Downhole optical imaging system and method

Abstract

This invention relates to the field of cased well logging technology, and discloses a downhole optical imaging system and method. The system includes a control system and a fiber optic image transmission and illumination unit. The fiber optic image transmission and illumination unit is used for image transmission. The unit includes a fiber optic image transmission bundle assembly and several illumination fibers. The several illumination fibers are distributed along the edge of the fiber optic image transmission bundle assembly, and the length of the several illumination fibers is equal to the length of the fiber optic image transmission bundle assembly. The light source input ends of the several illumination fibers are connected to the light source output ends of the control system, and the image output ends of the fiber optic image transmission bundle assembly are connected to the image input ends of the control system. This invention, through the fiber optic image transmission bundle assembly, enables the system to achieve high-quality image transmission. The several illumination fibers distributed along the edge of the fiber optic image transmission bundle assembly provide uniform and sufficient illumination to the imaging area, effectively improving imaging quality and reducing energy waste.

Description

Technical Field

[0001] This invention relates to the field of casing well logging technology, specifically to a downhole optical imaging system and method. Background Technology

[0002] Oil and gas exploration and development has entered a new stage, with increased difficulty in discovering oil and gas resources and low-grade newly discovered reserves. Developed oilfields are in a "double-high" stage of high water cut and high recovery rate, resulting in poor economic benefits. Exploration and development face key technological bottlenecks. The increased difficulty in oil and gas exploration and development has led to an extension of exploration areas into deep / ultra-deep and complex regions. New oil and gas reserves are mainly unconventional, represented by tight, low-permeability, heavy oil, and special lithological reservoirs. Breakthroughs in technologies such as ultra-deep / complex, concealed oil and gas reservoir exploration, enhanced oil recovery in old oilfields (displacement, fracturing, etc.), and unconventional oil and gas extraction have become crucial for stabilizing oil and gas production, increasing reserves, improving quality, and enhancing efficiency in my country. Following the success of fracturing technology in the North American shale oil and gas revolution, China has also made some progress in utilizing fracturing technology. Currently, fracturing stimulation of unconventional oil and gas and "ballast engineering" in old oilfields have become two major tools for stabilizing oil and gas production and increasing reserves in my country.

[0003] Fracturing has become a key technology for optimizing reservoir development and a crucial process for stabilizing and improving the quality and efficiency of oil and gas resources. Scientific and effective monitoring and evaluation of fracturing effects are central to adjusting fracturing schemes and improving fracturing technology. How to effectively monitor the opening efficiency of multiple fracturing clusters, fracturing inflow characteristics, and fracture propagation characteristics has become crucial for fracturing monitoring. Before and after fracturing, accurate identification and erosion of perforations are key to evaluating the effective opening of multiple clusters and perforations and the uniform injection of fluid and sand. Currently, downhole imaging systems, including downhole television, can identify perforation dimensions to a certain extent, supporting the analysis and interpretation of fracturing fluid and sand injection. Meanwhile, the "ballast project" in old oilfields requires detailed characterization of remaining oil and gas reservoirs. Due to long-term operation of old wells, casing faces various problems such as deformation, corrosion, and cracking, restricting the long-term stability of oil and gas production. Wellbore integrity monitoring has become an important factor for stable production in old oilfields, urgently requiring a more intuitive logging technology to monitor wellbore integrity. Downhole television can provide a direct view of wellbore images, but due to limitations in cable transmission rates, the maximum speed is only megabits. Wellbore integrity monitoring images often require additional storage on the instrument, resulting in a delay in image acquisition. The instrument needs to be brought to the surface for analysis, which greatly reduces construction efficiency.

[0004] However, as oil and gas exploration and development extend towards deeper / ultra-deep formations, downhole temperatures and pressures are further increasing (temperatures can reach 260℃, and pressures can reach 210 MPa), while wellbore sizes are shrinking. Existing downhole television systems have a maximum temperature resistance of 125℃ and a pressure resistance of 100 MPa, which are insufficient. Even using thermos flask technology cannot significantly improve the instrument's temperature resistance, and it also increases system complexity and significantly reduces reliability. Patent CN201687463U—a downhole optical imaging measurement device—includes connectors and optical imaging and parameter measurement devices, lighting, and circuit processing devices located at both ends of the connectors. However, this patent also suffers from reliability issues due to insufficient temperature and pressure resistance. Meanwhile, fracturing monitoring and the "ballast stone project" in old oilfields require real-time online acquisition of downhole images for calibration and analysis. Therefore, existing cable transmission and storage methods are insufficient to meet the real-time transmission requirements of detailed downhole images.

