An axial oscillation drag reduction tool based on flow control

Abstract

The present invention relates to an axial oscillation drag reduction tool based on flow control, comprising a connecting pipe, a primary casing, a secondary casing, and an anti-drop casing, which are sequentially and sealably connected along the longitudinal axis. The primary casing is sealed with a primary piston, a flow channel is provided on the outer periphery of the primary piston, one end of the primary piston is connected to a primary piston rod, a first drain channel is provided within the primary piston and the primary piston rod, a first elastic member is connected between the primary piston and the secondary casing, a secondary piston is sealed with a secondary piston, one end of the secondary piston is connected to a secondary piston rod, the secondary piston rod extends into the anti-drop casing, a second drain channel is provided within the secondary piston and the secondary piston rod, a second elastic member is connected between the secondary piston and the anti-drop casing, a connecting mandrel is sealed with a third drain channel in the connecting mandrel, and one end of the connecting mandrel is sealably connected to one end of the secondary piston rod. Advantages: Effectively reduces frictional resistance between the coiled tubing and the wellbore wall, improving the stability of the biting pressure.

Description

Technical Field

[0001] The present invention relates to the field of oil and gas mining engineering machinery, and in particular to an axial oscillation drag reduction tool based on flow control. Background Art

[0002] Coiled tubing technology has been widely used in oil exploration and shale gas drilling and workover, showing promising development prospects and becoming a key feature of petroleum engineering. Since its successful application in the 1990s in China, including well rehabilitation, sidetracking, and wellbore maintenance, the technology has been widely applied in various fields, including workover, drilling, and oil production, and has continuously improved its system structure and equipment architecture. In recent years, with the advancement of slim-hole drilling technology, the advantages of coiled tubing in various complex operations have become increasingly apparent, and its application has expanded. However, due to its small size, high flexibility, and lack of rotation, pressurization difficulties, coiled tubing has high frictional resistance against the wellbore wall, resulting in low effective weight on bit transmission. During coiled tubing operations, the combined effects of its own weight, lowering force, and formation friction can easily cause buckling, resulting in improper lowering of the coiled tubing string or even "stuckness," thus limiting its application in extended-reach and horizontal wells. Therefore, there is a particular need for a tool that can reduce the frictional resistance between the formation and the drill bit during coiled tubing drilling / workover, allowing the weight on bit to be smoothly applied to the drill bit. To this end, based on field conditions and the special requirements of shale gas drilling / workover, it is necessary to develop a weight on bit loading tool to reduce the friction generated by the drill bit. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide an axial oscillation drag reduction tool based on flow control, which effectively overcomes the defects of the prior art.

[0004] The technical solution of the present invention to solve the above technical problems is as follows:

[0005] An axial oscillation drag reduction tool based on flow control comprises a connecting pipe, a primary sleeve, a secondary sleeve and an anti-drop sleeve which are sequentially sealed and connected along the long axis direction, a primary piston which can be moved axially is sealed in the primary sleeve, a flow channel which extends axially to both ends of the primary piston is provided on the outer periphery of the primary piston, a primary piston rod which has a smaller diameter than the primary piston is coaxially connected to the end of the primary piston away from the connecting pipe, a first drainage channel which axially penetrates the primary piston and the primary piston rod is provided in the primary piston and the primary piston rod, a diameter of the first drainage channel is reduced at a section away from the primary piston, a first elastic member is connected between the primary piston and one end of the secondary sleeve, a first piston which can be moved axially is sealed in the secondary sleeve The movable secondary piston, the secondary piston is coaxially connected to the end of the secondary piston away from the primary sleeve with a secondary piston rod having a smaller diameter than the secondary piston, the secondary piston rod extends into the anti-drop sleeve, and a second leakage channel axially penetrating the two is provided in the secondary piston and the secondary piston rod, the primary piston rod can be axially moved to the port of the second leakage channel close to it, a second elastic member is connected between the secondary piston and one end of the anti-drop sleeve, the anti-drop sleeve is sealed with a connecting core shaft which can move along its axial direction, the connecting core shaft is provided with a third leakage channel axially penetrating therein, one end of the connecting core shaft is sealed and communicated with the end of the secondary piston rod extending into the anti-drop sleeve.

[0006] On the basis of the above technical solution, the present invention can also be improved as follows.

[0007] Furthermore, one end of the connecting pipe is provided with a tubular first connecting sealing portion which is coaxially inserted into one end of the primary casing, and the first connecting sealing portion is threadedly connected to the inner wall of one end of the primary casing.

[0008] Furthermore, the end of the first connection sealing portion is configured as a conical surface, and the end of the first-stage piston close to the first connection sealing portion is configured as a conical sealing surface adapted to the conical surface.

