Closed coring tool
The method of triggering the inner cylinder to clamp the core of the leaf spring claws is solved, and the problem of large wear and reduced clamping force in the closed centering tool is solved, which extends the service life of the leaf spring claws, simplifies the replacement process, and reduces costs.
Patent Information
- Application Number
- CN202421841260.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-08-01
- Publication Date
- 2025-05-02
- Estimated Expiration
- 2034-08-01
AI Technical Summary
In existing closed heart extraction tools, the core claws are long-term in contact with the core, resulting in large wear, reduced clamping force, easy core falls, and the process of replacing the core claws is cumbersome, which increases economic and time costs.
The inner cylinder triggers the leaf spring claw to clamp the core, so that the core does not contact the core in the early stage of drilling the core, reducing wear and extending the service life.
It effectively reduces the wear of the leaf spring claws, extends its service life, avoids the risk of core falling, simplifies the replacement process, and reduces costs.
Smart Images
Figure CN222823207U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of downhole tools, in particular to a closed coring tool used for straightening downhole equipment, such as a sucker rod. Background Art
[0002] When using conventional coring tools to drill cores, the cores will come into contact with mud and be corroded and contaminated by it, resulting in distortion of core measurement data. In response to this, people have proposed a closed coring technology, which is achieved through the action of a closed coring tool and a closed liquid (or protective liquid). The closed coring tool includes an outer cylinder and an inner cylinder. The piston and the inner cylinder are located in the outer cylinder, and the annulus between the two is a fluid channel. The tops of the inner cylinder and the outer cylinder are both closed. The piston is located in the inner cylinder, and one end of the piston extends downward from the outer cylinder. When in use, the closed liquid is loaded into the cavity between the inner cylinder and the piston. When the bottom of the closed coring tool touches the formation, the piston is compressed, and the closed liquid flows to the bottom of the formation through the annulus between the inner cylinder and the outer cylinder, thereby protecting the core to be drilled and preventing it from being affected by the mud. There are many existing closed coring tools. In order to facilitate the removal of cores from the formation, many of them are equipped with core claws to clamp the cores and prevent them from falling to the bottom of the well when the pipe column is lifted to the ground. However, in terms of the use effect, they are not ideal. The reason is that most of the core grippers currently rely mainly on abutting the side walls of the core to provide it with support. The core claws abut the core for a long time, and the core will always be equivalent to the rotation of the core claws during the transfer process. If the core claws have a small clamping force on the core, it is easy to directly cause the core to fall out of the inner tube during coring. If the core claws have a large clamping force on the core, the core will wear the core claws greatly. As the core claws are worn, their clamping force on the core will gradually decrease, causing the core to fall easily. If the core claws are replaced after each coring, on the one hand, the economic cost will increase, and on the other hand, the operation of replacing the core claws is cumbersome and time-consuming. Utility Model Content
[0003] In order to solve the above problems, the utility model provides a closed coring tool, which triggers the core claw to clamp the core through the inner tube. In the early stage of drilling the core, the core claw does not abut the core, which can reduce the wear of the core claw and extend the service life of the core claw.
[0004] The specific scheme of the utility model is as follows:
[0005] A closed coring tool, comprising:
[0006] An outer cylinder, the lower end of which is connected to a drill bit, and an inner wall of which is provided with an annular groove;
[0007] An inner cylinder is slidably and sealingly connected to the inner wall of the outer cylinder, and an annular sealing cavity is formed between the outer wall of the inner cylinder and the inner wall of the outer cylinder; an upper flow channel and a lower flow channel communicating with the sealing cavity are respectively provided at the upper and lower ends of the inner cylinder, and the upper end of the inner cylinder is closed;
[0008] A plunger is slidably and sealingly connected to the inner wall of the inner cylinder, and a fluid cavity containing a sealing fluid is formed between the upper end of the plunger and the inner cylinder;
[0009] At least two leaf spring claws fixed to the bottom of the inner cylinder and arranged around the circumference of the inner cylinder, the side walls of the leaf spring claws abutting against the inner wall of the outer cylinder;
[0010] A non-return mechanism for preventing the inner cylinder from moving relative to the outer cylinder in the direction of the drill bit;
[0011] Among them, the plunger is fixed on the drill bit through a shear pin, and after fixation, the plunger blocks the lower flow channel, the lower end of the plunger extends out of the drill bit, and the leaf spring claw is located in the groove. At this time, the size of the circular hole surrounded by the leaf spring claw is larger than the size of the core drilled by the drill bit; when the plunger moves upward to the extreme position relative to the inner tube, the plunger can push the inner tube to move together, thereby pushing the leaf spring claw out of the groove. When the leaf spring claw is out of the groove, the size of the circular hole surrounded by the leaf spring claw is smaller than or equal to the size of the core drilled by the drill bit, thereby clamping the core.