[0005] Currently, conventional downhole television systems acquire visual images of the wellbore through cameras, which can monitor fracturing perforations and wellbore conditions to some extent. However, they suffer from insufficient temperature and pressure resistance. Furthermore, the image transmission method using cables and storage devices is insufficient to meet the demands for high-resolution, real-time image and video transmission, hindering the widespread application of downhole imaging systems. Therefore, developing a high-resolution, high-temperature-resistant, high-pressure-resistant downhole optical imaging instrument that supports high-speed, high-capacity data transmission is crucial. Summary of the Invention

[0006] In order to overcome the shortcomings of the existing technology, the present invention aims to provide a downhole optical imaging system and method to solve the technical problem of how to improve the accuracy and convenience of image measurement in the prior art.

[0007] This invention is achieved through the following technical solution: In a first aspect, the present invention provides a downhole optical imaging system, including a control system and a fiber optic image transmission illumination unit; the fiber optic image transmission illumination unit is used for image transmission. The fiber optic image transmission illumination unit includes a fiber optic image transmission bundle assembly and several illumination fibers; the several illumination fibers are distributed along the edge of the fiber optic image transmission bundle assembly within the fiber optic image transmission bundle assembly, and the length of the several illumination fibers is equal to the length of the fiber optic image transmission bundle assembly. The light source input ends of several lighting optical fibers are connected to the light source output ends of the control system, and the image output ends of the optical fiber image bundle assembly are connected to the image input ends of the control system.

[0008] Preferably, the fiber optic image bundle assembly includes a fiber optic image bundle and a sampling lens; Several illumination optical fibers are distributed along the edge of the optical fiber image transmission bundle within the bundle, and the sampling lens is positioned at the downhole insertion end of the optical fiber image transmission bundle.

[0009] Furthermore, the fiber optic image bundle includes several optical fibers and tubing. Several optical fibers are arranged sequentially to form an optical fiber bundle; the tubing has a central hole; the optical fiber bundle is fitted inside the central hole of the tubing; wherein, the lengths of the several optical fibers correspond to the lengths of the tubing and the lighting optical fiber, respectively. The sampling lens is installed at the downhole insertion end of the hose, and the input end of the sampling lens is connected to several optical fibers.

[0010] Furthermore, the tubing has several through holes around its edge, and several lighting optical fibers are correspondingly fitted into these through holes.

[0011] Furthermore, the positions of several optical fibers are fixed, and the endpoints of several optical fibers at both ends of the tube are set accordingly.

[0012] Preferably, the control system includes an industrial computer, an image input module, a light source output module, and a display; The input terminal of the industrial control computer is connected to the output terminal of the image input module, and the input terminal of the image output module is connected to the output terminal of the fiber optic image bundle assembly. The drive end of the industrial control computer is connected to the input end of the light source output module, and the output end of the light source output module is connected to the input end of several lighting optical fibers. The output terminal of the industrial control computer is connected to the input terminal of the display.

[0013] Furthermore, the image input module includes a CCD image sensor and a zoom lens; The input end of the zoom lens is connected to the output end of the fiber optic image transmission bundle assembly, the output end of the zoom lens is connected to the input end of the CCD image sensor, and the output end of the CCD image sensor is connected to the industrial control computer.

[0014] Furthermore, the light source output module includes a white laser and a coupler; The input end of the white laser is connected to the drive end of the industrial control computer; the output end of the white laser is connected to the input end of the coupler, and the output end of the coupler is connected to the input end of several illumination optical fibers.

[0015] Furthermore, the industrial control computer is equipped with a controller; the input terminal of the controller is connected to a signal input module, and the input terminal of the signal input module is connected to the output terminal of an image input module; the output terminal of the controller is connected to the input terminal of a signal output module, and the output terminal of the signal output module is connected to a processor, a driver module, and a human-machine interaction module; the output terminal of the driver module is connected to the input terminal of a light source output module, and the output terminal of the human-machine interaction module is connected to a display.

[0016] Secondly, the present invention also provides a downhole optical imaging method, based on the downhole optical imaging system described above, comprising the following steps: The fiber optic image transmission bundle assembly, together with several illumination fibers, is inserted into the well. Turn on the industrial control computer, preheat the light source output module, and set the parameters of the light source output module so that the light source emitted by the light source output module can couple into several lighting optical fibers to illuminate the target area downhole. When the fiber optic image transmission bundle assembly, together with several illumination fibers, enters the target area downhole, the image input module acquires the image of the target area downhole through the fiber optic image transmission bundle assembly; and transmits it to the industrial control computer, which then displays it on the monitor, completing the downhole high-resolution optical imaging work.

