Ultra-deep well pressure maintaining coring ball valve assembly

Abstract

The utility model relates to the technical field of downhole tools, in particular to an ultra-deep well pressure maintaining coring ball valve assembly. The ultra-deep well pressure maintaining coring ball valve assembly comprises a ball valve connector, an upper ball seat, a ball valve shell and a lower ball seat. The upper ball seat is arranged at the right end of the ball valve connector, the ball valve shell is connected with the ball valve connector and the ball valve base, the wave spring and the gaskets are arranged between the upper ball seat and the ball valve connector, the steel ball is arranged at the right end of the upper ball seat, and the lower ball seat and the ball valve base are arranged at the right end of the steel ball. According to the ultra-deep well pressure maintaining coring ball valve assembly, a spring is changed into a combination of a wave spring and a plurality of gaskets, the design space is greatly saved, the structural strength is improved, the sealing performance and the high temperature resistance of the device are improved through direct contact of the steel ball seat, the sealing performance of the device is improved through the ball valve shell, and the service life of the device is prolonged. The elastic semi-ring is used for controlling the working state of the steel ball, and therefore the purpose that the strength and the sealing performance of the device meet the use requirement of a myriameter deep well is achieved.

Description

Technical Field

[0001] The utility model relates to the technical field of downhole tools, in particular to a pressure-maintaining coring ball valve assembly for ultra-deep wells. Background Art

[0002] The pressure-maintaining principle is that after coring and core cutting are completed, a steel ball is dropped from the ground, and a series of downhole actions are started. The inner barrel string moves upward. After passing through the ball valve, the ball valve is closed under the drive of a half ring to block the inner barrel and achieve the pressure-maintaining function. In the prior art, the ball valve housing is connected by two ribs. Through holes for fixing the ball valve are drilled on the ribs, and the holes are biased to one side. The outer surface of the rib is an arc, and the inner surface is a plane. The rib wall thins along the arc surface. There is a through hole in the middle of the sphere (the inner barrel passes through it during coring). The two side surfaces are symmetric planes, with a rotating shaft hole and a driving groove machined on them. The other two spherical surfaces are reserved. One is machined with a driving start groove, and the other spherical surface is the closed ball valve sealing surface. The ball seal seat is a non-metallic composite seal. The two half rings are connected into one body by a pin shaft, which drives the ball valve to rotate 90° to close the ball valve. The pressure-bearing capacity of this ball valve structure is 80 MPa, and the composite seal can resist a temperature of 170 °C, which cannot meet the strength and sealing requirements under the conditions of 140 MPa and 240 °C in a ten-thousand-meter deep well. Summary of the Invention

[0003] (I) Technical Problems to be Solved

[0004] The utility model provides a pressure-maintaining coring ball valve assembly for ultra-deep wells to overcome the problems that the pressure-bearing capacity of the coring ball valve structure and the temperature resistance of the seal in the prior art cannot meet the working conditions of a ten-thousand-meter deep well.

[0005] (II) Technical Solutions

[0006] To achieve the above object, the utility model provides a pressure-maintaining coring ball valve assembly for ultra-deep wells, including: a ball valve joint, an upper ball seat, a ball valve housing, and a lower ball seat;

[0007] The ball valve joint is a hollow cylindrical structure. The inner wall of its left end is provided with threads. The right end of the ball valve joint is provided with a stepped outer edge, and the right end of the ball valve joint is provided with an upper ball seat;

[0008] The ball valve housing is sleeved on the upper ball seat. The ball valve housing is a hollow cylindrical structure. The lower end of the ball valve housing is provided with a stepped outer edge. A rectangular hole is provided on the outer wall of the ball valve housing. A wave spring and several gaskets are provided between the upper ball seat and the ball valve joint. A steel ball is provided at the right end of the upper ball seat, and a through hole is provided at the center of the steel ball;

[0009] A lower ball seat and a ball valve base are provided at the right end of the steel ball. The wave spring presses the upper ball seat, so that the upper ball seat and the lower ball seat are closely attached to the steel ball. The ball valve housing connects the ball valve joint and the ball valve base;

[0010] An elastic semi-ring is provided on the outer wall of the steel ball. The elastic semi-ring is sleeved on the steel ball. The upper end of the elastic semi-ring passes through a rectangular hole provided on the outer wall of the ball valve housing. Two long grooves are symmetrically provided on the inner wall of the lower end of the elastic semi-ring, and ball bearings are respectively provided in the two long grooves.

[0011] Preferably, the ball valve housing limits the elastic semi-ring, and the elastic semi-ring can axially move along the rectangular hole at the upper end of the ball valve housing.

[0012] Preferably, it further includes a plurality of sealing rings, and the sealing rings are respectively provided between the ball valve joint and the ball valve housing, between the ball valve housing and the ball valve base, between the upper ball seat and the ball valve housing, and between the lower ball seat and the ball valve housing.

