A kind of underground bidirectional shock absorber

Abstract

The present invention relates to an underground bidirectional shock absorber used for absorbing vibration of drill string and reducing impact load of drill string in drilling engineering. It solves the problem of vibration caused by axial and rotational impact loads on underground drill string. The technical scheme is as follows: the upper end of the outer cylinder is connected with the upper drill string by thread, and the lower end of the output shaft is connected with the lower drill string by thread; a circle of raised steps is arranged at the lower part of the outer circle of the support seat, and the disc spring is installed on the outer circle of the support seat; the inner magnetic shoe is evenly arranged in the middle of the outer circle of the output shaft, and the outer magnetic shoe is evenly arranged in the middle of the inner cavity of the outer cylinder, and the upper end of the end cover is connected with the lower end of the outer cylinder by thread. The present invention is installed in the bottom drilling tool assembly, which can be applied to formations with large differences such as gravel, soft and hard formations, etc. It can absorb the axial impact load and rotational impact load of the drill string, and can effectively eliminate the instability of the bottom hole operation of the drill bit caused by the vibration of the upper drill string in all directions, and effectively protect and greatly extend the service life of the PDC drill bit.

Description

Technical Field

[0001] The invention relates to an underground bidirectional shock absorber used for absorbing drill string vibration and reducing the impact load of the drill string in drilling engineering. Background Art

[0002] The shock absorber is one of the downhole tools required in drilling operations. It uses the shock absorbing elements inside the tool to absorb or reduce the impact load of the drill bit, the vibration load of the drill string, and the torsion load during the rotation and rock breaking process, thereby protecting the drill bit and drilling tools, reducing drilling costs, and improving drilling efficiency. Commonly used shock absorbers include mechanical shock absorbers and hydraulic shock absorbers. The vibration generated by the drill string is a composite vibration of longitudinal and torsional vibration. The use of a bidirectional shock absorber can reduce or eliminate the vibration caused by the rotation of the drill bit, and can eliminate the vibration source to a large extent. Therefore, a bidirectional shock absorber with dual axial and torsional shock absorption effects often has a better shock absorption effect.

[0003] Hydraulic shock absorbers use silicone oil as liquid springs, and their stiffness depends on the volume of silicone oil and the degree of filling. However, hydraulic shock absorbers have extremely high requirements for sealing. Wear of seals leads to oil leakage, and well temperature changes are very sensitive to silicone oil, so their reliability is not as good as mechanical shock absorbers. The core of mechanical two-way shock absorbers is a pair of large spiral thread pairs, which have extremely high requirements for the processing accuracy of the thread pairs, and the structure generally uses multi-thread pairs, which are expensive.

[0004] In view of the above technical background, the present invention particularly provides an underground bidirectional shock absorber, which has a simple structure and reliable operation, and overcomes the shortcomings of the existing bidirectional shock absorber. Summary of the invention

[0005] The purpose of the present invention is to provide a downhole bidirectional shock absorber in order to solve the problem of vibration caused by axial and rotational impact loads on downhole drill strings.

[0006] In order to achieve the above-mentioned purpose, the present invention adopts the following technical scheme: a downhole bidirectional shock absorber, which is composed of an outer cylinder, a support seat, a disc spring, an inner magnetic tile, an outer magnetic tile, an output shaft and an end cover. Its structural characteristics are: the upper end of the outer cylinder is threadedly connected to the upper drill string, and the lower end of the output shaft is threadedly connected to the lower drill string; a circle of raised steps is arranged at the lower part of the outer circle of the support seat, and the disc spring is installed on the outer circle of the support seat, and the disc spring is pressed by the raised steps at the lower part of the outer circle of the support seat; the lower end of the support seat is threadedly connected to the upper end of the output shaft; the inner magnetic tile has strong magnetism, and a plurality of inner magnetic tiles are evenly arranged circumferentially in the middle of the outer circle of the output shaft. The N pole and S pole of the inner magnetic tile are connected together in sequence to form a ring. There are several groups of tiles arranged in the axial direction, and the inner magnetic tiles are bonded to the output shaft with high-temperature glue; the outer magnetic tiles have strong magnetism, and several outer magnetic tiles are evenly arranged circumferentially in the middle of the inner cavity of the outer cylinder, and the N poles and S poles of the outer magnetic tiles are connected together in sequence to form a ring, and there are several groups of outer magnetic tiles arranged in the axial direction, and the outer magnetic tiles are bonded to the outer cylinder with high-temperature glue; the number of outer magnetic tiles and inner magnetic tiles corresponds to one by one, and there is a gap between the outer magnetic tiles and the inner magnetic tiles; after installation, the outer magnetic tiles and the inner magnetic tiles at the opposite position have opposite polarities and are in a state of mutual attraction; the outer magnetic tiles and the adjacent inner magnetic tiles at the opposite position have the same polarity and are in a state of mutual repulsion; the upper end of the end cover and the lower end of the outer cylinder are threadedly connected.

