A graded cementing head with optical fiber protection function

Abstract

The present application relates to cementing operation technical field, specifically provide a kind of hierarchical cementing device with optical fiber protection function. Including hierarchical cementing device body. Hierarchical cementing device body includes outer tube, outer tube is eccentric circular structure, the wall thickness of outer tube is continuously changed along the circumferential direction, and maximum wall thickness and minimum wall thickness are formed;Outer tube is set with the accommodating groove for accommodating optical fiber at maximum wall thickness along its axial direction;Accommodating groove is detachably provided with protective pressing plate, and the outer surface of protective pressing plate is flush with the outer surface of hierarchical cementing device body after installation.The position of accommodating groove of the present application is outer tube at maximum wall thickness, and sufficient residual wall thickness is reserved, to ensure the structural strength of outer tube under deep well high pressure, stretching and torsion working condition.Optical fiber is completely protected in accommodating groove, and is not contacted with well wall, to avoid the risk that optical fiber is abraded, extruded or cut off by formation rock.

Description

Technical Field

[0001] This invention relates to the field of cementing operation technology, and specifically to a staged cementing injector with fiber optic protection function. Background Technology

[0002] Staged cementing devices (also known as staged clamps) are key tools in staged cementing operations for deep and ultra-deep wells. By dividing the long cementing section into two stages from bottom to top for cementing operations, they can reduce the risk of well leakage during cementing, while also reducing construction pressure and shortening cementing time. In recent years, with the increasing demand for permanent downhole monitoring in deep well (depth ≥ 2000m) cementing operations, long-term real-time monitoring of parameters such as downhole temperature, acoustic waves, and strain can be achieved by laying optical fibers on the outer wall of the casing, providing important data support for the full life cycle management of oil and gas wells.

[0003] However, the maximum outer diameter of a conventional staged cement injector is usually larger than the outer diameter of the casing coupling. When an optical fiber is installed on the outer wall of the casing, the optical fiber is suspended or pressed against the outer wall of the staged cement injector when it passes the staged cement injector body. During the well process, it comes into direct contact with the well wall and is easily worn, squeezed or even cut by the formation rocks, resulting in the optical fiber signal attenuation or complete failure.

[0004] Currently, external fiber optic protection devices are generally chosen. These devices are independently attached to the casing coupling or casing body. After installation, the overall outer diameter of the staged cement injector is further increased, which not only increases the risk of obstruction when going downhole, but also makes the segmented structure prone to loosening or falling off under complex stress conditions downhole, posing a safety hazard to downhole operations. Summary of the Invention

[0005] This invention provides a graded cement injector with optical fiber protection function, which solves the technical problem that external optical fibers are easily worn and damaged when passing through the body of the graded cement injector.

[0006] To address the above problems, this invention provides a graded cement injector with fiber optic protection function, comprising: The graded cement injection device body includes an outer cylinder, which is an eccentric ring structure. The wall thickness of the outer cylinder changes continuously along the circumferential direction, forming a maximum wall thickness and a minimum wall thickness. The outer cylinder has a receiving groove for accommodating optical fibers along its axial direction at the maximum wall thickness. The receiving groove is detachably provided with a protective pressure plate, and after the protective pressure plate is installed, its outer surface is flush with the outer surface of the graded cement injector body.

[0007] Preferably, the receiving groove is a stepped groove, which includes a first groove segment and a second groove segment that are sequentially connected from the outer surface of the graded cement injector body inward. The first groove segment is used to receive the protective pressure plate, and the second groove segment is used to receive the optical fiber.

[0008] Preferably, the second groove segment includes one or two independently arranged grooves, each groove having a cross-sectional shape of either an arc or a square.

[0009] Preferably, the graded cement injector body further includes a closing sleeve, an opening plug seat, a closing plug seat, a lower connector, and an upper connector. The upper connector and the lower connector are respectively connected to the upper end and the lower end of the outer cylinder. The closing sleeve is axially slidably disposed inside the outer cylinder. The opening plug seat and the closing plug seat are respectively connected to the closing sleeve by shear pins.

