Long-term dynamic monitoring construction technology and system for optical cable laying in oil pipe

Abstract

The invention discloses a long-term dynamic monitoring construction technology and system for optical cable laying in an oil pipe, and belongs to the technical field of oil field geological exploration. The construction technology comprises the steps that a sensing optical cable penetrates through a blowout prevention pipe and a blowout prevention control head and then is connected with an optical cable halter; the blowout prevention pipe is connected with a wellhead blowout prevention device; closing a semi-closed flashboard of the wellhead blowout preventer, and opening a wellhead gate and the semi-closed flashboard to balance the pressure in the blowout preventer and the pressure in the well; lowering the sensing optical cable to a preset position, closing a semi-closed flashboard of the wellhead blowout preventer, disconnecting the blowout preventer from the wellhead blowout preventer, and cutting off the sensing optical cable; a sensing optical cable needing to be arranged in a well penetrates out of a blowout prevention pipe, the sensing optical cable penetrates into a ground static sealing device, and a ground leakage prevention safety device and a ground data acquisition device are installed on the sensing optical cable reserved on the ground. And the sensing optical cable is damaged by the pressure in the well.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of oilfield geological exploration, and relates to optical fiber sensing dynamic monitoring, in particular to a long-term dynamic monitoring construction process and system for optical cable laying in a tubing. BACKGROUND

[0002] The optical fiber monitoring has the characteristics of embedding, high sensitivity, corrosion resistance, full well section and full time domain. The sensing optical cable is protected by a corrosion-resistant steel pipe, and a steel wire is used for armoring outside the protection steel pipe in order to have excellent mechanical properties such as tensile and compression resistance. The core material of the sensing optical cable is quartz, which makes the optical fiber reduce electromagnetic signal interference and even directly eliminate other information interference. If the on-site collection and remote data transmission technology is used, the monitoring personnel can realize remote monitoring without going to the scene, thereby improving the convenience of monitoring. The pressure in the three and four wells can damage the sensing optical cable, accelerate hydrogen damage, and reduce the service life of the optical cable, so how to lay the sensing optical cable in the well is the primary problem that technicians in this field need to face.

[0003] The invention patent application "A gas storage optical fiber permanent monitoring equipment and method" (publication number: CN116699698A) discloses a gas storage well optical fiber permanent monitoring equipment and method, which relates to the optical fiber permanent monitoring equipment used in the gas storage well and the method of laying the core pipe optical cable after cementing the well. The invention patent application "A natural gas storage temperature pressure and vibration monitoring system" (publication number: CN111577255A) discloses an optical fiber temperature pressure and vibration monitoring system. The two patents do not explain in detail how to lay the sensing optical cable, and do not involve the construction process of laying the optical cable under pressure in the tubing. SUMMARY

[0004] The present application provides a long-term dynamic monitoring construction process and system for optical cable laying in a tubing, which solves the problem that the sealing pressure-bearing performance does not meet the long-term working requirements and the well pressure damages the sensing optical cable.

[0005] In order to achieve the above purpose, the present application adopts the following technical scheme: A long-term dynamic monitoring construction process for optical cable laying in a tubing, comprising the following steps: Step 1, connecting the blowout pipe and the blowout control head on the ground, connecting the sensing optical cable with the optical cable male head after passing through the blowout pipe and the blowout control head, and testing whether the sensing optical cable is intact: If it is intact, step 2 is executed; otherwise, a new sensing optical cable is replaced, and the step is repeated; Step 2, closing the wellhead gate, installing the wellhead blowout preventer under the condition of no well fluid leakage, and connecting the blowout pipe with the wellhead blowout preventer; Step 3, close the half sealing board of the wellhead blowout preventer, open the wellhead gate, open the half sealing board of the wellhead blowout preventer under the condition of no leakage at the wellhead, fill the blowout preventer with well fluid, and balance the pressure in the blowout preventer with the pressure in the well; Step 4, lower the sensing optical cable to the predetermined position, detect the integrity of the sensing optical cable, close the half sealing board of the wellhead blowout preventer, vent the pressure of the blowout preventer, disconnect the blowout preventer from the wellhead blowout preventer, and cut off the sensing optical cable; Step 5, after the sensing optical cable to be left in the well is threaded out of the blowout preventer, the sensing optical cable is threaded into the ground static sealing device, the sensing optical cable is lifted, the ground static sealing device and the wellhead blowout preventer are connected, the sensing optical cable left in the well is fixed on the upper end of the ground static sealing device, and the ground leakage prevention safety device and the ground data acquisition device are installed on the sensing optical cable reserved on the ground.

