Optical cable straightening structure for logging while drilling, and drilling device

Abstract

The present application proposes an optical cable straightening structure for logging while drilling, and a drilling device, and relates to the technical field of measurement while drilling. The optical cable straightening structure includes a support ring, a protective sleeve, a sealing clamp, and a compression member. An inner ring of the support ring is provided with a penetration groove allowing an optical cable to pass through. An outer ring is anchored to an inner wall of a drill pipe. After the optical cable is sleeved with the protective sleeve with a helical slit, a shaft shoulder of the protective sleeve abuts against a limiting portion of the inner ring via the sealing clamp and is compressed and fixed by the compression member, thereby achieving straightening and protection of the optical cable in the drill pipe.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] The present application claims priority to Chinese patent application No. 202510364184.8 filed on Mar. 26, 2025 to the China National Intellectual Property Administration, and entitled “OPTICAL CABLE STRAIGHTENING STRUCTURE FOR LOGGING WHILE DRILLING, AND DRILLING DEVICE”, the entire content of which is incorporated herein by reference.TECHNICAL FIELD

[0002] The present application relates to the technical field of measurement while drilling, in particular to an optical cable straightening structure for logging while drilling, and a drilling device.BACKGROUND

[0003] Currently, the field of oil and gas exploration and development is constantly advancing into complex oil and gas fields such as low permeability, unconventionality, deep and ultra-deep layers, and deepwater environments, posing significant challenges to the efficiency, safety, and quality of drilling engineering, thus giving rise to the development of a logging while drilling technology. To solve the problem of a low transmission rate in the logging while drilling technology, optical cable logging while drilling is an innovative logging technology. Compared to traditional cable logging, an optical cable is less susceptible to electromagnetic interference, the propagation speed of a signal is significantly higher than that of a cable, and stable signal transmission can be maintained under complex geological conditions, with a maximum data transmission volume of up to a GB level per second, enabling more efficient data transmission.

[0004] Despite the numerous technical advantages of optical fiber logging while drilling, the optical cable inside the drill pipe must continuously endure scouring of downhole mud and the intense vibration environment during a drilling process, which makes it difficult to ensure the reliability of the optical cable. These factors directly determine the reception of downhole measurement signals at a ground information processing terminal. Therefore, an optical cable straightening structure is a critical component in optical cable sensing.

[0005] In the related art, optical cable straightening structures only provide straightening without applying a pretightening force to the optical cable. Failure to straighten the optical fiber may cause significant swaying, easily leading to optical cable breakage and failing to ensure the reliability of data transmission by the optical cable.SUMMARY

[0006] In view of this, the present application proposes an optical cable straightening structure for logging while drilling, and a drilling device, to solve technical problems that in the related art, optical cable straightening structures only provide straightening without applying a pretightening force to an optical cable, failure to straighten an optical fiber may cause significant swaying, easily leading to optical cable breakage and failing to ensure the reliability of data transmission by the optical cable.

[0007] A technical solution of the present application is realized in this way.

[0008] In a first aspect, the present application provides an optical cable straightening structure for logging while drilling, including a support ring, a protective sleeve, a sealing clamp, and a compression member, wherein:

[0009] the support ring includes an inner ring and an outer ring; one end of the inner ring is provided with a limiting portion, the inner ring is provided, in an axial direction, with a penetration groove penetrating through a peripheral wall, and the penetration groove allows an optical cable to pass through; the outer ring and the inner ring are connected to each other and coaxial, and the outer ring is anchored to an inner wall of a drill pipe;

[0010] a peripheral wall of the protective sleeve is provided with a helical slit extending from one end to the other end, the optical cable is installed into the protective sleeve through the helical slit, and the protective sleeve is provided with a shaft shoulder and is made of an elastic material;

[0011] the sealing clamp is arranged outside the shaft shoulder in a sleeving mode, the sealing clamp and the protective sleeve are integrally inserted into the inner ring, and one end of the shaft shoulder abuts against the limiting portion; and

[0012] the compression member is detachably connected to the inner ring, and the compression member abuts against the other end of the shaft shoulder.

