Optical fiber releasing device and gas storage injection-production well leakage point detection device and method

Abstract

The invention discloses an optical fiber putting device and a gas storage injection and production well leakage point detection device and method.The optical fiber putting device is arranged to put an optical fiber into a gas storage injection and production well and comprises an outer cylinder, an inner cylinder, an inner cylinder and an outer cylinder, and the outer cylinder is provided with a lower opening used for being connected to a well mouth in a sealed mode and an upper cover; the optical fiber winding part is arranged in the outer cylinder and provides a wound optical fiber, an optical fiber tail end and an optical fiber front end are led out of the wound optical fiber, the optical fiber tail end upwards penetrates through and is fixed to the upper cover in a sealed mode, and the optical fiber front end downwards extends; a counterweight connected to the front end of the optical fiber and configured to pull out the optical fiber; and the limiting part is arranged in the outer cylinder and can limit or release the counterweight device. The construction efficiency can be effectively improved, the construction period is shortened, and the cost is saved.

Description

Technical Field

[0001] The present invention relates to the technical field of oil well logging, and particularly relates to an optical fiber delivery device, a leak point detection device and method for gas storage injection-production wells. Background Art

[0002] Underground gas storage plays an important role in the fields of oil and gas consumption and energy security. Gas storage injection-production wells are the most basic components of gas storage. When the gas storage is in injection-production operation, the pressure changes periodically, with characteristics such as strong injection and production, and frequent pressure fluctuations. The wellbore string and cement sheath are affected by alternating temperature and stress for a long time, and wellbore leakage is likely to occur, resulting in annular pressure in different degrees in gas storage injection-production wells, which is a safety hazard. It is necessary to detect leak points, accurately locate the depth, evaluate the risk level and take corresponding measures. Among them, how to determine the position of the leak point is particularly crucial, and the position of the downhole leak point can be determined by distributed optical fiber temperature monitoring (DTS) and distributed optical fiber acoustic / vibration monitoring (DAS). During the monitoring process, the optical fiber is not only a sensor but also a communication medium, and distributed monitoring of temperature and acoustic vibration along the optical fiber is realized through Raman scattering and Rayleigh scattering. Distributed optical fiber monitoring has high efficiency and long measurement time, and has many advantages compared with traditional monitoring technologies.

[0003] At present, the leak point detection of annular pressure in gas storage injection-production wells mainly adopts the method of combining wellhead leak point detection technology and downhole leak point detection technology. The wellhead pressure relief technology is simple and easy to implement, and the cost is relatively low. It is a commonly used technology at present. However, this technology can only judge whether the wellhead seal fails, qualitatively judge the failure part, and cannot determine the accurate depth, making it difficult to achieve quantitative interpretation. Downhole leak point detection technology generally uses a noise detector or optical fiber monitoring. At present, distributed optical fiber monitoring technology is mostly used. The commonly used test process is to wind the armored optical fiber onto the drum of the logging vehicle before the test, and lower the armored optical fiber into the well by means of the drum. During the construction process, a logging vehicle, a crane, a crown block, a traveling block and a supporting wellhead blowout prevention device are required. During the entire logging construction process, the logging vehicle and the crane cannot leave the site, and the well fluid needs to be controlled to flow out from the wellhead optical cable seal. There are problems such as slow optical fiber lowering speed, long logging time and low construction efficiency during the test construction process. On the other hand, the armored optical fiber used in the current test process is to wrap the bare optical fiber in a thin steel pipe and add armored steel wires, steel pipes and other materials on the outside, which improves the strength and durability of the optical fiber, but the manufacturing cost is high, and a special blowout prevention device is required for sealing the armored optical fiber, with high operation difficulty and high use cost. Summary of the Invention

[0004] The main object of the present invention is to provide an optical fiber delivery device, a leak point detection device and method for an injection-production well of a gas storage reservoir, so as to solve the problems of slow optical fiber lowering speed, low construction efficiency and high cost in the prior art when the armored optical fiber is delivered through a drum.