[0010] Preferably, the outer walls of the upper and lower ends of the outer cylinder are respectively provided with a first slope surface, and the upper connector and the lower connector are respectively provided with a second slope surface at the end adjacent to the outer cylinder. The first slope surface and the second slope surface have the same inclination direction, which is used to form a transition slope structure.

[0011] Preferably, the upper connector and / or the lower connector are provided with an optical fiber retainer on their outer walls. The optical fiber retainer is provided with a cable groove for the optical fiber to pass through. The cable groove and the receiving groove extend in the same direction, and the end of the cable groove is close to the end of the receiving groove, so as to smoothly guide the optical fiber from the receiving groove into the cable groove.

[0012] Preferably, the fiber optic fastener includes a fixing body and a buckle. The fixing body is provided with the cable groove. One side of the buckle is rotatably connected to the fixing body by a folding pin. After the buckle and the fixing body are aligned, they together form two annular clamps arranged at intervals along the axial direction. The annular clamps are tightly clamped to the outer wall of the upper connector and / or the lower connector. The other side of the buckle is locked and fixed to the fixing body by the cooperation of a locking nut and a locking bolt.

[0013] Preferably, the outer cylinder and the closing sleeve are respectively provided with circulation holes, and the circulation holes on the outer cylinder and the circulation holes on the closing sleeve are correspondingly arranged, and the circulation holes are blocked by the opening plug seat.

[0014] Preferably, it further includes an opening plug, which is adapted to the opening plug seat. The opening plug seat is pushed by the opening plug to cut off the corresponding shearing pin and move axially to open the circulation hole.

[0015] Preferably, it further includes a shut-off plug, which is adapted to the shut-off plug seat. The shut-off plug seat, under the push of the shut-off plug, cuts off the corresponding shear pin and drives the shut-off sleeve to move axially to close the circulation hole.

[0016] Beneficial technical effects of the present invention: This invention discloses a graded cement injector with optical fiber protection, comprising a graded cement injector body, which includes an outer cylinder. The outer cylinder has an eccentric annular structure, and its wall thickness continuously varies along the circumference, forming a maximum wall thickness and a minimum wall thickness. At the maximum wall thickness, the outer cylinder has an axially oriented receiving groove for accommodating the optical fiber. A protective pressure plate is detachably mounted on the receiving groove, and its outer surface is flush with the outer surface of the graded cement injector body after installation. The receiving groove is located at the maximum wall thickness of the outer cylinder, thus preserving sufficient remaining wall thickness to ensure the structural strength of the outer cylinder under high pressure, tension, and torsion conditions in deep wells. Simultaneously, the protective pressure plate, after installation, is flush with the outer surface of the graded cement injector body, without additionally increasing the overall outer diameter of the graded cement injector. During downhole operation, the protective pressure plate directly contacts and rubs against the well wall, while the optical fiber is completely protected within the receiving groove, preventing contact with the well wall and thus avoiding the risk of the optical fiber being worn, squeezed, or cut by the formation rock. Attached Figure Description

[0017] Figure 1 This is a half-sectional schematic diagram of a graded cement injector with optical fiber protection function in one embodiment of the present invention; Figure 2 for Figure 1 A schematic diagram of the radial section; Figure 3 A schematic diagram of the structure of the optical fiber fixator in one embodiment of the present invention; Figure 4 A schematic diagram of the closing plug in one embodiment of the present invention; Figure 5 A schematic diagram of the opening plug in one embodiment of the present invention.

[0018] Explanation of reference numerals in the attached drawings: 1-Cement injector body; 2-Opening plug; 3-Closing plug; 11-Outer cylinder; 12-Closing sleeve; 13-Opening plug seat; 14-Closing plug seat; 15-Lower connector; 16-Upper connector; 17-Fiber optic fixer; 171-Cable trough; 172-Fixing body; 173-Clip tile; 174-Folding pin; 175-Locking nut; 176-Locking bolt; 110-First slope; 111-Receiving groove; 112-Protective pressure plate; 120-Second slope. Detailed Implementation

[0019] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Although some embodiments of the present invention are shown in the drawings, it should be understood that the present invention can be implemented in various forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of the present invention. It should be understood that the accompanying drawings and embodiments of the present invention are for illustrative purposes only and are not intended to limit the scope of protection of the present invention.