[0013] In some embodiments, the optical cable straightening structure further includes set screws, a peripheral wall of the outer ring is provided with a plurality of installation holes in a radial direction, the set screws are in threaded connections with the installation holes, two ends of each set screw are respectively an operating end and a connecting end, the operating end is located on one side of an inner wall of the inner ring, and the connecting end protrudes from an outer wall of the outer ring and abuts against the inner wall of the drill pipe.

[0014] In some embodiments, the connecting end is provided with an inner concave portion.

[0015] In some embodiments, the optical cable straightening structure further includes a connecting screw. The compression member includes a compression cap and a washer, the compression cap is provided with a first connecting hole, an end face of the inner ring is provided with a second connecting hole, the second connecting hole is a threaded hole, and the connecting screw passes through the first connecting hole and is in a threaded connection with the second connecting hole; and the washer is arranged on the protective sleeve in a sleeving mode and is located between one ends of the compression cap and the shaft shoulder away from the limiting portion.

[0016] In some embodiments, the outer ring includes at least a ring body, and the ring body is provided with a notch allowing a cable to penetrate in.

[0017] In some embodiments, the outer ring further includes a sealing block and a connecting member, the sealing block is movably inserted into the notch, and the connecting member connects the sealing block to the ring body.

[0018] In some embodiments, an outer wall of the outer ring is provided with a guide face, the guide face is attached to the inner wall of the drill pipe, and the guide face is located at an end of the outer ring close to a bottom of the drill pipe.

[0019] In some embodiments, the support ring further includes a middle rod, a gap is arranged between an outer wall of the inner ring and an inner wall of the outer ring, and the middle rod is connected between the inner ring and the outer ring.

[0020] In a second aspect, the present application provides a drilling device, including a drill pipe and an optical cable, and the optical cable straightening structure for logging while drilling as described in the first aspect, the outer ring is connected to the inner wall of the drill pipe, and the optical cable is installed into the protective sleeve through the helical slit.

[0021] In some embodiments, the drill pipe includes a plurality of sequentially connected subs, and the optical cable straightening structure is located at a joint between the two adjacent subs.BRIEF DESCRIPTION OF DRAWINGS

[0022] FIG. 1 is a three-dimensional view of an optical cable straightening structure for logging while drilling in an embodiment of the present application.

[0023] FIG. 2 is a sectional view of an optical cable straightening structure for logging while drilling in an embodiment of the present application.

[0024] FIG. 3 is an exploded view of an optical cable straightening structure for logging while drilling in an embodiment of the present application.

[0025] FIG. 4 is a schematic structural diagram of a support ring in an embodiment of the present application.

[0026] FIG. 5 is a three-dimensional view of a protective sleeve in an embodiment of the present application.

[0027] FIG. 6 is a sectional view of a set screw in an embodiment of the present application.

[0028] FIG. 7 is a schematic structural diagram of a drilling device in an embodiment of the present application.

[0029] FIG. 8 is a partially enlarged diagram at A of FIG. 7.DETAILED DESCRIPTION

[0030] Referring to FIGS. 1-8, an embodiment of a first aspect of the present application provides an optical cable straightening structure for logging while drilling, including a support ring 1, a protective sleeve 2, a sealing clamp 3, and a compression member 4, wherein:

[0031] the support ring 1 includes an inner ring 11 and an outer ring 12; one end of the inner ring 11 is provided with a limiting portion 111, the inner ring 11 is provided, in an axial direction, with a penetration groove 112 penetrating through a peripheral wall, and the penetration groove 112 allows an optical cable 200 to pass through; the outer ring 12 and the inner ring 11 are connected to each other and coaxial, and the outer ring 12 is anchored to an inner wall of a drill pipe 100;

[0032] a peripheral wall of the protective sleeve 2 is provided with a helical slit 21 extending from one end to the other end, the helical slit 21 is formed from the outer wall to the inner wall, so that the optical cable 200 may be installed into the protective sleeve 2 through the helical slit 21, the optical cable 200 is straightened after installed into the protective sleeve 2, and the protective sleeve 2 is provided with a shaft shoulder 22 and is made of an elastic material;

[0033] the sealing clamp 3 is arranged outside the shaft shoulder 22 in a sleeving mode, the sealing clamp 3 and the protective sleeve 2 are integrally inserted into the inner ring 11, and one end of the shaft shoulder 22 abuts against the limiting portion 111. The sealing clamp 3 is a hollow cylinder with an opening in an axial direction in the outer wall. An inner diameter of the sealing clamp 3 is slightly larger than the outer diameter of the protective sleeve 2 when the protective sleeve 2 is not compressed. The sealing clamp 3 may sleeve the protective sleeve 2 and may limit the expansion of the protective sleeve 2 toward the outer wall.