[0005] According to one aspect of the present invention, an optical fiber delivery device is proposed. The optical fiber delivery device is configured to deliver an optical fiber into an injection-production well of a gas storage reservoir, and includes:

[0006] An outer cylinder, the outer cylinder having a lower opening for sealing connection to the wellhead and an upper cover;

[0007] An optical fiber winding part, arranged inside the outer cylinder and providing the wound optical fiber. The wound optical fiber leads out an optical fiber tail end and an optical fiber front end. The optical fiber tail end passes through and is fixed to the upper cover upwardly in a sealed manner, and the optical fiber front end extends downward;

[0008] A counterweight, connected to the optical fiber front end and configured to pull out the optical fiber;

[0009] A limiting part, arranged inside the outer cylinder and capable of restricting or releasing the counterweight.

[0010] According to an embodiment of the present invention, the counterweight is configured to pull out the optical fiber along a spiral path.

[0011] According to an embodiment of the present invention, the optical fiber winding part includes a reel arranged vertically and the optical fiber wound on the reel. The reel can rotate around its axis.

[0012] According to an embodiment of the present invention, the optical fiber winding part includes a self-winding optical fiber winding body.

[0013] According to an embodiment of the present invention, the optical fiber winding part includes a housing. The wound optical fiber is arranged inside the housing, and the optical fiber tail end and the optical fiber front end pass out from the lead holes on the housing.

[0014] According to an embodiment of the present invention, it further includes a fixing seat. The fixing seat is arranged along the radial direction of the outer cylinder and connected to the inner wall of the outer cylinder, and the optical fiber winding part is installed on the fixing seat.

[0015] According to an embodiment of the present invention, a flange for connection to the wellhead is provided at the lower opening of the outer cylinder.

[0016] According to an embodiment of the present invention, it further includes a sealing member for being arranged between the flange and the wellhead.

[0017] According to an embodiment of the present invention, it further includes: a sealing kit hermetically arranged in the lead hole of the upper cover and a sealing filler arranged between the lead hole of the sealing kit and the optical fiber tail end.

[0018] According to an embodiment of the present invention, the sealing kit is a conical sealing sleeve.

[0019] According to an embodiment of the present invention, the upper cover is detachably connected to the barrel of the outer cylinder.

[0020] According to an embodiment of the present invention, the upper cover is a plug, and the plug is threadedly connected to the barrel of the outer cylinder.

[0021] According to an embodiment of the present invention, a seal is further included and disposed between the upper cover and the barrel of the outer cylinder.

[0022] According to an embodiment of the present invention, the limiting portion is pivotally or telescopically disposed on the outer cylinder and has a closed state and an open state, wherein when in the closed state, the limiting portion supports the counterweight.

[0023] According to another aspect of the present invention, a leak point detection device for a gas storage injection and production well is provided, including: the optical fiber delivery device as described above and a ground optical fiber monitoring device connected to the tail end of the optical fiber.

[0024] According to another aspect of the present invention, a leak point detection method for a gas storage injection and production well is provided, including: using the optical fiber delivery device as described above to deliver the optical fiber into the well, and using the ground optical fiber monitoring device connected to the tail end of the optical fiber to determine the depth of the leak point longitudinally.

[0025] According to an embodiment of the present invention, it further includes: determining the annulus where the leak point occurs from a plane based on the wellhead bleed-off pressure detection technology.

[0026] According to another aspect of the present invention, a manufacturing method of the optical fiber delivery device as described above is provided, including:

[0027] Manufacturing an optical fiber winding portion;

[0028] Connecting the front end of the optical fiber to the counterweight;

[0029] Passing the tail end of the optical fiber through the upper cover of the outer cylinder in a disassembled state;

[0030] Installing the optical fiber winding portion into the barrel of the outer cylinder;

[0031] Installing the limiting portion to the barrel of the outer cylinder and making the limiting portion in a restricted state;

[0032] Installing the upper cover to the barrel of the outer cylinder;

[0033] Performing sealing and fixing of the tail end of the optical fiber.