[0020] The term "comprising" and its variations as used herein are open-ended, meaning "including but not limited to"; the term "based on" means "at least partially based on"; the term "one embodiment" means "at least one embodiment"; the term "another embodiment" means "at least one additional embodiment"; the term "some embodiments" means "at least some embodiments"; and the term "optionally" means "optional embodiments". Definitions of other terms will be given in the following description. It should be noted that the concepts of "first," "second," etc., mentioned in this invention are used only to distinguish different devices, modules, or components, and are not intended to limit the order of functions performed by these devices, modules, or components or their interdependencies.

[0021] It should be noted that the terms "a" and "a plurality of" used in this invention are illustrative rather than restrictive. Those skilled in the art should understand that, unless otherwise expressly indicated in the context, they should be understood as "one or more".

[0022] To address the problems existing in the aforementioned related technologies, the present invention provides a graded cement injector with optical fiber protection function.

[0023] See Figure 1 and Figure 2 As shown, a specific embodiment of the present invention provides a graded cement injector with optical fiber protection function, including a graded cement injector body 1. The graded cement injector body 1 includes an outer cylinder 11, which is an eccentric ring structure. The wall thickness of the outer cylinder 11 changes continuously along the circumferential direction, forming a maximum wall thickness and a minimum wall thickness. The outer cylinder 11 has a receiving groove 111 for accommodating optical fibers along its axial direction at the maximum wall thickness. A protective pressure plate 112 is detachably provided on the receiving groove 111. After the protective pressure plate 112 is installed, its outer surface is flush with the outer surface of the graded cement injector body 1.

[0024] Specifically, the outer cylinder 11 has an eccentric annular cross-section, with the center of its inner hole not coinciding with the center of its outer circle, resulting in a continuous variation in wall thickness along the circumference of the outer cylinder 11. The outer cylinder 11 has the maximum wall thickness on one side of the eccentric direction, and the minimum wall thickness on the opposite side. The receiving groove 111 is located at the maximum wall thickness and extends along the axial direction of the outer cylinder 11, with the groove's direction parallel to the axis of the outer cylinder 11. A protective pressure plate 112 is installed on top of the receiving groove 111 using fixing screws or other detachable connection methods. When installing the optical fiber, the protective pressure plate 112 is first removed, the optical fiber is placed into the receiving groove 111, and then the protective pressure plate 112 is closed and fixed, thus enclosing the optical fiber within the receiving groove 111.

[0025] It should be noted that in this embodiment, by setting the outer cylinder 11 as an eccentric ring structure and opening a receiving groove 111 on the side with the largest wall thickness, the outer cylinder 11 at the location of the receiving groove 111 still retains sufficient remaining wall thickness, thereby ensuring the structural strength of the outer cylinder 11 under deep well high pressure, tension, and torsion conditions. Simultaneously, after installation, the protective pressure plate 112 is flush with the outer surface of the staged cement injector body 1, without additionally increasing the overall outer diameter of the staged cement injector. This solves the technical problem in the prior art where the outer diameter of a conventional staged cement injector is larger than the outer diameter of the casing coupling, leading to the fiber optic cable protruding and being easily worn. Because the protective pressure plate 112 is flush with the outer diameter surface of the staged cement injector body 1, it directly contacts and rubs against the well wall during downhole operation, while the optical fiber is completely protected within the receiving groove 111 and does not contact the well wall, thus avoiding the risk of the optical fiber being worn, squeezed, or cut by the formation rock.

[0026] In one embodiment of the present invention, the wall thickness difference between the maximum wall thickness and the minimum wall thickness is 5 mm to 10 mm.

[0027] It should be noted that the specific value of the wall thickness difference is determined based on the specifications and dimensions of the graded cement injection device and the diameter of the installed optical fiber.

[0028] In one embodiment of the present invention, the receiving groove 111 is a stepped groove, which includes a first groove segment and a second groove segment that are sequentially connected from the outer surface of the cement injection body 1. The first groove segment is used to receive the protective pressure plate 112, and the second groove segment is used to receive the optical fiber.

