Downhole monitoring sensor device and method of encapsulating the same, monitoring system having the same

Abstract

This invention provides a downhole monitoring sensor device and its packaging method, as well as a monitoring system having the same. The sensor device includes an optical fiber body and a housing. The housing includes an inner cylinder and an outer cylinder fitted over the inner cylinder. End caps are respectively provided at both ends of the outer cylinder. The optical fiber body passes through the end caps and the inner cylinder, penetrating the housing. A grating segment of the optical fiber body is located within the inner cylinder. A flow guide hole is provided on the outer cylinder to allow fluid to enter the housing and contact the grating segment. Based on the technical solution of this invention, direct impact on the optical fiber body and the introduction of irrelevant parameters can be avoided in the downhole environment. This enables the installation and protection of the fiber optic strain sensor downhole, improves sensor reliability and accuracy, and prevents oil well malfunction due to sensor damage.

Description

Technical Field

[0001] This invention relates to the field of sensor technology, and in particular to a downhole monitoring sensor device and its packaging method, and a monitoring system having the same. Background Technology

[0002] Petroleum, as a vital strategic resource, plays an indispensable role in socio-economic and industrial development. Temperature and pressure are essential monitoring factors for the environment surrounding the well tubing during oil and gas extraction. Real-time acquisition of downhole temperature and pressure conditions helps optimize oil production techniques, improve oil recovery rates and production, and is crucial for determining oil reservoir locations and ensuring safe operation. However, in the extreme and harsh environments of oil and gas wells, such as high temperature, high pressure, corrosion, strong electromagnetic interference, and confined spaces, the reliability and long-term stability of traditional electrical sensors are extremely limited. Fiber optic sensors, due to their small size, light weight, and strong resistance to extreme downhole environments such as high temperature and high pressure, have become the preferred choice for downhole testing sensors. Distributed fiber optic sensors, which can be implanted in the earth as a kind of "nerve" for sensing the earth, are widely used in oil and gas well monitoring both domestically and internationally.

[0003] Conventional fiber Bragg gratings (FBGs) offer a wide measurement range for pressure and temperature, reaching up to 70 MPa and 150°C, sufficient to cover the downhole measurement range. However, FBGs suffer from extremely low pressure sensitivity and cross-sensitivity to temperature and pressure, making it difficult to distinguish between temperature and pressure within the limited space of a downhole enclosure using encapsulation structures. Dual-hole fiber is a novel type of special fiber. The two holes within its cladding cause stress concentration when the fiber senses pressure, thus improving sensitivity. Furthermore, the symmetrical rather than uniformly distributed holes on both sides prevent degeneracy of the two polarization modes within the fiber, resulting in separation. These characteristics offer the possibility of simultaneously measuring pressure and temperature downhole.

[0004] However, the downhole environment is complex, and the dual-hole fiber optic cable itself is relatively fragile, easily damaged by impacts from various materials and other environmental factors. Furthermore, the dual-hole fiber optic grating is also susceptible to measurement errors due to factors such as strain transmission to the fiber and the influence of its own gravity. Therefore, it is necessary to design the structure and packaging of the fiber optic sensor to protect the fiber and avoid the introduction of unintended parameters, thereby improving the reliability and accuracy of the downhole dual-hole fiber optic grating pressure and temperature sensor. Summary of the Invention

[0005] To address the problem that optical fibers in fiber optic sensors are easily damaged by external factors and cause measurement errors, this invention proposes a downhole monitoring sensor device and its packaging method, as well as a monitoring system with the same.

[0006] In a first aspect, the present invention proposes a downhole monitoring sensor device, comprising an optical fiber body and a housing. The housing includes an inner cylinder and an outer cylinder sleeved outside the inner cylinder. End caps are respectively provided at both ends of the outer cylinder. The optical fiber body passes through the end caps and the inner cylinder and penetrates the housing. A grating segment of the optical fiber body with a grating is located in the inner cylinder. A flow guide hole is provided on the outer cylinder to allow fluid to enter the housing and contact the grating segment.

[0007] In one embodiment, the guide hole is positioned on the outer cylinder directly opposite the inner cylinder.

[0008] In one embodiment, the optical fiber body is fixedly connected to the inner cylinder, the inner cylinder is axially movable within the outer cylinder, and an elastic element is provided between one end of the inner cylinder and the end cap at one end of the outer cylinder.