[0006] Further, in step 1, the sensing optical cable is tested for integrity by the downhole instrument string.

[0007] Further, in step 4, before cutting off the sensing optical cable, the sensing optical cable is fixed by the optical cable hanger. Further, step 5 includes the following steps: S1, lifting the blowout preventer to keep a distance from the wellhead blowout preventer, installing the wellhead optical cable suspension device in the interval, relaxing the sensing optical cable so that the wellhead optical cable suspension device is placed on the wellhead blowout preventer, and the sensing optical cable will not fall off; S2, threading the sensing optical cable out of the blowout preventer and into the ground static sealing device, and installing another wellhead optical cable suspension device on the upper end of the ground static sealing device; S3, lifting the wellhead optical cable suspension device at the upper end of the ground static sealing device, so that the wellhead optical cable suspension device placed on the wellhead blowout preventer is separated from the wellhead blowout preventer, the wellhead optical cable suspension device is removed, the sensing optical cable is lowered, the ground static sealing device is placed on and connected to the wellhead blowout preventer, and the upper end of the ground static sealing device is connected to the lower end of the wellhead optical cable suspension device; S4, open the half sealing board of the wellhead blowout preventer, install the ground leakage prevention safety device on the sensing optical cable reserved on the ground under the condition that the fluid in the well will not leak, and connect the ground data acquisition device.

[0008] The oil pipe in optical cable laying long-term dynamic monitoring construction system comprises an optical cable swivel, a ground static sealing device, a ground leakage prevention safety device, a ground data acquisition device, a wellhead blowout preventer and a blowout preventer pipe; when the oil pipe in optical cable laying long-term dynamic monitoring construction is carried out, the sensing optical cable to be laid is connected with the optical cable swivel after passing through the blowout preventer pipe and the blowout control head, the optical cable swivel is located in the well, the wellhead blowout preventer is located at the wellhead, the ground static sealing device is located above the wellhead blowout preventer and is connected with the ground static sealing device, and the ground leakage prevention safety device and the ground data acquisition device are installed on the sensing optical cable reserved on the ground.

[0009] Further, the wellhead optical cable suspension device is used for clamping the sensing optical cable when the sensing optical cable penetrates into the ground static sealing device.

[0010] Further, the wellhead optical cable suspension device comprises a compression fixing cap, a steel cable lifting ring and a slip type optical cable fixing mandrel, the compression fixing cap and the slip type optical cable fixing mandrel are fixedly connected, and the steel cable lifting ring is located between the compression fixing cap and the slip type optical cable fixing mandrel.

[0011] Further, the optical cable swivel comprises a sleeve type optical cable fixing mandrel, a downhole sealing joint, a sensing optical cable sealing compression cap, a sealing pressure bearing cylinder and an optical cable fixing mandrel limiting pin, one end of the sleeve type optical cable fixing mandrel extends into the cavity of the first end of the downhole sealing joint and is fixedly connected with the downhole sealing joint, the downhole sealing joint is connected with the sealing pressure bearing cylinder, and the sensing optical cable sealing compression cap is inserted into the opening of the first end of the sealing joint for sealing the sensing optical cable.