[0029] It should be noted that by setting the receiving groove 111 as a stepped groove, the optical fiber is accommodated in the second groove segment, and the protective pressure plate 112 is embedded in the first groove segment, so that the protective pressure plate 112 has precise positioning in the thickness direction. The thickness (1.5mm) of the protective pressure plate 112 is consistent with the depth of the first groove segment, which structurally ensures that the protective pressure plate 112 is flush with the outer surface of the graded cement injector body 1 after installation.

[0030] In one embodiment of the present invention, the second groove segment includes one or two independently arranged grooves, each groove having a cross-sectional shape of arc or square.

[0031] It should be noted that setting one or two independent grooves can flexibly adapt to the fiber optic installation requirements in different scenarios. The independently designed grooves provide each fiber with its own space, preventing multiple fibers from being squeezed or tangled in the same groove, effectively preventing frictional damage between fibers. The cross-sectional shape matches the fiber's cross-sectional shape, ensuring good constraint within the groove and preventing it from moving freely. This also increases the contact area between the fiber and the groove wall, reducing localized stress concentration and further protecting the fiber from damage. When the groove's cross-sectional shape is square, its corners are rounded to avoid stress concentration points that could reduce the overall strength.

[0032] In one embodiment of the present invention, the graded cement injector body 1 further includes a closing sleeve 12, an opening plug seat 13, a closing plug seat 14, a lower connector 15, and an upper connector 16. The upper connector 16 and the lower connector 15 are respectively connected to the upper end and the lower end of the outer cylinder 11. The closing sleeve 12 is axially slidably disposed inside the outer cylinder 11. The opening plug seat 13 and the closing plug seat 14 are respectively connected to the closing sleeve 12 by shear pins.

[0033] Specifically, the upper connector 16 and the lower connector 15 are respectively provided with threads for connecting the sleeves. The upper connector 16 connects to the upper sleeve, and the lower connector 15 connects to the lower sleeve. The closing sleeve 12 has a cylindrical structure, and its outer wall slides in fit with the inner wall of the outer cylinder 11, allowing it to slide axially up and down inside the outer cylinder 11. The opening plug seat 13 is located inside the lower end of the closing sleeve 12 and is fixedly connected to the closing sleeve 12 by a shear pin. The closing plug seat 14 is located inside the upper end of the closing sleeve 12 and is also fixedly connected to the closing sleeve 12 by a shear pin. The shear pin is made of shearable metal and can be sheared under a predetermined shear force.

[0034] The closing sleeve 12, opening plug seat 13, and closing plug seat 14 together constitute the opening and closing control mechanism of the circulation hole. Therefore, while having fiber optic protection function, the staged cementing machine can still perform staged cementing operations normally, realizing the integration of the two major functions of staged cementing and fiber optic protection.

[0035] In one embodiment of the present invention, the outer walls of the upper end and the lower end of the outer cylinder 11 are respectively provided with a first slope surface 110, and the upper connector 16 and the lower connector 15 are respectively provided with a second slope surface 120 at the end adjacent to the outer cylinder 11. The first slope surface 110 and the second slope surface 120 have the same inclination direction, and the two together form a transition slope structure.

[0036] Specifically, the first slope 110 is a conical slope on the outer wall of the outer cylinder 11, gradually widening in diameter from the end of the outer cylinder 11 towards the center; the second slope 120 is a conical slope at the end of the joint, gradually widening in diameter from the end of the joint towards its main body. Both slopes are in the same direction, creating a continuous and smooth transition zone at the joint between the first slope 110 and the second slope 120.

[0037] It should be noted that, since the maximum outer diameter of the outer cylinder 11 is larger than the outer diameters of the upper connector 16 and the lower connector 15, the end of the outer cylinder 11 is a section with a sudden change in diameter during the process of lowering the staged cementing device into the well. By setting a transition slope structure formed by the first slope surface 110 and the second slope surface 120 at the end, the original step-like diameter abrupt change is transformed into a smooth conical transition, reducing the risk of jamming when the staged cementing device encounters well wall steps or diameter reduction sections during the process of lowering into the well.

