Fiber optic cable centralizing structure for logging while drilling and drilling apparatus

Abstract

The present application relates to the technical field of measurement while drilling, and provides a fiber optic cable centralizing structure for logging while drilling and a drilling apparatus. The fiber optic cable centralizing structure comprises a support ring, a protective sleeve, a sealing retaining member, and a pressing member; an inner ring of the support ring is provided with a feed-through opening for a fiber optic cable to extend therethrough, and an outer ring is anchored to an inner wall of a drill pipe; after the fiber optic cable is sleeved in the protective sleeve having a helical gap, a shaft shoulder thereof abuts against an inner ring limiting portion by means of the sealing retaining member, and is pressed and secured by the pressing member, thereby achieving centralization and protection of the fiber optic in the drill pipe.

Description

Optical cable straightening structure and drilling equipment for logging while drilling

[0001] This application claims priority to Chinese Patent Application No. 202510364184.8, filed with the State Intellectual Property Office of China on March 26, 2025, entitled "An Optical Cable Straightening Structure and Drilling Device for Logging While Drilling", the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application relates to the field of measurement while drilling technology, and in particular to an optical cable straightening structure and drilling device for logging while drilling. Background Technology

[0003] Currently, oil and gas exploration and development is increasingly moving towards complex oil and gas fields such as low-permeability, unconventional, deep and ultra-deep formations, and deep water, posing significant challenges to the efficiency, safety, and quality of drilling engineering. This has led to the development of logging-while-drilling (LOD) technology. To address the low transmission rate issue in LWD, fiber optic LWD is an innovative logging technology. Compared to traditional cable logging, fiber optic cables are less susceptible to electromagnetic interference and have a much higher signal propagation speed, enabling stable signal transmission even under complex geological conditions. Data transmission rates can reach GB per second, achieving more efficient data transmission.

[0004] Although fiber optic logging while drilling has many technical advantages, the optical cable inside the drill pipe has to withstand the scouring of downhole mud and the strong vibration environment during drilling, making it difficult to guarantee the reliability of the optical cable. These factors directly determine the reception of downhole measurement signals by the ground information processing terminal. Therefore, the optical cable straightening structure is a key component in optical cable sensing.

[0005] In related technologies, optical cable straightening structures only provide straightening but cannot provide pre-tension to the optical cable. If the optical fiber cannot be straightened, it may swing significantly, which can easily lead to the breakage of the optical cable and cannot ensure the reliability of data transmission. Summary of the Invention

[0006] In view of this, this application proposes a fiber optic cable straightening structure and drilling device for logging while drilling, in order to solve the technical problem that fiber optic cable straightening structures in related technologies only provide straightening but cannot provide pre-tension to the fiber optic cable. The fiber optic cable may not be straightened, which may lead to large swings and easy breakage of the fiber optic cable, and thus cannot ensure the reliability of data transmission.

[0007] The technical solution of this application is implemented as follows:

[0008] In a first aspect, this application provides a fiber optic cable straightening structure for logging while drilling, comprising a support ring, a protective sleeve, a sealing clip, and a clamping element, wherein:

[0009] The support ring includes an inner ring and an outer ring; one end of the inner ring is provided with a limiting part, and the inner ring is provided with a through groove along the axial direction that penetrates the peripheral wall, the through groove allowing the optical cable to pass through; the outer ring is connected to the inner ring and coaxial, and the outer ring is anchored to the inner wall of the drill pipe;

[0010] The protective sleeve has a spiral slit extending from one end to the other. The optical cable is inserted into the protective sleeve through the spiral slit. The protective sleeve has a shoulder and is made of elastic material.

[0011] The sealing clip is sleeved on the outside of the shaft shoulder, and the sealing clip and the protective sleeve are inserted into the inner ring as a whole, with one end of the shaft shoulder abutting against the limiting part;

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

[0013] In some embodiments, the device further includes a set screw. The outer ring has a plurality of mounting holes in the radial direction on its peripheral wall. The set screw is threaded to the mounting holes. The two ends of the set screw are an operating end and a connecting end, respectively. The operating end is located on one side of the inner wall of the inner ring, and the connecting end protrudes from the outer wall of the outer ring and abuts against the inner wall of the drill rod.

[0014] In some embodiments, the connecting end is provided with a recess.

[0015] In some embodiments, a connecting screw is also included. The clamping member includes a pressure cap and a washer. The pressure cap has a first connecting hole, and the end face of the inner ring has a second connecting hole. The second connecting hole is a threaded hole. The connecting screw passes through the first connecting hole and is threadedly connected to the second connecting hole. The washer is sleeved on the protective sleeve and is located between the pressure cap and the end of the shoulder away from the limiting portion.

