A one-way valve for oil drilling

Abstract

The present application relates to the technical field of drilling, and discloses a one-way valve for oil drilling, which comprises an upper joint and a lower joint both used for being connected with drilling tools, the upper joint is detachably connected with the lower joint, a valve seat is arranged in one of the upper joint and the lower joint, a through flow hole and a lateral hole are arranged in the valve seat, a limiting portion for limiting upward movement of a valve ball is arranged at the top end of the through flow hole, the lateral hole is obliquely communicated with a bifurcation opening in the middle part of the through flow hole, the diameter of the lateral hole is larger than that of the valve ball, the diameter of the through flow hole after the bifurcation opening is smaller than that of the valve ball, when drilling fluid moves downward at high speed, the drilling fluid pushes the valve ball to move downward and enters the lateral hole through the bifurcation opening, the flow rate of the drilling fluid flowing out from the bottom of the lateral hole through the gap between the valve ball and the lateral hole is smaller than the flow rate of the drilling fluid flowing out through the through flow hole, so that the erosion of the valve ball surface by high-speed drilling fluid is reduced under the normal working condition of the downward movement of the drilling fluid, and the service life and sealing reliability of the one-way valve are effectively improved.

Description

Technical Field

[0001] This invention relates to the field of drilling technology, and more specifically, to a one-way valve for oil drilling. Background Technology

[0002] In oil and gas drilling, check valves are required to allow drilling fluid to flow in one direction within the drill string. Existing check valves mainly fall into two categories:

[0003] One type is the arrow-type float valve, which has a guide pin connected below the conical valve core body. When the drilling fluid passes through in one direction, it pushes the valve core body to compress the spring around the guide pin, causing the valve core body to move down and open the flow channel. However, since the conical sealing surface faces the high-speed fluid directly under normal conditions, the sealing surface is severely eroded and damaged after long-term operation, and cannot seal, causing the one-way valve to fail. In addition, the alignment and centering effect of the guide pin is poor, which leads to easy wear of the sealing parts and poor sealing effect.

[0004] Another type is the flap valve, in which the sealing plate can be pressed against the sealing seat under the elastic action of the torsion spring. When the drilling fluid passes through in one direction, it pushes the sealing plate to rotate around the pin around the torsion spring to open the flow channel. However, since the sealing plate faces the high-speed fluid under normal conditions, the sealing surface is severely eroded and damaged after long-term operation, which leads to the sealing surface being unable to seal or even causing the one-way valve to fail.

[0005] In summary, how to reduce the erosion of the sealing surface of a one-way valve by high-speed fluid under normal conditions is a problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0006] In view of this, the purpose of the present invention is to provide a one-way valve for oil drilling, in which, under normal operating conditions of drilling fluid flowing downwards, high-speed drilling fluid is mostly discharged directly through the flow hole, and only a small amount of drilling fluid is discharged between the valve ball and the side hole, thereby reducing the erosion of the valve ball surface by the high-speed drilling fluid.

[0007] To achieve the above objectives, the present invention provides the following technical solution:

[0008] A one-way valve for oil drilling includes an upper connector and a lower connector, both for connection to drill strings. The upper connector and the lower connector are detachably connected. A valve seat is fitted inside one of the upper connector and the lower connector. The valve seat has a through-hole and a lateral hole. The top of the through-hole has a limiting part for restricting the upward movement of a valve ball. The lateral hole is obliquely connected to a bifurcation in the middle of the through-hole. The diameter of the lateral hole is larger than the diameter of the valve ball, and the diameter of the through-hole after the bifurcation is smaller than the diameter of the valve ball.

[0009] When the drilling fluid moves downward at high speed, it pushes the valve ball downward and enters the side hole through the bifurcation. The flow rate of the drilling fluid flowing out from the bottom of the side hole through the gap between the valve ball and the side hole is less than the flow rate of the drilling fluid flowing out through the overflow hole.

[0010] Preferably, the bottom of the lateral hole is detachably provided with a plug, the plug having a through hole for discharging drilling fluid downwards when the drilling fluid flows in one direction.