[0007] A sealing device is provided between the inner cavity at the upper end of the outer cylinder and the outer circle of the support seat; a sealing device is provided between the inner cavity at the lower end of the end cover and the outer circle of the output shaft.

[0008] The present invention can absorb the axial impact load and the rotational impact load of the drill string; the rotational torque of the outer cylinder is transmitted to the output shaft by utilizing the magnetic attraction and repulsion between the outer magnetic tile and the inner magnetic tile; when the lower drill string is subjected to a rotational impact, the circumferential relative position of the output shaft and the outer cylinder can be adaptively deflected to overcome the influence of the rotational impact load on the upper drill string; when the lower drill string is subjected to an axial impact load, the magnetic attraction and repulsion between the outer magnetic tile and the inner magnetic tile, as well as the pressure of the disc spring, allow the axial position of the output shaft and the outer cylinder to be adaptively offset to overcome the influence of the axial impact load on the upper drill string.

[0009] The beneficial effects of the present invention are: (1) the use of magnetic force to transmit torque and drilling pressure, when bearing axial and rotational impact loads, the drill string is not damaged, and the shock absorption effect is good; (2) the structure is simple and adaptable to complex working conditions downhole; (3) it has the ability to absorb axial vibration and circumferential vibration at the same time. The present invention is installed in the bottom drilling tool assembly and can be applied to formations with large differences such as gravel, soft and hard formations, etc. It can effectively eliminate the instability of the bottom hole operation of the drill bit caused by the vibration of the upper drill string in all directions, and effectively protect and greatly extend the life of the PDC drill bit. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 It is a structural schematic diagram of an underground bidirectional shock absorber of the present invention.

[0011] Figure 2 yes Figure 1 Cross-sectional view of section AA.

[0012] In the figure: 1 - outer cylinder, 2 - support seat, 3 - disc spring, 4 - inner magnetic shoe, 5 - outer magnetic shoe, 6 - output shaft, 7 - end cover. DETAILED DESCRIPTION

[0013] like Figure 1 and Figure 2 As shown, a downhole bidirectional shock absorber of the present invention is composed of an outer cylinder 1, a support seat 2, a disc spring 3, an inner magnetic tile 4, an outer magnetic tile 5, an output shaft 6 and an end cover 7. Its structural characteristics are: the upper end of the outer cylinder 1 is threadedly connected to the upper drill string, and the lower end of the output shaft 6 is threadedly connected to the lower drill string; a circle of raised steps is arranged at the lower part of the outer circle of the support seat 2, and the disc spring 3 is installed on the outer circle of the support seat 2, and the disc spring 3 is pressed by the raised steps at the lower part of the outer circle of the support seat 2; the lower end of the support seat 2 is threadedly connected to the upper end of the output shaft 6; the inner magnetic tile 4 has strong magnetism, and several inner magnetic tiles 4 are evenly arranged in the middle of the outer circle of the output shaft 6 in the circumferential direction, and the N pole and S pole of the inner magnetic tile 4 are connected together in sequence to form a ring, and the inner magnetic tile 4 is arranged in several groups in the axial direction, and the inner magnetic tile 4 and the output shaft 6 are bonded with high-temperature glue. In this embodiment, the inner magnetic tile 4 is circumferentially There are twelve evenly distributed outer magnetic tiles 4, and five groups of inner magnetic tiles 4 are arranged axially; the outer magnetic tiles 5 have strong magnetism, and several outer magnetic tiles 5 are evenly arranged circumferentially in the middle of the inner cavity of the outer cylinder 1, and the N pole and S pole of the outer magnetic tiles 5 are connected together in sequence to form a ring, and several groups of outer magnetic tiles 5 are arranged axially, and the outer magnetic tiles 5 and the outer cylinder 1 are bonded with high-temperature glue. In this embodiment, there are twelve evenly distributed outer magnetic tiles 5 along the circumferential direction, and five groups of outer magnetic tiles 5 are arranged axially; the number of outer magnetic tiles 5 and inner magnetic tiles 4 corresponds one to one, and there is a gap between the outer magnetic tiles 5 and the inner magnetic tiles 4; after installation, the outer magnetic tiles 5 and the inner magnetic tiles 4 at the opposite position have opposite polarities and are in a state of mutual attraction; the outer magnetic tiles 5 and the adjacent inner magnetic tiles 4 at the opposite position have the same polarity and are in a state of mutual repulsion; the upper end of the end cover 7 is threadedly connected to the lower end of the outer cylinder 1. A sealing device is provided between the inner cavity at the upper end of the outer cylinder 1 and the outer circle of the support seat 2 ; a sealing device is provided between the inner cavity at the lower end of the end cover 7 and the outer circle of the output shaft 6 .