[0009] In one embodiment, there is one and only one fixed connection point between the optical fiber body and the inner cylinder.

[0010] In one embodiment, the end of the inner cylinder opposite to the end where the elastic element is located has a notch, the inner cylinder and the cylinder corresponding to the notch form a groove, the optical fiber body passes through the groove and is fixedly connected to the inner cylinder by the adhesive in the groove to form the fixed connection point.

[0011] In one embodiment, a lug is provided on the outer circumferential surface of the inner cylinder, and a guide groove extending axially along the outer cylinder is provided on the outer cylinder body, with the lug fitting in the guide groove.

[0012] In one embodiment, the guide groove is located at one end of the outer cylinder, and the guide groove extends from the end face of the outer cylinder onto the cylinder body.

[0013] In one embodiment, the end cap has a through hole for the optical fiber body to pass through, and the end cap is threadedly connected to the outer cylinder.

[0014] In one embodiment, a sleeve is provided on the outer end face of the end cap at the through hole, and the optical fiber body passes through the sleeve into the through hole.

[0015] In one embodiment, the outer cylinder is further provided with a threaded mounting hole for connecting a downhole pipeline, and the threaded mounting hole and the guide hole are respectively located on opposite sides of the outer cylinder.

[0016] Secondly, the present invention proposes a monitoring system that includes the aforementioned downhole monitoring sensor device, thereby possessing all the technical effects it has.

[0017] Thirdly, the present invention provides a packaging method for the above-mentioned downhole monitoring sensor device, the method comprising:

[0018] Insert the optical fiber body into the inner cylinder, so that the grating segment of the optical fiber body with the grating is located in the inner cylinder, and fix the optical fiber body to the inner cylinder.

[0019] The inner cylinder is inserted into the outer cylinder, and an elastic element is inserted into the outer cylinder at a position corresponding to the end of the inner cylinder.

[0020] End caps are installed at both ends of the outer cylinder, so that the end cap at one end abuts the elastic element against the end of the inner cylinder.

[0021] In one embodiment, inserting the inner cylinder into the outer cylinder and inserting an elastic element into the outer cylinder at a position corresponding to the end of the inner cylinder includes:

[0022] Insert the inner cylinder into the outer cylinder from the end where the guide groove on the outer cylinder is located, so that the lug on the inner cylinder slides into the guide groove;

[0023] An elastic element is inserted into the outer cylinder at the position corresponding to the guide groove.

[0024] The above-mentioned technical features can be combined in various suitable ways or replaced by equivalent technical features, as long as the purpose of the present invention can be achieved.

[0025] The downhole monitoring sensor device and its packaging method provided by this invention, as well as the monitoring system having the same, have at least the following advantages compared with the prior art:

[0026] The present invention provides a downhole monitoring sensor device and its packaging method, and a monitoring system thereof, which can avoid direct impact on the optical fiber body and the introduction of irrelevant parameters in the downhole environment, realize the installation and protection of fiber optic strain sensors downhole, improve the reliability and accuracy of the sensors, and avoid the oil well from being unable to work normally due to sensor damage. Attached Figure Description

[0027] The invention will now be described in more detail with reference to embodiments and the accompanying drawings.

[0028] Figure 1 A three-dimensional schematic diagram of the structure of the sensor device of the present invention is shown;

[0029] Figure 2 This shows an orthographic projection schematic diagram of the structure of the sensor device of the present invention;

[0030] Figure 3 Showing Figure 2 A schematic diagram of the structure along the AA direction.

[0031] In the accompanying drawings, the same parts use the same reference numerals. The drawings are not to scale.

[0032] Figure label:

[0033] 1. Fiber optic body; 2. First end cap; 3. Elastic element; 4. Inner cylinder; 5. Threaded mounting hole; 6. Outer cylinder; 7. Second end cap; 8. Perforation; 9. Groove; 10. Guide hole; 11. Lug; 12. Guide groove; 13. Sleeve. Detailed Implementation

[0034] The invention will now be further described with reference to the accompanying drawings.

