A downhole throttling device

Abstract

This invention discloses a downhole throttling device, relating to the field of oilfield gas production technology, applicable to variable-diameter wellbores, enabling smooth transition from the large pipe to the small pipe within the wellbore. The device includes a throttling device body with multiple auxiliary grooves circumferentially formed on its bottom outer side. Each auxiliary groove contains a temporarily fixed locking block. The outer end of the locking block extends beyond the throttling device body, with its circumscribed circle diameter larger than the maximum diameter of the throttling device body. The inner end of the locking block penetrates the auxiliary groove. When the locking block encounters an obstacle during the throttling device body's penetration into the wellbore, it is pressed further into the auxiliary groove. Through the locking block design, this invention allows the throttling device body to enter the small pipe at the junction of the large and small pipe sections of the wellbore, while the locking block retracts into the auxiliary groove due to the obstruction at this section, thus ensuring the smooth transition of the entire throttling device body from the large pipe to the small pipe.

Description

Technical Field

[0001] This invention relates to the field of oilfield gas production technology, specifically to a downhole throttling device. Background Technology

[0002] Downhole throttling devices use downhole nozzles to reduce pressure in gas wells, allowing natural gas to absorb heat from the formation as it travels from the well to the surface. This ensures the gas temperature returns to near its pre-throttling temperature, reducing pressure without causing hydrates or ice buildup in the wellbore or on the surface. Downhole throttling devices are now widely used.

[0003] Currently, downhole chokes are mainly used in wellbores with relatively uniform inner diameters. However, in some cases where the flow needs to enter from the large casing to the small casing in the wellbore, the downhole choke may be blocked at the diameter change point between the small and small casings, causing premature setting and making it difficult to enter the preset position in the wellbore to play its due role. When the bridge plug needs to enter from the large casing to the small casing, the diameter change point may block the end of the bridge plug, preventing the bridge plug from penetrating into the small casing. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a downhole throttling device that is suitable for variable diameter wellbores and can smoothly enter the small pipe from the large pipe in the wellbore.

[0005] This invention is achieved through the following technical solution:

[0006] A downhole throttling device includes a throttling device body, the throttling device body including a lower connector disposed at the bottom end, a plurality of auxiliary grooves being circumferentially formed on the outer side of the lower connector, and a locking block being temporarily fixed in each of the auxiliary grooves, the outer end of the locking block extending beyond the outer surface of the lower connector, and the outer diameter of the circumscribed circle of all the outer ends being larger than the maximum diameter of the throttling device body, the inner end of the locking block penetrating into the auxiliary groove, when the locking block contacts an obstacle during the process of the throttling device body penetrating into the wellbore, the locking block can be pressed into the auxiliary groove, so that the throttling device body passes through the variable diameter wellbore section.

[0007] Optionally, the auxiliary groove is inclined towards the bottom end of the lower connector, and the angle between the groove direction of the auxiliary groove and the axis of the throttling device body is 10° to 45°. This ensures that the locking block can be subjected to sufficient force to disengage from the fixed connection with the auxiliary groove and penetrate into the auxiliary groove, thereby ensuring that the throttling device can enter the small tube.

[0008] Optionally, a shear pin is provided at the opening of the auxiliary groove. The shear pin passes through both the groove wall of the auxiliary groove and the corresponding locking block. When the locking block encounters an obstacle during the process of the throttling device body penetrating the wellbore, the locking block can cut off the shear pin and penetrate into the auxiliary groove.

[0009] Alternatively, the axis of the shear pin is perpendicular to the axis of the throttling device body.

[0010] Optionally, an elastic element is provided between the card block and the auxiliary groove, the elastic element being used to pull the card block deeper into the auxiliary groove.

[0011] Optionally, the outer end surface of the portion of the lower connector extending from the locking block has a spherical crown structure. This reduces the probability that the locking block will be affected by some protrusions on the inner wall of the wellbore during its insertion into the wellbore, thereby reducing the possibility that the locking block will be blocked by the protrusions before reaching the variable diameter wellbore section, causing it to prematurely penetrate into the auxiliary groove, thus ensuring the fit between the locking block and the variable diameter wellbore section.

[0012] Optionally, at least three auxiliary slots are provided, and the plurality of auxiliary slots are evenly circumferentially arranged on the throttling device body around the axis of the throttling device body.

