A multi-sensor unit integrated monitoring device based on optical fiber and a monitoring method thereof

Abstract

The application discloses a kind of based on optical fiber multiple sensor unit integrated monitoring device and its monitoring method, which belongs to oil and gas resource development and greenhouse gas storage field.The monitoring device includes: data processing module, sensor integrated module and signal transmission module, wherein sensor integrated module includes temperature detection unit, pressure detection unit, strain detection unit.Based on optical fiber sensor, multiple sensor structures are optimized and combined simultaneously, efficient fusion monitoring of temperature, pressure and strain in wellbore can be realized through the integration of sensing units, which is used to explore the complex temperature, pressure and strain conditions in wellbore, improves the complex situation of traditional different types of sensors arranged separately, simplifies the complex sensor system, and provides convenient and reliable monitoring equipment and method for gas storage in actual engineering.

Description

Technical Field

[0001] This invention relates to the fields of oil and gas resource development and greenhouse gas sequestration, and particularly to an integrated monitoring device based on optical fiber and a method for optimizing the arrangement of multiple sensing units for monitoring. Background Technology

[0002] A shaft refers to a vertical or inclined excavation project from the surface to the ore body in underground mining or construction. In practice, the environment within a shaft is complex, making real-time monitoring and safety early warning of the entire production process difficult. Current traditional shaft monitoring devices have various limitations; some sensors have complex structures, and their placement within the shaft is cumbersome when facing the tracking requirements of multiple parameters in actual engineering projects. Fiber optic sensing technology, since its inception, has been widely applied in coal mines, oil fields, aviation, civil engineering, and other fields. It can be used in situations where the use of traditional sensors is limited, such as difficult placement, strong electromagnetic interference, or highly corrosive environments. Therefore, this paper proposes a fiber optic-based integrated monitoring device and method for multiple sensing units to address the aforementioned problems.

[0003] In the optimization of fiber optic sensor layout, how to save costs while efficiently integrating the functions of various sensors for high-precision measurement, and how to make the detected wellbore status information most comprehensive through reasonable sensor layout are also the main issues we need to consider. Summary of the Invention

[0004] To overcome the various shortcomings of the existing technologies, this invention proposes a novel fiber-optic integrated device for multiple sensing units and its optimized arrangement monitoring method, focusing on sensor structure optimization and sensor layout in wells. This greatly simplifies the arrangement of sensors in the well, provides a more reliable real-time monitoring solution for wellbore monitoring in practical engineering, and more accurately grasps the complex environment in the wellbore. At the same time, it has a versatility far exceeding that of conventional single logging technologies.

[0005] The technical solution of the present invention: a multi-sensor integrated monitoring device based on optical fiber, characterized in that: the device includes a data processing module, a sensor integration module and a signal transmission module, wherein the sensor integration module includes a temperature detection unit, a pressure detection unit, a strain detection unit and a coating unit;

[0006] The signal transmission module includes an optical fiber cable, which is responsible for transmitting optical signals to the data processing module; the data processing module includes an optical fiber demodulator and a computer module, which are used for optical signal modulation, data analysis and processing, and output; the computer module is connected to the optical fiber demodulator, and the optical fiber demodulator is connected to an optical fiber.

[0007] The sensor integration module consists of a temperature sensing unit, a pressure sensing unit, a strain sensing unit, and an enclosure unit. The temperature sensing unit is located in the upper cavity, where an optical fiber cable containing a temperature grating is fixed. It obtains temperature information by detecting changes in the refractive index of the temperature grating caused by external temperature changes and then measuring changes in the light frequency. The pressure sensing unit is located in the middle cavity and includes an optical fiber cable, a temperature compensation grating, and a Fabry-Perot cavity formed inside the optical fiber. It communicates with external pressure information by changing the cavity length and performs temperature compensation simultaneously. The strain sensing unit is located in the lower cavity and includes an optical fiber cable containing a strain grating. It monitors strain by detecting corresponding changes in the grating caused by external strain conditions.

[0008] The encapsulation unit includes a sensor housing and a sheath. The sensor integrated modules are all distributed inside the sensor housing, which fixes and protects the internal sensing units and is encapsulated by a polyethylene sheath.

[0009] A monitoring method for an integrated monitoring device with multiple sensing units based on optical fiber includes the following steps:

[0010] S1. The sensor integration module and signal transmission module, i.e. the detection section, are arranged on the surface of the sleeve, while the power supply facilities and data processing module are placed in an open area around the well.