[0034] According to an embodiment of the present invention, before installing the optical fiber winding portion into the barrel of the outer cylinder, the method further includes: passing the tail end of the optical fiber through the fixing seat;

[0035] Install the optical fiber winding part into the inner cylinder of the outer cylinder, including: installing the optical fiber winding part on the fixing seat and installing the fixing seat into the inner cylinder of the outer cylinder.

[0036] According to an embodiment of the present invention, the sealing and fixing of the optical fiber tail end are carried out, including:

[0037] Pass the optical fiber tail end through the sealing kit and seal and install the sealing kit in the lead hole of the upper cover;

[0038] Set a sealing filler between the optical fiber tail end and the lead hole of the sealing kit.

[0039] In the technical solution of the present invention, an optical fiber (such as a bare optical fiber) is adopted instead of an armored optical fiber. At the same time, a counterweight can quickly pull out the optical fiber to make it enter the well. The optical fiber delivery device of the present invention is small and flexible, the optical fiber delivery method is simple and reliable, the construction difficulty is significantly reduced, the cost of materials such as optical fibers is low, and the construction efficiency can be effectively improved, the construction period can be shortened, and costs can be saved. Through the optical fiber delivery device of the present invention, it can ensure that the annulus pressure leakage point detection technology of the gas storage injection-production well is better carried out, which is conducive to promoting the development of this technology, so as to provide reliable data support for the risk level assessment of the annulus pressure of the gas storage injection-production well. Description of the Drawings

[0040] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0041] Figure 1 Show a schematic structural diagram of an optical fiber delivery device according to an embodiment of the present invention;

[0042] Figure 2 Show a process flow diagram of an optical fiber delivery process according to an embodiment of the present invention. Detailed Embodiments

[0043] To make the purpose, technical solutions and advantages of the present invention clearer, the following will further describe the embodiments of the present invention in detail with reference to specific embodiments and the accompanying drawings.

[0044] It should be noted that all the expressions using "first" and "second" in the embodiments of the present invention are used to distinguish two entities or parameters with the same name but different. It can be seen that "first" and "second" are only for the convenience of expression and should not be understood as a limitation to the embodiments of the present invention. This will not be repeated in the subsequent embodiments.

[0045] As mentioned in the above background art, the inventors of the present application recognized that the prior art has problems such as slow fiber lowering speed, low construction efficiency, and high cost when deploying armored optical fibers through a drum. The inventors further recognized that for gas storage injection and production wells, the environment is not highly corrosive, and using optical fibers (bare optical fibers) can meet the usage requirements. And based on the smaller size and lighter weight of the optical fibers, a more convenient and rapid method can be adopted to pull out the optical fibers and quickly introduce them into the well. Based on the above understanding, the present application proposes one or more embodiments to be described below to solve the problems existing in the prior art.

[0046] Referring Figure 1 , the present invention provides an optical fiber deployment device 100 configured to deploy an optical fiber into a gas storage injection and production well, and includes: an outer cylinder 10 having a lower opening 12 for sealing connection to the wellhead and an upper cover 14; an optical fiber winding part 20 disposed inside the outer cylinder 10 and providing a wound optical fiber, the wound optical fiber leading out an optical fiber tail end 22 and an optical fiber front end 24, the optical fiber tail end 22 sealingly passing through and being fixed to the upper cover 14 upward, and the optical fiber front end 24 extending downward; a counterweight 30 connected to the optical fiber front end 24 and configured to pull out the optical fiber; and a limiting part 40 disposed inside the outer cylinder 10 and capable of restricting or releasing the counterweight 30.