[0013] Optionally, the throttling device body includes a central tube, and the central tube is provided with a sealing element for sealing. The sealing element includes a first rubber sleeve seat, a first auxiliary rubber sleeve, a main rubber sleeve, a second auxiliary rubber sleeve, and a second rubber sleeve seat, which are sequentially sleeved on the central tube from top to bottom. The second rubber sleeve seat is fixedly connected to the central tube and the lower connector. The second rubber sleeve seat can move towards the first rubber sleeve seat under the pull of the central tube, so that the first auxiliary rubber sleeve, the main rubber sleeve, and the second auxiliary rubber sleeve are squeezed and expanded outward to abut against the inner wall of the well shaft to achieve the purpose of sealing the well shaft.

[0014] Optionally, the main rubber tube includes a first cylindrical section and two frustum sections disposed at both ends of the first cylindrical section. The first and second auxiliary rubber tubes each include a second cylindrical section. The end of the second cylindrical section of the first and second auxiliary rubber tubes facing the main rubber tube has a frustum groove that can match the adjacent frustum section. The first and second auxiliary rubber tubes respectively contact the adjacent frustum section of the main rubber tube through the frustum groove.

[0015] Optionally, the first auxiliary rubber tube, the main rubber tube, and the second auxiliary rubber tube are made of rubber.

[0016] The present invention has the following advantages and beneficial effects:

[0017] 1. An embodiment of the present invention provides a downhole throttling device. Through the setting of the locking block, the bottom end of the throttling device body can be supported, so that the bottom end of the throttling device body is approximately at the center of the wellbore. When the throttling device needs to enter the small pipe from the large pipe of the wellbore, a throttling device body with a diameter adapted to the small pipe is selected, and the circumscribed circle formed by the outer ends of the locking block is adapted to the diameter of the large pipe. The throttling device body is placed in the wellbore, at which time the locking block preferably contacts the inner wall of the large pipe of the wellbore, supporting the bottom end of the throttling device body. When the throttling device body penetrates to the diameter-changing section at the junction of the large and small pipes during pumping, the bottom end of the throttling device body can be aligned and entered into the small pipe by the support of the locking block, while the outer end of the locking block is obstructed by the diameter-changing section, causing the locking block to retract into the auxiliary groove, thereby ensuring that the entire throttling device body can smoothly enter the small pipe from the large pipe.

[0018] 2. The downhole throttling device provided in this embodiment of the invention ensures that the throttling block can enter the auxiliary groove after shearing the shear pin by the traction of the elastic element, and will not come out of the auxiliary groove. This avoids the throttling block from getting stuck between the throttling device and the wellbore due to the block coming out, which would affect the depth of the throttling device. Attached Figure Description

[0019] The accompanying drawings, which are included to provide a further understanding of embodiments of the invention and form part of this application, do not constitute a limitation thereof. In the drawings:

[0020] Figure 1 This is an overall schematic diagram of Embodiment 1 of the present invention;

[0021] Figure 2 for Figure 1 Schematic diagram at point A in the middle;

[0022] Figure 3 for Figure 1 Another diagram at point A in the middle;

[0023] Figure 4 This is a schematic diagram of the throttling device body in the wellbore according to Embodiment 1 of the present invention;

[0024] Figure 5 This is another schematic diagram of the throttling device body inside the wellbore in Embodiment 1 of the present invention.

[0025] Figure 6 This is another schematic diagram of the throttling device body in the wellbore according to Embodiment 1 of the present invention.

[0026] The attached diagram shows the markings and corresponding component names:

[0027] 1-Throttle device body, 11-Central pipe, 12-First rubber sleeve seat, 13-First auxiliary rubber sleeve, 14-Main rubber sleeve, 15-Second auxiliary rubber sleeve, 16-Second rubber sleeve seat, 17-Lower connector, 2-Auxiliary groove, 3-Clamping block, 4-Shearing pin, 5-Elastic element, 6-Wellbore, 61-Variable diameter wellbore section. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the embodiments and accompanying drawings. The illustrative embodiments and descriptions of the present invention are only used to explain the present invention and are not intended to limit the present invention.

[0029] In the following description, numerous specific details are set forth in order to provide a thorough understanding of the invention. However, it will be apparent to those skilled in the art that these specific details are not necessary to practice the invention. In other embodiments, well-known structures, circuits, materials, or methods have not been specifically described in order to avoid obscuring the invention.