[0013] Preferably, the left and right sides of the steel ball are of a flat structure, and semi-circular ball sockets for ball bearings are symmetrically machined on the flat structure.

[0014] Preferably, half of the ball bearing is embedded in the long groove of the elastic semi-ring and the other half is in close contact with the ball socket of the steel ball.

[0015] Preferably, the elastic semi-ring is of a C-shaped structure. The arc-shaped surface at the upper end of the elastic semi-ring exceeds the radius of the ball valve joint, and a drilling fluid channel is provided between the elastic semi-ring and the steel ball.

[0016] Preferably, the arc-shaped surface at the upper end of the elastic semi-ring is of an elastic structure and the lower end is of a rigid structure.

[0017] Preferably, the radius of the steel ball is greater than the radius of the upper ball seat. The steel ball can rotate 90°, and the arc-shaped surface of the steel ball can completely seal the upper ball seat.

[0018] (III) Beneficial effects

[0019] The present utility model provides a pressure-retaining coring ball valve assembly for ultra-deep wells, which can realize that by changing the spring into a combination of a wave spring and a plurality of gaskets, the wave spring occupies a small space and has a large elastic force, and the magnitude of the spring force can be adjusted by changing the number of gaskets, greatly saving the design space and being beneficial to improving the structural strength. The steel ball is in direct contact with the upper ball seat and the lower ball seat, and the sealing performance and high-temperature resistance of the device are improved through the metal sealing method. The ball valve housing is used to prevent the sealing surface of the steel ball from being eroded by mud, improving the sealing performance of the device. An elastic semi-ring is sleeved on the outer wall of the steel ball, and the elastic semi-ring is limited by the ball valve housing. The elastic semi-ring is used to control the working state of the steel ball, so as to achieve the purpose of making the strength and sealing performance of the device meet the use requirements of ten-thousand-meter deep wells. Description of the drawings

[0020] Figure 1 Shows a schematic structural diagram of a pressure-retaining coring ball valve assembly of the present utility model;

[0021] Figure 2 Shows a cross-sectional view of a pressure-retaining coring ball valve assembly of the present utility model.

[0022] Wherein: 1: ball valve joint; 2: wave spring; 3: gasket; 4: upper ball seat; 5: steel ball; 6: ball valve housing; 7: lower ball seat; 8: ball valve base; 9: elastic half-ring; 10: ball. Specific embodiments

[0023] The present invention will be described in detail below in conjunction with the accompanying drawings and embodiments.

[0024] In the description of the present invention, it is necessary to understand that the orientation or positional relationship indicated by "upper", "lower", "left", "right", "inner", "outer", "top", "bottom", etc. is based on the orientation or positional relationship shown in the accompanying drawings. The purpose is only to facilitate the description of the present invention and simplify the description, and does not indicate or imply that the components referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be construed as a limitation of the present invention.

[0025] As Figure 1-2 shown, the present invention provides a pressure-retaining coring ball valve assembly for ultra-deep wells, comprising: a ball valve joint 1, an upper ball seat 4, a ball valve housing 6 and a lower ball seat 7;

[0026] The ball valve joint 1 is a hollow cylindrical structure, the inner wall of its left end is provided with threads, the right end of the ball valve joint 1 is provided with a stepped outer edge, and this step is used for positioning and fixing with the ball valve housing 6. The right end of the ball valve joint 1 is provided with an upper ball seat 4. The upper ball seat 4 is an annular structure, and it extends leftward with a cylindrical structure. This cylindrical structure is inserted into the ball valve joint 1, and its size matches the inner wall size of the ball valve joint 1, ensuring the sealing performance;

[0027] The ball valve housing 6 is sleeved on the upper ball seat 4. The ball valve housing 6 is a hollow cylindrical structure. The lower end of the ball valve housing 6 is provided with a stepped outer edge, and the upper end of the ball valve housing 6 is provided with a rectangular hole. The ball valve housing 6 connects the ball valve joint 1 and the ball valve base 8. A wave spring 2 and several gaskets 3 are provided between the upper ball seat 4 and the ball valve joint 1. The wave spring 2 has good elasticity and fatigue resistance and can provide a stable pre-tightening force. The gasket 3 can increase the contact area of the sealing surface and improve the sealing performance. The right end of the upper ball seat 4 is provided with a steel ball 5. The ball valve housing 6 is a semi-surrounding structure, which greatly improves the strength of the ball valve housing 6 and at the same time protects the sealing surface of the steel ball 5, avoiding the erosion of the drilling fluid on the sealing spherical surface;

[0028] It should be noted that in actual use, the wave spring 2 may have a decrease in elastic performance due to factors such as service time, temperature, and pressure, resulting in insufficient pre-tightening force between the upper ball seat 4 and the lower ball seat 7 and the steel ball 5. The pre-tightening force can be adjusted by increasing the number of gaskets 3;

