Guide nipple for straight injection well

Abstract

The utility model provides a guiding short section for a straight injection well. The guiding short section comprises a mandrel, a flexible assembly, a centralizer and a guiding head, wherein the flexible assembly, the centralizer and the guiding head are sequentially connected to the mandrel. Wherein the flexible assembly is connected to one end of the core shaft, the guide head is connected to the other end of the core shaft, and the centralizer is arranged in the middle of the core shaft in a sliding and sleeving mode; the flexible assembly can swing relative to the mandrel, and the centralizer can centralize the guiding head to be close to the center position in the well. The guiding device has the advantages that the guiding freedom degree can be improved by swinging the flexible assembly relative to the mandrel, the guiding effect can be improved by keeping the guiding head in the middle through the centralizer, then the probability of encountering resistance can be reduced, and the trafficability under the complex well condition is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of well logging equipment, in particular to a steering nipple for direct well logging. Background Art

[0002] Traditional wireline logging is suitable for vertical and shallowly deviated wells. However, with the advancement of drilling technology, the number of highly deviated and horizontal wells is increasing to improve oil recovery. In highly deviated and horizontal wells, traditional wireline logging cannot rely on gravity to lower the instrument to the target formation. However, direct push storage logging, leveraging drill bit transport and storage technology, effectively solves the instrument lowering problem, enabling measurement in long horizontal well sections. This technology also offers unparalleled advantages over traditional wireline logging in complex well conditions or wells with well control risks.

[0003] Direct-push storage logging technology uses the drill string to directly transport the instrument to the bottom of the well during logging. Specifically, the upper end of the logging instrument is connected to the drill string via an adapter, and the configuration is completed at the wellhead. The drill string then transports the logging instrument to the target layer to complete the formation information measurement. However, the direct-push storage logging instrument is directly connected to the lower end of the drill string. In complex well conditions, if the logging instrument encounters resistance, the downward pressure load will instantly increase. When the load exceeds the compressive limit of the logging instrument, the logging instrument will bend and even cause serious logging accidents such as falling into the well. Therefore, it is crucial to effectively protect the logging instrument during the downhole process, reduce the probability of encountering resistance, and improve the passability in complex well conditions.

[0004] Although there are prior arts such as the Chinese invention patent with publication number CN112922539A which discloses a flexible connector centralizer for downhole tools, comprising a centralizer body and a downhole tool through-hole, wherein the downhole tool through-hole is offset in the centralizer body, and the centralizer body can be connected to the oil pipe string via a short joint, thus providing a certain degree of protection for the downhole tool, the centralizer still has disadvantages such as a long structural design, poor passability, and poor guiding effect.

[0005] Therefore, it is necessary to study a steering sub for direct drilling of wells to solve the above problems or alleviate the impact of the above problems. Utility Model Content

[0006] The utility model provides a guiding nipple for vertical well drilling, which can be flexibly rotated and centrally guided by the cooperation of a flexible component and a centralizer, so as to effectively solve the above problems or alleviate the effects of the above problems.

[0007] The guiding sub for vertical drilling of the utility model may include a core shaft and a flexible component, a centralizer and a guiding head connected to the core shaft in sequence;

[0008] The flexible component is connected to one end of the core shaft, the guide head is connected to the other end of the core shaft, and the centralizer is slidably sleeved on the middle part of the core shaft;

[0009] The flexible component can swing relative to the core shaft, and the centralizer can centralize the guide head toward a central position in the well.

[0010] In one embodiment, the flexible component includes a spherical joint and a clamping ring, a ball head is provided at one end of the spherical joint, the clamping ring is connected to the core shaft, and a spherical space for matching the ball head is formed between the clamping ring and the core shaft.

[0011] In one embodiment, a first arcuate surface is provided in the clamping ring, and a second arcuate surface is provided at one end of the core shaft connected to the clamping ring. The first arcuate surface and the second arcuate surface cooperate to form the spherical space.

[0012] In one embodiment, a tapered hole is provided at one end of the clamping ring away from the core shaft, and the diameter of the tapered hole gradually increases in a direction away from the core shaft.

[0013] In one embodiment, the angle between the wall of the tapered hole and its central axis is 5° to 8°.

[0014] In one embodiment, the end of the clamping ring away from the tapered hole has an internal thread, the clamping ring is threadedly connected to the core shaft, and a first anti-rotation screw is provided at the threaded connection between the two.