[0047] In an embodiment of the present invention, an optical fiber (such as a bare optical fiber) is used instead of an armored optical fiber, and in combination with the use of a counterweight, the optical fiber can be quickly pulled out and introduced into the well. Compared with the prior art that requires many devices such as a logging truck, a crane, a crown block, a traveling block, and a supporting wellhead blowout preventer device, the optical fiber deployment device of the present invention has a simple structure, is small and flexible, and the optical fiber deployment method is simple and reliable, with significantly reduced construction difficulty, lower costs of materials such as optical fibers, and can effectively improve construction efficiency, shorten the construction period, and save costs. Through the optical fiber deployment device of the present invention, it can ensure better development of the annulus pressure leak point detection technology for gas storage injection and production wells, which is conducive to promoting the development of this technology, thereby providing reliable data support for the risk level assessment of the annulus pressure in gas storage injection and production wells.

[0048] In an embodiment of the present invention, the outer cylinder 10 may be a cylindrical tube, for example, which includes a hollow cylinder body, a lower opening 12 and an upper cover 14. When in use, the outer cylinder 10 is installed at the wellhead, the lower opening 12 is sealingly connected to the wellhead, and at the same time, the upper cover 14 is sealingly connected to the optical fiber tail end 22, ensuring that the entire device communicating with the wellhead has good sealing performance. The optical fiber winding part 20 can be installed on the inner wall of the outer cylinder 10 by means of a connecting mechanism, and the optical fiber winding part 20 can be arranged coaxially with the outer cylinder 10. The optical fiber tail end 22 passes through the upper cover 14 for connection to a ground optical fiber monitoring device. The weight 30 can guide the optical fiber front end 24 to travel into the well under the action of gravity, thereby continuously pulling the optical fiber out of the optical fiber winding part 20 until the weight 30 pulls the optical fiber front end 24 to the bottom of the well, thus completing the laying of the optical fiber in the wellbore. When it is not necessary to lay the optical fiber, the limiting part 40 can limit the weight 30 inside the outer cylinder 10; when it is necessary to lay the optical fiber, the limiting part 40 releases the weight 30 so that it can move freely downward under the action of gravity.

[0049] In some embodiments of the present invention, the weight 30 is arranged to pull out the optical fiber along a spiral path. Compared with the conventional method of pulling out the optical fiber along a straight path, the method of pulling out the optical fiber along a spiral path in the present invention can avoid the optical fiber being damaged due to large frictional force or other acting forces exerted by the outer layer of wound optical fiber on the inner layer of wound optical fiber when being pulled out. In some embodiments, the optical fiber winding part 20 includes a vertically arranged reel and the optical fiber wound on the reel. The reel can rotate around its axis, and the vertically arranged reel facilitates the optical fiber being pulled out along a spiral path. In some other embodiments, the optical fiber winding part 20 may not include a reel but only include a self-winding optical fiber winding body, and the winding mode and / or the setting direction / attitude of the optical fiber winding body can be set to realize the optical fiber being pulled out along a spiral path. In some embodiments, a damper can also be used to control the optical fiber laying speed.

[0050] In some embodiments, the optical fiber winding part 20 includes a housing, and the wound optical fiber is arranged inside the housing. The optical fiber tail end 22 and the optical fiber front end 24 respectively pass through the upper lead hole and the lower lead hole on the housing. By providing the housing, on the one hand, it is convenient to protect the wound optical fiber, and on the other hand, it is convenient to install the wound optical fiber, and the installation of the optical fiber winding part 20 is realized through the installation of the housing.

[0051] Reference Figure 1 , in some embodiments, the optical fiber laying device 100 further includes a fixing seat 50. The fixing seat 50 is arranged along the radial direction of the outer cylinder 10 and is connected to the inner wall of the outer cylinder 10, and the optical fiber winding part 20 is installed on the fixing seat 50. Thus, the optical fiber winding part 20 is installed on the outer cylinder 10 via the fixing seat 50. The fixing seat 50 can be in the form of a rod, a plate, a frame, etc., for example. A lead hole can be provided on the fixing seat 50, and the optical fiber tail end 22 passes through the lead hole on the fixing seat 50 and then passes through the upper cover 14.