[0009] Furthermore, the flow channels are provided in plurality and are evenly spaced along the circumference of the first-stage piston.

[0010] Furthermore, one end of the secondary casing is provided with a tubular second connection sealing portion which is inserted into the other end of the primary casing, and the second connection sealing portion is threadedly connected to the inner wall of the other end of the primary casing.

[0011] Furthermore, the first elastic member is connected between the first-stage piston and the second connecting sealing portion.

[0012] Furthermore, one end of the anti-drop sleeve is provided with a tubular third connection sealing portion inserted into the other end of the secondary sleeve, and the third connection sealing portion is threadedly connected to the inner wall of the other end of the secondary sleeve.

[0013] Furthermore, the second elastic member is connected between the secondary piston and the third connecting sealing portion.

[0014] Furthermore, one end of the connecting core shaft is sleeved on the outside of one end of the secondary piston rod extending into the anti-drop sleeve, and the two are threadedly connected to each other.

[0015] Furthermore, the first-stage piston rod is integrally formed with an extension pipe section with a diameter smaller than the first-stage piston at one end away from the first-stage piston. The first-stage piston rod can be axially moved to the extension pipe section and sealedly inserted into the port of the second leakage channel close to it. The diameter of the first leakage channel is reduced in a section located in the extension pipe section.

[0016] The beneficial effects of the present invention are: effectively reducing the friction resistance between the coiled tubing and the well wall, improving the stability of the bit pressure, shortening the operation cycle, improving the efficiency of coiled tubing drilling and well repair operations, and extending the horizontal footage and service life of the coiled tubing. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 A structural cross-sectional view of the flow control-based axial oscillation drag reduction tool of the present invention;

[0018] Figure 2 This is an enlarged view of the local structure in the figure;

[0019] Figure 3 Schematic diagram of the structure of the connecting pipe in the axial oscillation drag reduction tool based on flow control of the present invention;

[0020] Figure 4 Schematic diagram of the structure of the primary casing and its internal components in the axial oscillation drag reduction tool based on flow control of the present invention;

[0021] Figure 5 Schematic diagram of the structure of the secondary casing and its internal components in the axial oscillation drag reduction tool based on flow control of the present invention;

[0022] Figure 6 It is a structural schematic diagram of the connection between the core shaft and the secondary piston rod in the axial oscillation drag reduction tool based on flow control of the present invention.

[0023] In the accompanying drawings, the components represented by the reference numerals are as follows:

[0024] 1. Connecting pipe; 2. Primary sleeve; 3. Secondary sleeve; 4. Anti-drop sleeve; 5. Connecting core shaft; 11. First connecting seal; 21. Primary piston; 22. Primary piston rod; 23. First leakage channel; 24. First elastic member; 31. Secondary piston; 32. Secondary piston rod; 33. Second leakage channel; 34. Second elastic member; 35. Second connecting seal; 41. Third connecting seal; 51. Third leakage channel; 211. Flow channel; 221. Extension pipe section. DETAILED DESCRIPTION

[0025] The principles and features of the present invention are described below with reference to the accompanying drawings. The examples given are only used to explain the present invention and are not used to limit the scope of the present invention.

[0026] Example: Figures 1 to 6 As shown, the axial oscillation drag reduction tool based on flow control of this embodiment includes a connecting pipe 1, a primary sleeve 2, a secondary sleeve 3 and an anti-drop sleeve 4 which are sealed and connected in sequence along the long axis direction, the primary sleeve 2 is sealed with a primary piston 21 which can move along its axial direction, the outer periphery of the primary piston 21 is provided with a flow channel 211 which extends axially to both ends thereof, the end of the primary piston 21 away from the connecting pipe 1 is coaxially connected with a primary piston rod 22 which has a smaller diameter than the primary piston, the primary piston 21 and the primary piston rod 22 are provided with a first drainage channel 23 which axially passes through the two, the diameter of the first drainage channel 23 is reduced at a section away from the primary piston 21, a first elastic member 24 is connected between the primary piston 21 and one end of the secondary sleeve 3, the secondary sleeve 3 is sealed with a The secondary piston 31 moves in the direction of the primary sleeve 2, and the secondary piston 31 is coaxially connected to the end thereof away from the primary sleeve 2 with a secondary piston rod 32 having a smaller diameter than the secondary piston rod 32. The secondary piston rod 32 extends into the anti-drop sleeve 4. A second leakage channel 33 axially passing through the secondary piston 31 and the secondary piston rod 32 is provided. The primary piston rod 22 can move axially to the port close to the second leakage channel 33 for sealing. A second elastic member 34 is connected between the secondary piston 31 and one end of the anti-drop sleeve 4. The anti-drop sleeve 4 is sealed with a connecting core shaft 5 that can move along its axial direction. The connecting core shaft 5 is provided with a third leakage channel 51 axially passing through it. One end of the connecting core shaft 5 is sealed and connected to the end of the secondary piston rod 32 extending into the anti-drop sleeve 4.