[0017] Compared with the prior art, the present invention has the following beneficial technical effects: This invention provides a downhole optical imaging system that achieves high-quality image transmission through a fiber optic image transmission bundle assembly. Several illumination fibers are distributed along the edge of the fiber optic image transmission bundle assembly, providing uniform and sufficient illumination to the imaging area. This not only improves image quality but also makes illumination more efficient, reducing energy waste. Furthermore, the integrated design of the illumination fibers and the image transmission bundle assembly results in a more compact overall system structure, facilitating use in confined spaces such as downholes. The fiber optic image transmission and illumination units are connected to the control system via optical fibers, offering high flexibility. The optical fibers not only possess excellent electromagnetic interference resistance but also maintain stable performance in harsh environments, thereby improving the system's reliability and stability.

[0018] Furthermore, the fiber optic image transmission bundle assembly includes a fiber optic image transmission bundle and a sampling lens; several illumination fibers are distributed along the edge of the fiber optic image transmission bundle, and the sampling lens is positioned at the downhole insertion end of the fiber optic image transmission bundle. As the core component for image transmission, the fiber optic image transmission bundle possesses excellent image fidelity and resolution, enabling efficient transmission of downhole image information and ensuring clear visibility of image details. The sampling lens, positioned at the downhole insertion end of the fiber optic image transmission bundle, plays a crucial role in precise sampling and focusing. It accurately focuses downhole image information onto the fiber optic image transmission bundle, guaranteeing image clarity and quality.

[0019] Furthermore, the fiber optic image transmission bundle includes several optical fibers and a tubing; the optical fibers are arranged sequentially to form the fiber bundle; the tubing has a central hole; the fiber bundle is fitted inside the central hole of the tubing; wherein, the lengths of the optical fibers correspond to those of the tubing and the illumination optical fiber; a sampling lens is positioned at the bottom of the tubing, and the input end of the sampling lens is connected to the optical fibers. The fiber bundle is effectively fixed and protected by being fitted inside the central hole of the tubing. The tubing not only provides a stable support structure for the fiber bundle but also resists external impacts and vibrations to a certain extent, thereby extending the service life of the fiber optic image transmission bundle. The sequential arrangement of the optical fibers to form the fiber bundle ensures a tight fit and uniform distribution between the fibers. This helps reduce distortion and aberration during image transmission, improving image clarity and quality.

[0020] Furthermore, the tubing has several through-holes along its edge, and several illumination optical fibers are correspondingly nested within these through-holes. These through-holes along the edge of the tubing provide a compact and orderly arrangement space for the illumination optical fibers. This allows the fibers to fit tightly against the tubing, reducing space requirements and achieving uniform illumination of the downhole environment. This uniform illumination helps reduce shadow areas in the image, improving image sharpness and contrast, thereby enhancing image quality.

[0021] Furthermore, the arrangement of several optical fibers is fixed, and the endpoints of the fibers at both ends of the tubing are aligned. The fixed arrangement ensures that image distortion is not caused by displacement or deformation of the fibers during transmission. The aligned endpoints of the fibers at both ends of the tubing allow for accurate alignment during connection, reducing the risk of signal loss or image quality degradation due to improper connection. This improves the reliability and stability of the fiber optic connection, ensuring accurate transmission of image information.

[0022] Furthermore, the control system includes an industrial computer, an image input module, a light source output module, and a display. The input terminal of the industrial computer is connected to the output terminal of the image input module, and the input terminal of the image output module is connected to the output terminal of the fiber optic image transmission bundle assembly. The drive terminal of the industrial computer is connected to the input terminal of the light source output module, and the output terminal of the light source output module is connected to the input terminals of several illumination fibers. The output terminal of the industrial computer is connected to the input terminal of the display. The control system highly integrates the image input module, the light source output module, and the display through the industrial computer, realizing automated control of the entire imaging system. This integrated design not only simplifies the operation process but also improves the system's response speed and stability. The industrial computer receives image information transmitted by the fiber optic image transmission bundle assembly through the image input module and performs necessary image processing, such as enhancement, filtering, and correction, to optimize image quality. The processed image is displayed in real time on the display, providing operators with a clear and intuitive imaging effect.

[0023] Furthermore, the image input module includes a CCD image sensor and a zoom lens. The input end of the zoom lens is connected to the output end of the fiber optic image bundle assembly, the output end of the zoom lens is connected to the input end of the CCD image sensor, and the output end of the CCD image sensor is connected to the industrial control computer. As the core component of the image input module, the CCD image sensor features high sensitivity, high resolution, and low noise. It can accurately acquire image information transmitted by the fiber optic image bundle assembly and convert it into high-quality digital signals, providing a reliable data foundation for subsequent image processing. The zoom lens allows users to flexibly adjust the image magnification according to actual needs. This adjustment function not only helps capture finer image details but also adapts to imaging requirements at different distances while maintaining image clarity.