[0015] In one embodiment, the end of the spherical joint away from the ball head is a cylinder, and the outer side of the cylinder is provided with an external thread;

[0016] The guide short joint also includes an upper joint, which is threadedly connected to the cylindrical body of the spherical joint, and a second anti-rotation screw is provided at the threaded connection between the upper joint and the cylindrical body.

[0017] In one embodiment, the centralizer includes two sliders slidably mounted on the core shaft, a plurality of leaf springs are connected between the two sliders, and the plurality of leaf springs are evenly distributed around the circumference of the core shaft to form an elliptical structure.

[0018] In one embodiment, the slider includes two half rings, which are symmetrically distributed and detachably connected.

[0019] In one embodiment, the guide head is a bullet-shaped structure and is made of rubber.

[0020] The utility model provides a steering sub for direct drilling of wells, which has at least the following beneficial effects compared with the prior art:

[0021] This utility model provides a guide sub for direct drilling. Through the cooperation of a flexible component and a centralizer, it can be flexibly rotated and centered. In this way, the measuring instrument is connected to the guide sub. The flexible component swings relative to the core shaft to increase the degree of freedom of guidance. The centralizer maintains the centering of the guide head to improve the guidance effect, thereby reducing the probability of encountering obstacles and improving the passability in complex well conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The present invention will be described in more detail below based on embodiments with reference to the accompanying drawings.

[0023] Figure 1 This is a structural diagram of a guide sub according to an embodiment of the present invention;

[0024] Figure 2 It is a structural schematic diagram of the connection between the flexible component and the core shaft in an embodiment of the utility model.

[0025] In the drawings, like reference numerals are used for like parts, but the drawings are not necessarily drawn to scale.

[0026] Reference numerals:

[0027] 1-core shaft, 2-centralizer, 21-slider, 22-leaf spring, 3-guide head, 4-spherical joint, 41-ball head, 5-pressure ring, 51-tapered hole, 6-first anti-rotation screw, 7-upper joint, 8-second anti-rotation screw, 9-upper cap. DETAILED DESCRIPTION

[0028] The present invention will be further described below with reference to the accompanying drawings.

[0029] like Figure 1 As shown, the steering sub for direct drilling of wells of the present invention may include a core shaft 1 and a flexible component, a centralizer 2 and a steering head 3 connected to the core shaft 1 in sequence;

[0030] The flexible component is connected to one end of the core shaft 1, the guide head 3 is connected to the other end of the core shaft 1, and the centralizer 2 is slidably sleeved in the middle of the core shaft 1;

[0031] The flexible component can swing relative to the core shaft 1, and the centralizer 2 can centralize the guide head 3 to a central position in the well.

[0032] Specifically, the overall structure of the guide sub comprises a core shaft 1, a flexible assembly, a centralizer 2, and a guide head 3. The core shaft 1 serves as the connection base, with one end connected to the flexible assembly and the other to the guide head 3. The centralizer 2 is slidably mounted in the middle of the core shaft 1. The flexible assembly can swing within a certain range relative to the core shaft 1 to adapt to the complex environmental changes within the wellbore, while the centralizer 2 drives the guide head 3 to the center of the wellbore, ensuring that the logging instrument can be smoothly lowered into the well for data measurement.

[0033] Overall, the guide sub used for direct drilling, through the flexible assembly and centralizer 2, allows for flexible rotation and centering. Connecting the measuring instrument to the guide sub, the flexible assembly swings relative to the mandrel 1, enhancing the freedom of guidance. Centralizer 2 maintains the centering of the guide head 3, improving guidance effectiveness. This reduces the probability of encountering obstructions, improving maneuverability and safety in complex well conditions.

[0034] In one example, Figure 1 and Figure 2 As shown, the flexible component includes a spherical joint 4 and a clamping ring 5. A ball head 41 is provided at one end of the spherical joint 4. The clamping ring 5 is connected to the core shaft 1, and a spherical space for matching the ball head 41 is formed between the clamping ring 5 and the core shaft 1.

[0035] Specifically, a spherical space is formed between the clamping ring 5 and the core shaft 1 through a special design, and a ball head 41 is provided at one end of the spherical joint 4. The ball head 41 is matched and installed in the spherical space. The ball head 41 can rotate in the spherical space, allowing the spherical joint 4 to swing relative to the core shaft 1. In this way, the flexible component can achieve flexible swinging of the guide short section in the well to adapt to the irregularities of the well wall.

