Downhole fiber optic fixation device and method of installation

Abstract

The application provides a downhole optical fiber fixing device and a mounting method thereof. The optical fiber is fixed in the downhole through an outer pipe during well drilling. The outer pipe of the device is in contact with the well wall through a fixing part and a supporting part, so that the optical fiber is effectively protected from being damaged in the later carbon dioxide injection process. The device can fix the optical fiber at the central part outside the downhole casing, so as to prevent the optical fiber from being too close to the downhole casing or the outer well wall and forming measurement error, and affecting the measurement accuracy of the instrument. The included angle between the supporting part and the fixing part is adjustable, so that the downhole operation of different diameters can be met. Meanwhile, the fixing part and the outer pipe are detachably connected, so that the installation and the later disassembly are facilitated.

Description

Technical Field

[0001] This application relates to the field of oil and gas field development technology, specifically to a downhole fiber optic fixing device and its installation method. Background Technology

[0002] Pressure and temperature are fundamental reservoir engineering parameters in oil and gas resource development. Real-time, high-precision measurements of these parameters are crucial for determining the location and thickness of oil layers, the depth of aquifers, and the type of working pipe for water / vapor reservoirs. Currently, fiber optic logging offers numerous advantages, including high measurement accuracy, fast signal response, no electrical charge, immunity to electromagnetic interference, and high operating temperatures (up to 300°C), enabling effective and continuous monitoring of oil and gas reservoir development dynamics. Especially during carbon dioxide saline water layer storage, reservoir pressure gradually increases with carbon dioxide injection. To adjust the injection method in real time, monitoring of underground temperature and pressure is necessary, requiring the addition of fiber optic equipment within the injection well.

[0003] Traditional downhole fiber optic fixing devices suffer from problems such as large drift, low accuracy, and short lifespan in high-temperature environments, making them unsuitable for permanent downhole monitoring. Currently, the common method is to install the fiber optic cable inside the wellbore after carbon dioxide injection stops. This approach is not only time-consuming and labor-intensive but also cannot provide long-term monitoring. However, fiber optic sensors cannot be deployed into the well during the injection process. Therefore, a downhole fiber optic fixing device is needed that can ensure the fiber optic cable can function normally and without damage during carbon dioxide injection. Summary of the Invention

[0004] To address the aforementioned issues, this application provides a permanent downhole fiber optic fixing device and method for use, which fixes the fiber optic cable downhole during the drilling process and protects the fiber optic cable from damage during subsequent carbon dioxide injection.

[0005] To solve the above-mentioned technical problems, this application provides the following technical solution:

[0006] In a first aspect, this application provides a downhole fiber optic fixing device and its installation method, comprising:

[0007] The outer tube is a ring structure, and the optical fiber is disposed within the ring space of the outer tube;

[0008] A fastener, which is coaxially arranged with the outer tube and detachably connected to the outer tube, and includes multiple fasteners;

[0009] A support member connects the fixing member to the well wall. The angle formed between the support member and the fixing member is adjustable, which can adjust the distance between the outer pipe and the well wall.

[0010] Preferably, the outer wall of the outer tube is provided with a plurality of protruding lock heads, and the fastener is provided with a groove of the same size as the lock heads on the side near the outer tube, and the grooves correspond one-to-one with the lock heads.

[0011] Preferably, the spacing between each of the fasteners is equal.

[0012] Preferably, one end of the support member is connected to the fixing member via a rotating shaft, and the other end of the support member abuts against the well wall.

[0013] Preferably, springs are provided on the outer side of the end of the fixing member near the support member and on the inner side of the end of the support member near the fixing member.

[0014] Preferably, the support member has a ring-shaped structure, and the opening at the end of the support member near the well wall is larger than the opening at the end near the fixing member.

[0015] Preferably, the support member is a tubular structure, and the end of the support member near the well wall is located above the end near the fixing member.

[0016] Preferably, each of the fixing members is provided with a plurality of the supporting members.

[0017] Preferably, the spacing between each of the support members is equal.

[0018] Secondly, this application provides an application of the downhole fiber optic fixing device as described above, characterized in that it includes:

[0019] The optical fiber is placed inside the outer tube, which is then placed inside the well.