[0024] Furthermore, the light source output module includes a white laser and a coupler. The input of the white laser is connected to the driver of the industrial control computer; the output of the white laser is connected to the input of the coupler, and the output of the coupler is connected to the input of several illumination optical fibers. As the core component of the light source output module, the white laser features high brightness, good monochromaticity, and high stability, providing stable and uniform illumination to ensure the quality of light transmitted through the illumination optical fibers, thereby improving the sharpness and contrast of the imaging system. The coupler's function is to efficiently couple the light output from the white laser into several illumination optical fibers. By optimizing the coupler design, light loss during the coupling process can be reduced, improving light energy utilization and ensuring sufficient illumination intensity for the imaging system.

[0025] Furthermore, the industrial computer houses a controller; the controller's input is connected to a signal input module, which in turn connects to the image input module's output; the controller's output is connected to the signal output module's input, which in turn connects to the processor, driver module, and human-machine interface module; the driver module's output is connected to the light source output module's input, and the human-machine interface module's output is connected to the display. The controller within the industrial computer, as the core of the entire system, is responsible for receiving, processing, and sending various signals, achieving centralized control of the entire imaging system. This design improves system operating efficiency and ensures coordinated operation between all modules.

[0026] This invention also provides a downhole optical imaging method that replaces traditional downhole television cameras with fiber optic image bundles, significantly improving image resolution. Specifically, the resolution of the downhole image can be adjusted according to the number of fiber optic image bundles. Image measurement and calibration can be performed by adjusting the number and diameter of the fiber optic image bundles, improving the accuracy and convenience of image measurement. Replacing the transmission mode using a combination of ordinary cables and memory with fiber optic transmission significantly increases the transmission capacity and rate of images and signals. Replacing downhole television lighting LEDs with optical fibers reduces the complexity of the lighting system. The downhole optical imaging system utilizes the number of fiber bundles to achieve high-resolution imaging and signal transmission within the wellbore. The optical fibers provide illumination, achieving passive operation downhole, greatly simplifying system components and improving reliability. The high temperature and pressure resistance of optical fibers ensures long-term continuous and reliable operation of the imaging system in deep, ultra-deep, and confined spaces. The downhole high-resolution optical imaging system and method of this invention features high resolution, simple structure, passive operation downhole, high temperature and pressure resistance, simple image measurement, and support for high-speed, high-capacity image and video transmission. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the overall structure of the downhole optical imaging system in an embodiment of the present invention; Figure 2 This is a schematic diagram of the structure of the optical fiber image transmission bundle in an embodiment of the present invention; Figure 3 This is a schematic diagram of the interface of the optical fiber image transmission bundle in an embodiment of the present invention; Figure 4 This is a schematic diagram of the industrial control computer's principle structure in an embodiment of the present invention; Figure 5 This is a flowchart of the downhole optical imaging method in an embodiment of the present invention; In the diagram: 1. Control system; 2. Fiber optic image bundle; 3. Illumination fiber; 4. Sampling lens; 11. Industrial computer; 12. CCD image sensor; 13. White laser; 14. Coupler; 15. Zoom lens; 16. Display; 21. Fiber optic cable; 22. Adhesive tube. Detailed Implementation

[0028] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0029] The purpose of this invention is to provide a downhole optical imaging system and method that achieves high-resolution acquisition of wellbore images through an optical fiber image bundle, provides illumination inside the wellbore through the optical fiber to provide lighting conditions for image imaging, and enables high-speed transmission of downhole images and videos to the surface through the optical fiber. Only optical fiber is needed downhole, and a CCD image sensor and white light source are required on the surface to achieve high-resolution real-time acquisition of images and videos inside the wellbore. It features high temperature resistance, simple structure, high resolution, and support for high-speed and large-capacity data transmission, thereby solving the technical problem of how to improve the accuracy and convenience of image measurement in the prior art.

[0030] The present invention will now be described in further detail with reference to the accompanying drawings: Example 1 See Figure 1 In one embodiment of the present invention, a downhole optical imaging system is provided, including a control system 1 and an optical fiber image transmission illumination unit; the optical fiber image transmission illumination unit is used for image transmission; the optical fiber image transmission illumination unit includes an optical fiber image bundle assembly and a plurality of illumination optical fibers 3; the plurality of illumination optical fibers 3 are distributed along the edge of the optical fiber image bundle assembly within the optical fiber image bundle assembly, and the length of the plurality of illumination optical fibers 3 is equal to the length of the optical fiber image bundle assembly; the light source input end of the plurality of illumination optical fibers 3 is connected to the light source output end of the control system 1, and the image output end of the optical fiber image bundle assembly is connected to the image input end of the control system 1.