[0036] Furthermore, a first arcuate surface is provided in the clamping ring 5 , and a second arcuate surface is provided at one end of the core shaft 1 connected to the clamping ring 5 . The first arcuate surface and the second arcuate surface cooperate to form a spherical space.

[0037] It should be noted that the first curved surface and the second curved surface cooperate with each other to form a spherical space for the ball head 41 to rotate. The size of the spherical space should match the size of the ball head 41, that is, the size of the spherical space is slightly larger than or equal to the size of the ball head 41.

[0038] In one example, Figure 1 and Figure 2 As shown, the end of the clamping ring 5 away from the core shaft 1 is provided with a tapered hole 51, and the diameter of the tapered hole 51 gradually increases in the direction away from the core shaft 1. In this way, the tapered hole 51 can provide swing space for the swing of the spherical joint 4 and also limit the swing amplitude of the spherical joint 4.

[0039] Furthermore, the angle between the wall of the tapered hole 51 and its central axis is 5° to 8°, which can ensure the swing range of the ball head 41 while avoiding the problem of unstable connection caused by too large an angle.

[0040] Furthermore, the angle between the wall of the tapered hole 51 and its central axis is 6°. This allows the spherical joint 4 to rotate freely within a 6° range of the spatial circumference, thereby ensuring the freedom of the guide head 3, making the guide short section more flexible, and effectively avoiding obstacles when encountering obstacles, thereby reducing the probability of encountering obstacles.

[0041] In one example, the end of the clamping ring 5 away from the tapered hole 51 has an internal thread, the clamping ring 5 is threadedly connected to the core shaft 1, and a first anti-rotation screw 6 is provided at the threaded connection between the two.

[0042] Specifically, the end of the clamping ring 5 away from the tapered hole 51 has an internal thread, which is threadedly connected to the external thread of the core shaft 1. At the same time, to enhance the stability of the connection, a first anti-rotation screw 6 is also provided at the threaded connection between the two to prevent loosening due to vibration and other reasons.

[0043] In one example, the end of the spherical joint 4 away from the ball head 41 is a cylinder, and an external thread is provided on the outside of the cylinder;

[0044] The guide short joint further includes an upper joint 7 , which is threadedly connected to the cylindrical body of the spherical joint 4 , and a second anti-rotation screw 8 is provided at the threaded connection between the upper joint 7 and the cylindrical body of the spherical joint 4 .

[0045] Specifically, to connect the guide sub with other parts of the logging system, the guide sub also includes an upper connector 7. This upper connector 7 is threadedly connected to the external threads of the cylindrical body of the spherical joint 4 via internal threads. A second anti-rotation screw 8 is also provided at the threaded connection to ensure a secure connection. The upper connector 7 can be a standard interface for the logging system, used for docking with other subs.

[0046] In one example, Figure 1 As shown, the centralizer 2 includes two sliders 21 slidably sleeved on the core shaft 1, and a plurality of leaf springs 22 are connected between the two sliders 21. The plurality of leaf springs 22 are evenly distributed around the circumference of the core shaft 1 and form an elliptical structure.

[0047] Specifically, as the wellbore shrinks, the leaf spring 22 is compressed and deformed, generating a deformation force. The two sliders 21 are forced to slide relative to each other on the mandrel 1. The force acting on the mandrel 1 causes the guide head 3 to return to its central position within the wellbore. This allows the centralizer 2 to effectively center the guide head 3 within the wellbore while maintaining a certain degree of flexibility to adapt to changes within the wellbore.

[0048] Furthermore, the centralizer 2 may be provided with six leaf springs 22 in a six-arm structure. The leaf springs 22 are made of high-elasticity alloy 3J21, which has corrosion resistance and high resilience. The leaf springs 22 may be fixedly connected to the slider 21 by rivet pins.

[0049] In one example, the slider 21 includes two half rings, which are symmetrically distributed and detachably connected.

[0050] Specifically, the two half-rings are symmetrically distributed and connected by fasteners such as bolts, so that the slider 21 can be quickly disassembled and assembled, which facilitates the maintenance and replacement of the centralizer 2.

[0051] In one example, the guide head 3 is a bullet-shaped structure, and the guide head 3 is made of rubber material.