[0035] Example 1

[0036] An embodiment of the present invention provides a downhole monitoring sensor device, including an optical fiber body 1 and a housing. The housing includes an inner cylinder 4 and an outer cylinder 6 that is sleeved outside the inner cylinder 4. End caps are respectively provided at both ends of the outer cylinder 6. The optical fiber body 1 passes through the inner cylinder 4 through the end caps and the housing. The grating segment with a grating of the optical fiber body 1 is located in the inner cylinder 4. A flow guide hole 10 is provided on the outer cylinder 6 to allow fluid to enter the housing and contact the grating segment.

[0037] Specifically, the sensor monitoring device of the present invention is based on fiber optic sensing, and more specifically, on dual-hole fiber optics, that is, the fiber optic body 1 of the present invention adopts dual-hole fiber optics. The principle of the dual-hole fiber optic grating sensor for monitoring downhole pressure and temperature is as follows: when pressure acts on the fiber optic, it causes the reflected wave to deviate, and the amount of deviation is positively correlated with the pressure; when temperature acts on the fiber optic, it causes the reflected wave to drift overall, and the amount of drift is positively correlated with the temperature.

[0038] As shown in the attached figure. Figure 1 As shown, the sensor device of the present invention mainly comprises two parts: an optical fiber body 1 and a housing. The outer cylinder 6 within the housing, along with the first end cap 2 and the second end cap 7 at both ends of the outer cylinder 6, together form a cavity. The inner cylinder 4 is disposed within the cavity inside the outer cylinder 6. The optical fiber body 1 enters the housing through the first end cap 2 at one end, passes through the inner cylinder 4, and exits through the second end cap 7 at the other end. The grating segment of the optical fiber body 1, etched with a grating, is located within the inner cylinder 4. The inner cylinder 4 and the outer cylinder 6 are not completely sealed; there is a gap between them to allow fluid (gas or liquid) to flow downhole. Thus, the fluid can enter the outer cylinder 6 through the guide holes 10 (which can be multiple) and further into the inner cylinder 4, thereby contacting the grating segment of the optical fiber body 1.

[0039] By allowing the fluid to contact the optical fiber body 1, temperature and pressure can be applied to the grating segment, thereby detecting the magnitude of temperature and pressure. Furthermore, since the fluid can only enter the outer cylinder 6 through the guide hole 10 and then enter the inner cylinder 4 before contacting the optical fiber body 1, the pressure transmission must also follow this path. This effectively avoids the direct impact of fluid with a certain pressure on the optical fiber body 1, thus effectively protecting the optical fiber.

[0040] Furthermore, the guide hole 10 is positioned on the outer cylinder 6 directly opposite the inner cylinder 4.

[0041] Specifically, as shown in the attached diagram. Figure 3 As shown, the guide hole 10 is directed to the inner cylinder 4, so that the fluid entering the outer cylinder 6 through the guide hole 10 will not come into contact with the optical fiber body 1 at the first time. Thus, the inner cylinder 4 can protect the optical fiber and prevent the optical fiber body 1 from being damaged by direct impact.

[0042] Furthermore, the optical fiber body 1 is fixedly connected to the inner cylinder 4, the inner cylinder 4 can move axially within the outer cylinder 6, and an elastic element 3 is provided between one end of the inner cylinder 4 and the end cap of one end of the outer cylinder 6.

[0043] Specifically, as shown in the attached diagram. Figures 1 to 3 As shown, in order to avoid the stretching or other deformation of the optical fiber body 1 caused by external factors, the inner cylinder 4 that is fixedly connected to the optical fiber body 1 is set to be able to slide inside the outer cylinder 6. Thus, the optical fiber body 1 can also move relative to the cylinder. In this way, the position of the optical fiber body 1 relative to the outer cylinder 6 can be naturally adjusted according to the specific situation during use (the outer cylinder 6 is fixedly connected to the corresponding components downhole), avoiding the problem of deformation caused by tightness that may result from complete fixation.

[0044] Furthermore, during use, the elastic element 3 supports the overall structure formed by the inner cylinder 4 and the optical fiber body 1 (in actual use downhole, the elastic element 3 is located below the inner cylinder 4). The weight of the inner cylinder 4 is offset by the spring force, so it will not act on the optical fiber body 1, keeping the optical fiber body 1 in a relaxed state and avoiding the introduction of tensile deformation that causes changes in the grating wavelength.

[0045] Furthermore, there is one and only one fixed connection point between the optical fiber body 1 and the inner cylinder 4. This prevents external strain from being transmitted to the part with the grating and causing measurement errors. At the same time, even if external strain is generated, the single-point connection structure does not restrict the transmission of strain, and the corresponding strain can diffuse to other parts, thereby dissipating it.