[0031] Specifically, the fiber optic image bundle assembly includes a fiber optic image bundle 2 and a sampling lens 4; several illumination fibers 3 are distributed along the edge of the fiber optic image bundle 2 within the fiber optic image bundle 2, and the sampling lens 4 is located at the downhole insertion end of the fiber optic image bundle 2.

[0032] Among them, according to Figure 2 As shown, the fiber optic image bundle 2 includes several optical fibers 21 and a tubing 22; the several optical fibers 21 are arranged sequentially to form an optical fiber bundle; the tubing 22 has a central hole; the optical fiber bundle is sleeved in the central hole of the tubing 22; wherein, the several optical fibers 21 are respectively arranged to correspond to the length of the tubing 22 and the illumination optical fiber 3; the sampling lens 4 is arranged at the downhole insertion end of the tubing 22, and the input end of the sampling lens 4 is connected to the several optical fibers 21.

[0033] Among them, according to Figure 3 As shown, the tubing 22 has several through holes around its edge, and several lighting optical fibers 3 are correspondingly fitted into the several through holes.

[0034] The arrangement of several optical fibers 21 is fixed, and the endpoints of several optical fibers 21 at both ends of the tube 22 are correspondingly arranged.

[0035] In this embodiment, the plurality of optical fibers 21 can be silica optical fibers, chalcogenide optical fibers, or multi-component glass optical fibers. The cross-section of the fiber bundle formed by the plurality of optical fibers 21 arranged sequentially with each other can be circular, rectangular, or hexagonal, to achieve different filling coefficients for different fiber image bundles. Simultaneously, they can be bundled in triangular close-packing, rectangular close-packing, or hexagonal close-packing to achieve different array stacking. The end face of the fiber image bundle 2 needs to be encapsulated and polished to ensure high smoothness and low transmission loss. A high-temperature resistant sealing process must be used when sealing the sampling lens 4 and the fiber image bundle 2 to meet the high-temperature imaging conditions in downhole. A wear-resistant and pressure-bearing lens needs to be installed in front of the sampling lens 3 to meet the imaging requirements under pressure and wear conditions in downhole.

[0036] In this embodiment, the sampling lens 4 is located at the downhole insertion end of the fiber optic image bundle 2, responsible for capturing image information from downhole. The design of the sampling lens 4 enables it to effectively collect light and focus it onto the fiber optic bundle at its rear end. The fiber optic bundle is formed by several optical fibers 21 arranged sequentially to transmit the image information captured by the sampling lens 4. Each optical fiber acts as a tiny light guide, transmitting light from one end to the other, thereby maintaining the integrity and clarity of the image. The tubing 22 has a central hole for housing the fiber optic bundle and providing protection and support. The material and design of the tubing 22 should be able to resist the erosion of the harsh downhole environment (such as high temperature, high pressure, corrosion, etc.) to ensure the stability and durability of the fiber optic bundle. Several illumination optical fibers 3 are distributed along the edge of the fiber optic image bundle 2 and are correspondingly housed in several through holes along the edge of the tubing 22. This provides necessary illumination for the sampling lens 4 to ensure that a clear image can be captured even in low-light conditions downhole.

[0037] In this embodiment, the relative positions of the several optical fibers 21 are fixed to ensure that the image information will not be misaligned or distorted during transmission. The endpoints of the several optical fibers 21 at both ends of the tube 22 are correspondingly arranged, which means that after the image information is captured at one end of the optical fiber bundle, it can be accurately transmitted to the other end through the optical fiber image bundle and received by the receiving device.

[0038] Specifically, the control system 1 includes an industrial computer 11, an image input module, a light source output module, and a display 16; the input terminal of the industrial computer 11 is connected to the output terminal of the image input module, and the input terminal of the image output module is connected to the output terminal of the fiber optic image bundle assembly; the drive terminal of the industrial computer 11 is connected to the input terminal of the light source output module, and the output terminal of the light source output module is connected to the input terminals of several lighting optical fibers 3; the output terminal of the industrial computer 11 is connected to the input terminal of the display 16.

[0039] The image input module includes a CCD image sensor 12 and a zoom lens 15; the input end of the zoom lens 15 is connected to the output end of the fiber optic image bundle assembly, the output end of the zoom lens 15 is connected to the input end of the CCD image sensor 12, and the output end of the CCD image sensor 12 is connected to the industrial control computer 11.