[0034] The compression member 4 is detachably connected to the inner ring 11, and the compression member 4 abuts against the other end of the shaft shoulder 22.

[0035] According to the optical cable straightening structure for logging while drilling proposed in this embodiment, the optical cable 200 is installed into the protective sleeve 2 through the helical slit 21. The protective sleeve 2 is provided with the shaft shoulder 22. The protective sleeve 2 is made of the elastic material. The outer ring 12 is anchored to the inner wall of the drill pipe 100. The sealing clamp 3 is arranged outside the shaft shoulder 22 in a sleeving mode and then inserted together into the inner ring 11. One end of the shaft shoulder 22 abuts against the limiting portion 111. The compression member 4 abuts against the other end of the shaft shoulder 22 and applies a compression force to the shaft shoulder 22. This increases a clamping force of the protective sleeve 2 in the axial direction. While being straightened, the optical cable 200 is clamped and tensioned, thereby reducing fatigue damage caused by the swaying of the optical cable 200 during a drilling process.

[0036] In some embodiments, the optical cable straightening structure further includes set screws 5, a peripheral wall of the outer ring 12 is provided with a plurality of installation holes 1211 in a radial direction, the set screws 5 are in threaded connections with the installation holes 1211, two ends of each set screw 5 are respectively an operating end 51 and a connecting end 52, the operating end 51 is located on one side of an inner wall of the inner ring 11, and the connecting end 52 protrudes from an outer wall of the outer ring 12 and abuts against the inner wall of the drill pipe 100. The set screws 5 may be of a straight cylindrical and capless end structure. The installation holes 1211 are non-stepped threaded holes, enabling a smaller hole diameter of the installation holes 1211 to enhance the strength of the outer ring 12. The operating end 51 may be of a hexagonal socket structure for ease of operation in a confined space. The outer ring 12 is anchored to the inner wall of the drill pipe 100 by the connecting end 52 protruding from the outer wall of the outer ring 12 and abutting against the inner wall of the drill pipe 100, so that the outer ring 12 is fixed at a designated position on the drill pipe 100, preventing it from moving under the action of various external forces. This provides stable support and fixation for the optical cable straightening structure, improving the stability and reliability of the device. The anchoring effect of the outer ring 12 and the inner wall of the drill pipe 100: on one hand, it firmly fixes the optical cable straightening structure in a specific position like an anchor, preventing it from moving under the action of various external forces. This provides stable support and fixation for the optical cable straightening structure. On the other hand, this anchoring effect may ensure that the optical cable straightening structure maintains its correct position and posture during the working process, thereby effectively performing its straightening function. Whether responding to vibrations, impacts, or other dynamic loads, the anchoring effect of the set screws 5 may keep the optical cable straightening structure stable, guaranteeing the normal operation of the equipment.

[0037] In some embodiments, the connecting end 52 is provided with an inner concave portion 521. By arranging the inner concave portion 521, the contact area between the connecting end 52 and the inner wall of the drill pipe 100 can be reduced, thereby increasing the intensity of pressure, enhancing the ability of the straightening structure to withstand tensile forces, torque, pressure, and other acting forces during the drilling process, and improving the reliability of the device.