[0052] refer to Figure 1 In some embodiments, the optical fiber delivery device 100 further includes: a sealing kit 60 sealed in the lead-in hole of the upper cover 14 and a sealing filler provided between the lead-in hole of the sealing kit 60 and the optical fiber tail end 22. The sealing kit 60 may be, for example, a conical sealing sleeve. By providing the sealing kit 60, on the one hand, the sealing effect can be enhanced, and on the other hand, a finer lead-in hole can be formed, ensuring that the sealing filler filled between the optical fiber tail end 22 and the fine lead-in hole has a reliable sealing performance.

[0053] In some embodiments, the upper cover 14 is detachably connected to the body of the outer cylinder 10, which facilitates the manufacture and maintenance of the optical fiber delivery device 100. For example, when the optical fiber winding part 20 is installed inside the outer cylinder 10 or when the optical fiber winding part 20 is removed from the outer cylinder 10, the upper cover 14 can be removed first so as to operate through the opening of the outer cylinder 10. In some embodiments, the optical fiber delivery device 100 also includes a sealing member (such as a sealing ring) disposed between the upper cover 14 and the body of the outer cylinder 10, so as to ensure good sealing at the connection between the upper cover 14 and the body of the outer cylinder 10. The upper cover 14 can be, for example, a threaded plug, which is connected to the body of the outer cylinder 10 by threaded connection, and the threaded plug can have a sealing ring.

[0054] In some embodiments, a flange for connecting to a wellhead is provided at the lower opening 12 of the outer tube 10. In some embodiments, the optical fiber delivery device 100 further includes a seal (e.g., a sealing ring) provided between the flange and the wellhead to ensure the sealing of the connection between the lower opening 12 and the wellhead under high pressure conditions.

[0055] In some embodiments, the limiting portion 40 can be pivotally or telescopically disposed on the outer cylinder 10 and has a closed state and an open state, wherein when in the closed state, the limiting portion 40 supports the counterweight 30 so that the counterweight 30 will not separate from the outer cylinder 10 under the action of gravity; when the limiting portion 40 is in the open state, the limiting portion 40 does not support the counterweight 30, and the counterweight 30 moves freely downward under the action of gravity.

[0056] When using the optical fiber delivery device 100, the limit portion 40 can be first adjusted to a restricted state (e.g., a closed state), and then the optical fiber delivery device 100 can be installed at the wellhead. After that, the production valve can be opened, and then the limit portion 40 can be adjusted to a released state (e.g., an open state). At this time, the counterweight 30 guides the front end 24 of the optical fiber to move downward, and the optical fiber is continuously pulled out until it reaches the bottom of the well, thereby completing the delivery of the optical fiber.

[0057] The present invention also provides a leak point detection device for gas storage injection and production wells, comprising: the optical fiber deployment device 100 as described above and a ground optical fiber monitoring device connected to the tail end 22 of the optical fiber (such as a ground DAS demodulation device, which is used to complete distributed temperature monitoring and distributed acoustic wave / vibration monitoring of gas storage injection and production wells and obtain monitoring data).

[0058] The present invention also provides a leak point detection method for gas storage injection and production wells, comprising: using the optical fiber deployment device 100 as described above to deploy the optical fiber into the well, and using the ground optical fiber monitoring device connected to the tail end 22 of the optical fiber to determine the depth of the leak point longitudinally.