[0046] Furthermore, the inner cylinder 4 has a notch on the end of the cylinder body at the other end where the elastic member 3 is located. The inner cylinder 4 and the cylinder body corresponding to the notch form a groove 9. The optical fiber body 1 passes through the groove 9 and is fixedly connected to the inner cylinder 4 through the adhesive in the groove 9 to form a fixed connection point.

[0047] Specifically, since the optical fiber body 1 is structurally fragile, using other rigid connection structures would easily cause stress at the connection point and damage the optical fiber body 1. Therefore, this embodiment considers using adhesive fixation, specifically using liquid adhesive to wrap the optical fiber body 1 and then allowing it to cure naturally. This ensures that no localized stress is generated and the optical fiber body 1 is not damaged.

[0048] As shown in the attached figure. Figure 3 As shown, when using liquid adhesive for curing and bonding, a structure capable of accommodating the liquid adhesive must be constructed. Therefore, in this embodiment, a notch is formed in the original cylindrical structure of the inner cylinder 4, and the remaining cylindrical portion corresponding to the notch forms the groove 9 (see attached figure). Figure 3 The semi-cylindrical structure shown in the tank 9 can contain liquid adhesive, which is then applied to connect the inner cylinder 4 to the optical fiber body 1.

[0049] Furthermore, the end cap has a through hole 8 for the optical fiber body 1 to pass through, and the end cap is threadedly connected to the outer cylinder 6.

[0050] Specifically, as shown in the attached diagram. Figure 3 As shown, both the first end cap 2 and the second end cap 7 can be screw-type structures, which are threaded to the end of the outer cylinder 6, with their heads fastened to the end face of the outer cylinder 6. The optical fiber body 1 is routed through the perforations 8 on the end caps.

[0051] Furthermore, a sleeve 13 is provided on the outer end face of the end cap at the through hole 8, and the optical fiber body 1 passes through the sleeve 13 into the through hole 8.

[0052] Specifically, as shown in the attached diagram. Figure 1 and Figure 3 As shown, the sleeve is fixed to the end cap, which is used to further protect the portion of the optical fiber body located outside the housing.

[0053] Furthermore, the outer cylinder 6 is also provided with threaded mounting holes 5 for connecting downhole pipelines. The threaded mounting holes 5 and the guide holes 10 are located on opposite sides of the outer cylinder 6.

[0054] Specifically, as shown in the attached diagram. Figures 1 to 3 As shown, the threaded mounting holes 5 (four in this embodiment) on the outer cylinder 6 facilitate the installation and fixation of the sensor to the pipeline during use. The sensor is pre-installed on the pipeline before it is lowered into the well, and then lowered into the well along with the pipeline after connection and fixation. Furthermore, the threaded mounting holes 5 and the guide holes 10 are located on opposite sides of the outer cylinder 6, ensuring that the sensor device, after being connected to the pipeline through the threaded mounting holes 5, does not obstruct the flow of fluid at the guide holes 10.

[0055] Example 2

[0056] An embodiment of the present invention provides a downhole monitoring sensor device, including an optical fiber body 1 and a housing. The housing includes an inner cylinder 4 and an outer cylinder 6 that is sleeved outside the inner cylinder 4. End caps are respectively provided at both ends of the outer cylinder 6. The optical fiber body 1 passes through the inner cylinder 4 through the end caps and the housing. The grating segment with a grating of the optical fiber body 1 is located in the inner cylinder 4. A flow guide hole 10 is provided on the outer cylinder 6 to allow fluid to enter the housing and contact the grating segment.

[0057] Specifically, the sensor monitoring device of the present invention is based on fiber optic sensing, and more specifically, on dual-hole fiber optics, that is, the fiber optic body 1 of the present invention adopts dual-hole fiber optics. The principle of the dual-hole fiber optic grating sensor for monitoring downhole pressure and temperature is as follows: when pressure acts on the fiber optic, it causes the reflected wave to deviate, and the amount of deviation is positively correlated with the pressure; when temperature acts on the fiber optic, it causes the reflected wave to drift overall, and the amount of drift is positively correlated with the temperature.