[0038] In some embodiments, the optical cable straightening structure further includes a connecting screw 6. The compression member 4 includes a compression cap 41 and a washer 42, the compression cap 41 is provided with a first connecting hole 411, an end face of the inner ring 11 is provided with a second connecting hole 113, the second connecting hole 113 is a threaded hole, and the connecting screw 6 passes through the first connecting hole 411 and is in a threaded connection with the second connecting hole 113; and the washer 42 is arranged on the protective sleeve 2 in a sleeving mode and is located between one ends of the compression cap 41 and the shaft shoulder 22 away from the limiting portion 111. The washer 42 is arranged in an inner hole of the outer ring 12. One end of the compression cap 41 is inserted into the outer ring 12 and arranged on the protective sleeve 2 in a sleeving mode. The compression cap 41 presses against the washer 42. By adjusting the depth to which the connecting screw 6 is screwed into the second connecting hole 113, the compression force applied to the shaft shoulder 22 can be adjusted. The shaft shoulder 22 of the protective sleeve 2 is externally sleeved with the sealing clamp 3, enabling the shaft shoulder 22 part of the protective sleeve 2 to contract inward only, thereby clamping the optical cable 200 and thus enhancing the clamping force on the optical cable 200. This ensures that the optical cable 200 remains in a state of tension, improving the reliability and stability of the device.

[0039] In some embodiments, the outer ring 12 includes at least a ring body 121, and the ring body 121 is provided with a notch 1212allowing a cable to penetrate in. The arrangement of the notch 1212 facilitates the installation of the optical cable 200, improving assembly convenience and improving assembly efficiency.

[0040] In some embodiments, the outer ring 12 further includes a sealing block 122 and a connecting member 123, the sealing block 122 is movably inserted into the notch 1212, and the connecting member 123 connects the sealing block 122 to the ring body 121. The sealing block 122 complements the ring body 121 to form a complete circle, improving the overall stability and reliability of the optical cable straightening structure. A pin may be adopted as the connecting member 123. The ring body 121 is provided with a first pin hole 1213 in an end face at the position of the notch 1212, and the first pin hole 1213 is perpendicular to the end face. The sealing block 122 is provided with a second pin hole 1221 corresponding to the first pin hole 1213. The pin passes through the first pin hole 1213 and the second pin hole 1221 to connect the sealing block 122 to the ring body 121.

[0041] In some embodiments, an outer wall of the outer ring 12 is provided with a guide face 124, the guide face 124 is attached to the inner wall of the drill pipe 100, and the guide face 124 is located at an end of the outer ring 12 close to a bottom of the drill pipe 100. The guide face 124 is a tapered face, larger at the top and smaller at the bottom. The guide face 124 is located at the end of the outer ring 12 close to the bottom of the drill pipe 100. The drill pipe 100 can exert an upward support force on the outer ring 12, enabling the outer ring 12 to withstand greater axial tensile forces, which further enhances the reliability and stability of the device.

[0042] In some embodiments, the support ring 1 further includes a middle rod 13, a gap is arranged between an outer wall of the inner ring 11 and an inner wall of the outer ring 12, and the middle rod 13 is connected between the inner ring 11 and the outer ring 12. The arrangement of the gap between the outer wall of the inner ring 11 and the inner wall of the outer ring 12 enables the support ring 1 to be of a hollowed-out structure. This may provide a larger flow area, reduce the flow resistance of the drilling fluid, reduce the impact and wear of the drilling fluid on the optical cable 200, reduce the action of external forces on the optical cable 200, and prolong the service life of the optical cable 200.

[0043] The working principle of the optical cable straightening structure for logging while drilling in this embodiment is as follows. The outer ring 12 is anchored to the inner wall of the drill pipe 100, such that the optical cable straightening structure is fixed at a designated position in the drill pipe 100. The optical cable 200 is installed into the protective sleeve 2 through the helical slit 21. The protective sleeve 2 is made of an elastic material. The sealing clamp 3 is arranged outside the shaft shoulder 22 in a sleeving mode and then inserted together into the inner ring 11. One end of the shaft shoulder 22 abuts against the limiting portion 111. The compression member 4 abuts against the other end of the shaft shoulder 22 and applies a compression force to the shaft shoulder 22. This increases a clamping force of the protective sleeve 2 in the axial direction. While being straightened, the optical cable 200 is clamped and tensioned, thereby reducing fatigue damage caused by the swaying of the optical cable 200 during a drilling process.