[0052] Specifically, the guide head 3 is a bullet-shaped structure, which helps reduce collision and friction with the wellbore during logging, thereby improving logging efficiency. Furthermore, the guide head 3 is made of rubber, which has excellent elasticity and wear resistance. This means it can provide guidance and cushioning when encountering obstacles. It is also resistant to high temperatures and hydrogen sulfide corrosion, further extending the service life of the guide sub.

[0053] In one example, the guide sub may further include an upper cover cap 9 connected to the upper joint 7. The upper cover cap 9 may be used to protect the instrument interface and may also be used for hoisting the instrument and daily transportation.

[0054] In order to better understand the above embodiment, the working principle of the guide sub of the present invention will be further described below with reference to the accompanying drawings.

[0055] The guide sub is highly integrated, with an effective length of less than 1 meter, enabling better adaptation to changes in the wellbore trajectory and improving direct-push passability. During logging, the guide sub is connected to the rest of the logging equipment at the lower end via the upper connector 7. When the wellbore wall is irregular or tilted, the flexible assembly's spherical joint 4 can swing relative to the core shaft 1 to adapt to the changes. Simultaneously, the centralizer 2 uses its elliptical leaf spring 22 to stabilize the guide head 3, ensuring it remains centered within the wellbore.

[0056] In this way, the guide sub can enhance the freedom of the guide head 3 through the flexible component, can effectively avoid obstacles, and can keep the guide head 3 in the center of the wellbore as much as possible through the stabilizer 2, reducing the probability of encountering obstacles. Therefore, the guide sub can effectively improve the safety of construction.

[0057] While the present invention has been described with reference to preferred embodiments, various modifications may be made and equivalent components may be substituted without departing from the scope of the present invention. In particular, the various technical features described in the various embodiments may be combined in any manner, provided no structural conflicts exist. The present invention is not limited to the specific embodiments disclosed herein, but encompasses all technical solutions within the scope of the claims.

Claims

1. A steering sub for direct drilling of wells, characterized in that: The guide sub includes a core shaft and a flexible component, a centralizer and a guide head connected to the core shaft in sequence; The flexible component is connected to one end of the core shaft, the guide head is connected to the other end of the core shaft, and the centralizer is slidably sleeved on the middle part of the core shaft; The flexible component can swing relative to the core shaft, and the centralizer can centralize the guide head toward a central position in the well.

2. The steering sub for direct drilling of wells according to claim 1, characterized in that: The flexible component includes a spherical joint and a clamping ring. A ball head is provided at one end of the spherical joint. The clamping ring is connected to the core shaft, and a spherical space for matching and installing the ball head is formed between the clamping ring and the core shaft.

3. The steering sub for direct drilling of wells according to claim 2, characterized in that: A first arcuate surface is provided in the clamping ring, and a second arcuate surface is provided on one end of the core shaft connected to the clamping ring. The first arcuate surface and the second arcuate surface cooperate to form the spherical space.

4. The steering sub for direct drilling of wells according to claim 2, characterized in that: A tapered hole is provided at one end of the clamping ring away from the core shaft, and the diameter of the tapered hole gradually increases in a direction away from the core shaft.

5. The steering sub for direct drilling of wells according to claim 4, characterized in that: The angle between the hole wall of the tapered hole and its central axis is 5° to 8°.

6. The steering sub for direct drilling of wells according to claim 4, characterized in that: One end of the clamping ring away from the tapered hole is provided with an internal thread. The clamping ring is threadedly connected to the core shaft, and a first anti-rotation screw is provided at the threaded connection between the two.

7. The steering sub for direct drilling of wells according to claim 2, characterized in that: The end of the spherical joint away from the ball head is a cylinder, and the outer side of the cylinder is provided with an external thread; The guide short joint also includes an upper joint, which is threadedly connected to the cylindrical body of the spherical joint, and a second anti-rotation screw is provided at the threaded connection between the upper joint and the cylindrical body.

8. The steering sub for direct drilling of a well according to any one of claims 1 to 7, characterized in that: The centralizer includes two sliders slidably sleeved on the core shaft, and a plurality of leaf springs are connected between the two sliders. The plurality of leaf springs are evenly distributed around the circumference of the core shaft and form an elliptical structure.

9. The steering sub for direct drilling of a well according to claim 8, characterized in that: The slider includes two semi-ring bodies, which are symmetrically distributed and detachably connected.

10. The steering sub for direct drilling of a well according to any one of claims 1 to 7, characterized in that: The guide head is in a bullet-shaped structure and is made of rubber material.

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