[0020] The fixing device is fitted onto the outside of the outer tube. The fixing device is rotated so that the locking head on the side wall of the outer tube falls into the groove on the inside of the fixing device. The fixing device abuts against the well wall through the support member, which is rotatable.

[0021] As can be seen from the above technical solution, the downhole fiber optic fixing device and its installation method provided in this application fix the fiber optic cable to the wellbore through an outer tube during the drilling process. The outer tube of the device is connected to the well wall through fixing and support components, effectively protecting the fiber optic cable from damage during subsequent carbon dioxide injection. This device can fix the fiber optic cable to the center of the outer part of the downhole casing, preventing measurement errors caused by the fiber optic cable being too close to the downhole casing or outer well wall, thus affecting the measurement accuracy of the instrument. The angle between the support component and the fixing component is adjustable to meet the needs of downhole operations with different diameters. At the same time, the fixing component and the outer tube are detachably connected, which facilitates installation and subsequent disassembly.

[0022] To make the above and other objects, features and advantages of the present invention more apparent and understandable, preferred embodiments are described below in detail with reference to the accompanying drawings. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 This is a schematic diagram of the structure of a downhole fiber optic fixing device in an embodiment of this application.

[0025] Figure 2 This is a top view of the fixing component of the downhole fiber optic fixing device in the embodiments of this application.

[0026] Figure 3 This is a side view of the fixing component of the downhole fiber optic fixing device in an embodiment of this application.

[0027] Reference numerals in the attached diagram: 1. Optical fiber; 2. Outer tube; 3. Fixer; 4. Support; 5. Shaft; 6. Inner groove; 7. Spring; 8. Fixing platform; 9. Fixing platform slot; 10. Lock head. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0029] During carbon dioxide sequestration in saline aquifers, the reservoir pressure gradually increases with the injection of carbon dioxide, necessitating monitoring of underground temperature and pressure. This requires the addition of fiber optic equipment within the injection well. Currently, the common method is to install the fiber optic cable inside the wellbore after carbon dioxide injection is stopped. However, this approach is not only time-consuming and labor-intensive but also cannot provide long-term monitoring.

[0030] Based on the above, this application provides an embodiment of a permanent fiber optic fixing device for underground applications, see [link to embodiment]. Figure 1 The underground fiber optic permanent fixing device includes: an outer tube 2, a fixing component 3, and a support component 4.

[0031] The outer tube 2 is a ring structure, and the optical fiber 1 is disposed in the ring space of the outer tube 2;

[0032] Fixing member 3, which is coaxially arranged with the outer tube 2 and detachably connected to the outer tube 2, and includes multiple fixing members 3;

[0033] Support member 4 connects the fixing member 3 to the well wall. The angle formed by the support member 4 and the fixing member 3 is adjustable, which can adjust the distance between the outer pipe 2 and the well wall.

[0034] In a specific implementation, the optical fiber 1 is placed inside the outer tube 2, see [reference]. Figure 2 The outer tube 2 has multiple protruding locking heads 10 on its outer wall. The fixing member 3 includes a groove 6 matching the locking head 10, a fixing platform 8, and a fixing platform slot 9. The fixing platform slot 9 is located next to the groove 6. The fixing member 3 is inserted into the outer tube 2 and lowered down to the locking head 10. Rotating the outer tube 2 causes the locking head 10 to fall into the groove 6 of the fixing member 3, thus locking the fixing member 3. Rotating the outer tube 2 in the opposite direction causes the locking head 10 to move onto the fixing platform slot 9, thus unlocking the fixing member 3. Therefore, this device has self-locking and unlocking functions, that is, between the fixing member 3 and the outer tube 2, rotating the outer tube 2 in a certain direction locks the fixing member 3; rotating the outer tube 2 in the opposite direction unlocks the fixing member 3, facilitating installation and disassembly during construction. In this application, in order for the outer tube 2 to effectively protect the optical fiber, the material of the selected outer tube 2 should have a certain hardness and be resistant to high temperature, while not affecting the optical fiber data acquisition.