[0044] Based on the same concept, an embodiment of the second aspect of the present application proposes a drilling device, including a drill pipe 100 and an optical cable 200, and the optical cable straightening structure for logging while drilling as described in the embodiment of the first aspect, the outer ring 12 is connected to the inner wall of the drill pipe 100, and the optical cable 200 is installed into the protective sleeve 2 through the helical slit 21.

[0045] In some embodiments, the drill pipe 100 includes a plurality of sequentially connected subs 101, and the optical cable straightening structure is located at a joint between the two adjacent subs 101. An inner wall of an upper end of each sub 101 is provided with a connecting surface 1011, which is a tapered face. The guide face 124 abuts against the connecting face 1011. The connecting end 52 of the set screw 5 abuts against the inner wall of the drill pipe 100, so that the outer ring 12 is anchored to the inner wall of the drill pipe 100, the outer ring 12 is fixed at a designated position of the drill pipe 100, preventing it from moving under the action of various external forces.

Claims

1. An optical cable straightening structure for logging while drilling, comprising a support ring, a protective sleeve, a sealing clamp, a compression member, and a connecting screw, wherein:the support ring comprises an inner ring and an outer ring; one end of the inner ring is provided with a limiting portion, the inner ring is provided, in an axial direction, with a penetration groove penetrating through a peripheral wall, and the penetration groove allows an optical cable to pass through; the outer ring and the inner ring are connected to each other and coaxial, and the outer ring is anchored to an inner wall of a drill pipe;a peripheral wall of the protective sleeve is provided with a helical slit extending from one end to the other end, the optical cable is installed into the protective sleeve through the helical slit, and the protective sleeve is provided with a shaft shoulder and is made of an elastic material;the sealing clamp is arranged outside the shaft shoulder in a sleeving mode, the sealing clamp and the protective sleeve are integrally inserted into the inner ring, and one end of the shaft shoulder abuts against the limiting portion;the compression member is detachably connected to the inner ring, and the compression member abuts against the other end of the shaft shoulder; the compression member comprises a compression cap and a washer, the compression cap is provided with a first connecting hole, an end face of the inner ring is provided with a second connecting hole, the second connecting hole is a threaded hole, and the connecting screw passes through the first connecting hole and is in a threaded connection with the second connecting hole; and the washer is arranged on the protective sleeve in a sleeving mode and is located between one ends of the compression cap and the shaft shoulder away from the limiting portion.

2. The optical cable straightening structure for logging while drilling according to claim 1, further comprising set screws, wherein a peripheral wall of the outer ring is provided with a plurality of installation holes in a radial direction, the set screws are in threaded connections with the installation holes, two ends of each set screw are respectively an operating end and a connecting end, the operating end is located on one side of an inner wall of the inner ring, and the connecting end protrudes from an outer wall of the outer ring and abuts against the inner wall of the drill pipe.

3. The optical cable straightening structure for logging while drilling according to claim 2, wherein the connecting end is provided with an inner concave portion.

4. The optical cable straightening structure for logging while drilling according to claim 1, wherein the outer ring comprises at least a ring body, and the ring body is provided with a notch allowing a cable to penetrate in.

5. The optical cable straightening structure for logging while drilling according to claim 4, wherein the outer ring further comprises a sealing block and a connecting member, the sealing block is movably inserted into the notch, and the connecting member connects the sealing block to the ring body.

6. The optical cable straightening structure for logging while drilling according to claim 1, wherein an outer wall of the outer ring is provided with a guide face, the guide face is attached to the inner wall of the drill pipe, and the guide face is located at an end of the outer ring close to a bottom of the drill pipe.

7. The optical cable straightening structure for logging while drilling according to claim 1, wherein the support ring further comprises a middle rod, a gap is arranged between an outer wall of the inner ring and an inner wall of the outer ring, and the middle rod is connected between the inner ring and the outer ring.

8. A drilling device, comprising a drill pipe and an optical cable, and the optical cable straightening structure for logging while drilling according to claim 1, wherein the outer ring is connected to the inner wall of the drill pipe, and the optical cable is installed into the protective sleeve through the helical slit.

9. The drilling device according to claim 8, wherein the drill pipe comprises a plurality of sequentially connected subs, and the optical cable straightening structure is located at a joint between the two adjacent subs.

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