[0058] As shown in the attached figure. Figure 1 As shown, the sensor device of the present invention mainly comprises two parts: an optical fiber body 1 and a housing. The outer cylinder 6 within the housing, along with the first end cap 2 and the second end cap 7 at both ends of the outer cylinder 6, together form a cavity. The inner cylinder 4 is disposed within the cavity inside the outer cylinder 6. The optical fiber body 1 enters the housing through the first end cap 2 at one end, passes through the inner cylinder 4, and exits through the second end cap 7 at the other end. The grating segment of the optical fiber body 1, etched with a grating, is located within the inner cylinder 4. The inner cylinder 4 and the outer cylinder 6 are not completely sealed; there is a gap between them to allow fluid (gas or liquid) to flow downhole. Thus, the fluid can enter the outer cylinder 6 through the guide holes 10 (which can be multiple) and further into the inner cylinder 4, thereby contacting the grating segment of the optical fiber body 1.

[0059] By allowing the fluid to contact the optical fiber body 1, temperature and pressure can be applied to the grating segment, thereby detecting the magnitude of temperature and pressure. Furthermore, since the fluid can only enter the outer cylinder 6 through the guide hole 10 and then enter the inner cylinder 4 before contacting the optical fiber body 1, the pressure transmission must also follow this path. This effectively avoids the direct impact of fluid with a certain pressure on the optical fiber body 1, thus effectively protecting the optical fiber.

[0060] Furthermore, the guide hole 10 is positioned on the outer cylinder 6 directly opposite the inner cylinder 4.

[0061] Specifically, as shown in the attached diagram. Figure 3 As shown, the guide hole 10 is directed to the inner cylinder 4, so that the fluid entering the outer cylinder 6 through the guide hole 10 will not come into contact with the optical fiber body 1 at the first time. Thus, the inner cylinder 4 can protect the optical fiber and prevent the optical fiber body 1 from being damaged by direct impact.

[0062] Furthermore, the optical fiber body 1 is fixedly connected to the inner cylinder 4, the inner cylinder 4 can move axially within the outer cylinder 6, and an elastic element 3 is provided between one end of the inner cylinder 4 and the end cap of one end of the outer cylinder 6.

[0063] Specifically, as shown in the attached diagram. Figures 1 to 3 As shown, in order to avoid the stretching or other deformation of the optical fiber body 1 caused by external factors, the inner cylinder 4 that is fixedly connected to the optical fiber body 1 is set to be able to slide inside the outer cylinder 6. Thus, the optical fiber body 1 can also move relative to the cylinder. In this way, the position of the optical fiber body 1 relative to the outer cylinder 6 can be naturally adjusted according to the specific situation during use (the outer cylinder 6 is fixedly connected to the corresponding components downhole), avoiding the problem of deformation caused by tightness that may result from complete fixation.

[0064] Furthermore, during use, the elastic element 3 supports the overall structure formed by the inner cylinder 4 and the optical fiber body 1 (in actual use downhole, the elastic element 3 is located below the inner cylinder 4). The weight of the inner cylinder 4 is offset by the spring force, so it will not act on the optical fiber body 1, keeping the optical fiber body 1 in a relaxed state and avoiding the introduction of tensile deformation that causes changes in the grating wavelength.

[0065] Furthermore, there is one and only one fixed connection point between the optical fiber body 1 and the inner cylinder 4. This prevents external strain from being transmitted to the part with the grating and causing measurement errors. At the same time, even if external strain is generated, the single-point connection structure does not restrict the transmission of strain, and the corresponding strain can diffuse to other parts, thereby dissipating it.

[0066] Furthermore, the inner cylinder 4 has a notch on the end of the cylinder body at the other end where the elastic member 3 is located. The inner cylinder 4 and the cylinder body corresponding to the notch form a groove 9. The optical fiber body 1 passes through the groove 9 and is fixedly connected to the inner cylinder 4 through the adhesive in the groove 9 to form a fixed connection point.

[0067] Specifically, since the optical fiber body 1 is structurally fragile, using other rigid connection structures would easily cause stress at the connection point and damage the optical fiber body 1. Therefore, this embodiment considers using adhesive fixation, specifically using liquid adhesive to wrap the optical fiber body 1 and then allowing it to cure naturally. This ensures that no localized stress is generated and the optical fiber body 1 is not damaged.

