Reducing ball seat
By designing lateral contact surfaces and opposite angles on both sides of the ball seat core's segmented body, the problem of unstable pressure in variable diameter ball seat pumps was solved, resulting in reduced liquid leakage, improved operational reliability, and lower costs.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- WEIQIXIN PETROLEUM MASCH (TIANJIN) CO LTD
- Filing Date
- 2024-11-01
- Publication Date
- 2026-05-08
AI Technical Summary
The existing variable diameter ball seat has unstable pump pressure during the setting operation, resulting in serious liquid leakage, which affects the reliability and cost of operation.
A variable diameter ball seat is designed with a segmented body structure. The contact surfaces on both sides of the segmented body are transverse contact surfaces, and the first included angle and the second included angle have the same or opposite directions, which increases the bends in the flow channel and the flow resistance, and prevents liquid leakage.
It improves the reliability of the ball seat, ensures the ball seat core falls smoothly, reduces the liquid leakage rate, stabilizes the pump pressure during the setting operation, and reduces operating costs.
Smart Images
Figure CN121993099A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of downhole tools technology for oilfield development, and in particular relates to a variable diameter ball seat for oil and gas well completion, especially on tubing strings with downhole hydraulic packers, installed below the packer for setting the hydraulic packer. Background Technology
[0002] A downhole hydraulic pressure-regulating ball seat is a commonly used downhole tool. It is typically installed on a tubing string with a downhole hydraulic packer, with the ball seat located below the packer for setting it. The hydraulic pressure-regulating ball seat usually comes with a steel ball. After the tubing string is installed, the steel ball is dropped from the wellhead onto the ball seat core. When the set pressure is reached, the core shears off the shear pins, and the ball and core fall together into the completion tubing or to the bottom of the well.
[0003] To achieve clean completion and increase the inner diameter of the completion string, soluble balls and variable-diameter ball seat cores are required. In this type of ball seat core, the core is segmented. After the setting shear pin is cut, the core descends, enlarging the inner diameter to enter its receiving cavity. The soluble ball passes through the core and falls to the bottom of the well, while the core itself does not fall to the bottom.
[0004] In current variable diameter ball seats, the contact surfaces between the segments of the ball seat core are longitudinal. After the ball is inserted and lands on the ball seat core, hydraulic pressure is applied. Under the action of hydraulic pressure, each segment moves radially outward, increasing the gap between the segments. The pumped liquid flows out from the gap, causing unstable pump pressure during the setting operation. Sometimes, due to excessively large gaps, the ball seat core cannot be removed, which complicates subsequent operations and increases operating costs. Summary of the Invention
[0005] To solve the above-mentioned technical problems, a variable diameter ball seat was invented, which solved the problem of unstable pump pressure in current setting operations and improved the reliability of the ball seat.
[0006] To achieve the above objectives, the present invention adopts the following technical solution:
[0007] A variable diameter ball seat includes a ball seat core, which is a cylindrical body composed of segmented bodies. The two sides of each segmented body are a first contact surface and a second contact surface, respectively. The first contact surface has a first transverse contact surface, and the second contact surface has a second transverse contact surface. The distance between the first and second transverse contact surfaces and the ball sealing line is less than 15 mm. The number of segmented bodies is three or more.
[0008] Furthermore, the distance between the first and second transverse contact surfaces and the ball sealing line is less than 3 mm.
[0009] Preferably, the number of the segmented bodies is 3, and the central angle of each segmented body is 120°; the first included angle and the second included angle are equal in size and the included angles turn in the same or opposite directions.
[0010] Preferably, the number of the segmented bodies is 4, and the central angle of each segmented body is 90°; the first included angle and the second included angle are equal in size, and the included angles turn in the same or opposite directions.
[0011] Preferably, the number of the segments is 5, and the central angle of each segment is 72°; the first included angle and the second included angle are equal in size and the included angles turn in the same or opposite directions.
[0012] Preferably, the number of the segmented bodies is 6, and the central angle of each segmented body is 60°; the first included angle and the second included angle are equal in size, and the included angles turn in the same or opposite directions.
[0013] Preferably, the number of the segmented bodies is 8, and the central angle of each segmented body is 45°; the first included angle and the second included angle are equal in size and the included angles turn in the same or opposite directions.