[0030] Throughout this specification, references to "an embodiment," "an example," or "an example" mean that a particular feature, structure, or characteristic described in connection with that embodiment or example is included in at least one embodiment of the invention. Therefore, the phrases "an embodiment," "an example," "an example," or "an example" appearing in various places throughout the specification do not necessarily refer to the same embodiment or example. Furthermore, specific features, structures, or characteristics can be combined in one or more embodiments or examples in any suitable combination and / or sub-combination. Moreover, those skilled in the art will understand that the illustrations provided herein are for illustrative purposes and are not necessarily drawn to scale. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0031] In the description of this invention, the terms "front", "rear", "left", "right", "up", "down", "vertical", "horizontal", "high", "low", "inner", and "outer" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting the scope of protection of this invention.

[0032] Example 1:

[0033] A downhole throttling device, such as Figure 1 As shown, it includes a throttling device body 1, which includes a lower connector 17 disposed at the bottom end, the outer side of which is as shown... Figure 2As shown, multiple auxiliary grooves 2 are circumferentially provided, and each auxiliary groove 2 temporarily has a locking block 3. The outer end of the locking block 3 extends beyond the outer surface of the lower connector 17, and the outer diameter of all the outer ends is larger than the maximum diameter of the throttling device body 1. The inner end of the locking block 3 penetrates the auxiliary groove 2. When the locking block 3 comes into contact with an obstacle during the process of the throttling device body 1 penetrating into the wellbore 6, such as... Figure 3 As shown, the locking block 3 can be pressed into the auxiliary groove 2 so that the throttling device body 1 passes through the variable diameter wellbore section 61.

[0034] The locking block 3 supports the bottom of the throttling device body 1, positioning it approximately at the center of the wellbore 6. When the throttling device needs to move from the large pipe to the small pipe in the wellbore 6, a throttling device body 1 with a diameter matching the small pipe is selected, and the circumscribed circle formed by the outer ends of the locking block 3 is aligned with the diameter of the large pipe. The throttling device body 1 is then placed into the wellbore 6. Figure 4 As shown, the locking block 3 preferably contacts the inner wall of the large pipe of the wellbore 6 to support the bottom end of the throttling device body 1. When the throttling device body 1 penetrates into the variable diameter wellbore section 61 at the junction of the large and small pipes during pumping, as... Figure 5 As shown, the bottom end of the throttling device body 1 can be supported and aligned by the locking block 3 and enter the small tube, while the outer end of the locking block 3 is obstructed by the diameter-changing section, causing the locking block 3 to retract into the auxiliary groove 2, thereby ensuring that the entire throttling device body 1 is as shown. Figure 6 As shown, it can smoothly enter the small tube from the large tube.

[0035] It is understandable that the aforementioned locking block 3 is mainly used to support the lower connector 17 of the throttling device body 1, so that it can smoothly enter the small pipe from the large pipe when it encounters the diameter change position of the diameter change well 6. Therefore, any support component that can support the bottom end of the lower connector 17 during the conveying of the throttling device and can be retracted when it encounters an obstruction can be applied to the aforementioned throttling device.

[0036] The auxiliary groove 2 is inclined towards the bottom of the lower connector 17, and the angle between the groove direction of the auxiliary groove 2 and the axis of the throttling device body 1 is 10° to 45°. This ensures that when the locking block 3 is subjected to the resistance force exerted by the variable diameter well section 61, the resistance force can form a large component force that pushes the locking block 3 into the auxiliary groove 2, so that the locking block 3 can disengage from the fixed connection with the auxiliary groove 2 and penetrate into the auxiliary groove 2. This ensures that the throttling device can enter the small pipe and will not be stuck at the variable diameter well section 61 due to the obstruction of the locking block 3.

[0037] For the temporary fixed connection between the locking block 3 and the auxiliary groove 2, in one or more embodiments, a shear pin 4 is provided at the opening of the auxiliary groove 2. The shear pin 4 passes through both the groove wall of the auxiliary groove 2 and the corresponding locking block 3. When the locking block 3 encounters an obstacle during the process of the throttling device body 1 penetrating into the wellbore 6, the locking block 3 can cut off the shear pin 4 and penetrate into the auxiliary groove 2. When the outer end of the locking block 3 is obstructed by the variable diameter wellbore section 61, the shear pin 4 is subjected to increased pressure and is sheared off, the locking block 3 disengages from the fixed relationship with the auxiliary groove 2, and the locking block 3 can thus be retracted into the auxiliary groove 2.