[0040] The light source output module includes a white laser 13 and a coupler 14; the input end of the white laser 13 is connected to the drive end of the industrial control computer 11; the output end of the white laser 13 is connected to the input end of the coupler 14, and the output end of the coupler 14 is connected to the input end of several lighting optical fibers 3.

[0041] Among them, according to Figure 4 As shown, the industrial computer 11 is equipped with a controller; the input terminal of the controller is connected to the signal input module, and the input terminal of the signal input module is connected to the output terminal of the image input module; the output terminal of the controller is connected to the input terminal of the signal output module, and the output terminal of the signal output module is connected to the processor, the drive module, and the human-machine interaction module; the output terminal of the drive module is connected to the input terminal of the light source output module, and the output terminal of the human-machine interaction module is connected to the display 16.

[0042] In this embodiment, when the system starts, the industrial control computer 11 first initializes, loading necessary software programs and configuration parameters. The white laser 13 in the light source output module is preheated under the drive of the industrial control computer 11 to ensure stable laser operation. The industrial control computer 11 sends commands to the light source output module via the driver, and the white laser 13 responds and emits light. The light source is efficiently coupled to several illumination optical fibers 3 via coupler 14. These optical fibers transmit light to the target area downhole, providing necessary illumination. Under the illumination of the optical fibers, the image of the target area downhole is captured by the optical fiber image bundle assembly. The sampling lens 4 focuses the light and transmits it to the optical fiber image bundle 2. The optical fiber image bundle 2 transmits the captured image to the surface. After being magnified or reduced by the zoom lens 15, the image is projected onto the photosensitive surface of the CCD image sensor 12. The CCD image sensor 12 converts the received light signal into an electrical signal, i.e., digital image data. The digital image data is transmitted to the input terminal of the industrial control computer 11 through the output terminal of the image input module. The processor within the industrial computer 11 processes the received digital image data, including but not limited to noise reduction, enhancement, and correction, to improve image quality and readability. The processed image data is transmitted from the output of the industrial computer 11 to the input of the display 16, ultimately displaying a high-resolution image of the target area in the well on the display.

[0043] In summary, the downhole optical imaging system provided by this invention enables high-quality image transmission through a fiber optic image transmission bundle assembly. Several illumination fibers are distributed along the edge of the fiber optic image transmission bundle assembly, providing uniform and sufficient illumination to the imaging area. This not only improves image quality but also makes illumination more efficient, reducing energy waste. Furthermore, the integrated design of the illumination fibers and the image transmission bundle assembly results in a more compact overall system structure, facilitating use in confined spaces such as downholes. The fiber optic image transmission and illumination units are connected to the control system via optical fibers, offering high flexibility. Optical fibers not only possess excellent electromagnetic interference resistance but also maintain stable performance in harsh environments, thereby improving the system's reliability and stability.

[0044] Example 2 This embodiment provides a downhole optical imaging method, based on the downhole optical imaging system described above, such as... Figure 5 As shown, it includes the following steps: The optical fiber image bundle 2, together with several illumination optical fibers 3, is inserted into the well. Turn on the industrial control computer 11, preheat the white light laser 13, set the parameters of the white light laser 13 so that the light source emitted by the white light laser 13 can be coupled into several lighting optical fibers 3 through the coupler 14 to illuminate the target area downhole. When the fiber optic image transmission bundle 2, together with several illumination fibers 3, enters the target area downhole, it provides illumination through the several illumination fibers 3, and the sampling lens 4 performs image imaging. The formed image is transmitted through the fiber optic image transmission bundle 2, through the zoom lens 15 and the CCD image sensor 12, to the industrial control computer 11, and then fed back to the display 16, completing the downhole high-resolution optical imaging work.

[0045] In this embodiment, by coordinating the insertion of the optical fiber image transmission bundle 2 with several illumination fibers 3 into the well, efficient illumination and image acquisition of the target area in the well are achieved. This method not only improves the imaging speed but also ensures high resolution and clarity of the images, providing accurate and reliable visual information for well exploration and monitoring.

[0046] The industrial control computer 11, acting as the control center, can flexibly adjust the parameters of the white laser, such as light source intensity and illumination angle, to adapt to different downhole environments and imaging requirements. This flexibility allows the imaging system to better adapt to complex and changing downhole conditions, improving the system's practicality and adaptability.

[0047] The imaging method is based on a highly integrated downhole optical imaging system. The various components work collaboratively to automate the entire process from illumination and imaging to transmission and display. This highly integrated system not only improves work efficiency but also reduces maintenance costs, making the imaging system easier to manage and operate. Imaging results are fed back to the display in real time for operators to observe and analyze. This real-time feedback mechanism allows operators to understand the downhole situation promptly, make accurate judgments and decisions, and improve work efficiency and safety.

