Valve seat connecting and sealing structure for subsurface safety valve

Abstract

The utility model relates to the technical field of sealing structures, and provides a valve seat connection sealing structure for a subsurface safety valve, which comprises a valve seat main body and a spring cylinder, the upper end of the valve seat main body is in threaded connection with the lower end of the spring cylinder, the inner edge of the lower end of the spring cylinder and the valve seat main body form a sealing pair, and the lower end of the spring cylinder is provided with an annular groove. The inner side of the lower end of the spring barrel is elastic. The thickness of the inner side of the lower end of the spring barrel is controlled to enable the spring barrel to have elasticity, the inner side of the lower end of the spring barrel can elastically deform after the threads are tightened, and effective sealing (namely tighter sealing) of metal contact is achieved. And the annular groove can contain solid impurities such as fracturing sand, after the annular groove is filled, abrasion of the solid impurities to the sealing face can be blocked, and the sealing reliability and durability are greatly improved.

Description

Technical Field

[0001] This utility model relates to the field of sealing structure technology, and more specifically, to a valve seat connection sealing structure for a downhole safety valve. Background Technology

[0002] A downhole safety valve is a downhole tool installed inside the wellbore and connected to the tubing to prevent blowouts and ensure production safety. In a downhole safety valve, the lower end of the valve seat is typically used to mount the valve plate, and the upper end of the valve seat is usually threaded to the lower end of the spring sleeve. An O-ring is installed at the contact surface between the two. Both the valve seat and the spring sleeve are generally made of hard metal. After the valve seat and spring sleeve are tightened, the O-ring is compressed to form a sealing pair. This sealing method is only suitable for operation in conventional environments, mainly used to block gas and liquid impurities. However, in fracturing environments with solid impurities such as fracturing sand, the above sealing method is less effective. Utility Model Content

[0003] The purpose of this utility model is to provide a valve seat connection sealing structure for downhole safety valves, thereby solving the above-mentioned defects of the prior art.

[0004] This utility model is achieved through the following technical solution:

[0005] A valve seat connection sealing structure for a downhole safety valve includes a valve seat body and a spring cylinder. The upper end of the valve seat body and the lower end of the spring cylinder are connected by threads. The inner edge of the lower end of the spring cylinder forms a sealing pair with the valve seat body. The lower end of the spring cylinder is provided with an annular groove so that the inner side of the lower end of the spring cylinder is elastic.

[0006] Optionally, the sealing surface between the spring cylinder and the valve seat body is a conical surface.

[0007] Optionally, the upper end of the valve seat body is provided with an outer step, and the outer step is provided with an external thread; the lower end of the spring cylinder is provided with an inner step, and the inner step is provided with an internal thread for connecting the external thread.

[0008] Optionally, a gap is left between the lower end face of the spring cylinder and the shoulder formed by the outer step.

[0009] The technical solution of this utility model has at least the following advantages and beneficial effects: In this utility model, the valve seat body and the lower end of the spring cylinder are connected by threads. After connection, the inner edge of the lower end of the spring cylinder and the valve seat body form a sealing pair. At the same time, an annular groove is provided at the lower end of the spring cylinder, so that the sealing part on the spring cylinder forms a cantilever beam structure. In this way, on the one hand, by controlling the thickness of the inner side of the lower end of the spring cylinder, it can be made elastic. After the threads are tightened, the inner side of the lower end of the spring cylinder can be elastically deformed, achieving effective sealing of metal-to-metal contact (i.e., tighter sealing). On the other hand, the annular groove can accommodate solid impurities such as fracturing sand. After the annular groove is filled, it can prevent solid impurities from wearing the sealing surface, greatly improving the reliability and durability of the seal. Attached Figure Description

[0010] Figure 1 A diagram illustrating the usage status of a valve seat connection sealing structure for a downhole safety valve provided by this utility model;

[0011] Figure 2 for Figure 1 Enlarged view of point A in the image;

[0012] Reference numerals: 1-Spring cylinder, 101-Annular groove, 2-Valve seat body, 201-Shoulder. Detailed Implementation

[0013] refer to Figure 1 and Figure 2 A valve seat connection sealing structure for a downhole safety valve includes a valve seat body 2 and a spring cylinder 1. The upper end of the valve seat body 2 is threadedly connected to the lower end of the spring cylinder 1. The inner edge of the lower end of the spring cylinder 1 forms a sealing pair with the valve seat body 2. The lower end of the spring cylinder 1 is provided with an annular groove 101. In this way, on the one hand, by controlling the thickness of the inner side of the lower end of the spring cylinder 1, it can be made elastic. After the thread is tightened, the inner side of the lower end of the spring cylinder 1 can be elastically deformed to achieve effective sealing between metal and metal (i.e., tighter sealing). On the other hand, the annular groove 101 can accommodate solid impurities such as fracturing sand. After the annular groove 101 is filled, it can prevent solid impurities from wearing the sealing surface, which greatly improves the reliability and durability of the seal.

[0014] As an alternative, the sealing surface between the spring cylinder 1 and the valve seat body 2 is a conical surface to ensure the sealing effect. In practical applications, a conical surface is provided on the inner edge of the lower end of the spring cylinder 1, and a matching conical surface is provided at the contact point between the spring cylinder 1 and the valve seat body 2.

[0015] As an alternative, the upper end of the valve seat body 2 is provided with an outer step and an external thread at the outer step, and the lower end of the spring cylinder 1 is provided with an inner step and an internal thread for connecting the external thread at the inner step. This arrangement makes it easier to ensure that the inner diameters of the valve seat body 2 and the spring cylinder 1 are similar, avoiding affecting the installation of other parts, and also avoiding the formation of a large gap between one of the valve seat body 2 and the spring cylinder 1 and other parts.

[0016] In this embodiment, a gap is left between the lower end face of the spring cylinder 1 and the shoulder 201 formed by the outer step, so that solid impurities such as fracturing sand can enter and fill the annular groove 101, thereby preventing solid impurities from wearing the sealing surface.

[0017] The above are merely preferred embodiments of this utility model and are not intended to limit the scope of this utility model. Various modifications and variations can be made to this utility model by those skilled in the art. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. A valve seat connection seal structure for a downhole safety valve, comprising a valve seat body and a spring cylinder, the upper end of the valve seat body being connected to the lower end of the spring cylinder by a threaded connection, characterized in that The lower end of the spring barrel is provided with an annular groove, so that the inner side of the lower end of the spring barrel is elastic.

2. The valve seat connection seal structure for a downhole safety valve according to claim 1, characterized in that, The sealing surface between the spring barrel and the valve seat body is a conical surface.

3. The valve seat connection seal structure for a downhole safety valve according to claim 1, characterized in that, The upper end of the valve seat body is provided with an outer step, and the outer step is provided with an external thread.

4. The valve seat connection seal structure for a downhole safety valve according to claim 3, characterized in that, The lower end of the spring barrel is provided with an inner step, and the inner step is provided with an internal thread for connecting the external thread. A gap is left between the shoulder formed by the lower end face of the spring barrel and the outer step.

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