[0027] In this embodiment, the connecting pipe 1, the primary sleeve 2, the secondary sleeve 3 and the anti-drop sleeve 4 are all circular tubular components (or cylindrical components with a channel inside). The use process is as follows:

[0028] Before use, the other end of the connecting pipe 1 is sealed and connected to the joint of the coiled pipe. At the same time, the other end of the connecting core shaft 5 is connected to the screw motor of the drill pipe. When in use, a fluid passage is formed between the interior of the entire tool and the inner cavity of the coiled pipe and the drill pipe. During drilling, the drilling fluid enters the connecting pipe 1 through the coiled pipe, and then flows into the first drainage channel 23, the second drainage channel 33, and the third drainage channel 51 to the inside of the drill pipe. As drilling proceeds, the fluid flows out. During normal drilling, the fluid pressure in the tool is stable. When the drill bit encounters a stuck point in the well, the operation of the drilling fluid pump is stopped first, and then the drilling fluid pump is turned on. After the drilling fluid pump is turned on, the drilling fluid quickly enters the connecting pipe 1, and then the drilling fluid is pumped out of the first piston. 21 is split, and after the split, part of the fluid enters the first discharge channel 23, and the other part enters the annular cavity between the first piston rod 22 and the first sleeve 2 through the flow channel 211 on the outer periphery of the first piston 21. When the fluid enters the first discharge channel 23, since the diameter of the first discharge channel 23 is reduced at a section away from the above-mentioned first piston 21, the fluid will be pressurized in the first discharge channel 23 to push the first piston 21 toward the second sleeve 3 (this process will gradually compress the first elastic member 24 to store energy). During this process, another part of the fluid forms a high pressure in the annular cavity between the first piston rod 22 and the first sleeve 2, and then pushes the second piston 31 which is sealed and plugged with the first piston rod 22. The second resilient member 34 is compressed and moves toward the anti-drop sleeve 4 (this process will gradually compress the second elastic member 34 to store energy), that is, drive the connecting core shaft 5 and the screw motor and drill rod to impact downward quickly (that is, generate axial oscillation) to break the stuck point. At the same time, in a short time, the secondary piston 31 will be pushed to separate from the end of the primary piston rod 22 (the secondary piston 31 and the primary piston rod 22 move relative to each other, so that the primary piston rod 22 exits the second drainage channel 33 away from the end of the primary piston 21). At this time, the channel mouth of the second drainage channel 33 is opened, and the fluid in the annular cavity flows out through the second drainage channel 33 and is transported to the drill rod. At the same time, the fluid exits the second drainage channel 33 at the end of the primary piston rod 22 away from the primary piston 21. At the same time as the flow discharge channel 33 is opened, the second elastic member 34 and the first elastic member 24 release energy due to the decrease in fluid pressure, thereby driving the first piston rod 22 and the first piston 21 to move back toward the connecting pipe 1, and driving the second piston rod 32 and the second piston 31 to move back toward the connecting pipe 1 together with the connecting core shaft 5. After that, the drilling fluid flows normally through the tool into the drill pipe. If a stuck point is encountered during the next drilling, the stuck point can be broken according to the above operation steps. The entire tool can effectively reduce the frictional resistance between the coiled tubing and the well wall, improve the stability of the bit pressure, shorten the operation cycle, improve the efficiency of coiled tubing drilling and well repair operations, and extend the horizontal footage and service life of the coiled tubing.

[0029] It should be noted that the direction of the arrow in the accompanying drawings is the flow direction of the fluid inside the tool.

[0030] As a preferred embodiment, one end of the connecting pipe 1 is provided with a tubular first connecting sealing portion 11 coaxially inserted into one end of the primary sleeve 2 , and the first connecting sealing portion 11 is threadedly connected to the inner wall of one end of the primary sleeve 2 .

[0031] In the above embodiment, an external thread is provided on the outer periphery of the first connection sealing portion 11, and an internal thread is provided on the inner wall of one end of the first-level casing 2. The outer diameter of the first connection sealing portion 11 is consistent with the inner diameter of one end of the first-level casing 2, and the two can be connected by threads. At the same time, a sealing ring can be sandwiched between the connections to improve the sealing performance.