[0011] Preferably, the bottom of the lateral hole is provided with a plug mounting hole arranged along the axial direction of the valve seat, and the plug is threadedly installed in the plug mounting hole.

[0012] Preferably, the valve seat is installed inside the upper connector, and the lateral hole communicates with the outer wall surface of the valve seat so that a gap for the drilling fluid to pass through is formed between the inner side surface of the lateral hole and the positioning step of the lower connector.

[0013] Preferably, the flow passage is provided with a blocking slope at the bifurcation, the blocking slope being used to guide the valve ball into the lateral hole.

[0014] Preferably, the slope of the upper slope of the blocking slope is the same as the inclination angle of the lateral hole relative to the flow hole.

[0015] Preferably, the limiting part includes an annular boss arranged circumferentially around the flow hole, and the axis of the annular boss is collinear with the axis of the flow hole.

[0016] Preferably, the lower end face of the annular boss that abuts against the valve ball is an inclined surface, and the upper end face of the annular boss is also an inclined surface.

[0017] Preferably, the slope and length of the upper end face of the annular boss are the same as the slope and length of the lower end face of the annular boss.

[0018] Preferably, the outer circumferential surface of the lower end of the upper connector is provided with an external thread, and the inner circumferential surface of the upper end of the lower connector is provided with an internal thread for engaging with the external thread.

[0019] The one-way valve for oil drilling provided by this invention allows the entire drill string to be immersed in drilling fluid when the pump is not turned on on the surface and there is no overflow in the well. However, there is no flow of drilling fluid inside the drill string. The valve ball moves upward to the limiting part of the flow hole under the action of buoyancy, and the valve ball forms a seal with the lower end face of the limiting part.

[0020] When the pump is started on the surface, the drilling fluid descends at high speed inside the drill string. The drilling fluid pushes the valve ball down against buoyancy and enters the side hole through the bifurcation of the flow hole. When the valve ball descends to the bottom of the side hole, only a small amount of drilling fluid flows out through the gap between the valve ball and the side hole, while a large amount, or even the vast majority, of the drilling fluid flows out through the flow hole.

[0021] When a blowout or overflow occurs downhole, the drilling fluid rises and pushes the valve ball upward to the limit part of the flow hole, where the valve ball and the lower end face of the limit part form a seal.

[0022] Therefore, the one-way valve for oil drilling provided by this invention, under normal operating conditions where drilling fluid flows downwards, high-speed drilling fluid is mostly discharged directly through the flow hole, and only a small amount of drilling fluid is discharged between the valve ball and the side hole. This reduces the erosion of the valve ball surface by high-speed drilling fluid, and even makes the valve ball surface, as the sealing surface, not subject to erosion by high-speed drilling fluid, effectively improving the working life and sealing reliability of the one-way valve. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0024] Figure 1 This is a schematic diagram of the structure of a specific embodiment of the one-way valve for oil drilling provided by the present invention in the passage state;

[0025] Figure 2 for Figure 1 A schematic diagram of the structure of a one-way valve for oil drilling in the one-way check state;

[0026] Figure 3 for Figure 1 A magnified view of a portion of the image;

[0027] Figure 4 A schematic diagram of the structure of a specific embodiment two of the one-way valve for oil drilling provided by the present invention in the passage state;

[0028] Figure 5 for Figure 4 A schematic diagram of the structure of a one-way valve for oil drilling in the one-way check state;

[0029] Figure 6 for Figure 4 A magnified view of a portion of the image;

[0030] Figure 7This is a schematic diagram of the structure of a specific embodiment three of the one-way valve for oil drilling provided by the present invention in the passage state;

[0031] Figure 8 for Figure 7 A schematic diagram of the structure of a one-way valve for oil drilling in the one-way check state;

[0032] Figure 9 for Figure 7 A magnified view of a portion of the image;

[0033] Figures 1-9 middle:

[0034] 1-Upper connector; 2-Lower connector; 3-Valve seat; 31-Flow hole; 311-Annular boss; 312-Blocking slope; 32-Side hole; 4-Valve ball; 5-Plug; 51-Small hole. Detailed Implementation

[0035] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0036] The core of this invention is to provide a one-way valve for oil drilling. Under normal operating conditions where drilling fluid flows downwards, high-speed drilling fluid is mostly discharged directly through the flow hole, and only a small amount of drilling fluid is discharged between the valve ball and the side hole, thereby reducing the erosion of the valve ball surface by the high-speed drilling fluid.