[0038] See Figure 3 As shown, in one embodiment of the present invention, an optical fiber retainer 17 is provided on the outer wall of the upper connector 16 and / or the lower connector 15. The optical fiber retainer 17 is provided with a cable groove 171 for the optical fiber to pass through. The cable groove 171 and the receiving groove 111 extend in the same direction, and the end of the cable groove 171 is close to the end of the receiving groove 111, so as to smoothly guide the optical fiber from the receiving groove 111 into the cable groove 171.

[0039] It should be noted that the cable groove 171 and the receiving groove 111 extend in the same direction and their ends are close to each other. The end of the cable groove 171 is close to the end of the receiving groove 111, which allows the optical fiber to directly enter the cable groove 171 after extending from the receiving groove 111, maintaining a smooth transition of the optical fiber. At the same time, it also further constrains the optical fiber, preventing it from slipping out due to cement slurry impact or casing string vibration during cementing, thus ensuring the continuity of the optical fiber and the stability of signal transmission at the staged cementing device.

[0040] In one embodiment of the present invention, the fiber optic fixer 17 includes a fixing body 172 and a buckle 173. The fixing body 172 is provided with a cable groove 171. One side of the buckle 173 is rotatably connected to the fixing body 172 by a folding pin 174. After the buckle 173 and the fixing body 172 are engaged, they together form two annular clamps arranged axially at intervals. The annular clamps are tightly clamped to the outer wall of the upper connector 16 and / or the lower connector 15. The other side of the buckle 173 is locked and fixed to the fixing body 172 by the cooperation of a locking nut 175 and a locking bolt 176.

[0041] It should be noted that in this embodiment, the buckle 173 and the fixing body 172 are fitted together to form two axially spaced annular clamps, creating two clamping points on the outer walls of the upper connector 16 and / or lower connector 15 for the fiber optic fixator 17. Compared with the single-ring structure, this provides higher resistance to torsion and axial movement. When subjected to cement slurry impact or casing vibration downhole, the double-ring structure can provide more reliable resistance to torsion and axial movement, preventing the fiber optic fixator 17 from rotating or sliding axially along the outer wall of the connector. Simultaneously, the fixing body 172 is provided with a cable groove 171, and after the buckle 173 is closed, the cable groove 171 is enclosed inside the annular clamps, further improving the reliability of fiber optic protection.

[0042] In one embodiment of the present invention, circulation holes are respectively provided on the outer cylinder 11 and the closing sleeve 12, and the circulation holes on the outer cylinder 11 and the circulation holes on the closing sleeve 12 are correspondingly arranged, and the circulation holes are blocked by the opening plug seat 13.

[0043] It should be noted that during the running-in of the staged cementing tool with the casing and during the first stage of cementing, the circulation port is closed, preventing fluid exchange between the inside and outside of the casing and ensuring that the first-stage cement slurry can smoothly reach the bottom section of the well. When the second stage of cementing is required, the opening plug can be inserted to push the opening plug seat 13 to shear the pin and move downwards, opening the circulation port and establishing a channel between the inside of the casing and the annulus, thus realizing the establishment of circulation for staged cementing and the second-stage cementing operation. The circulation port is provided in pairs on the outer cylinder 11 and the closing sleeve 12, ensuring precise alignment of the open and closed positions and reliable sealing.

[0044] In one embodiment of the present invention, a plurality of petals are spaced apart on the upper part of the closing sleeve 12 along the circumferential direction. The outer wall of the petals and the inner wall of the outer cylinder 11 are respectively provided with serrations in opposite directions, which are used to prevent the closing sleeve 12 from moving in the opposite direction after it slides into place.

[0045] Specifically, the closing sleeve 12 can be an integral cylindrical structure with multiple axial slits spaced apart along the circumference on its upper part, and the cylindrical wall between adjacent slits forms a valve. The valve has radial elastic deformation capability, and can contract inward or open outward. The outer wall surface of the valve is provided with serrations, and the inner wall surface of the upper part of the outer cylinder 11 is provided with corresponding serrations. The tips of the serrations on the outer wall of the closing sleeve 12 face downward, and the tips of the serrations on the inner wall of the outer cylinder 11 face upward, with the tips of the two facing opposite directions, forming a mating relationship with opposite directions.