[0012] Further, the ground static sealing device comprises a connecting by the Chinese character ren, a sealing device body, a pressure test interface and a connecting joint, the connecting by the Chinese character ren is fixed to the lower end of the sealing device body, the sidewall of the sealing device body is provided with the pressure test interface, and the connecting joint is fixed to the upper end of the sealing device body.

[0013] Further, the ground leakage prevention safety device comprises an optical unit sealing fastening cap, a leakage prevention device pressure bearing body and a fiber core sealing fastening cap, the optical unit sealing fastening cap seals the optical unit of the sensing optical cable and is connected with the leakage prevention device pressure bearing body, and the fiber core sealing fastening cap seals the fiber core of the sensing optical cable and is connected with the leakage prevention device pressure bearing body.

[0014] Compared with the prior art, the present application has at least the following beneficial technical effects: The application provides a construction process of oil pipe optical cable laying for long-term dynamic monitoring, and provides a method of optical cable laying in the oil pipe under the condition of wellhead pressure in the oil well production process, the sensing optical cable is placed in the well for long-term dynamic monitoring through the wellhead sealing blowout preventer and the suspension device. The construction process places the sensing optical cable into the well under the condition of wellhead pressure, and the well killing operation is not needed in the whole construction process, the wellhead sealing state is maintained, the well fluid leakage is prevented, the optical cable laying efficiency and safety are effectively improved, the sensing optical cable laying process is optimized, and the scale application of the optical fiber dynamic monitoring technology is promoted.

[0015] The construction process places the sensing optical cable into the well under the condition of wellhead pressure, greatly shortens the laying time, improves the laying efficiency, and reduces the laying cost; meanwhile, in combination with the remote data transmission technology, the monitoring personnel can realize remote monitoring without being present, and the convenience of monitoring is improved.

[0016] Further, the ground static sealing device adopts modular design, can replace the damaged module under the condition that the wellhead blowout preventer is used to close the wellhead, and ensures the long-term static sealing performance. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 is the overall flow chart in the application; Figure 2 is the overall schematic diagram of optical cable laying in the application; Figure 3 is the step diagram of installing the ground static sealing device in the application; Figure 4 is the schematic diagram of the wellhead optical cable suspension device in the application; Figure 5 is the schematic diagram of the downhole sealing pressure bearing device in the application; Figure 6 is the schematic diagram of the ground static sealing device in the application; Figure 7 is the schematic diagram of the ground leakage prevention insurance device in the application.

[0018] In the drawings: 1, wellbore; 2, sensing optical cable; 3, optical cable swivel head; 4, ground static sealing device; 5, wellhead optical cable suspension device; 6, ground leakage prevention insurance device; 7, ground data acquisition device; 8, wellhead gate; 9, wellhead blowout preventer; 10, blowout pipe; 11, compression fixing cap; 12, steel cable hanger ring; 13, slip type optical cable fixing mandrel; 14, sleeve type optical cable fixing mandrel; 15, downhole sealing joint; 16, sensing optical cable sealing compression cap; 17, sealing pressure bearing cylinder; 18, optical cable fixing mandrel limiting pin; 19, wellhead flange; 20, connecting yoke; 21, sealing device body; 22, pressure test interface; 23, connecting joint; 24, sensing optical cable optical unit; 25, optical unit sealing compression screw cap; 26, leakage prevention device pressure bearing body; 27, sensing optical cable fiber core; 28, fiber core sealing compression screw cap. DETAILED DESCRIPTION

[0019] The present application will be described in detail below with reference to the drawings and specific embodiments.

[0020] In order to make the technical personnel in the art better understand the technical solutions in the present application, the technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings and specific embodiments. Obviously, the described embodiments are only a part of the embodiments of the present application, not all. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor should belong to the scope of protection of the present application.