[0014] Compared with the prior art, the advantages of the present invention are as follows:
[0015] The presence of the first and second transverse contact surfaces overcomes the problems of the current technology, where the contact surfaces between the segmented bodies are longitudinally straight, resulting in excessive gaps and severe liquid leakage. In this invention, on each contact surface on both sides of the segmented body, the longitudinal straight gaps of the original technology are now curved, forming a transverse contact surface between the two longitudinal gaps. The leaking liquid must pass through the side wall of the ball seat core, lengthening the flow channel and adding a flow direction bend, thus increasing the flow resistance and reducing the leakage rate.
[0016] In particular, the design of the first included angle and the second included angle turning in opposite directions causes the lateral contact surfaces between the segments to be squeezed together under liquid pressure, which has a self-pressurizing effect. Leaking liquid is difficult to pass through here. This design structure ensures the reliability of the variable diameter ball seat and prevents the ball seat from becoming unusable due to liquid leakage.
[0017] The technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments. Attached Figure Description
[0018] When considered in conjunction with the accompanying drawings, the invention will be more fully understood and its many accompanying advantages will become readily apparent from the following detailed description. However, the accompanying drawings, which are provided to further illustrate the invention and form part of this invention, are intended to explain the invention and do not constitute an undue limitation thereof.
[0019] Figure 1 This is a schematic diagram of the structure of a variable diameter ball seat according to the present invention.
[0020] Figure 2 This is a schematic diagram of the ball seat core.
[0021] Figure 3 yes Figure 2 The top view shows a ball seat core composed of four segments, with the first and second included angles facing the same direction.
[0022] Figure 4 yes Figure 3 The diagram shows the outer periphery development of the ball seat core.
[0023] Figure 5 yes Figure 2 The top view shows a ball seat core composed of four segments, with the first included angle and the second included angle facing opposite directions.
[0024] Figure 6 yes Figure 5 The diagram shows the outer periphery development of the ball seat core.
[0025] Figure 7 It is an outer peripheral unfolding diagram of a ball seat core composed of 3 segments, with the first included angle and the second included angle having the same direction.
[0026] Figure 8 It is an outer peripheral unfolding diagram of a ball seat core composed of 3 segments, with the first included angle and the second included angle having opposite or the same direction.
[0027] Figure 9 It is an outer peripheral unfolding diagram of a ball seat core composed of 5 segments, with the first included angle and the second included angle having the same direction.
[0028] Figure 10 It is an outer peripheral unfolding diagram of a ball seat core composed of 5 segments, with the first included angle and the second included angle turning in opposite directions.
[0029] Figure 11 This is an outer peripheral unfolding diagram of a ball seat core composed of four segments, with different structures shown on its transverse contact surfaces.
[0030] In the picture:
[0031] 1-Upper connector, 2-Ball, 3-Ball seat core, 4-Spring, 5-Cut pin sleeve, 6-Cut ring, 7-Cut pin, 8-Lower connector;
[0032] 2-1-First transverse contact surface, 2-2-Second transverse contact surface, 2-3-Ball sealing line;
[0033] 3-1-First longitudinal contact surface, 3-2-Second longitudinal contact surface, 3-3-Third longitudinal contact surface, 3-4-Fourth longitudinal contact surface;
[0034] 4-1-First contact surface, 4-2-Second contact surface
[0035] 8-1 - First lobe, 8-2 - Second lobe, 8-3 - Third lobe;
[0036] H - Distance between the transverse contact surface and the ball seal line;
[0037] A - First included angle, B - Second included angle;
[0038] a, b, c, d, e - central angles of the split circle. Detailed Implementation
[0039] The terms "upper" and "lower" used in this application specification and claims refer to the state of the tool during use, and will not be elaborated further in the accompanying description.
[0040] Example 1
[0041] See Figure 1 As shown, this is the basic structure of a variable diameter ball joint according to the present invention. Both the upper connector 1 and the lower connector 8 are tubular bodies and threaded together. A ball joint core 3, a shear pin sleeve 5, and a shear ring 6 are installed within the resulting cavity. The ball joint core 3 and the shear pin sleeve 5 are coaxially mounted, abutting each other. The shear ring 6 is fitted around the outer circumference of the shear pin sleeve 5, and the shear pin sleeve and shear ring are axially fixed together by shear pins 7. The upper end of the ball joint core and the lower end of the shear ring each have stepped limits.