[0068] As shown in the attached figure. Figure 3 As shown, when using liquid adhesive for curing and bonding, a structure capable of accommodating the liquid adhesive must be constructed. Therefore, in this embodiment, a notch is formed in the original cylindrical structure of the inner cylinder 4, and the remaining cylindrical portion corresponding to the notch forms the groove 9 (see attached figure). Figure 3 The semi-cylindrical structure shown in the tank 9 can contain liquid adhesive, which is then applied to connect the inner cylinder 4 to the optical fiber body 1.

[0069] Furthermore, the end cap has a through hole 8 for the optical fiber body 1 to pass through, and the end cap is threadedly connected to the outer cylinder 6.

[0070] Specifically, as shown in the attached diagram. Figure 3 As shown, both the first end cap 2 and the second end cap 7 can be screw-type structures, which are threaded to the end of the outer cylinder 6, with their heads fastened to the end face of the outer cylinder 6. The optical fiber body 1 is routed through the perforations 8 on the end caps.

[0071] Furthermore, a sleeve 13 is provided on the outer end face of the end cap at the through hole 8, and the optical fiber body 1 passes through the sleeve 13 into the through hole 8.

[0072] Specifically, as shown in the attached diagram. Figure 1 and Figure 3 As shown, the sleeve is fixed to the end cap, which is used to further protect the portion of the optical fiber body located outside the housing.

[0073] Furthermore, the outer cylinder 6 is also provided with threaded mounting holes 5 for connecting downhole pipelines. The threaded mounting holes 5 and the guide holes 10 are located on opposite sides of the outer cylinder 6.

[0074] Specifically, as shown in the attached diagram. Figures 1 to 3 As shown, the threaded mounting holes 5 (four in this embodiment) on the outer cylinder 6 facilitate the installation and fixation of the sensor to the pipeline during use. The sensor is pre-installed on the pipeline before it is lowered into the well, and then lowered into the well along with the pipeline after connection and fixation. Furthermore, the threaded mounting holes 5 and the guide holes 10 are located on opposite sides of the outer cylinder 6, ensuring that the sensor device, after being connected to the pipeline through the threaded mounting holes 5, does not obstruct the flow of fluid at the guide holes 10.

[0075] Furthermore, a lug 11 is provided on the outer circumferential surface of the inner cylinder 4, and a guide groove 12 extending along the axial direction of the outer cylinder 6 is provided on the cylinder body of the outer cylinder 6, with the lug 11 fitting in the guide groove 12.

[0076] Specifically, as shown in the attached diagram. Figure 1 As shown, since the optical fiber body 1 is relatively fragile, it is necessary to prevent it from being impacted or subjected to strain in the length direction, and also to prevent it from twisting. Therefore, it is necessary to prevent the inner cylinder 4, which is fixedly connected to the optical fiber body 1, from rotating relative to the outer cylinder 6 in the circumferential direction. Therefore, the use of lug 11 and guide groove 12 for cooperation does not affect the axial movable structure and can also prevent circumferential twisting. Furthermore, after installation, under the elastic force of elastic element 3, lug 11 is pressed against the end of guide groove 12, which can prevent unnecessary axial shaking of the whole formed by inner cylinder 4 and optical fiber body 1.

[0077] Preferably, the guide groove 12 is located at one end of the outer cylinder 6, and the guide groove 12 extends from the end face of the outer cylinder 6 onto the cylinder body of the outer cylinder 6. In this way, when the inner cylinder 4 enters the outer cylinder 6, its lug 11 can directly enter the guide groove 12 through the slot formed on the end face of the outer cylinder 6 by the guide groove 12.

[0078] Example 3

[0079] The embodiments of the present invention provide a monitoring system, which includes the downhole monitoring sensor device described above, and thus possesses all the technical effects described above.

[0080] Example 4

[0081] An embodiment of the present invention provides a packaging method for the above-described downhole monitoring sensor device, the method comprising:

[0082] Step S100: Prepare the inner and outer cylinders that will serve as the outer shell of the device;

[0083] Step S200: Insert the optical fiber body into the inner cylinder, so that the grating section of the optical fiber body is located in the inner cylinder, and fix the optical fiber body and the inner cylinder with resin glue at the groove of the inner cylinder.

[0084] Step S300: After the colloid has completely cured, insert the inner cylinder into the outer cylinder and insert the elastic element into the outer cylinder at the position corresponding to the end of the inner cylinder.