[0021] It should be noted that when an element is referred to as being "disposed on" another element, it can be directly on the other element or there can be an intervening element between them. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or there can be an intervening element between them. The terms "upper", "lower", "front", "rear", "left", "right", "top", "bottom", "inner", "outer" and the like as used herein refer to the orientation or positional relationship as shown in the drawings, and are for purposes of convenience and brevity in describing and illustrating the present application and its preferred and alternative embodiments and are not intended to limit or in any way suggest the specific orientation of the devices or elements with respect to one another. Hence, such terms do not imply or create any particular ordering among the described or illustrated devices or elements.

[0022] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in the description of the application herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0023] Example 1 Referring to Figure 1 and Figure 2 A tubing inside optical cable laying long-term dynamic monitoring construction process, comprising the following steps: Step 1, connect the blowout pipe 10 and the blowout control head on the ground, pass the sensing optical cable 2 through the blowout pipe 10 and the blowout control head, then connect the optical cable swivel 3, ensure that the bottom of the sensing optical cable 2 is sealed well, connect the downhole instrument string, and test whether the sensing optical cable 2 is intact; if it is intact, execute step 2, otherwise replace a sensing optical cable 2 and repeat this step; Step 2, close the wellhead gate, confirm that there is no well fluid leakage, replace the wellhead flange, install the wellhead blowout preventer 9, and connect the blowout pipe 10 with the sensing optical cable 2 inside to the wellhead blowout preventer 9 after passing the ground pressure test; Step 3, close the half-closed gate plate of the wellhead blowout preventer 9, open the wellhead gate 8, confirm that there is no leakage at the wellhead, open the half-closed gate plate of the blowout preventer 9, make the well fluid fill the blowout pipe 10, and make the pressure in the blowout pipe 10 and the pressure in the well reach a balanced state; Step 4, lower the sensing optical cable 2 to the predetermined position, after confirming that the optical cable is lowered to the predetermined position, detect the sensing optical cable 2, close the half-closed gate plate of the wellhead blowout preventer 9, open the pressure relief switch of the blowout pipe 10, vent the pressure of the blowout pipe 10, disconnect the blowout pipe 10 and the wellhead blowout preventer 9, use the optical cable hanger to fix the sensing optical cable 2, and then cut the sensing optical cable 2; Step 5, pass the sensing optical cable 2 that needs to be left in the well through the blowout pipe 10, pass the sensing optical cable 2 into the ground static sealing device 4, raise the sensing optical cable to release the optical cable hanger, connect the ground static sealing device 4 and the wellhead blowout preventer 9, use the optical cable hanger to fix the sensing optical cable 2 left in the well on the upper end of the ground static sealing device 4, ensure that the sensing optical cable 2 in the well does not fall off, and install the ground leakage prevention device 6 and the ground data acquisition device 7 on the sensing optical cable 2 reserved on the ground.

[0024] Referring to Figure 3 , step 5 is the installation of the ground static sealing device in the present application, comprising the following steps: Step 5.1: after confirming that the optical cable is lowered to the predetermined position, close the half-closed gate plate of the wellhead blowout preventer (9), ensure that the sealing performance of the sensing optical cable is good, the well fluid does not leak, and the optical cable is intact; Step 5.2, disconnect the wellhead blowout preventer 9 and the blowout pipe 10, raise the blowout pipe 10 to keep a 2-5 meter interval with the wellhead blowout preventer 9, install the wellhead optical cable suspension device 5 in the interval, loosen the sensing optical cable 2 to make the wellhead optical cable suspension device 5 placed on the wellhead blowout preventer 9, and the sensing optical cable 2 does not fall off; Step 5.3, the sensing optical cable 2 is pulled out from the blowout preventer 10 and into the ground static sealing device 4, and another wellhead optical cable suspension device 5 is installed on the upper end of the ground static sealing device 4; Step 5.4, the wellhead optical cable suspension device 5 on the upper end of the ground static sealing device 4 is pulled up, so that the wellhead optical cable suspension device 5 placed on the wellhead blowout preventer 9 is separated from the wellhead blowout preventer 9, the wellhead optical cable suspension device 5 is removed, the sensing optical cable 2 is lowered, the ground static sealing device 4 is placed on the wellhead blowout preventer 9 and firmly connected, the upper end of the ground static sealing device 4 and the lower end of the wellhead optical cable suspension device 5 are connected, and it is confirmed that the optical cable in the well will not fall off; Step 5.5, the half-shut plate of the wellhead blowout preventer 9 is opened, it is confirmed that the fluid in the well will not leak, the ground leakage prevention device 6 is installed on the sensing optical cable 2 reserved on the ground, and the ground data acquisition device 7 is connected.