[0038] If the axis of the shear pin 4 is inclined towards the top of the throttling device body 1, when the outer end of the locking block 3 is obstructed by the variable diameter wellbore section 61, the entire locking block 3 will tend to rotate towards the top of the throttling device body 1 under the pushing force of the obstruction and the guidance of the shear pin 4 itself. Therefore, the locking block 3 may be firmly stuck at the opening of the auxiliary groove 2, making it impossible to retract into the auxiliary groove 2. Therefore, in one or more embodiments, the axis of the shear pin 4 is perpendicular to the axis of the throttling device body 1. At this time, the locking block 3 is subjected to a shearing force that can reliably form for cutting the shear pin 4 when subjected to the obstruction force applied by the variable diameter wellbore section 61, ensuring that the shear pin 4 can be cut and retracted into the auxiliary groove 2 when subjected to the obstruction force applied by the variable diameter wellbore section 61.

[0039] Furthermore, in one or more embodiments, an elastic element 5 is provided between the card block 3 and the auxiliary groove 2, the elastic element 5 being used to pull the card block 3 deeper into the auxiliary groove 2.

[0040] By using the elastic element 5 to pull the locking block 3, it is ensured that the locking block 3 can enter the auxiliary groove 2 after cutting the shear pin 4, and will not come out of the auxiliary groove 2. This avoids the locking block 3 getting stuck between the throttling device and the wellbore 6 due to the locking block coming out, which would affect the depth of the throttling device.

[0041] In one or more embodiments, the outer end surface of the portion of the lower connector 17 extending from the locking block 3 has a spherical crown structure. The spherical crown is a curved surface remaining after a sphere is truncated by a plane. In this case, the spherical crown structure contacts the inner wall of the wellbore 6 before the throttling device body 1, and the contact is a point contact with a smooth contact area. This reduces the probability that the locking block 3 will be affected by protrusions on the inner wall of the wellbore 6 during its penetration into the wellbore 6, thereby reducing the possibility that the locking block 3 will be blocked by protrusions before reaching the variable diameter wellbore section 61, leading to premature penetration into the auxiliary groove 2. This ensures the cooperation between the locking block 3 and the variable diameter wellbore section 61. Furthermore, when the locking block 3 contacts the variable diameter wellbore section 61, the spherical crown structure preferentially contacts the inner wall of the variable diameter wellbore section 61. At this time, the resisting force exerted by the variable diameter wellbore section 61 on the spherical crown structure is tilted inward under the influence of the curved surface of the spherical crown structure, thus forming a component force that pushes the locking block 3 inward, making it easier for the locking block 3 to enter the auxiliary groove 2.

[0042] The auxiliary grooves 2 are provided in at least three, that is, the locking blocks 3 are also provided in at least three. This ensures that the bottom end of the throttling device body 1 can be roughly located at the center of the wellbore 6 with the support of each locking block 3, which facilitates the throttling device body 1 to enter the small tube. The multiple auxiliary grooves 2 are evenly circumferentially arranged on the throttling device body 1 around the axis of the throttling device body 1. This ensures that each locking block 3 bears approximately the same resistance force when it contacts the variable diameter wellbore section 61, and can be drawn into the corresponding auxiliary groove 2 in a similar time. This further ensures that the throttling device body 1 can smoothly enter the small tube.

[0043] In one or more embodiments, the throttling device body 1 includes a central tube 11, and the central tube 11 is provided with a sealing element for sealing. The sealing element includes a first rubber sleeve seat 12, a first auxiliary rubber sleeve 13, a main rubber sleeve 14, a second auxiliary rubber sleeve 15, and a second rubber sleeve seat 16, which are sequentially sleeved on the central tube 11 from top to bottom. The second rubber sleeve seat 16 is fixedly connected to both the central tube 11 and the lower connector 17. The second rubber sleeve seat 16 can move towards the first rubber sleeve seat 12 under the pull of the central tube 11, so that the first auxiliary rubber sleeve 13, the main rubber sleeve 14, and the second auxiliary rubber sleeve 15 are squeezed and expanded outward to abut against the inner wall of the well barrel 6 to achieve the purpose of sealing the well barrel 6.