[0012] As a specific implementation of the present utility model, the limit position is the position where the upper end of the plunger abuts against the top of the inner cylinder.
[0013] As a specific implementation of the utility model, it also includes a second pin for positioning the inner cylinder in the outer cylinder.
[0014] As a specific embodiment of the utility model, it also includes an elastic element for pushing the inner cylinder to move toward the drill bit. When the plunger moves upward to the limit position, the inner cylinder compresses the elastic element, thereby causing the inner cylinder to move relative to the outer cylinder.
[0015] As a specific embodiment of the utility model, it includes a first annular member, leaf spring claws are distributed around the circumference of the first annular member and fixedly connected thereto, each leaf spring claw is spaced a certain distance apart to form a petal shape, and the first annular member is detachably connected to the lower end of the inner cylinder.
[0016] As a specific embodiment of the utility model, the anti-return mechanism includes an annular support portion detachably connected to the outer cylinder and a support column fixedly connected to the top of the inner cylinder, wherein at least two leaf spring blocks are connected to the bottom of the annular support portion, and all the leaf spring blocks are arranged around the circumference of the annular support portion to form an accommodating hole matching the support column, the support column is inserted into the accommodating hole and anti-return teeth are provided on the annular contact surfaces of the two. When the anti-return teeth of the two are engaged, a anti-return structure is formed to prevent the inner cylinder from moving in a direction away from the opening end of the inner cylinder.
[0017] Compared with the existing technology, it has the following advantages:
[0018] The closed coring tool of the utility model clamps the core by triggering the movement of the leaf spring claws through the inner tube. In the early stage of drilling the core, the leaf spring claws do not abut the core, which can reduce the wear of the leaf spring claws and extend the service life of the leaf spring claws. BRIEF DESCRIPTION OF THE DRAWINGS
[0019] Figure 1 It is a structural schematic diagram of a specific embodiment of the closed coring tool of the utility model;
[0020] Figure 2 for Figure 1 Schematic diagram of the closed coring tool in the state of obtaining cores;
[0021] Figure 3 for Figure 1 Schematic diagram of the closed coring tool in the state of clamping the core;
[0022] Figure 4 yes Figure 1 A cross-sectional view of the outer barrel of a closed coring tool;
[0023] Figure 5 yes Figure 1 A cross-sectional view of the inner barrel of the closed coring tool;
[0024] Figure 6 yes Figure 1 Schematic diagram of the anti-return mechanism of the closed coring tool;
[0025] Figure 7 yes Figure 1 A schematic diagram of the connection structure between the leaf spring claw and the first annular member of the closed coring tool;
[0026] Figure 8 It is a structural schematic diagram of another specific embodiment of the closed coring tool of the utility model;
[0027] In the figure, an outer cylinder 100, an inner cylinder 200, a plunger 300, a leaf spring claw 400, a non-return mechanism 500, and a cover plate 700;
[0028] Connecting portion 110 , annular drill bit 120 , groove 130 , sealing ring 210 , fluid cavity 220 , upper flow channel 230 , lower flow channel 240 , first annular member 410 , annular support portion 510 , support column 520 , leaf spring block 530 , first pin 610 , and second pin 620 . DETAILED DESCRIPTION
[0029] The present invention will be further described in detail below in conjunction with the embodiments and drawings, but the implementation manner of the present invention is not limited thereto.