[0035] For a specific implementation method, see Figure 3 One end of the support member 4 is connected to the fixing member 3 via a rotating shaft 5, and the other end of the support member 4 abuts against the well wall. A spring 7 is provided on the outer side of the end of the fixing member 3 near the support member 4 and the inner side of the end of the support member 4 near the fixing member 3. Because of the spring 7, the angle between the support member 4 and the fixing member 3 can only be adjusted within a set range. At the same time, the end of the support member 4 near the fixing member 3 is located below the end away from the fixing member 3. Therefore, the support member 4 is fixed to the well wall in the direction of entering the well (that is, it can be freely entered in the direction of entering the well, but cannot be moved in the direction of exiting the well, thus playing a fixing role). This ensures that the outer tube where the optical fiber is located is kept in the center between the casing and the wellbore.

[0036] In some other embodiments, the support member 4 can be a ring-shaped structure or a tubular structure. When the support member 4 is a ring-shaped structure, each fixing member 3 is equipped with one support member 4, which is sleeved on the outside of the fixing member 3, and the upper opening diameter of the support member 4 is larger than the lower opening diameter. When the support member 4 is a tubular structure, in order to further fix the position of the support casing downhole, each fixing member 3 is equipped with multiple support members 4, which are inclined downwards towards the well.

[0037] In a specific implementation, the spacing between any two adjacent fasteners 3 on the outer tube 2 is equal. In this application, the spacing between the fasteners 3 is preferably 3 meters.

[0038] As described above, the downhole fiber optic fixing device and its installation method provided in this application fix the fiber optic cable to the wellbore via an outer tube during drilling. The outer tube of the device is connected to the wellbore wall through fixing and support components, effectively protecting the fiber optic cable from damage during subsequent carbon dioxide injection. This device can fix the fiber optic cable at the center of the casing outside the wellbore, preventing measurement errors caused by the fiber optic cable being too close to the casing or the outer wellbore wall (wellbore), thus affecting the instrument's measurement accuracy. The angle between the support component and the fixing component is adjustable to meet the needs of downhole operations with different diameters. Furthermore, the fixing component and the outer tube are detachably connected, facilitating installation and subsequent disassembly.

[0039] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the embodiments described in this specification. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example.

[0040] Furthermore, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples, without contradiction. The above descriptions are merely embodiments of the embodiments described in this specification and are not intended to limit the embodiments of this specification. Various modifications and variations can be made to the embodiments described in this specification by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principle of the embodiments described in this specification should be included within the scope of the claims of the embodiments described in this specification.

Claims

1. A method for installing an underground optical fiber fixing device, characterized in that, The downhole fiber optic fixing device includes: The outer tube is a ring-shaped structure, and the optical fiber is disposed within the ring-shaped space of the outer tube; A fastener, which is coaxially arranged with the outer tube and detachably connected to the outer tube, and includes multiple fasteners; A support member connects the fixing member to the well wall, and the angle formed between the support member and the fixing member is adjustable, thereby adjusting the distance between the outer pipe and the well wall; Installation methods include: The optical fiber is placed inside the outer tube, which is then placed inside the well. The fixing device is fitted onto the outside of the outer tube. The fixing device is rotated so that the locking head on the side wall of the outer tube falls into the groove on the inside of the fixing device. The fixing device abuts against the well wall through the support member, and the support member is rotatable. The outer wall of the outer tube is provided with multiple protruding lock heads, and the fastener is provided with a groove of the same size as the lock head on the side near the outer tube, and the groove corresponds one-to-one with the lock head; The spacing between each of the aforementioned fasteners is equal; One end of the support member is connected to the fixing member via a rotating shaft, and the other end of the support member abuts against the well wall.

2. The installation method of the downhole fiber optic fixing device according to claim 1, characterized in that, Springs are provided on the outer side of the end of the fixing member near the support member and on the inner side of the end of the support member near the fixing member.

3. The installation method of the downhole fiber optic fixing device according to claim 2, characterized in that, The support member has a ring-shaped structure, and the opening at the end of the support member near the well wall is larger than the opening at the end near the fixing member.

4. The installation method of the downhole fiber optic fixing device according to claim 3, characterized in that, The support member is a tubular structure, with one end of the support member near the well wall located above the end near the fixing member.

5. The installation method of the downhole fiber optic fixing device according to claim 4, characterized in that, Each of the aforementioned fasteners is provided with a plurality of the aforementioned support members.

6. The installation method of the downhole fiber optic fixing device according to claim 5, characterized in that, The spacing between each of the aforementioned support members is equal.

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