[0048] In summary, the downhole optical imaging method provided in this embodiment is based on a system design with good scalability and compatibility, and can be integrated with other downhole equipment or systems to achieve a wider range of functions and applications. For example, it can be combined with downhole positioning systems, environmental monitoring systems, etc., to provide more comprehensive support and protection for downhole operations. Through efficient imaging and illumination methods, the need for downhole workers to enter hazardous areas is reduced, lowering operational risks. Simultaneously, real-time imaging and monitoring functions provide a safer working environment for downhole workers. The use of the zoom lens 15 and CCD image sensor 12 further improves image quality. The zoom lens 15 can adjust the magnification as needed, enabling the imaging system to capture finer image details; while the CCD image sensor 12 features high sensitivity and high resolution, ensuring high fidelity and clarity of the image.

[0049] Example 3 This embodiment provides a downhole optical imaging method based on the aforementioned downhole optical imaging system. 200,000 2000-meter-long silica optical fibers are fabricated into a hexagonal close-packed fiber image bundle 2 using acid dissolution or stacking methods. Twelve illumination optical fibers 3 are evenly distributed around the outer ring of the fiber image bundle 2, covered with an outer tubing 22 and armored to provide a certain tensile strength.

[0050] The bottom of the fiber optic image bundle 2 is polished and packaged with the sampling lens 4 through a high-temperature resistant sealing process. The sampling lens 4 is further reinforced with a pressure-resistant and wear-resistant lens to meet the imaging requirements of high temperature, high pressure and harsh environment downhole.

[0051] The top of the fiber optic image transmission bundle 2 is connected to the zoom lens 15, the zoom lens 15 is connected to the CCD image sensor 12, and the CCD image sensor 12 is connected to the display 16 via the industrial control computer 11.

[0052] The illumination fiber 3 at the top of the fiber optic image bundle 2 is connected to one end of the coupler 14, and the other end of the coupler 14 is connected to the white light laser 13. The white light laser 13 is connected to the industrial control computer 11.

[0053] The specific process is as follows: Turn on the industrial control computer 11, and control the white light emitted by the white laser 13 to be coupled into the illumination fiber 3 through the coupler 14 to illuminate the area to be imaged in the well. The sampling lens 4 acquires the image of the target area, which is transmitted to the ground zoom lens 15 through the fiber optic image bundle 2. After being converted by the CCD image sensor 12, it is displayed on the display 16. By adjusting the power of the white laser 13, the lumen of the imaging target area can be adjusted, thereby adjusting the brightness of the downhole imaging area, so as to realize high-resolution real-time acquisition of downhole images and videos.

[0054] In summary, this invention also provides a downhole optical imaging method that replaces the traditional downhole television camera with an optical fiber image bundle, significantly improving image resolution. Specifically, the resolution of the downhole image can be adjusted according to the number of optical fiber image bundles. Image measurement and calibration can be performed by adjusting the number of optical fiber image bundles and their diameter, improving the accuracy and convenience of image measurement. Replacing the transmission mode using a combination of ordinary cables and memory with optical fiber transmission significantly increases the transmission capacity and rate of images and signals. Replacing the downhole television lighting LEDs with optical fibers reduces the complexity of the lighting system. The downhole optical imaging system utilizes the number of optical fiber bundles to achieve high-resolution imaging and signal transmission within the wellbore. The optical fiber can provide illumination, achieving passive operation downhole, greatly simplifying system components and improving reliability. The high temperature and pressure resistance of optical fibers can meet the long-term continuous and reliable practicality of the imaging system in deep and ultra-deep environments and confined spaces. The downhole optical imaging system and method of this invention feature high resolution, simple structure, passive operation downhole, high temperature and pressure resistance, simple image measurement, and support for high-speed, high-capacity image and video transmission.

[0055] This invention achieves the necessary illumination for downhole imaging using an optical fiber 3, and adjusts the lumen output of the downhole imaging area by regulating the white light laser 15. Images and videos of the target area downhole are acquired via an optical fiber image bundle 2 and transmitted to a surface CCD image sensor 12 for display on a monitor 16. High-speed, high-capacity, real-time transmission of downhole images and videos is achieved through the optical fiber image bundle 2. Different resolution images can be acquired by combining different numbers of optical fiber image bundles 2. High-temperature resistant packaging and pressure-resistant, wear-resistant lenses ensure the downhole imaging system is resistant to high temperatures, high pressures, and abrasion. This invention is passive downhole, requiring only surface power to the white light laser 13, CCD image sensor 12, and monitor 16 to achieve high-resolution downhole imaging. It features a simple structure, high resolution, high temperature resistance, and high pressure resistance. The use of an optical fiber image bundle for real-time, high-speed, high-capacity transmission of downhole images and videos meets the requirements for downhole fracturing perforation imaging and wellbore integrity monitoring.