[0085] Step S310: Insert the inner cylinder into the outer cylinder from the end where the guide groove on the outer cylinder is located, so that the lug on the inner cylinder slides into the guide groove;

[0086] Step S320: Insert the elastic element into the outer cylinder at the position corresponding to the guide groove;

[0087] Step S400: Install end caps on both ends of the outer cylinder, so that the end cap at one end abuts the elastic element against the end of the inner cylinder;

[0088] Step S500: Insert the fiber body, which is exposed outside the end cap, into the sleeve, and use resin glue to fix the sleeve at the perforation of the end cap.

[0089] In the description of this invention, it should be understood that the terms "upper", "lower", "bottom", "top", "front", "rear", "inner", "outer", "left", "right", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0090] While the invention has been described herein with reference to specific embodiments, it should be understood that these embodiments are merely examples of the principles and applications of the invention. Therefore, it should be understood that many modifications can be made to the exemplary embodiments, and other arrangements can be designed without departing from the spirit and scope of the invention as defined by the appended claims. It should be understood that different dependent claims and features described herein can be combined in ways different from those described in the original claims. It is also understood that features described in conjunction with individual embodiments can be used in other described embodiments.

Claims

1. A downhole monitoring sensor device, characterized in that, The device includes an optical fiber body and a housing. The housing includes an inner cylinder and an outer cylinder that is fitted over the inner cylinder. End caps are provided at both ends of the outer cylinder. The optical fiber body passes through the end caps and the inner cylinder and penetrates the housing. The grating segment of the optical fiber body is located in the inner cylinder. The outer cylinder has a flow guide hole on its body to allow fluid to enter the housing and contact the grating segment. The guide hole is positioned on the outer cylinder directly opposite the inner cylinder. The optical fiber body is fixedly connected to the inner cylinder, the inner cylinder can move axially inside the outer cylinder, and an elastic element is provided between one end of the inner cylinder and the end cap at one end of the outer cylinder. There is one and only one fixed connection point between the optical fiber body and the inner cylinder; The inner cylinder has a notch on the end of the cylinder opposite to the end where the elastic element is located. The inner cylinder and the cylinder corresponding to the notch form a groove. The optical fiber body passes through the groove and is fixedly connected to the inner cylinder by the adhesive in the groove to form the fixed connection point. The inner cylinder has a lug on its outer circumferential surface, and the outer cylinder has a guide groove extending along the axial direction of the outer cylinder, with the lug fitting into the guide groove.

2. The downhole monitoring sensor device according to claim 1, characterized in that, The guide groove is located at one end of the outer cylinder, and the guide groove extends from the end face of the outer cylinder onto the cylinder body.

3. The downhole monitoring sensor device according to claim 1, characterized in that, The end cap has a through hole for the optical fiber body to pass through, and the end cap is threadedly connected to the outer cylinder.

4. The downhole monitoring sensor device according to claim 3, characterized in that, A sleeve is provided on the outer end face of the end cap at the through hole, and the optical fiber body passes through the sleeve into the through hole.

5. The downhole monitoring sensor device according to claim 1, characterized in that, The outer cylinder is also provided with threaded mounting holes for connecting downhole pipelines. The threaded mounting holes and the guide holes are located on opposite sides of the outer cylinder.

6. A monitoring system, characterized in that, It includes the downhole monitoring sensor device as described in any one of claims 1 to 5.

7. A packaging method for the downhole monitoring sensor device according to any one of claims 1 to 5, characterized in that, include: Insert the optical fiber body into the inner cylinder, so that the grating segment of the optical fiber body with the grating is located in the inner cylinder, and fix the optical fiber body to the inner cylinder. The inner cylinder is inserted into the outer cylinder, and an elastic element is inserted into the outer cylinder at a position corresponding to the end of the inner cylinder. End caps are installed at both ends of the outer cylinder, so that the end cap at one end abuts the elastic element against the end of the inner cylinder.

8. The packaging method according to claim 7, characterized in that, Inserting the inner cylinder into the outer cylinder, and inserting an elastic element into the outer cylinder at a position corresponding to the end of the inner cylinder, including: Insert the inner cylinder into the outer cylinder from the end where the guide groove on the outer cylinder is located, so that the lug on the inner cylinder slides into the guide groove; An elastic element is inserted into the outer cylinder at the position corresponding to the guide groove.

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