[0011] S2. Connect the detection section, power supply facilities and data processing module in step 1 in sequence;

[0012] S3. Monitor using the temperature grating, temperature compensation fiber, Fabry-Perot cavity and strain grating in the sensor integration module respectively, and obtain the corresponding relevant data information;

[0013] S4. The signal transmitted in the optical fiber cable enters the optical fiber demodulator for demodulation;

[0014] S5. The computer module analyzes and processes the data, then outputs information such as temperature, pressure, and strain.

[0015] Through the above technical solution, the present invention has the following beneficial effects:

[0016] This invention integrates temperature, pressure, and strain sensors with optical fibers, greatly simplifying the complex layout inside wellbores in actual engineering projects and reducing monitoring costs. It enables simultaneous overall evaluation and high-precision monitoring of temperature, strain, and pressure inside the wellbore, rather than describing them individually. It accurately and comprehensively explores the complex conditions inside the wellbore, providing a reliable evaluation method for actual underground CO2 sequestration. Attached Figure Description

[0017] The accompanying drawings described herein are for illustrative purposes only and are not intended to limit the scope of the invention in any way. Furthermore, the shapes and proportions of the components in the drawings are merely illustrative to aid in understanding the invention and do not specifically limit the shapes and proportions of the components. Those skilled in the art, guided by the teachings of this invention, can select various possible shapes and proportions to implement the invention according to specific circumstances.

[0018] Figure 1 This is a schematic diagram of a multi-sensor unit integration device based on optical fiber.

[0019] Figure 2 This is a schematic diagram of the internal structure of the sensor integrated component.

[0020] In the figure: 1. Fiber optic demodulator, 2. Computer module, 3. Fiber optic cable, 4. Temperature grating, 5. Temperature compensation grating, 6. Fabry-Perot cavity, 7. Strain grating, 8. Sensor housing, 9. Sheath, 10. Fiber core, 11. Cladding, 12. Protective layer, 13. Sensor mounting hole. Detailed Implementation

[0021] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings.

[0022] Figure 1 and Figure 2 An integrated monitoring device based on optical fiber and multiple sensing units is shown, including: a data processing module, a sensor integration module, a signal transmission module, and a housing. The sensor integration module includes a temperature detection unit, a pressure detection unit, a strain detection unit, and a covering unit.

[0023] The signal transmission module, consisting of optical fiber cable 3, is responsible for transmitting the detected optical signal to the data processing module. The data processing module consists of an optical fiber demodulator 1 and a computer module 2. After the optical fiber demodulator 1 modulates the collected signal, it carries key information such as amplitude, frequency, and phase. The computer module 2 analyzes and processes this information, displaying the excitation intensity corresponding to different points on the optical fiber in real time on the computer. The computer module 2 is connected to the optical fiber demodulator 1, and the optical fiber demodulator 1 is connected to the optical fiber cable 3. The optical fiber cable 3, consisting of a fiber core 10, a cladding 11, and a protective layer 12, plays a connecting role in the entire system.

[0024] The sensor integration module consists of a temperature sensing unit, a pressure sensing unit, a strain sensing unit, and an enclosure unit. The temperature sensing unit is located in the upper cavity, where an optical fiber cable 3 containing a temperature grating 4 is fixed to the upper wall of the cavity. It obtains temperature information by detecting the change in refractive index of the temperature grating caused by external temperature changes and then measuring the change in light frequency. The pressure sensing unit is located in the middle cavity and includes an optical fiber cable 3, a temperature compensation grating 5, and a Fabry-Perot cavity 6 formed inside the optical fiber by laser etching. When the pressure changes, the cavity length of the Fabry-Perot cavity 6 changes. The pressure-related information is obtained by the relationship between the cavity length and the external measured quantity. At the same time, the grating 5 in this part plays a role in temperature compensation. The strain sensing unit is located in the lower cavity and includes an optical fiber cable 3 containing a strain grating 7. It monitors strain by detecting the corresponding changes in the grating caused by external strain conditions.

[0025] The enclosure unit includes a sensor housing 8 and a sheath 9. Sensor housing 8 has sensor mounting holes 13 on both sides. Temperature sensing units, pressure sensing units, and strain sensing units are all arranged inside the cavity of the sensor housing 8. The temperature sensing unit is placed in the upper cavity, the pressure sensing unit in the middle cavity, and the strain sensing unit in the lower cavity. The sensor housing 8 provides fixation and protection for the internal sensing units and is encapsulated by the polyethylene sheath 9. The optical fiber cable 3 consists of a fiber core 10, a cladding 11, and a protective layer 12, and is used for strain data monitoring and signal transmission.