[0025] Example 2 The embodiment provides a long-term dynamic monitoring construction system for tubing optical cable laying, which comprises an optical cable swivel head 3, a ground static sealing device 4, a wellhead optical cable suspension device 5, a ground leakage prevention device 6, a ground data acquisition device 7, a wellhead blowout preventer 9 and a blowout preventer 10. When the long-term dynamic monitoring construction for tubing optical cable laying is performed, the sensing optical cable 2 to be laid is connected with the optical cable swivel head 3 after passing through the blowout preventer 10 and the blowout control head, the optical cable swivel head 3 is located in the well, the wellhead blowout preventer 9 is located at the wellhead, the ground static sealing device 4 is located above the wellhead blowout preventer 9 and connected with the wellhead blowout preventer 9, and the ground leakage prevention device 6 and the ground data acquisition device 7 are installed on the sensing optical cable 2 reserved on the ground. The ground static sealing device 4 is mainly used for sealing the outside of the sensing optical cable 2 to prevent well fluid leakage. The wellhead optical cable suspension device 5 is used for clamping the sensing optical cable 2 during the process of passing the sensing optical cable 2 into the ground static sealing device 4. The ground leakage prevention device 6 is mainly used for sealing the optical unit and the core of the sensing optical cable 2 to prevent the well fluid from leaking from the space between the optical unit and the core to the ground in the case that the downhole sealing pressure device fails. The ground data acquisition device 7 is used for acquiring the data of the wellbore temperature, vibration and the like of the whole wellbore.

[0026] Example 3 Referring to Figure 4 The embodiment provides a wellhead optical cable suspension device, which comprises a compression fixing cap 11, a steel cable lifting ring 12 and a slip-type optical cable fixing mandrel 13, the slip-type optical cable fixing mandrel 13 is used for fixing the sensing optical cable 2, the compression fixing cap 11 is used for fixing the slip-type optical cable fixing mandrel 13, and the steel cable lifting ring 12 is used for pulling the wellhead optical cable suspension device.

[0027] The compression fixing cap 11 and the slip-type optical cable fixing mandrel 13 are fixedly connected, and the steel cable lifting ring 12 is located between the compression fixing cap 11 and the slip-type optical cable fixing mandrel 13, and the steel cable lifting ring 12 is fixedly connected with the compression fixing cap 11.

[0028] Embodiment 4 With reference to Figure 5 , the embodiment provides a downhole sealing pressure-bearing device, i.e., an optical cable swabbing head 3, which comprises a sleeve-type optical cable fixing mandrel 14, a downhole sealing joint 15, a sensing optical cable sealing pressure cap 16, a sealing pressure-bearing cylinder 17, and an optical cable fixing mandrel limiting pin 18. One end of the sleeve-type optical cable fixing mandrel 14 extends into a cavity in a first end of the downhole sealing joint 15 and is fixedly connected with the downhole sealing joint 15 through the optical cable fixing mandrel limiting pin 18, and the sleeve-type optical cable fixing mandrel 14 is used for fixing the sensing optical cable 2. The downhole sealing joint 15 is connected with the sealing pressure-bearing cylinder 17 together to form an integral sealing space to prevent well fluid from invading. The sensing optical cable sealing pressure cap 16 is inserted into an opening in the first end of the sealing joint 15, and the sensing optical cable sealing pressure cap 16 is used for sealing the sensing optical cable to prevent well fluid from entering the downhole sealing joint 15 and the sealing pressure-bearing cylinder 17 connected together to form an integral sealing space.