[0037] The one-way valve for oil drilling provided by the present invention includes an upper connector 1 and a lower connector 2, both for connecting to the drill string. The upper connector 1 and the lower connector 2 are threaded together. A valve seat 3 is provided inside one of the upper connector 1 and the lower connector 2. The valve seat 3 is provided with a through flow hole 31 and a side hole 32. The top end of the flow hole 31 is provided with a limiting part for restricting the upward movement of the valve ball 4. The side hole 32 is inclinedly connected to the bifurcation in the middle of the flow hole 31. The diameter of the side hole 32 is larger than the diameter of the valve ball 4, and the diameter of the flow hole 31 after the bifurcation is smaller than the diameter of the valve ball 4.

[0038] When the drilling fluid moves downward at high speed, it pushes the valve ball 4 downward and enters the side hole 32 through the bifurcation. The flow rate of the drilling fluid flowing out from the bottom of the side hole 32 through the gap between the valve ball 4 and the side hole 32 is less than the flow rate of the drilling fluid flowing out through the overflow hole 31.

[0039] The upper connector 1 and the lower connector 2 are used to connect with other drilling tools in the drill string assembly, usually by threaded connection. At the same time, the lower end of the upper connector 1 and the upper end of the lower connector 2 are connected by common detachable connection methods such as threaded connection, so as to use the positioning steps or end faces in the two connectors to perform axial positioning of the valve seat 3.

[0040] Specifically, the outer circumferential surface of the lower end of the upper connector 1 may be provided with an external thread, and the inner circumferential surface of the upper end of the lower connector 2 may be provided with an internal thread that mates with the external thread, such as... Figure 1 As shown;

[0041] Alternatively, the inner circumferential surface of the lower end of the upper connector 1 may be provided with an internal thread, and the outer circumferential surface of the upper end of the lower connector 2 may be provided with an external thread that mates with the internal thread.

[0042] Of course, the upper connector 1 and the lower connector 2 can also be connected by a connecting pin or the like.

[0043] A valve seat 3 is fitted inside one of the upper connector 1 and the lower connector 2. When the valve seat 3 is located inside the lower connector 2, the upper connector 1 needs to be fitted inside the lower connector 2 to effectively limit the axial movement of the valve seat 3. Figure 1 As shown;

[0044] During assembly, the valve core assembly is first installed in the lower connector 2, so that the lower end face of the valve seat 3 abuts against the positioning step of the lower connector 2. Then, the upper connector 1 and the lower connector 2 are connected, so that the upper end face of the valve seat 3 abuts against the lower end face of the upper connector 1. Therefore, when repairing or replacing the valve core assembly, the check valve needs to be completely disassembled.

[0045] When valve seat 3 is located inside upper connector 1, the upper and lower end faces of valve seat 3 can respectively abut against the positioning steps of upper and lower connectors, such as... Figure 4 and Figure 7 As shown, when overhauling or replacing the valve core assembly, only the lower connector 2 needs to be removed to disassemble and replace the valve core assembly inside the upper connector 1. The structure is simple and the operation is convenient.

[0046] The valve seat 3 and the valve ball 4 located within the valve seat 3 together form the valve core assembly of the one-way valve. The density of the valve ball 4 is slightly less than that of the drilling fluid. Under conditions where the pump is not running on the surface and there is no overflow downhole, the entire drill string is immersed in the drilling fluid, but there is no drilling fluid flow within the drill string. The valve ball 4 can float upwards to the limiting part of the flow hole 31 of the valve seat 3 under buoyancy, allowing the valve ball 4 to form a sealing fit with the lower end face of the limiting part. Figure 2 , Figure 5 and Figure 8 As shown;

[0047] When the pump is started on the surface, the drilling fluid descends at high speed within the drill string. The drilling fluid pushes the valve ball 4 downwards against buoyancy, and enters the side hole 32 through the fork in the flow hole 31. When the valve ball 4 reaches the bottom of the side hole 32, only a small amount of drilling fluid flows downwards through the gap between the valve ball 4 and the side hole 32; the majority, if not the entire volume, of the drilling fluid flows out through the flow hole 31. Figure 1 , Figure 4 and Figure 7 As shown;

[0048] When a blowout or overflow occurs downhole, the drilling fluid rises, pushing the valve ball 4 upwards to the limiting part of the flow orifice 31. The valve ball 4 forms a seal with the lower end face of the limiting part. Figure 2 , Figure 5 and Figure 8 As shown.