[0026] Temperature monitoring is performed using a temperature grating 4 in the temperature sensing unit. When the temperature changes, the refractive index of the grating changes, causing a corresponding change in the frequency of the light wave. By measuring the change in the light wave frequency, the measured temperature information can be obtained. Pressure monitoring is performed using the optical fiber cable 3 itself. A laser is used to form an optical Fabry-Perot cavity 6 between the optical fibers in the cavity. When the pressure changes, the cavity length of the Fabry-Perot cavity 6 changes. The measured pressure information is obtained by observing the relationship between the cavity length and the external measured quantity. Strain monitoring is performed using a strain grating 7 in the strain sensing unit. When force is applied to the fiber optic grating region, the refractive index of the fiber changes accordingly, causing a change in the spectrum. By detecting the change in the spectrum, the measured strain information can be obtained. The signals transmitted in the optical fiber cable 3 are finally aggregated and sent to the optical fiber demodulator 1. After analysis and processing, the computer module 2 outputs the temperature, pressure, and strain data.

[0027] When working with the above technical solution,

[0028] (1) The sensor integration module and signal transmission module, i.e. the detection section, are fixed on the surface of the sleeve by commonly used clamps in the well. The power supply equipment and data processing module are placed stably in an open area around the well.

[0029] (2) Connect the detection section equipment in step 1 in series via optical fiber, and connect the detection section equipment, power supply equipment and data processing module in sequence, and perform continuity test;

[0030] (3) The temperature grating, temperature compensation fiber, Fabry-Perot cavity and strain grating in the sensor integration module are used for monitoring respectively, and the corresponding relevant data information is obtained;

[0031] (4) The signal transmitted in the optical fiber cable 3 enters the optical fiber demodulator 1 for demodulation;

[0032] (5) The computer module 2 receives and processes the collected data, and outputs information such as temperature, pressure and strain after analysis and processing.

Claims

1. A multi-sensor integrated monitoring device based on optical fiber, characterized in that: The device includes a data processing module, a sensor integration module, and a signal transmission module. The sensor integration module includes a temperature detection unit, a pressure detection unit, a strain detection unit, and a coating unit. The signal transmission module uses optical fiber cable (3) to transmit optical signals to the data processing module; the data processing module includes an optical fiber demodulator (1) and a computer module (2) for the modulation of optical signals and the analysis, processing and output of data; the computer module (2) is connected to the optical fiber demodulator (1), and the optical fiber demodulator (1) is connected to the optical fiber cable (3) to perform unified demodulation analysis and processing. The sensor integration module consists of a temperature sensing unit, a pressure sensing unit, a strain sensing unit, and a covering unit. The temperature sensing unit is located in the upper cavity, and an optical fiber cable (3) containing a temperature grating (4) is fixed in the upper cavity. It obtains temperature information by detecting the change in refractive index of the temperature grating caused by the change in external temperature, and then by measuring the change in light frequency. The pressure sensing unit is located in the middle cavity, and includes an optical fiber cable (3), a temperature compensation grating (5), and a Fabry-Perot cavity (6) formed inside the optical fiber. It obtains temperature information by changing the cavity length in response to external pressure information. The strain sensing unit is located in the lower cavity, and includes an optical fiber cable (3) containing a strain grating (7). It monitors strain by detecting the corresponding changes in the grating caused by external strain. The encapsulation unit includes a sensor housing (8) and a sheath (9). The sensor integrated modules are all distributed inside the sensor housing (8), which fixes and protects each sensing unit inside, and is encapsulated by the sheath (9).

2. The monitoring method of the integrated monitoring device for multiple sensing units based on optical fiber according to claim 1, characterized in that, Includes the following steps: S1. The sensor integration module and signal transmission module, i.e. the detection section, are arranged on the surface of the sleeve, while the power supply facilities and data processing module are placed in an open area around the well. S2. Connect the detection section, power supply facilities and data processing module in step 1 in sequence; S3. The temperature grating (4), temperature compensation grating (5), Fabry cavity (6) and strain grating (7) in the sensor integration module are used for monitoring and the corresponding relevant data information is obtained. S4. The signal transmitted in the optical fiber cable (3) enters the optical fiber demodulator (1) for demodulation; S5. The computer module (2) outputs temperature, pressure and strain information after analysis and processing.

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