[0016] In some embodiments, the outer ring includes at least a ring body having a notch that allows a cable to pass through.

[0017] In some embodiments, the outer ring further includes a sealing block and a connector, the sealing block being movably inserted into the notch, and the connector connecting the sealing block and the ring body.

[0018] In some embodiments, a guide surface is provided on the outer wall of the outer ring, the guide surface is in contact with the inner wall of the drill pipe, and the guide surface is located at one end of the outer ring near the bottom of the drill pipe.

[0019] In some embodiments, the support ring further includes an intermediate rod, and a gap is provided between the outer wall of the inner ring and the inner wall of the outer ring, with the intermediate rod connecting the inner ring and the outer ring.

[0020] Secondly, this application provides a drilling apparatus including a drill pipe and an optical cable, as well as the optical cable straightening structure for logging while drilling described in the first aspect, wherein the outer ring is connected to the inner wall of the drill pipe, and the optical cable is inserted into the protective sleeve through the spiral slot.

[0021] In some embodiments, the drill pipe includes a plurality of short sections connected in sequence, and the optical cable straightening structure is located at the junction of two adjacent short sections. Attached Figure Description

[0022] Figure 1 is a perspective view of the optical cable straightening structure for logging while drilling in an embodiment of this application;

[0023] Figure 2 is a cross-sectional view of the optical cable straightening structure for logging while drilling in an embodiment of this application;

[0024] Figure 3 is an exploded view of the optical cable straightening structure for logging while drilling in an embodiment of this application;

[0025] Figure 4 is a schematic diagram of the support ring structure in an embodiment of this application;

[0026] Figure 5 is a perspective view of the protective sleeve in the embodiment of this application;

[0027] Figure 6 is a cross-sectional view of the set screw in an embodiment of this application;

[0028] Figure 7 is a schematic diagram of the drilling apparatus in an embodiment of this application;

[0029] Figure 8 is a magnified view of part A in Figure 7. Detailed Implementation

[0030] Referring to Figures 1-8, a first aspect embodiment of this application proposes a fiber optic cable straightening structure for logging while drilling, comprising a support ring 1, a protective sleeve 2, a sealing clip 3, and a clamping 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 part 111, and the inner ring 11 is provided with a through groove 112 that penetrates the peripheral wall along the axial direction, the through groove 112 extending from the inner wall to the outer wall, the through groove 112 allowing the optical cable 200 to pass through; the outer ring 12 is connected to the inner ring 11 and is coaxial, the outer ring 12 is anchored to the inner wall of the drill rod 100;

[0032] The protective sleeve 2 has a spiral slit 21 extending from one end to the other on its peripheral wall. The spiral slit 21 is opened from the outer wall to the inner wall, so that the optical cable 200 can be inserted into the protective sleeve 2 through the spiral slit 21. After the optical cable 200 is inserted into the protective sleeve 2, it is straightened. The protective sleeve 2 has a shoulder 22 and is made of elastic material.

[0033] The sealing clip 3 is sleeved on the shoulder 22, and the sealing clip 3 and the protective sleeve 2 are inserted into the inner ring 11 as a whole. One end of the shoulder 22 abuts against the limiting part 111. The sealing clip 3 is a hollow cylinder with an opening in the axial direction on the outer wall. The inner diameter of the sealing clip 3 is slightly larger than the outer diameter of the protective sleeve 2 when it is not pressed. The sealing clip 3 can be sleeved on the protective sleeve 2 and can restrict the protective sleeve 2 from expanding in the direction of the outer wall.

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

[0035] The optical cable straightening structure for logging while drilling proposed in this embodiment involves inserting the optical cable 200 into the protective sleeve 2 through the spiral slit 21. The protective sleeve 2 has a shoulder 22 and is made of elastic material. The outer ring 12 is anchored to the inner wall of the drill pipe 100. The sealing clip 3 is fitted over the shoulder 22 and then inserted into the inner ring 11. One end of the shoulder 22 abuts against the limiting part 111, and the clamping member 4 abuts against the other end of the shoulder 22. The clamping member 4 applies a clamping force to the shoulder 22, thereby increasing the clamping force of the protective sleeve 2 axially. While straightening the optical cable 200, it also clamps and straightens the optical cable 200, reducing fatigue damage caused by the swing of the optical cable 200 during the logging process.