[0059] When using the optical fiber deployment device 100 to deploy the optical fiber into the well, the front end 24 of the optical fiber extends towards the bottom of the well under the self-weight of the weight 30, and at the same time, the optical fiber is pulled out from the optical fiber winding part 20. The optical fiber continuously extends towards the bottom of the well until the weight 30 pulls the front end 24 of the optical fiber to the bottom of the well, thus completing the layout of the optical fiber in the wellbore. Then, a ground optical fiber monitoring device (ground DAS demodulation device) can be connected to complete distributed temperature monitoring and distributed acoustic wave / vibration monitoring of gas storage injection and production wells and obtain monitoring data.

[0060] In some embodiments, the leak point detection method for gas storage injection and production wells further comprises: determining the annulus where the leak point occurs on the plane based on the wellhead pressure relief detection technology.

[0061] In the embodiments of the present invention, a technical solution of comprehensively applying the wellhead leak point detection process and the downhole leak point optical fiber detection process is adopted. The wellhead leak point detection process is aimed at the characteristics of strong injection and production and frequent pressure fluctuations of gas storage injection and production wells. The annulus pressure release and recovery diagnosis technology is used to qualitatively judge the sealing performance of the wellhead sealing components and realize wellhead leak point detection. First, the wellhead leak point qualitative analysis technology is applied to diagnose and analyze the integrity of the well; then, through the wellhead pressure relief detection and pressure recovery test technology, the gas component analysis of the pressure relief gas is carried out to judge the source and nature of the gas; then, the wellhead leak point inspection and detection technology and the wellhead high-pressure injection integrated device are applied and comprehensively used with the distributed optical fiber monitoring system to respectively judge whether there are leak points in each annulus and the severity of the leakage. Finally, through the processing and analysis of the distributed vibration / acoustic wave monitoring data obtained by optical fiber monitoring, the depth position of the downhole leak point is accurately located. On the one hand, it is determined which annulus in the wellbore the leak point is specifically in on the plane, and on the other hand, the accurate depth of the leak point is determined longitudinally, so as to complete the annulus pressure-bearing leak point detection of gas storage injection and production wells, analyze and evaluate the risk level of the leak point, and provide data support for the next step of taking countermeasures.

[0062] Reference Figure 2 The present invention also provides a manufacturing method of the optical fiber deployment device 100 as described above, comprising:

[0063] Manufacture the optical fiber winding part 20;

[0064] Connect the front end 24 of the optical fiber to the counterweight 30;

[0065] Pass the tail end 22 of the optical fiber through the upper cover 14 of the outer cylinder 10 in the disassembled state;

[0066] Install the optical fiber winding part 20 into the inner cylinder of the outer cylinder 10;

[0067] Install the limiting part 40 onto the inner cylinder of the outer cylinder 10 and make the limiting part 40 in a limiting state;

[0068] Install the upper cover 14 onto the inner cylinder of the outer cylinder 10;

[0069] Seal and fix the tail end 22 of the optical fiber.

[0070] In some embodiments, before installing the optical fiber winding part 20 into the inner cylinder of the outer cylinder 10, the manufacturing method further includes: passing the tail end 22 of the optical fiber through the fixing base 50; and installing the optical fiber winding part 20 into the inner cylinder of the outer cylinder 10, including: installing the optical fiber winding part 20 on the fixing base 50 and installing the fixing base 50 into the inner cylinder of the outer cylinder 10.

[0071] In some embodiments, sealing and fixing the tail end 22 of the optical fiber includes: passing the tail end 22 of the optical fiber through the sealing kit 60 and sealingly installing the sealing kit 60 in the lead hole of the upper cover 14; arranging a sealing filler between the tail end 22 of the optical fiber and the lead hole of the sealing kit 60.