[0030] Example
[0031] Please refer to Figures 1 to 8 , which shows the structures of two specific embodiments of the closed coring tool of the utility model. The closed coring tool of the utility model comprises an outer cylinder 100, an inner cylinder 200, a plunger 300, a leaf spring claw 400 and a backflow prevention mechanism 500. The outer cylinder 100 has an upper end provided with a connecting portion 110 for connecting with a drill string, and the lower end of the outer cylinder 100 is connected with an annular drill bit 120. When in use, the drill string drives the outer cylinder 100 and the annular drill bit 120 to rotate, thereby cutting the bottom hole reservoir to obtain a core. The inner wall of the outer cylinder 100 is provided with an annular groove 130, thereby forming annular sizes with different diameters on the inner wall of the outer cylinder 100. The groove 130 corresponds to an expanded diameter portion for accommodating leaf spring claws 400, so that the size of the channel surrounded by each leaf spring claw 400 is larger than the size of the core. The position outside the groove 130 corresponds to a reduced diameter portion for reducing the size of the channel surrounded by each leaf spring claw 400, thereby clamping the core. The outer wall of the inner cylinder 200 is spaced a certain distance from the inner wall of the outer cylinder 100. At the same time, the upper and lower ends of the outer wall of the inner cylinder 200 are respectively provided with sealing rings 210, so that the inner cylinder 200 and the outer cylinder 100 are slidingly sealed and connected, and at An annular sealed cavity is formed between the outer wall of the inner cylinder 200 and the inner wall of the outer cylinder 100; an upper flow channel 230 and a lower flow channel 240 communicating with the sealed cavity are respectively provided at the upper and lower ends of the inner cylinder 200; the plunger 300 is slidably sealedly connected to the inner wall of the inner cylinder 200, and a fluid cavity containing a sealed liquid is formed between the upper end of the plunger 300 and the inner cylinder 200; there are a plurality of leaf spring claws 400, and the plurality of leaf spring claws 400 are fixed at the bottom of the inner cylinder 200 and surround the inner cylinder 200. The leaf spring claw 400 is arranged around the outer cylinder 100, and its side wall abuts against the inner wall of the outer cylinder 100 by virtue of its own elasticity; wherein the plunger 300 is fixed on the annular drill bit 120 via the shearable first pin 610, and after being fixed, the plunger 300 blocks the lower flow channel 240, and the lower end of the plunger 300 extends out of the drill bit, and the side wall of the leaf spring claw 400 abuts against the inner wall of the groove 130. At this time, the size of the circular hole surrounded by the leaf spring claw 400 is larger than the size of the core drilled by the drill bit, such as Figure 1 As shown; after the closed coring tool is lowered into the bottom of the well, pressure is applied to the closed coring tool through the upper pipe string, and the plunger 300 abuts against the bottom of the well and can cut off the first pin 610 with the help of the reaction force of the bottom of the well, so that the plunger 300 moves upward relative to the inner tube 200, so that the lower flow channel 240 can be opened. During the upward movement of the plunger 300 relative to the inner tube 200, the sealing cavity will be continuously squeezed, so that the sealing liquid in the fluid cavity 220 enters the bottom of the well through the upper flow channel 230, the lower flow channel 240 and the annular drill bit 120, so as to protect the core to be drilled. During the movement, when the leaf spring claw 400 is located in the groove 130, the core will not be clamped, and the wear is very small or even zero. Figure 2As shown; when the plunger 300 moves upward to the limit position relative to the inner cylinder 200, the plunger 300 pushes the inner cylinder 200 to move together, that is, the inner cylinder 200 moves axially upward relative to the outer cylinder 100, thereby moving the leaf spring claw 400 out of the groove 130. When the leaf spring claw 400 moves out of the groove 130, the size of the circular hole surrounded by the leaf spring claw 400 is less than or equal to the size of the core drilled by the drill bit, thereby clamping the core. The anti-return mechanism 500 is used to prevent the inner cylinder 200 from moving toward the drill bit relative to the outer cylinder 100, so that the clamping effect of the leaf spring claw 400 on the core can be maintained, thereby preventing the leaf spring claw 400 from sliding into the groove 130 when the pipe string is lifted after coring, causing the core to fall off. Figure 3 shown.
[0032] In the present invention, the plunger 300 will push the inner cylinder 200 to move together only after the plunger 300 moves upward to the limit position relative to the inner cylinder 200. In some embodiments, the limit position is the position where the upper end of the plunger 300 abuts against the top of the inner cylinder 200. In other embodiments, components such as limit bosses can also be provided in the inner cylinder 200. When the upper end of the plunger 300 abuts against these limit components, the plunger 300 will drive the inner cylinder 200 to move upward together. In addition, during the specific implementation, it is necessary to ensure that the inner cylinder 200 will not move with the outer cylinder 100 before the plunger 300 moves to the limit position relative to the inner cylinder 200. In some embodiments, such as Figure 8 As shown, a second pin 620 may be provided to position the inner cylinder 200 in the outer cylinder 100. When the inner cylinder 200 reaches the limit position upward, a large thrust is applied to the inner cylinder 200. When the inner cylinder 200 cuts off the second pin 620, the inner cylinder 200 moves relative to the outer cylinder 100. Of course, in some embodiments, an elastic element, such as a spring, may also be provided to push the inner cylinder 200 to move downward. When the plunger 300 moves upward to the limit position, it pushes the inner cylinder 200 to compress the elastic element, thereby causing the inner cylinder 200 to move relative to the outer cylinder 100. Figure 3 As shown, in this embodiment, a cover plate 700 threadedly connected to the outer cylinder 100 is provided as a support for the elastic element.