[0036] In some embodiments, the optical cable straightening structure further includes a set screw 5. The outer ring 12 has a plurality of mounting holes 1211 along its radial direction on its peripheral wall. The set screw 5 is threadedly connected to the mounting holes 1211. The two ends of the set screw 5 are an operating end 51 and a connecting end 52, respectively. The operating end 51 is located on one side of the inner wall of the inner ring 11, and the connecting end 52 protrudes from the outer wall of the outer ring 12 and abuts against the inner wall of the drill rod 100. The set screw 5 can be a straight column with a capless end. The mounting holes 1211 are threaded holes without steps, resulting in a smaller hole diameter, which can improve the strength of the outer ring 12. The operating end 51 can be an internal hexagonal structure, facilitating operation in confined spaces. The connecting end 52 protrudes from the outer wall of the outer ring 12 and abuts against the inner wall of the drill rod 100, thus anchoring the outer ring 12 to the inner wall of the drill rod 100. This fixes the outer ring 12 to a designated position on the drill rod 100, preventing it from moving under 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 to the inner wall of the drill rod 100 is twofold: firstly, it acts like an anchor, firmly fixing the optical cable straightening structure in a specific position, preventing it from moving under various external forces, and providing stable support and fixation for the optical cable straightening structure; secondly, this anchoring effect ensures that the optical cable straightening structure maintains the correct position and posture during operation, thereby effectively performing its straightening function. Whether dealing with vibration, impact, or other dynamic loads, the anchoring effect of the set screw 5 ensures the stability of the optical cable straightening structure, guaranteeing the normal operation of the equipment.

[0037] In some embodiments, the connecting end 52 is provided with a recess 521. By providing the recess 521, the contact area between the connecting end 52 and the inner wall of the drill pipe 100 can be reduced, thereby increasing the pressure and increasing the ability of the straightening structure to withstand tensile, torque and compressive forces during the drilling process, thus improving the reliability of the device.

[0038] In some embodiments, the optical cable straightening structure further includes a connecting screw 6, the clamping member 4 includes a pressure cap 41 and a washer 42, the pressure cap 41 is provided with a first connecting hole 411, the end face of the inner ring 11 is provided with a second connecting hole 113, the second connecting hole 113 is a threaded hole, the connecting screw 6 passes through the first connecting hole 411 and is threadedly connected to the second connecting hole 113; the washer 42 is sleeved on the protective sleeve 2 and is located between the pressure cap 41 and the end of the shoulder 22 away from the limiting part 111. The gasket 42 is placed in the inner hole of the outer ring 12. One end of the pressure cap 41 is inserted into the outer ring 12 and sleeved on the protective sleeve 2. The pressure cap 41 presses against the gasket 42. By adjusting the depth of the connecting screw 6 screwed into the second connecting hole 113, the clamping force on the shoulder 22 can be adjusted. Since the shoulder 22 of the protective sleeve 2 is covered with a sealing clip 3, the shoulder 22 part of the protective sleeve 2 can only retract inward to clamp the optical cable 200, thereby increasing the clamping force on the optical cable 200, ensuring that the optical cable 200 remains taut, and improving the reliability and stability of the device.

[0039] In some embodiments, the outer ring 12 includes at least a ring body 121, which has a notch 1212 for cable insertion. The notch 1212 facilitates the insertion of the optical cable 200, improving assembly convenience and efficiency.

[0040] In some embodiments, the outer ring 12 further includes a sealing block 122 and a connector 123. The sealing block 122 is movably inserted into the notch 1212, and the connector 123 connects the sealing block 122 and the ring body 121. The sealing block 122 completes the ring body 121 into a full circle, improving the overall stability and reliability of the optical cable straightening structure. The connector 123 can be a pin. The ring body 121 has a first pin hole 1213 perpendicular to the end face at the notch 1212. The sealing block 122 has 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 and the ring body 121.

[0041] In some embodiments, a guide surface 124 is provided on the outer wall of the outer ring 12. The guide surface 124 is in contact with the inner wall of the drill rod 100, and the guide surface 124 is located at the end of the outer ring 12 near the bottom of the drill rod 100. The guide surface 124 is a conical surface, larger at the top and smaller at the bottom. The guide surface 124 is located at the end of the outer ring 12 near the bottom of the drill rod 100, so that the drill rod 100 can provide an upward supporting force to the outer ring 12, allowing the outer ring 12 to withstand greater axial tensile force, further improving the reliability and stability of the device.