[0049] In this embodiment, under normal operating conditions where drilling fluid flows downwards, high-speed drilling fluid is mostly discharged directly through the flow hole 31, and only a small amount of drilling fluid is discharged between the valve ball 4 and the side hole 32. This reduces the erosion of the valve ball surface by high-speed drilling fluid, and even makes the valve ball 4, as a sealing surface, not subject to erosion by high-speed drilling fluid, effectively improving the working life and sealing reliability of the one-way valve.

[0050] Based on the above embodiments, in order to achieve drilling fluid drainage and avoid erosion damage from large amounts of drilling fluid outflow, the bottom structure of the side hole 32 is defined. Please refer to [reference needed]. Figure 3 and Figure 6 The bottom of the side hole 32 is detachably provided with a plug 5, and the plug 5 is provided with a through hole 51, which is used to discharge drilling fluid downward when the drilling fluid flows in one direction.

[0051] During assembly, the valve ball 4 is inserted into the valve seat 3 through the bottom of the side hole 32, and then the plug 5 is installed at the bottom of the side hole 32 to form the valve core assembly.

[0052] To facilitate the installation of the plug 5, preferably, the bottom of the side hole 32 is provided with a plug mounting hole arranged along the axial direction of the valve seat 3, and the plug 5 is threaded into the plug mounting hole. Compared with the plug 5 being installed in the inclined plug mounting hole, this is more convenient for both the machining of the plug mounting hole and the installation of the plug 5.

[0053] Of course, in order to further simplify the structure of the one-way valve, the valve seat 3 can be installed inside the upper connector 1, and the side hole 32 can be connected to the outer wall of the valve seat 3 so that a gap for drilling fluid to pass through is formed between the inner side of the side hole 32 and the positioning step of the lower connector 2.

[0054] Therefore, when the ground pump is turned on and the drilling fluid moves downward inside the drill string, the drilling fluid can drive the valve ball 4 to move downward and enter the bottom of the side hole 32 through the bifurcation. Most of the drilling fluid flows out from the flow hole 31, while a small amount of drilling fluid flows out through the gap between the side hole 32 and the positioning step of the lower connector 2.

[0055] Based on the above embodiments, the flow passage 31 may be provided with a blocking slope 312 at the bifurcation. The blocking slope 312 is inclined to one side of the lateral hole 32 so as to guide the valve ball 4 into the lateral hole 32, thereby preventing the valve ball 4 from getting stuck at the bifurcation where the inner diameter of the flow passage 31 decreases.

[0056] The upper slope of the blocking slope 312 is used to contact the valve ball 4 to guide the movement direction of the valve ball 4. Preferably, the slope of the upper slope of the blocking slope 312 is the same as the inclination angle of the side hole 32 relative to the flow hole 31.

[0057] The lower end face of the blocking slope 312 can be set perpendicular to the inner wall of the flow hole 31, but in order to reduce the resistance encountered by the drilling fluid when flowing through the blocking slope 312, it is preferable to set the lower end face of the blocking slope 312 as a slope.

[0058] Based on the above embodiments, the limiting part can be provided including an annular boss 311 surrounding the flow hole 31 in the circumferential direction, and the axis of the annular boss 311 is collinear with the axis of the flow hole 31.

[0059] Compared to the arc-shaped limiting part, the annular boss 311 has a larger contact area with the valve ball 4, resulting in a better sealing effect. In order to further increase the contact area between the limiting part and the valve ball 4, it is preferable to set the lower end surface of the annular boss 311 that abuts against the valve ball 4 to be a slope, and the upper end surface of the annular boss 311 to be a slope.