[0046] When the closing sleeve 12 slides downwards along the inside of the outer cylinder 11 under the pressure from above, the serrations on the outer wall of the closing sleeve 12 meet and contact the serrations on the inner wall of the outer cylinder 11. Since the tips of the two serrations face opposite directions, the contact area is the inclined portion of the two serrations, and the two inclined portions slide relative to each other. During this process, the valve body is subjected to radial inward compressive force and contracts inwards, temporarily reducing the overall outer diameter of the closing sleeve 12. The protruding part of the serrations can slide through the groove between the teeth on the inner wall of the outer cylinder 11, allowing the closing sleeve 12 to continue moving downwards. When the closing sleeve 12 slides into place, the valve body opens outwards and resets under its own elastic restoring force. At this time, the serrations on the outer wall of the closing sleeve 12 are embedded in the groove between adjacent serrations on the inner wall of the outer cylinder 11, forming axial alignment. If the closing sleeve 12 tends to retract upwards, the steep portion of the serrations on the outer wall of the closing sleeve 12 abuts against the steep portion of the serrations on the inner wall of the outer cylinder 11, forming axial interference between the two steep surfaces, preventing the closing sleeve 12 from moving in the opposite direction.

[0047] It should be noted that, through the serrated structure with opposing directions, the closing sleeve 12 is locked after sliding down to the closed position and cannot be retracted in the opposite direction, thus achieving permanent closure of the circulation hole. This one-way locking structure is the key to ensuring the permanent closure function of the staged cementing machine, preventing the risk of the circulation hole reopening due to the retraction of the closing sleeve 12 caused by downhole pressure fluctuations or vibrations from subsequent operations.

[0048] See Figure 5 As shown, in one embodiment of the present invention, an opening plug 2 is also included. The opening plug 2 is adapted to the opening plug seat 13. The opening plug seat 13 is pushed by the opening plug 2 to cut off the corresponding shearing pin and move axially to open the circulation hole.

[0049] It should be noted that the opening plug 2 is a gravity-type opening plug, and its outer diameter is matched with the inner diameter of the opening plug seat 13. After the opening plug 2 is inserted from the wellhead, it falls into the casing under its own weight and finally sits on the opening plug seat 13. After the pressure-bearing surface of the opening plug seat 13 receives the opening plug 2, pump pressure is applied from the wellhead. The hydraulic pressure is transmitted to the opening plug seat 13 through the opening plug 2. When the pressure reaches the predetermined value, the shear pin is sheared, and the opening plug seat 13, together with the opening plug 2, descends, exposing the circulation hole on the closing sleeve 12, thus completing the opening of the circulation hole.

[0050] See Figure 4 As shown, in one embodiment of the present invention, a closing plug 3 is further included. The closing plug 3 is adapted to the closing plug seat 14. Under the push of the closing plug 3, the closing plug seat 14 cuts off the corresponding shearing pin and drives the closing sleeve 12 to move axially to close the circulation hole.

[0051] It should be noted that the outer diameter of the shut-off plug 3 is matched with the inner diameter of the shut-off plug seat 14. After the second stage of cementing is completed, the shut-off plug 3 is released from the wellhead, pushed downwards by the mud, and finally sits on the shut-off plug seat 14. Pump pressure continues to be applied from the wellhead, and the hydraulic pressure is transmitted to the shut-off plug seat 14 through the shut-off plug 3. When the pressure reaches the predetermined value, the shear pin connecting the shut-off plug seat 14 and the shut-off sleeve 12 is sheared off. The shut-off plug seat 14 drives the entire shut-off sleeve 12 downwards together, causing the circulation hole on the shut-off sleeve 12 to be radially offset from the circulation hole on the outer cylinder 11. The circulation hole is blocked by the cylinder wall of the shut-off sleeve 12.

[0052] While the present invention has been disclosed above, its scope of protection is not limited thereto. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention, and all such changes and modifications will fall within the scope of protection of the present invention.