[0042] The ball seat core has a smooth inner conical surface, and a ball sealing line 2-3 is formed between the ball and the inner conical surface. It is a circular sealing line, and the plane of the circular sealing line is perpendicular to the axis of the ball seat core.
[0043] The ball seat core is a cylindrical body composed of multiple segments, with an open C-shaped spring 4 installed in its inner groove. When the ball seat core descends to... Figure 1 When the outer annular space of the shear pin sleeve 5 shown is open, under the action of the circumferential force of the spring 4, the split body moves radially, the inner diameter expands, and the ball can pass through the ball seat core and descend.
[0044] See Figure 2 , Figure 3 and Figure 4 As shown, the two sides of any segmented body are the first contact surface 4-1 and the second contact surface 4-2, respectively. The first contact surface 4-1 and the second contact surface 4-2 simply represent the two sides of any segmented body and have no particular order.
[0045] The first contact surface 4-1 includes a first longitudinal contact surface 3-1, a first transverse contact surface 2-1, and a second longitudinal contact surface 3-2; the second contact surface 4-2 includes a third longitudinal contact surface 3-3, a second transverse contact surface 2-2, and a fourth longitudinal contact surface 3-4.
[0046] The distances H between the first and second transverse contact surfaces and the spherical sealing line 2-3 can be the same or different. The first and second transverse contact surfaces can be located below or above the spherical sealing line. The distance between the first and second transverse contact surfaces and the spherical sealing line 2-3 is less than 15 mm, with less than 3 mm being optimal.
[0047] The number of segments constituting the cylindrical ball seat core is more than three.
[0048] See Figure 3 , Figure 4 , Figure 5 and Figure 6 As shown, the projection of the first longitudinal contact surface 3-1 and the second longitudinal contact surface 3-2 onto the top view forms a first included angle A, and the projection of the third longitudinal contact surface 3-3 and the fourth longitudinal contact surface 3-4 onto the top view forms a second included angle B. Figure 3 and Figure 5 In the projection direction shown, the angle between the two longitudinal contact surfaces is positive in the clockwise direction and negative in the counterclockwise direction. Then, the first included angle A and the second included angle B are... Figure 3 In the examples, all are clockwise steering angles with the same direction of rotation; of course, they can also be designed to be the same counterclockwise steering angle; the first angle A and the second angle B are... Figure 5 In the example, the angles are opposite turning angles. The first angle A and the second angle B are also the central angles projected onto the top view of the lateral contact surfaces on both sides of the segment. The magnitudes of the first angle A and the second angle B can be the same or different. The first angle A and the second angle B are only used to distinguish the two sides of a segment and have no particular order.
[0049] See Figure 3 and Figure 4 As shown, the central angle between the first longitudinal contact surface 3-1 and the third longitudinal contact surface 3-3 is defined as the lobed central angle. The lobed central angles of the four lobed bodies in the figure are a, b, c, and d, respectively. The lobed central angles of the lobed bodies can be the same or different. The sum of the lobed central angles of the lobed bodies that make up a spherical core is 360°.
[0050] See Figure 11 , Figure 11The diagram shows the external development of different transverse contact surfaces. The first transverse contact surface 2-1 and the second transverse contact surface 2-2 can be planes perpendicular to the axis of the ball seat core, planes not perpendicular to the axis of the ball seat core, or curved surfaces of any shape. The shapes of the first transverse contact surface 2-1 and the second transverse contact surface 2-2 can be the same or different. The distance between the first and second transverse contact surfaces and the ball sealing line 2-3 refers to the farthest distance between the contact surfaces and the ball sealing line.
[0051] It should be noted that, in order to clearly show the contact surface between the segments in the attached diagram, the contact surface is represented by three parallel lines on the outer periphery of the ball seat core and its unfolded diagram: two solid lines and one dashed line. The dashed line on the contact surface is its contact surface.
[0052] Example 2
[0053] See Figure 3 and Figure 4 As shown, Embodiment 2 is a preferred embodiment of the ball seat core. The ball seat core consists of four segments, each segment having a central angle of 90°. The first included angle A and the second included angle B are equal in size and have the same direction of rotation.