[0060] In order to avoid the annular boss 311 reducing the inlet cross-sectional area of ​​the valve seat 3 and thus reducing the inlet flow rate, it is preferable to set the upper end face of the annular boss 311 as an inclined surface, and the inner diameter of the upper end face of the annular boss 311 gradually increases from top to bottom.

[0061] To simplify the structure of the valve seat 3 and facilitate the machining of the annular boss 311, it is preferable that the slope and length of the upper end face of the annular boss 311 are the same as the slope and length of the lower end face of the annular boss 311.

[0062] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0063] The foregoing has provided a detailed description of the one-way valve for oil drilling provided by this invention. Specific examples have been used to illustrate the principles and implementation methods of this invention. The descriptions of the embodiments above are merely for the purpose of helping to understand the method and core ideas of this invention. It should be noted that those skilled in the art can make various improvements and modifications to this invention without departing from its principles, and these improvements and modifications also fall within the protection scope of the claims of this invention.

Claims

1. A one-way valve for oil drilling, comprising an upper connector (1) and a lower connector (2) both for connection to a drill string, wherein the upper connector (1) and the lower connector (2) are detachably connected, characterized in that, A valve seat (3) is fitted inside one of the upper connector (1) and the lower connector (2). The valve seat (3) has a through flow hole (31) and a side hole (32). The top of the flow hole (31) has a limiting part for restricting the upward movement of the valve ball (4). The side hole (32) is inclined to the bifurcation in the middle of the flow hole (31). The diameter of the side hole (32) is larger than the diameter of the valve ball (4), and the diameter of the flow hole (31) after the bifurcation is smaller than the diameter of the valve ball (4). When the drilling fluid moves downward at high speed, it pushes the valve ball (4) downward and enters the side hole (32) through the bifurcation. The flow rate of the drilling fluid flowing out from the bottom of the side hole (32) through the gap between the valve ball (4) and the side hole (32) is less than the flow rate of the drilling fluid flowing out through the overflow hole (31).

2. The one-way valve for oil drilling according to claim 1, characterized in that, The bottom of the side hole (32) is detachably provided with a plug (5), the plug (5) having a through hole (51) for discharging drilling fluid downwards when the drilling fluid flows in one direction.

3. The one-way valve for oil drilling according to claim 2, characterized in that, The bottom of the side hole (32) is provided with a plug mounting hole arranged along the axial direction of the valve seat (3), and the plug (5) is threadedly installed in the plug mounting hole.

4. The one-way valve for oil drilling according to claim 1, characterized in that, The valve seat (3) is installed inside the upper connector (1), and the side hole (32) communicates with the outer wall surface of the valve seat (3) so that a gap for the drilling fluid to pass through is formed between the inner side surface of the side hole (32) and the positioning step of the lower connector (2).

5. The one-way valve for oil drilling according to any one of claims 1-4, characterized in that, The flow passage (31) has a blocking slope (312) at the bifurcation, and the blocking slope (312) is used to guide the valve ball (4) into the side hole (32).

6. The one-way valve for oil drilling according to claim 5, characterized in that, The slope of the upper slope of the blocking slope (312) is the same as the inclination angle of the lateral hole (32) relative to the flow hole (31).

7. The one-way valve for oil drilling according to any one of claims 1-4, characterized in that, The limiting part includes an annular boss (311) arranged in the circumferential direction around the flow hole (31), and the axis of the annular boss (311) is collinear with the axis of the flow hole (31).

8. The one-way valve for oil drilling according to claim 7, characterized in that, The lower end face of the annular boss (311) that abuts against the valve ball (4) is an inclined surface, and the upper end face of the annular boss (311) is also an inclined surface.

9. The one-way valve for oil drilling according to claim 8, characterized in that, The slope and length of the upper end face of the annular boss (311) are the same as the slope and length of the lower end face of the annular boss (311).

10. The one-way valve for oil drilling according to any one of claims 1-4, characterized in that, The outer circumferential surface of the lower end of the upper connector (1) is provided with an external thread, and the inner circumferential surface of the upper end of the lower connector (2) is provided with an internal thread for engaging with the external thread.

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