[0072] Reference Figure 2 , in some embodiments, the manufacturing and use of the optical fiber feeding device are carried out according to the following steps:

[0073] First step, wind the optical fiber inside the optical fiber reel (corresponding to the optical fiber winding part in the previous text) according to the optical fiber winding method, leaving sufficient lengths at both ends of the whole optical fiber to extend out of the optical fiber reel. The end connected to the ground demodulation device is called the tail end, and the end lowered into the well is called the front end;

[0074] Second step, install a counterweight at the front end of the optical fiber, and pass the tail end of the optical fiber through the lead hole of the optical fiber reel, the fixing base, and the lead hole of the plug;

[0075] Third step, install the optical fiber reel on the fixing base, install the fixing base onto the fixing base inside the outer cylinder, and install the plug onto the outer cylinder;

[0076] Fourth step, pass the tail end of the optical fiber through the sealing kit, install the sealing kit on the plug, add a sealing filler, and perform a sealing treatment on the optical fiber;

[0077] Fifth step, adjust the limiting device to ensure that the limiting device is in a closed state;

[0078] Step 6: Install the delivery device onto the wellhead valve;

[0079] Step 7: Open the production valve and observe the sealing condition of the optical fiber delivery device to ensure no air leakage;

[0080] Step 8: Open the limit device. Under the action of gravity, the counterweight pulls the optical fiber out of the optical fiber reel and drops it into the well until it reaches the bottom of the well, completing the deployment of the optical fiber in the well.

[0081] In summary, the present invention provides an optical fiber detection process for the depth of underground leakage points in injection-production wells with annulus pressure in gas storage reservoirs. Utilizing the advantages of high optical fiber monitoring accuracy, wide adaptation range, small outer diameter and volume, etc., it can conveniently and quickly deploy the optical fiber into the well to be detected, complete distributed optical fiber temperature monitoring and distributed optical fiber vibration monitoring, and combine wellhead leakage point detection technology and ground pressure relief technology to accurately locate the depth of underground leakage points, thereby providing reliable data support for the risk level assessment of annulus pressure in injection-production wells of gas storage reservoirs.

[0082] The present invention provides a leakage point detection process for annulus pressure in injection-production wells of gas storage reservoirs, including wellhead leak detection and pressure relief detection process, optical fiber monitoring and delivery process and device. The method of the present invention is simple and reliable, the device is small and flexible. Compared with the existing optical fiber testing process, large equipment and professional team cooperation can be saved, the construction difficulty is significantly reduced, and the cost of materials such as optical fiber is relatively low. The present invention can improve the construction efficiency, shorten the construction period, reduce the operation difficulty and cost of optical fiber monitoring in injection-production wells of gas storage reservoirs, and has obvious advantages in terms of technology and economy.

[0083] The economic benefit of the technical solution of the present invention is the cost savings generated by reducing the detection cost. It is estimated that the cost can be saved by 300,000 yuan per well. In the next 3 - 5 years, the economic benefit that can be created is 900,000 - 1,500,000 yuan per year. This technical solution will provide important data support for the safe operation of injection-production wells in gas storage reservoirs, ensure the safety of energy supply, and the social benefit is very significant.

[0084] Those of ordinary skill in the art should understand that: the discussion of any embodiment above is only exemplary, and is not intended to imply that the scope (including the claims) disclosed by the embodiments of the present invention is limited to these examples; under the idea of the embodiments of the present invention, the technical features between the above embodiments or different embodiments can also be combined, and there are many other variations in different aspects of the embodiments of the present invention as described above, which are not provided in detail for the sake of brevity. Therefore, any omission, modification, equivalent replacement, improvement, etc. made within the spirit and principle of the embodiments of the present invention shall be included in the protection scope of the embodiments of the present invention.

Claims

1. An optical fiber delivery device, characterized in that, the optical fiber delivery device is configured to deliver an optical fiber into an injection-production well of a gas storage reservoir, and includes: an outer cylinder having a lower opening for sealing connection to a wellhead and an upper cover; an optical fiber winding part disposed in the outer cylinder and providing a wound optical fiber, the wound optical fiber leading out an optical fiber tail end and an optical fiber front end, the optical fiber tail end sealingly passing through and being fixed to the upper cover upward, and the optical fiber front end extending downward; a weight connected to the optical fiber front end and configured to pull out the optical fiber; a limiting part disposed in the outer cylinder and capable of restricting or releasing the weight.