[0029] The optical cable swabbing head 3 has the functions of fixing the outer armor of the sensing optical cable to prevent the swabbing head from falling off and sealing to prevent well fluid from invading the sensing optical cable and causing damage to the fiber core.

[0030] Embodiment 5 With reference to Figure 6 , the embodiment provides a surface static sealing device, which is mainly used for sealing the outside of the sensing optical cable 2 to prevent well fluid from leaking. The surface static sealing device 4 comprises a connecting lug 20, a sealing device body 21, a pressure test interface 22, and a connecting joint 23. The connecting lug 20 is fixed to the lower end of the sealing device body 21 to connect the surface static sealing device and the wellhead flange 19 into an integral whole. The sealing device body 21 is used for sealing the sensing optical cable 2. The pressure test interface 22 is arranged on the side wall of the sealing device body 21 and is used for detecting pressure leakage. The connecting joint 23 is fixed to the upper end of the sealing device body 21 and is used for connecting the wellhead optical cable suspension device.

[0031] The surface static sealing device 4 adopts a modular design and can replace damaged modules under the condition that the wellhead blowout prevention device is used to close the wellhead, thereby ensuring long-term static sealing performance.

[0032] Embodiment 6 With reference to Figure 7This embodiment provides a surface leak-proof device 6, which is mainly used to seal the optical unit and fiber core of the sensing optical cable 2 to prevent well fluid from leaking to the surface from the space between the optical unit and the fiber core in the event of failure of the downhole sealing pressure device. The surface leak-proof device includes an optical unit sealing fastening nut 25, a leak-proof device pressure-bearing body 26, and a fiber core sealing fastening nut 28. The optical unit sealing fastening nut 25 seals the optical unit 24 of the sensing optical cable and is connected to the leak-proof device pressure-bearing body 26. The fiber core sealing fastening nut 28 seals the fiber core 27 of the sensing optical cable and is connected to the leak-proof device pressure-bearing body, forming a complete surface leak-proof device. The leak-proof device pressure-bearing body 26 is provided with sealing fastening seats at both ends for installing the optical unit sealing fastening nut 25 and the fiber core sealing fastening nut 27. The inner hole of the sealing fastening seat is conical. The leak-proof device pressure-bearing body 26 is provided with limit holes to prevent the optical unit from moving longitudinally and damaging the fiber core. The optical unit has a metal sealing ring inside the sealing fastening nut. The metal sealing ring is conical and fits around the optical unit. Its conical shape matches the conical shape of the sealing fastening seat. As the fastening nut is tightened, it forms two sealing surfaces with the outer surface of the optical unit and the sealing fastening seat to prevent fluid in the well from leaking to the surface.

[0033] The ground leak-proof safety device 6 can effectively seal the sensing optical cable, ensuring that in an emergency where well fluid enters the optical cable, it will not leak to the ground and cause a safety accident.

[0034] The term "constituting of" in describing a combination should include the identified elements, components, parts, or steps, as well as other elements, components, parts, or steps that do not substantially affect the essential novel features of the combination. The use of the terms "comprising" or "including" to describe combinations of elements, components, parts, or steps herein also contemplates embodiments that are essentially composed of such elements, components, parts, or steps. The use of the term "may" herein is intended to indicate that any described attribute included by "may" is optional.

[0035] Multiple elements, components, parts, or steps can be provided by a single integrated element, component, part, or step. Alternatively, a single integrated element, component, part, or step can be divided into multiple separate elements, components, parts, or steps. The use of "a" or "an" to describe an element, component, part, or step does not imply the exclusion of other elements, components, parts, or steps.

