beam away from the donkey head block is connected to a connecting rod. The lower end of the connecting rod is connected to a balance block, which is connected to a crank. The crank is connected to a drive motor, which is located on the upper end of the base. Both the base and the bracket are fixedly installed on the ground.

10. The condition monitoring system for intelligent sucker rods with built-in fiber optic sensors according to claim 9, characterized in that, The lower end of the intelligent sucker rod is connected to a sucker piston. An oil pipe extending underground is provided on the outside of the sucker piston. The outer wall of the sucker piston is slidably connected to the inner wall of the oil pipe. The inside of the sucker piston is a hollow structure. An oil inlet is opened at the bottom of the sucker piston. A sealing ball is installed inside the sucker piston. An oil outlet is opened at the top of the sucker piston. The upper end of the oil pipe is connected to a drain pipe.

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