[0054] Example 3
[0055] See Figure 5 and Figure 6 As shown, Embodiment 3 is a preferred embodiment of the ball seat core. The ball seat core is composed of 4 segments, each segment having a central angle of 90°. The first included angle and the second included angle are equal in size but opposite in direction.
[0056] Example 4
[0057] See Figure 7 As shown, Embodiment 4 is a preferred embodiment of the ball seat core. The ball seat core consists of three segments, each segment having a central angle of 120°. The first included angle and the second included angle are equal in size and have the same direction of rotation.
[0058] Example 5
[0059] See Figure 8 As shown, Embodiment 5 is a preferred embodiment of the ball seat core. The ball seat core consists of three segments, each with a central angle of 120°. The first included angle and the second included angle are equal in size and rotate in the same or opposite directions. Specifically, the first included angle of the first segment 8-1 rotates in opposite directions to the second included angle, the first included angle of the second segment 8-2 rotates in opposite directions to the second included angle, and the first included angle of the third segment 8-3 rotates in the same direction as the second included angle.
[0060] Example 6
[0061] See Figure 9 As shown, Embodiment 6 is a preferred embodiment of the ball seat core. The ball seat core is composed of 5 segments, each segment having a central angle of 72°. The first included angle and the second included angle are equal in size and have the same direction of rotation.
[0062] Example 7
[0063] See Figure 10 As shown, Embodiment 7 is a preferred embodiment of the ball seat core. The ball seat core consists of 5 segments, each segment having a central angle of 72°. The first and second included angles are equal in size and their directions are the same or opposite. Specifically, Figure 10 The first included angle of the first segment on the left side of the middle part turns in the same direction as the second included angle, while the first included angle of the other four segments turns in the opposite direction to the second included angle.
[0064] As can be clearly seen from the above preferred embodiments, when the ball seat core is composed of three or more segments, the preferred central angle of each segment is (360° / number of segments), the first included angle and the second included angle are equal in size, and the included angles turn in the same or opposite directions.
[0065] Obviously, many modifications and variations made by those skilled in the art based on the spirit of this invention fall within the scope of protection of this invention.
Claims
1. A variable diameter ball seat, comprising a ball seat core (3), the ball seat core being a cylindrical body composed of segmented bodies, wherein the two sides of the segmented bodies are respectively a first contact surface (4-1) and a second contact surface (4-2), characterized in that, The first contact surface has a first transverse contact surface (2-1); the second contact surface has a second transverse contact surface (2-2). The first and second transverse contact surfaces can be planes perpendicular or not perpendicular to the axis of the ball seat core, or they can be curved surfaces of any shape. The shapes of the first and second transverse contact surfaces can be the same or different. The distance between the first and second transverse contact surfaces and the ball sealing line (2-3) is less than 15mm. The number of split bodies is more than 3.
2. A variable diameter ball seat according to claim 1, characterized in that, The distance between the first and second transverse contact surfaces and the ball sealing line (2-3) is less than 3 mm.
3. A variable diameter ball seat according to claim 1, characterized in that, The number of the segmented bodies is 3, and the central angle of each segmented body is 120°; the first included angle and the second included angle are equal in size, and the included angles turn in the same or opposite directions.
4. A variable diameter ball seat according to claim 1, characterized in that, The number of the segmented bodies is 4, and the central angle of each segmented body is 90°; the first included angle and the second included angle are equal in size, and the included angles turn in the same or opposite directions.
5. A variable diameter ball seat according to claim 1, characterized in that, The number of the segmented bodies is 5, and the central angle of each segmented body is 72°; the first included angle and the second included angle are equal in size, and the included angles turn in the same or opposite directions.
6. A variable diameter ball seat according to claim 1, characterized in that, The number of the segmented bodies is 6, and the central angle of each segmented body is 60°; the first included angle and the second included angle are equal in size, and the included angles turn in the same or opposite directions.
7. A variable diameter ball seat according to claim 1, characterized in that, The number of the segmented bodies is 8, and the central angle of each segmented body is 45°; the first included angle and the second included angle are equal in size, and the included angles turn in the same or opposite directions.