[0036] It is to be understood that the above description is intended to be illustrative, and not restrictive. Many embodiments and applications other than the examples provided would be apparent to those of skill in the art upon reading the above description. The scope of the technology should be determined, not with reference to the above description, but should instead be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled. The disclosures of all articles and references, including patent applications and publications, are incorporated by reference for all purposes. The omission in the foregoing description of any aspect of the subject matter disclosed herein is not a disclaimer of such subject matter, nor should it be regarded that the applicant has disclaimed any such subject matter, nor should any such omission be regarded as affecting the scope of the claimed teaching.

Claims

1. A construction process for long-term dynamic monitoring of optical cable laying inside oil pipelines, characterized in that, Includes the following steps: Step 1: Connect the blowout preventer (10) and the blowout preventer control head on the ground. After passing the sensor fiber optic cable (2) through the blowout preventer (10) and the blowout preventer control head, connect it to the fiber optic cable head (3). Test whether the sensor fiber optic cable (2) is intact. If it is intact, proceed to step 2; otherwise, replace the sensing optical cable (2) and repeat this step. Step 2: Close the wellhead gate valve, install the wellhead blowout preventer (9) under the condition of no well fluid leakage, and connect the blowout preventer pipe (10) to the wellhead blowout preventer (9); Step 3: Close the semi-sealing gate of the wellhead blowout preventer (9), open the wellhead gate, and open the semi-sealing gate of the wellhead blowout preventer (9) under the condition that there is no leakage at the wellhead, so that the well fluid fills the blowout preventer pipe (10) and the pressure inside the blowout preventer pipe (10) reaches a state of equilibrium with the pressure inside the well. Step 4: Lower the sensing optical cable (2) to the predetermined position, check that the sensing optical cable (2) is intact, close the semi-sealing gate of the wellhead blowout preventer (9), release the pressure of the blowout preventer pipe (10), disconnect the blowout preventer pipe (10) from the wellhead blowout preventer (9), and cut off the sensing optical cable (2). Step 5: After passing the sensor fiber cable (2) that needs to be left in the well through the blowout preventer (10), pass the sensor fiber cable (2) through the ground static sealing device (4), lift the sensor fiber cable (2), connect the ground static sealing device (4) and the wellhead blowout preventer (9), fix the sensor fiber cable (2) left in the well to the upper end of the ground static sealing device (4), and install the ground leak prevention insurance device (6) and the ground data acquisition device (7) on the sensor fiber cable (2) reserved on the ground.

2. The construction process for long-term dynamic monitoring of optical cable laying inside oil pipelines according to claim 1, characterized in that, In step 1, the sensor optical cable (2) is tested for integrity using a string of instruments for testing.

3. The construction process for long-term dynamic monitoring of optical cable laying inside oil pipelines according to claim 1, characterized in that, In step 4, before cutting the sensing optical cable (2), the sensing optical cable (2) is fixed with an optical cable hanger.

4. The construction process for long-term dynamic monitoring of optical cable laying in oil pipelines according to claim 1, characterized in that, Step 5 includes the following steps: S1. Raise the blowout preventer (10) to maintain the distance between it and the wellhead blowout preventer (9), install the wellhead optical cable suspension device (5) within the distance, loosen the sensing optical cable (2) so that the wellhead optical cable suspension device (5) is placed on the wellhead blowout preventer (9) and the sensing optical cable (2) will not fall off. S2. Pass the sensing optical cable (2) out of the blowout preventer (10) and into the ground static sealing device (4). Install another wellhead optical cable suspension device (5) on the upper end of the ground static sealing device (4). S3. Raise the wellhead optical cable suspension device (5) at the top of the ground static sealing device (4) so ​​that the wellhead optical cable suspension device (5) placed on the wellhead blowout preventer (9) is separated from the wellhead blowout preventer (9). Remove the wellhead optical cable suspension device (5) here. Lower the sensing optical cable (2) so that the ground static sealing device (4) is placed on the wellhead blowout preventer (9) and connected. Connect the upper end of the ground static sealing device (4) and the lower end of the wellhead optical cable suspension device (5). S4. Open the semi-sealing gate of the wellhead blowout preventer (9). Under the condition that the fluid in the well will not leak, install the ground leak prevention insurance device (6) on the ground-preserved sensing optical cable (2) and connect it to the ground data acquisition device (7).