[0029] The through hole is arranged at the center of the steel ball 5. The left and right sides of the steel ball 5 are plane structures. The ball sockets for the rolling balls are symmetrically machined on the plane structures. The lower ball seat 7 and the ball valve base 8 are arranged at the right end of the steel ball 5. The wave spring 2 presses the upper ball seat 4, so that the upper ball seat 4 and the lower ball seat 7 are closely attached to the steel ball 5. The radius of the steel ball 5 is larger than that of the upper ball seat 4. The steel ball 5 can rotate by 90°. The arc surface of the steel ball 5 can completely seal the upper ball seat 4;

[0030] It should be noted that during the manufacturing process of the steel ball 5, in order to ensure the sealing performance between the steel ball 5, the upper ball seat 4 and the lower ball seat 7, it is usually necessary to grind the steel ball 5, the upper ball seat 4 and the lower ball seat 7 one by one. The grinding process can eliminate the microscopic unevenness on the surfaces of the steel ball 5 and the ball seats, improve the surface finish, and thus improve the sealing performance of the device.

[0031] An elastic half-ring 9 is arranged on the outer wall of the steel ball 5. The elastic half-ring 9 is sleeved on the steel ball 5. The upper end of the elastic half-ring 9 passes through a rectangular hole arranged on the outer wall of the ball valve housing 6. Two long grooves are symmetrically arranged on the inner wall of the lower end of the elastic half-ring 9. The rolling balls 10 are arranged in the long grooves. Half of the rolling balls 10 are embedded in the long grooves and the other half are closely attached to the outer wall of the steel ball 5. The ball valve housing 6 positions the elastic half-ring 9. The elastic half-ring 9 can axially move in the rectangular hole at the upper end of the ball valve housing 6. The elastic half-ring 9 is of a C-shaped structure. The arc surface at the upper end of the elastic half-ring 9 exceeds the radius of the ball valve joint 1. A drilling fluid channel is arranged between the elastic half-ring 9 and the steel ball 5. The drilling fluid channel ensures the smooth passage of the mud;

[0032] It should be noted that the arc surface at the upper end of the elastic half-ring 9 is an elastic structure, and the lower end is a rigid structure. The upper elastic structure has self-aligning property, can adapt to the rotation and axial movement of the steel ball 5, and provides a stable elastic force. The rigid structure at the lower end of the elastic half-ring 9 and the rolling balls 10 form the driving part of the elastic half-ring 9. The rolling ball driving structure can perform precise positioning and occupies a small space, which is beneficial to improving the overall strength of the device;

[0033] It should be noted that in order to ensure the sealing performance of the device, sealing rings are arranged between the ball valve joint 1 and the ball valve housing 6, between the ball valve housing 6 and the ball valve base 8, between the upper ball seat 4 and the ball valve housing 6, and between the lower ball seat 7 and the ball valve housing 6. The sealing rings can effectively prevent the medium from leaking inside the ball valve and improve the working reliability of the device.

[0034] The actual working scenario of a pressure-retaining coring ball valve assembly for ultra-deep wells is introduced in detail below.

[0035] In the actual working process, the upper ball seat 4 and the lower ball seat 7 are hermetically sealed with the steel ball 5 through metal to achieve the sealing between the ball valve assembly and the inner cylinder and the outside world. The gap between the elastic half-ring 9 and the spherical surface of the steel ball 5 and the gap between the semi-surrounded outer surface of the ball valve housing 6 and the inner wall of the outer cylinder serve as the drilling fluid flow channels. After coring, the core is cut off by lifting, and a ball is dropped into the drill string and pressure is built up to unlock the inner cylinder string and achieve hydraulic lifting. When the inner cylinder moves upward and exceeds the steel ball, it drives the entire ball valve assembly to move upward. The elastic half-ring 9 moves upward and contacts the shoulder of the outer cylinder joint and stops moving upward. It drives the ball 10 to move along the long groove provided on the inner wall at the lower end of the elastic half-ring 9. The elastic half-ring 9 drives the steel ball 5 to flip 90°. The spherical surface of the steel ball 5 seals the inner cylinder, realizing the function of pressure-holding coring.

[0036] It can be understood that for the above-mentioned various embodiments mentioned in the present invention, without violating the principle logic, they can be combined with each other to form combined embodiments. Due to space limitations, the present invention will not elaborate further.

[0037] Those skilled in the art can understand that in the above method of the specific implementation manner, the writing order of each step does not mean a strict execution order and does not constitute any limitation on the implementation process. The specific execution order of each step should be determined according to its function and possible internal logic.