[0042] In some embodiments, the support ring 1 further includes an intermediate rod 13, and a gap is provided between the outer wall of the inner ring 11 and the inner wall of the outer ring 12. The intermediate rod 13 connects the inner ring 11 and the outer ring 12. The gap between the outer wall of the inner ring 11 and the inner wall of the outer ring 12 makes the support ring 1 a hollow structure, providing a larger flow area, reducing the flow resistance of drilling fluid, reducing the impact and wear of drilling fluid on the optical cable 200, reducing the external force on the optical cable 200, and extending 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, so that the optical cable straightening structure is fixed in a designated position inside the drill pipe 100; the optical cable 200 is inserted into the protective sleeve 2 through the spiral gap 21. The protective sleeve 2 is made of elastic material. The sealing clip 3 is sleeved on the shoulder 22 and then inserted into the inner ring 11 together. One end of the shoulder 22 abuts against the limiting part 111, and the clamping member 4 abuts against the other end of the shoulder 22. The clamping member 4 applies a clamping force to the shoulder 22, so that the clamping force of the protective sleeve 2 increases axially. While straightening the optical cable 200, it also clamps and straightens the optical cable 200, reducing fatigue damage caused by the swing of the optical cable 200 during the drilling process.

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

[0045] In some embodiments, the drill rod 100 includes a plurality of short sections 101 connected in sequence, and the optical cable straightening structure is located at the connection point of two adjacent short sections 101. The inner wall of the upper end of the short section 101 is provided with a connecting surface 1011, the connecting surface 1011 is a conical surface, the guide surface 124 abuts against the connecting surface 1011, and the connecting end 52 of the set screw 5 abuts against the inner wall of the drill rod 100, thereby anchoring the outer ring 12 to the inner wall of the drill rod 100, so that the outer ring 12 is fixed at a designated position of the drill rod 100 and prevents it from moving under various external forces.

Claims

1. A fiber optic cable straightening structure for logging while drilling, comprising a support ring, a protective sleeve, a sealing clip, a clamping element, and connecting screws, wherein: The support ring includes an inner ring and an outer ring; one end of the inner ring is provided with a limiting part, and the inner ring is provided with a through groove along the axial direction that penetrates the peripheral wall, the through groove allowing the optical cable to pass through; the outer ring is connected to the inner ring and coaxial, and the outer ring is anchored to the inner wall of the drill pipe; The protective sleeve has a spiral slit extending from one end to the other. The optical cable is inserted into the protective sleeve through the spiral slit. The protective sleeve has a shoulder and is made of elastic material. The sealing clip is sleeved on the outside of the shaft shoulder, and the sealing clip and the protective sleeve are inserted into the inner ring as a whole, with one end of the shaft shoulder abutting against the limiting part; The clamping member is detachably connected to the inner ring, and the clamping member abuts against the other end of the shoulder; the clamping member includes a pressure cap and a washer, the pressure cap is provided with a first connecting hole, the end face of the inner ring is provided with a second connecting hole, the second connecting hole is a threaded hole, the connecting screw passes through the first connecting hole and is threadedly connected to the second connecting hole; the washer is sleeved on the protective sleeve and is located between the pressure cap and the end of the shoulder away from the limiting part.

2. The optical cable straightening structure for logging while drilling as described in claim 1 further includes a set screw, wherein the outer ring has a plurality of mounting holes in the radial direction, the set screw is threaded to the mounting holes, and the two ends of the set screw are an operating end and a connecting end, respectively, the operating end is located on one side of the inner wall of the inner ring, and the connecting end protrudes from the 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 as described in claim 2, wherein, The connecting end is provided with a recessed portion.

4. The optical cable straightening structure for logging while drilling as described in claim 1, wherein, The outer ring includes at least a ring body, which has a notch that allows a cable to pass through.

5. The optical cable straightening structure for logging while drilling as described in claim 4, wherein, The outer ring also includes a sealing block and a connector. The sealing block is movably inserted into the notch, and the connector connects the sealing block and the ring body.

6. The optical cable straightening structure for logging while drilling as described in claim 1, wherein, The outer ring has a guide surface on its outer wall, which fits against the inner wall of the drill rod. The guide surface is located at one end of the outer ring near the bottom of the drill rod.

7. The optical cable straightening structure for logging while drilling as described in claim 1, wherein, The support ring also includes a middle rod, and a gap is provided between the outer wall of the inner ring and the inner wall of the outer ring. The middle rod is connected between the inner ring and the outer ring.

8. A drilling apparatus comprising a drill pipe and an optical cable, and an optical cable straightening structure for logging while drilling as described in claim 1, wherein the outer ring is connected to the inner wall of the drill pipe, and the optical cable is inserted into the protective sleeve through the spiral slot.

9. The drilling apparatus as claimed in claim 8, wherein, The drill pipe includes multiple short sections connected in sequence, and the optical cable straightening structure is located at the connection between two adjacent short sections.

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