[0014] The present invention can absorb the axial impact load and the rotational impact load of the drill string when working; the rotational torque of the outer cylinder 1 is transmitted to the output shaft 6 by the magnetic attraction and repulsion between the outer magnetic tile 5 and the inner magnetic tile 4; when the lower drill string is subjected to rotational impact, the circumferential relative position of the output shaft 6 and the outer cylinder 1 can be adaptively deflected to overcome the influence of the rotational impact load on the upper drill string; when the lower drill string is subjected to axial impact load, the magnetic attraction and repulsion between the outer magnetic tile 5 and the inner magnetic tile 4, as well as the pressure of the disc spring 3, allow the axial position of the output shaft 6 and the outer cylinder 1 to produce adaptive offset to overcome the influence of the axial impact load on the upper drill string. Therefore, the downhole bidirectional shock absorber of the present invention is installed in the bottom drilling tool assembly, which can be applied to strata with large differences such as gravel, soft and hard interlaced strata, and can effectively eliminate the instability of the bottom hole operation of the drill bit caused by the axial vibration of the upper drill string, and effectively protect and greatly extend the service life of the PDC drill bit.

Claims

1. A downhole bidirectional shock absorber, characterized by: The invention is composed of an outer cylinder (1), a support seat (2), a disc spring (3), an inner magnetic tile (4), an outer magnetic tile (5), an output shaft (6) and an end cover (7): the upper end of the outer cylinder (1) is threadedly connected to the upper drill string, and the lower end of the output shaft (6) is threadedly connected to the lower drill string; a circle of raised steps is arranged at the lower part of the outer circle of the support seat (2), the disc spring (3) is installed on the outer circle of the support seat (2), a step surface is arranged at the upper part of the inner cavity of the outer cylinder (1), the upper end of the disc spring (3) is tightly attached to the upper step surface of the inner cavity of the outer cylinder (1), and the disc spring (3) is pressed by the raised step at the lower part of the outer circle of the support seat (2); the lower end of the support seat (2) and the upper end of the output shaft (6) are threadedly connected. The invention relates to a buckle connection; the torque and drilling pressure are transmitted by magnetic force: the inner magnetic shoe (4) has strong magnetism, and a plurality of inner magnetic shoes (4) are evenly arranged in the circumferential direction in the middle of the outer circle of the output shaft (6); the N pole and the S pole of the inner magnetic shoe (4) are connected in sequence to form a ring; the inner magnetic shoe (4) is arranged in a plurality of groups in the axial direction; the inner magnetic shoe (4) and the output shaft (6) are bonded with high-temperature glue; the upper end surface of the inner magnetic shoe (4) group contacts the lower end surface of the support seat (2), and the lower end surface of the inner magnetic shoe (4) group contacts the step surface of the outer circle protrusion in the middle of the output shaft (6); the outer magnetic shoe (5) has strong magnetism, and a plurality of outer magnetic shoes (5) are evenly arranged in the circumferential direction on the outer cylinder (1); ) in the middle of the inner cavity, the N pole and the S pole of the outer magnetic tile (5) are connected together in sequence to form a ring, the outer magnetic tile (5) is arranged in a plurality of groups in the axial direction, and the outer magnetic tile (5) and the outer cylinder (1) are bonded with high-temperature glue; the number of the outer magnetic tile (5) and the inner magnetic tile (4) corresponds to each other, and there is a gap between the outer magnetic tile (5) and the inner magnetic tile (4); after installation, the outer magnetic tile (5) and the inner magnetic tile (4) at the opposite position have opposite polarities and are in a state of mutual attraction; the outer magnetic tile (5) and the adjacent inner magnetic tile (4) at the opposite position have the same polarity and are in a state of mutual repulsion; the upper end of the end cover (7) is threadedly connected to the lower end of the outer cylinder (1); The rotational torque of the cylinder (1) is transmitted to the output shaft (6) by utilizing the magnetic attraction and repulsion between the outer magnetic shoe (5) and the inner magnetic shoe (4); when the lower drill string is subjected to a rotational impact, the circumferential relative position of the output shaft (6) and the outer cylinder (1) can be adaptively deflected to overcome the influence of the rotational impact load on the upper drill string; when the lower drill string is subjected to an axial impact load, the magnetic attraction and repulsion between the outer magnetic shoe (5) and the inner magnetic shoe (4), as well as the pressure of the disc spring (3), allow the axial position of the output shaft (6) and the outer cylinder (1) to be adaptively offset to overcome the influence of the axial impact load on the upper drill string.

2. The downhole bidirectional shock absorber according to claim 1 is characterized in that: A sealing device is provided between the inner cavity at the upper end of the outer cylinder (1) and the outer circle of the support seat (2); and a sealing device is provided between the inner cavity at the lower end of the end cover (7) and the outer circle of the output shaft (6).

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