[0038] A pressure-holding coring ball valve assembly provided by the present invention replaces the spring with a combination of a wave spring 2 and several gaskets 3. The wave spring 2 occupies a small space and has a large elastic force, and the magnitude of the spring force can be adjusted by changing the number of gaskets 3, greatly saving the design space and being beneficial to improving the structural strength. The steel ball 5 is in direct contact with the upper ball seat 4 and the lower ball seat 7, and the sealing performance and high-temperature resistance of the device are improved through metal sealing. The use of the ball valve housing 6 prevents the sealing surface of the steel ball 5 from being eroded by mud, improving the sealing performance of the device. An elastic half-ring 9 is sleeved on the outer wall of the steel ball 5, and the elastic half-ring 9 is limited by the ball valve housing 6. The elastic half-ring 9 is used to control the working state of the steel ball 5, so as to achieve the purpose of making the strength and sealing performance of the device meet the requirements for use in a ten-thousand-meter deep well.

[0039] The above has described the various embodiments of the present invention. The above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and variations are obvious to those of ordinary skill in the art in the technical field without departing from the scope and spirit of the described embodiments. The choice of terms used herein is intended to best explain the principles of the embodiments, practical applications, or improvements to the technology in the market, or to enable other ordinary skilled persons in the technical field to understand the disclosed embodiments.

Claims

1. A pressure-maintaining coring ball valve assembly for ultra-deep wells, characterized in that, Comprising: Ball valve joint (1), upper ball seat (4), ball valve housing (6) and lower ball seat (7); The ball valve joint (1) is a hollow cylindrical structure, with internal threads provided on the inner wall of its left end. There is a stepped outer edge at the right end of the ball valve joint (1), and an upper ball seat (4) is provided at the right end of the ball valve joint (1); The ball valve housing (6) is sleeved on the upper ball seat (4). The ball valve housing (6) is a hollow cylindrical structure, with a stepped outer edge at the lower end of the ball valve housing (6). There is a rectangular hole on the outer wall of the ball valve housing (6). A wave spring (2) and several gaskets (3) are provided between the upper ball seat (4) and the ball valve joint (1). A steel ball (5) is provided at the right end of the upper ball seat (4), and a through hole is provided at the center of the steel ball (5); A lower ball seat (7) and a ball valve base (8) are provided at the right end of the steel ball (5). The wave spring (2) presses the upper ball seat (4) so that the upper ball seat (4) and the lower ball seat (7) are in close contact with the steel ball (5). The ball valve housing (6) connects the ball valve joint (1) and the ball valve base (8); Elastic half-rings (9) are provided on the outer wall of the steel ball (5). The elastic half-rings (9) are sleeved on the steel ball (5). The upper ends of the elastic half-rings (9) pass through the rectangular holes provided on the outer wall of the ball valve housing (6). Symmetrically arranged long grooves are provided on the inner wall at the lower ends of the elastic half-rings (9), and ball bearings (10) are respectively provided in the two long grooves; 2. The pressure-maintaining coring ball valve assembly for ultra-deep wells according to claim 1, characterized in that, The ball valve housing (6) limits the elastic half-rings (9), and the elastic half-rings (9) can axially move along the rectangular holes at the upper ends of the ball valve housing (6); 3. The pressure-maintaining coring ball valve assembly for ultra-deep wells according to claim 1, wherein Also included are several sealing rings, which are respectively provided between the ball valve joint (1) and the ball valve housing (6), between the ball valve housing (6) and the ball valve base (8), between the upper ball seat (4) and the ball valve housing (6), and between the lower ball seat (7) and the ball valve housing (6); 4. The pressure-maintaining coring ball valve assembly for ultra-deep wells according to claim 1, characterized in that, The left and right sides of the steel ball (5) are plane structures, and semi-circular ball sockets for ball bearings are symmetrically machined on the plane structures; 5. The pressure-maintaining coring ball valve assembly for ultra-deep wells according to claim 4, characterized in that, Half of the ball bearings (10) are embedded in the long grooves of the elastic half-rings (9), and the other half are in close contact with the ball sockets of the steel ball (5); 6. The hyper-deep well pressure-maintaining coring ball valve assembly according to claim 1, wherein The elastic half-rings (9) are of C-shaped structure. The upper arc surface of the elastic half-rings (9) exceeds the radius of the ball valve joint (1), and a drilling fluid channel is provided between the elastic half-rings (9) and the steel ball (5); 7. The pressure-maintaining coring ball valve assembly for ultra-deep wells according to claim 6, characterized in that, The upper arc surface of the elastic half-rings (9) is of elastic structure, and the lower end is of rigid structure; 8. The pressure-maintaining coring ball valve assembly for ultra-deep wells according to claim 1, characterized in that, The radius of the steel ball (5) is greater than the radius of the upper ball seat (4). The steel ball (5) can rotate by 90°, and the arc surface of the steel ball (5) can completely seal the upper ball seat (4).

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