Claims

1. A graded cement injector with fiber optic protection function, characterized in that, include: The graded cement injection device body (1) includes an outer cylinder (11), which is an eccentric ring structure. The wall thickness of the outer cylinder (11) changes continuously along the circumferential direction, forming a maximum wall thickness and a minimum wall thickness. The outer cylinder (11) has a receiving groove (111) for accommodating optical fibers along its axial direction at the maximum wall thickness. A protective pressure plate (112) is detachably provided on the receiving groove (111), and after the protective pressure plate (112) is installed, its outer surface is flush with the outer surface of the graded cement injector body (1).

2. The graded cement injector with fiber optic protection function according to claim 1, characterized in that, The receiving groove (111) is a stepped groove, which includes a first groove segment and a second groove segment that are sequentially connected from the outer surface of the graded cement injector body (1) inward. The first groove segment is used to receive the protective pressure plate (112), and the second groove segment is used to receive the optical fiber.

3. The graded cement injector with fiber optic protection function according to claim 2, characterized in that, The second groove segment includes one or two independently arranged grooves, each groove having a cross-sectional shape of either an arc or a square.

4. The graded cement injector with fiber optic protection function according to any one of claims 1 to 3, characterized in that, The graded cement injector body (1) also includes a closing sleeve (12), an opening plug seat (13), a closing plug seat (14), a lower connector (15), and an upper connector (16). The upper connector (16) and the lower connector (15) are respectively connected to the upper end and the lower end of the outer cylinder (11). The closing sleeve (12) is axially slidably disposed inside the outer cylinder (11). The opening plug seat (13) and the closing plug seat (14) are respectively connected to the closing sleeve (12) by shear pins.

5. The graded cement injector with fiber optic protection function according to claim 4, characterized in that, The outer walls of the upper and lower ends of the outer cylinder (11) are respectively provided with a first slope surface (110), and the upper connector (16) and the lower connector (15) are respectively provided with a second slope surface (120) at the end adjacent to the outer cylinder (11). The first slope surface (110) and the second slope surface (120) have the same inclination direction, which is used to form a transition slope structure.

6. The graded cement injector with fiber optic protection function according to claim 5, characterized in that, The upper connector (16) and / or the lower connector (15) are provided with fiber optic retainers (17), and the fiber optic retainers (17) are provided with cable grooves (171) for the fiber optic cable to pass through. The cable grooves (171) and the receiving grooves (111) extend in the same direction, and the end of the cable grooves (171) is close to the end of the receiving grooves (111) so as to smoothly guide the fiber optic cable from the receiving grooves (111) into the cable grooves (171).

7. The graded cement injector with fiber optic protection function according to claim 6, characterized in that, The fiber optic fastener (17) includes a fixing body (172) and a buckle (173). The fixing body (172) is provided with the cable groove (171). One side of the buckle (173) is rotatably connected to the fixing body (172) through a folding pin (174). After the buckle (173) and the fixing body (172) are engaged, they together form two annular clamps arranged at intervals along the axial direction. The annular clamps are tightly clamped to the outer wall of the upper connector (16) and / or the lower connector (15). The other side of the buckle (173) is locked and fixed to the fixing body (172) through the cooperation of a locking nut (175) and a locking bolt (176).

8. The graded cement injector with fiber optic protection function according to claim 4, characterized in that, The outer cylinder (11) and the closing sleeve (12) are respectively provided with circulation holes, and the circulation holes on the outer cylinder (11) and the circulation holes on the closing sleeve (12) are respectively provided, and the circulation holes are blocked by the opening plug (13).

9. The graded cement injector with fiber optic protection function according to claim 8, characterized in that, It also includes an opening plug (2), which is adapted to the opening plug seat (13). The opening plug seat (13) is pushed by the opening plug (2) to cut off the corresponding shearing pin and move axially to open the circulation hole.

10. The graded cement injector with fiber optic protection function according to claim 9, characterized in that, It also includes a shut-off plug (3), which is adapted to the shut-off plug seat (14). The shut-off plug seat (14) cuts off the corresponding shear pin under the push of the shut-off plug (3) and drives the shut-off sleeve (12) to move axially to close the circulation hole.

Images