[0056] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A downhole optical imaging system, characterized in that, It includes a control system (1) and an optical fiber image transmission illumination unit; the optical fiber image transmission illumination unit is used for image transmission; The fiber optic image transmission illumination unit includes a fiber optic image transmission bundle assembly and several illumination fibers (3); the several illumination fibers (3) are distributed along the edge of the fiber optic image transmission bundle assembly within the fiber optic image transmission bundle assembly, and the length of the several illumination fibers (3) is equal to the length of the fiber optic image transmission bundle assembly. The light source input ends of several lighting optical fibers (3) are connected to the light source output ends of the control system (1), and the image output end of the optical fiber image bundle assembly is connected to the image input end of the control system (1).

2. The downhole optical imaging system according to claim 1, characterized in that, The fiber optic image bundle assembly includes a fiber optic image bundle (2) and a sampling lens (4). Several illumination optical fibers (3) are distributed along the edge of the optical fiber image bundle (2) within the optical fiber image bundle (2), and the sampling lens (4) is located at the downhole insertion end of the optical fiber image bundle (2).

3. The downhole optical imaging system according to claim 2, characterized in that, The optical fiber image bundle (2) includes several optical fibers (21) and a rubber tube (22). A plurality of optical fibers (21) are arranged sequentially to form an optical fiber bundle; the tubing (22) has a central hole; the optical fiber bundle is fitted inside the central hole of the tubing (22); wherein, the plurality of optical fibers (21) are respectively arranged to correspond to the length of the tubing (22) and the illumination optical fiber (3); The sampling lens (4) is set at the downhole insertion end of the hose (22), and the input end of the sampling lens (4) is connected to several optical fibers (21).

4. A downhole optical imaging system according to claim 3, characterized in that, The tubing (22) has several through holes around its edge, and several lighting optical fibers (3) are correspondingly fitted into the several through holes.

5. A downhole optical imaging system according to claim 3, characterized in that, The positions of several optical fibers (21) are fixed, and the ends of several optical fibers (21) at both ends of the tube (22) are set accordingly.

6. A downhole optical imaging system according to claim 1, characterized in that, The control system (1) includes an industrial computer (11), an image input module, a light source output module, and a display (16). The input end of the industrial control computer (11) is connected to the output end of the image input module, and the input end of the image output module is connected to the output end of the fiber optic image bundle assembly. The drive end of the industrial control computer (11) is connected to the input end of the light source output module, and the output end of the light source output module is connected to the input end of several lighting optical fibers (3). The output terminal of the industrial control computer (11) is connected to the input terminal of the display (16).

7. A downhole optical imaging system according to claim 6, characterized in that, The image input module includes a CCD image sensor (12) and a zoom lens (15). The input end of the zoom lens (15) is connected to the output end of the fiber optic image bundle assembly, the output end of the zoom lens (15) is connected to the input end of the CCD image sensor (12), and the output end of the CCD image sensor (12) is connected to the industrial control computer (11).

8. A downhole optical imaging system according to claim 6, characterized in that, The light source output module includes a white laser (13) and a coupler (14). The input end of the white laser (13) is connected to the drive end of the industrial control computer (11); the output end of the white laser (13) is connected to the input end of the coupler (14), and the output end of the coupler (14) is connected to the input end of several lighting optical fibers (3).

9. A downhole optical imaging system according to claim 6, characterized in that, The industrial computer (11) is equipped with a controller; the input end of the controller is connected to the signal input module, the input end of the signal input module is connected to the output end of the image input module; the output end of the controller is connected to the input end of the signal output module, the output end of the signal output module is connected to the processor, the drive module and the human-machine interaction module; the output end of the drive module is connected to the input end of the light source output module, and the output end of the human-machine interaction module is connected to the display (16).

10. A downhole optical imaging method, characterized in that, A downhole optical imaging system according to any one of claims 1-9 includes the following steps: The fiber optic image bundle assembly, together with several illumination fibers (3), is inserted into the well. Turn on the industrial control computer (11), preheat the light source output module, set the parameters of the light source output module so that the light source emitted by the light source output module can couple into several lighting optical fibers (3) to illuminate the target area in the well. When the fiber optic image bundle assembly, together with several illumination fibers (3), enters the target area downhole, the image input module acquires the image of the target area downhole through the fiber optic image bundle assembly. The data is transmitted to the industrial control computer (11) and fed back to the display (16) to complete the downhole high-resolution optical imaging work.

Images