2. The device according to claim 1, characterized in that, the weight is configured to pull out the optical fiber along a spiral path.

3. The device according to claim 2, characterized in that, the optical fiber winding part includes a reel disposed vertically and an optical fiber wound around the reel, and the reel is rotatable about its axis.

4. The device according to claim 2, characterized in that, the optical fiber winding part includes a self-winding optical fiber winding body.

5. The device according to claim 1, characterized in that, the optical fiber winding part includes a housing, the wound optical fiber is disposed in the housing, and the optical fiber tail end and the optical fiber front end pass out through lead holes on the housing.

6. The device according to claim 1, characterized in that, it further includes a fixing seat disposed radially along the outer cylinder and connected to the inner wall of the outer cylinder, and the optical fiber winding part is mounted to the fixing seat.

7. The device according to claim 1, characterized in that, a flange for connection to the wellhead is provided at the lower opening of the outer cylinder.

8. The device according to claim 7, characterized in that, it further includes a seal for being disposed between the flange and the wellhead.

9. The device according to claim 1, characterized in that, it further includes: a seal kit sealingly disposed in the lead hole of the upper cover and a sealing filler disposed between the lead hole of the seal kit and the optical fiber tail end.

10. The device according to claim 9, characterized in that, the seal kit is a conical seal.

11. The device according to claim 1, characterized in that, the upper cover is detachably connected to the cylinder body of the outer cylinder.

12. The device according to claim 11, characterized in that, the upper cover is a plug, and the plug is threadedly connected to the cylinder body of the outer cylinder.

13. The device according to claim 11, characterized in that, it further includes a seal disposed between the upper cover and the cylinder body of the outer cylinder.

14. The device according to claim 1, characterized in that, the limiting part is pivotally or telescopically disposed in the outer cylinder and has a closed state and an open state, wherein when in the closed state, the limiting part supports the weight.

15. A leak point detection device for an injection-production well of a gas storage reservoir, characterized in that, it includes: the optical fiber delivery device according to any one of claims 1-14 and a ground optical fiber monitoring device connected to the optical fiber tail end.

16. A leak point detection method for an injection-production well of a gas storage reservoir, characterized in that, it includes: Use the optical fiber delivery device described in any one of claims 1-14 to deliver the optical fiber into the well, and use the ground optical fiber monitoring device connected to the end of the optical fiber to determine the depth of the leakage point longitudinally.

17. According to the method described in claim 16, wherein, it further includes: Determine the annulus where the leakage point occurs on the plane based on the wellhead pressure relief detection technology.

18. A manufacturing method of the optical fiber delivery device described in claim 1, wherein, it includes: Manufacture the optical fiber winding part; Connect the front end of the optical fiber to the counterweight; Pass the end of the optical fiber through the upper cover of the outer cylinder in a disassembled state; Install the optical fiber winding part into the cylinder body of the outer cylinder; Install the limiting part to the cylinder body of the outer cylinder and make the limiting part in a limiting state; Install the upper cover to the cylinder body of the outer cylinder; Perform sealing and fixing of the end of the optical fiber.

19. According to the method described in claim 18, wherein, Before installing the optical fiber winding part into the cylinder body of the outer cylinder, the method further includes: passing the end of the optical fiber through the fixing seat; The step of installing the optical fiber winding part into the cylinder body of the outer cylinder includes: installing the optical fiber winding part on the fixing seat and installing the fixing seat into the cylinder body of the outer cylinder.

20. According to the method described in claim 18, wherein, The step of performing sealing and fixing of the end of the optical fiber includes: Pass the end of the optical fiber through the sealing kit and seal and install the sealing kit in the lead hole of the upper cover; Set sealing filler between the end of the optical fiber and the lead hole of the sealing kit.

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