[0033] In the present invention, the number of leaf spring claws 400 can be selected as needed. For example, in some embodiments, three leaf spring claws are provided, and in other embodiments, four leaf spring claws are provided. In order to facilitate installation, in some embodiments, as shown in FIG. Figure 7 As shown, it also includes a first annular member 410, and the leaf spring claws 400 are distributed around the circumference of the first annular member 410 and fixedly connected thereto. Each leaf spring claw 400 is spaced a certain distance apart to form a petal shape. The first annular member 410 is connected to the lower end of the inner cylinder 200 in a detachable manner, such as a threaded connection.
[0034] In the present invention, the anti-return mechanism 500 is used to prevent the inner cylinder 200 from moving in a direction away from the opening end of the inner cylinder 200. Various existing anti-return structures can be used. In some embodiments, the anti-return mechanism 500 is used. Figure 6 The anti-return structure shown includes an annular support portion 510 detachably connected to the outer cylinder 100, and a support column 520 fixedly connected to the top of the inner cylinder 200, wherein at least two leaf spring blocks 530 are connected to the bottom of the annular support portion 510, and all leaf spring blocks 530 are arranged around the circumference of the annular support portion 510 to form a receiving hole matching the support column 520, and the support column 520 is inserted into the receiving hole and anti-return teeth are provided on the annular contact surfaces of the two. When the anti-return teeth of the two are engaged, a anti-return structure is formed to prevent the inner cylinder 200 from moving in a direction away from the open end of the inner cylinder 200. When the core needs to be unloaded later, it is only necessary to use a hole expansion tool to expand the leaf spring block 530 to release the anti-return effect.
[0035] The above is only a preferred specific implementation of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by any technician familiar with the technical field within the technical scope disclosed in the embodiments of the present invention should be covered within the protection scope of the present invention.
Claims
1. A closed coring tool, characterized in that: include: An outer cylinder, the lower end of which is connected to a drill bit, and an inner wall of which is provided with an annular groove; An inner cylinder is slidably and sealingly connected to the inner wall of the outer cylinder, and an annular sealing cavity is formed between the outer wall of the inner cylinder and the inner wall of the outer cylinder; the upper and lower ends of the inner cylinder are respectively provided with an upper flow channel and a lower flow channel connected to the sealing cavity, and the upper end of the inner cylinder is closed; A plunger is slidably and sealingly connected to the inner wall of the inner cylinder, and a fluid cavity containing a sealing fluid is formed between the upper end of the plunger and the inner cylinder; at least two leaf spring claws fixed to the bottom of the inner cylinder and arranged around the circumference of the inner cylinder, the side walls of the leaf spring claws abutting against the inner wall of the outer cylinder; A non-return mechanism for preventing the inner cylinder from moving relative to the outer cylinder in the direction of the drill bit; The plunger is fixed on the drill bit through a first shearable pin, and after being fixed, the plunger blocks the lower flow channel, the lower end of the plunger extends out of the drill bit, and the leaf spring claw is located in the groove. At this time, the size of the circular hole surrounded by the leaf spring claw is larger than the size of the core drilled by the drill bit; when the plunger moves upward to the limit position relative to the inner tube, the plunger can push the inner tube to move together, thereby pushing the leaf spring claw out of the groove. When the leaf spring claw is out of the groove, the size of the circular hole surrounded by the leaf spring claw is smaller than or equal to the size of the core drilled by the drill bit, thereby clamping the core.
2. A closed coring tool according to claim 1, characterized in that: The limit position is the position where the upper end of the plunger abuts against the top of the inner cylinder.
3. A closed coring tool according to claim 2, characterized in that: A second pin is also included for positioning the inner cylinder in the outer cylinder.
4. A closed coring tool according to claim 1, characterized in that: It also includes an elastic element for pushing the inner cylinder to move toward the drill bit. When the plunger moves upward to the limit position, the inner cylinder compresses the elastic element, thereby causing the inner cylinder to move relative to the outer cylinder.
5. A closed coring tool according to claim 1, characterized in that: It comprises a first annular member, the leaf spring claws are distributed around the circumference of the first annular member and are fixedly connected thereto, each leaf spring claw is spaced a certain distance apart to form a petal shape, and the first annular member is detachably connected to the lower end of the inner cylinder.
6. A closed coring tool according to claim 1, characterized in that: The anti-return mechanism includes: An annular support portion detachably connected to the outer cylinder; A support column fixedly connected to the top of the inner tube; At least two leaf spring claws fixed to the bottom of the annular support portion and arranged around the circumference of the annular support portion; Among them, all the leaf spring claws are arranged around the circumference of the annular support part to form a accommodating hole matching the support column, the support column is inserted into the accommodating hole and the annular contact surfaces of the two are provided with anti-return teeth, and when the anti-return teeth of the two are engaged, a anti-return structure is formed to prevent the inner cylinder from moving in a direction away from the opening end of the inner cylinder.
Citation Information
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