[0044] The main rubber sleeve 14 includes a first cylindrical section and two frustum sections disposed at both ends of the first cylindrical section. The first auxiliary rubber sleeve 13 and the second auxiliary rubber sleeve 15 each include a second cylindrical section. The ends of the second cylindrical sections of the first auxiliary rubber sleeve 13 and the second auxiliary rubber sleeve 15 facing the main rubber sleeve 14 have frustum grooves that can match adjacent frustum sections. The first auxiliary rubber sleeve 13 and the second auxiliary rubber sleeve 15 respectively contact adjacent frustum sections of the main rubber sleeve 14 through these frustum grooves. When the second rubber sleeve seat 16 moves towards the first rubber sleeve seat 12, the first auxiliary rubber sleeve 13 and the second auxiliary rubber sleeve 15 expand outwards under the influence of the cooperation between their frustum grooves and the frustum sections of the main rubber sleeve 14, thereby abutting against the inner wall of the well casing 6.

[0045] The first auxiliary rubber tube 13, the main rubber tube 14, and the second auxiliary rubber tube 15 are made of rubber.

[0046] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A downhole throttling device, characterized in that, The device includes a throttling device body (1), which includes a lower connector (17) at the bottom end. The lower connector (17) has multiple auxiliary grooves (2) circumferentially opened on its outer side. Each of the auxiliary grooves (2) has a temporarily fixed locking block (3). The outer end of the locking block (3) extends out of the outer surface of the lower connector (17), and the outer diameter of all the outer ends is greater than the maximum diameter of the throttling device body (1). The inner end of the locking block (3) penetrates the auxiliary groove (2). When the locking block (3) comes into contact with an obstacle during the process of the throttling device body (1) penetrating into the wellbore (6), the locking block (3) can be pressed and penetrated into the auxiliary groove (2). The auxiliary groove (2) is inclined towards the bottom of the lower connector (17), and the angle between the groove of the auxiliary groove (2) and the axis of the throttling device body (1) is 10°~45°. A shear pin (4) is provided at the groove opening of the auxiliary groove (2). The shear pin (4) passes through the groove wall of the auxiliary groove (2) and the corresponding locking block (3). When the locking block (3) encounters an obstacle during the process of the throttling device body (1) penetrating into the wellbore (6), the locking block (3) can cut off the shear pin (4) and penetrate into the auxiliary groove (2). An elastic element (5) is provided between the card block (3) and the auxiliary groove (2), and the elastic element (5) is used to pull the card block (3) deeper into the auxiliary groove (2).

2. The downhole throttling device according to claim 1, characterized in that, The axis of the shear pin (4) is perpendicular to the axis of the throttling device body (1).

3. The downhole throttling device according to claim 1, characterized in that, The outer end surface of the lower connector (17) extending from the card block (3) has a spherical crown structure.

4. A downhole throttling device according to claim 1, characterized in that, At least three auxiliary slots (2) are provided, and the multiple auxiliary slots (2) are evenly arranged circumferentially around the axis of the throttling device body (1) on the throttling device body (1).

5. A downhole throttling device according to claim 1, characterized in that, The throttling device body (1) includes a central tube (11), and the central tube (11) is provided with a sealing element for sealing. The sealing element includes a first rubber sleeve seat (12), a first auxiliary rubber sleeve (13), a main rubber sleeve (14), a second auxiliary rubber sleeve (15), and a second rubber sleeve seat (16) sequentially sleeved on the central tube (11) from top to bottom. The second rubber sleeve seat (16) is fixedly connected to the central tube (11) and the lower connector (17). The second rubber sleeve seat (16) can move towards the first rubber sleeve seat (12) under the pull of the central tube (11), so that the first auxiliary rubber sleeve (13), the main rubber sleeve (14), and the second auxiliary rubber sleeve (15) are squeezed and expanded outward.

6. A downhole throttling device according to claim 5, characterized in that, The main rubber tube (14) includes a first cylindrical section and two frustum sections disposed at both ends of the first cylindrical section. The first auxiliary rubber tube (13) and the second auxiliary rubber tube (15) both include a second cylindrical section. The end of the second cylindrical section of the first auxiliary rubber tube (13) and the second auxiliary rubber tube (15) facing the main rubber tube (14) has a frustum groove that can match the adjacent frustum section. The first auxiliary rubber tube (13) and the second auxiliary rubber tube (15) respectively contact the adjacent frustum section of the main rubber tube (14) through the frustum groove.

7. A downhole throttling device according to claim 5, characterized in that, The first auxiliary rubber tube (13), the main rubber tube (14), and the second auxiliary rubber tube (15) are made of rubber.

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