5. A long-term dynamic monitoring system for fiber optic cable laying within oil pipelines, characterized in that, It includes a fiber optic cable header (3), a ground static sealing device (4), a ground leak prevention safety device (6), a ground data acquisition device (7), a wellhead blowout preventer (9), and a blowout preventer pipe (10). During the long-term dynamic monitoring construction of fiber optic cable laying in the oil pipe, the sensor fiber optic cable (2) to be laid passes through the blowout preventer pipe (10) and the blowout preventer control head and is connected to the fiber optic cable header (3). The fiber optic cable header (3) is located in the well. The wellhead blowout preventer (9) is located at the wellhead. The ground static sealing device (4) is located above the wellhead blowout preventer (9) and is connected to the ground static sealing device (4). The ground leak prevention safety device (6) and the ground data acquisition device (7) are installed on the sensor fiber optic cable (2) reserved on the ground.

6. The long-term dynamic monitoring construction system for optical cable laying in oil pipelines according to claim 5, characterized in that, It also includes a wellhead optical cable suspension device (5), which is used to hold the sensing optical cable (2) when it is inserted into the ground static sealing device (4).

7. The long-term dynamic monitoring construction system for optical cable laying in oil pipelines according to claim 6, characterized in that, The wellhead optical cable suspension device (5) includes a clamping and fixing cap (11), a steel cable shackle (12), and a clasp-type optical cable fixing spindle (13). The clamping and fixing cap (11) and the clasp-type optical cable fixing spindle (13) are fixedly connected, and the steel cable shackle (12) is located between the clamping and fixing cap (11) and the clasp-type optical cable fixing spindle (13).

8. The long-term dynamic monitoring construction system for optical cable laying in oil pipelines according to claim 5, characterized in that, The optical cable headstock (3) includes a sleeve-type optical cable fixing mandrel (14), a downhole sealing joint (15), a sensor optical cable sealing cap (16), a sealing pressure cylinder (17), and an optical cable fixing mandrel limiting pin (18). One end of the sleeve-type optical cable fixing mandrel (14) extends into the cavity of the first end of the downhole sealing joint (15) and is fixedly connected to the downhole sealing joint (15). The downhole sealing joint (15) is connected to the sealing pressure cylinder (17). The sensor optical cable sealing cap (16) is inserted into the opening of the first end of the sealing joint (15) to seal the sensor optical cable.

9. A long-term dynamic monitoring system for optical cable laying in oil pipelines according to claim 5, characterized in that, The ground static sealing device (4) includes a connecting union (20), a sealing device body (21), a pressure test interface (22), and a connecting joint (23). The connecting union (20) is fixed to the lower end of the sealing device body (21). The sealing device body (21) has a pressure test interface (22) on its side wall, and the sealing device body (21) has a connecting joint (23) fixed to its upper end.

10. A long-term dynamic monitoring system for optical cable laying in oil pipelines according to claim 5, characterized in that, The ground leak-proof safety device (6) includes an optical unit sealing fastening nut (25), a leak-proof device pressure-bearing body (26), and a fiber core sealing fastening nut (28). The optical unit sealing fastening nut (25) seals the sensing optical cable optical unit (24) and is connected to the leak-proof device pressure-bearing body (26). The fiber core sealing fastening nut (28) seals the sensing optical cable fiber core (27) and is connected to the leak-proof device pressure-bearing body.

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