[0032] It should be noted that: multiple sealing rings are nested on the outer circumference of the first-stage piston 21, the second-stage piston 31 and the connecting core shaft 5 (or multiple axial seals are set), so that the first-stage piston 21, the second-stage piston 31 and the connecting core shaft 5 are well sealed and connected with their corresponding first-stage sleeve 2, the second-stage sleeve 3 and the anti-drop sleeve 4.

[0033] As a preferred embodiment, the end of the first connection sealing portion 11 is set as a conical surface, and the end of the first-stage piston 21 close to the first connection sealing portion 11 is set as a conical sealing surface adapted to the conical surface.

[0034] In the above embodiment, when the drilling fluid flows normally in the tool, the sealing surface at the end of the first-stage piston 21 is tightly fitted with the conical surface at the end of the first connecting sealing portion 11, which plays a role in limiting the first-stage piston 21. The structures are designed and matched relatively compactly.

[0035] As a preferred embodiment, a plurality of the flow channels 211 are provided and are evenly spaced apart along the circumference of the first-stage piston 21 .

[0036] In the above embodiment, the design of the multiple flow channels 211 allows part of the fluid to smoothly enter the annular cavity (high-pressure annular cavity) between the primary piston rod 22 and the primary casing 2 through the multiple flow channels 211 .

[0037] As a preferred embodiment, one end of the secondary casing 3 is provided with a tubular second connection sealing portion 35 inserted into the other end of the primary casing 2 , and the second connection sealing portion 35 is threadedly connected to the inner wall of the other end of the primary casing 2 .

[0038] In the above embodiment, the secondary casing 3 and the primary casing 2 are connected by threaded connection, which is relatively firm. At the same time, a sealing ring can be sandwiched between the connections to improve the sealing performance, so that the connection is better sealed.

[0039] As a preferred embodiment, the first elastic member 24 is connected between the primary piston 21 and the second connection sealing portion 35 .

[0040] In the above embodiment, the first elastic member 24 is connected between the primary piston 21 and the end of the second connection sealing portion 35 , and the assembly is relatively stable, and can play a relatively stable energy storage role under the push of fluid high pressure.

[0041] In this embodiment, the first elastic member 24 is a conventional spring, and is sleeved outside the first-stage piston rod 22 .

[0042] As a preferred embodiment, one end of the anti-drop sleeve 4 is provided with a tubular third connection sealing portion 41 inserted into the other end of the secondary sleeve 3 , and the third connection sealing portion 41 is threadedly connected to the inner wall of the other end of the secondary sleeve 3 .

[0043] In the above embodiment, the anti-drop sleeve 4 and the secondary sleeve 3 are connected by threaded connection, which is relatively firm. At the same time, a sealing ring can be sandwiched between the connections to improve the sealing performance, so that the connection is better sealed.

[0044] As a preferred embodiment, the second elastic member 34 is connected between the secondary piston 31 and the third connection sealing portion 41 .

[0045] In the above embodiment, the second elastic member 34 is connected between the secondary piston 31 and the end of the third connection sealing portion 41 , and the assembly is relatively stable, and can play a relatively stable energy storage role under the push of fluid high pressure.

[0046] In this embodiment, the second elastic member 34 is a conventional disc spring and is sleeved outside the secondary piston rod 32 .

[0047] As a preferred embodiment, one end of the connecting core shaft 5 is sleeved on the outside of one end of the secondary piston rod 32 extending into the anti-drop sleeve 4, and the two are threadedly connected to each other.

[0048] In the above embodiment, the connecting core shaft 5 and the secondary piston rod 32 are connected by threaded connection, which is relatively firm.

[0049] As a preferred embodiment, the first-stage piston rod 22 is coaxially provided with an extension pipe section 221 having a smaller diameter than the first-stage piston rod 21 at one end thereof which is away from the first-stage piston 21. The first-stage piston rod 22 can be axially moved to the extension pipe section 221 and sealedly inserted into the port of the second leakage channel 33 close thereto. The diameter of a section of the first leakage channel 23 located within the extension pipe section 221 is reduced.

[0050] In the above embodiment, the outer diameter of the extension pipe section 221 is consistent with the inner diameter of the second leakage channel 33. When the primary piston rod 22 is pushed by the fluid to move toward the secondary sleeve 3, the extension pipe section 221 will be inserted into the second leakage channel 33 and block the second leakage channel 33, thereby forming a high pressure in the annular cavity between the primary piston rod 22 and the primary sleeve 2 to push the secondary piston 31 to move, and the connection between the two is relatively tight.

[0051] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like to indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0052] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present invention, "plurality" means at least two, such as two, three, etc., unless otherwise specifically defined.

[0053] In the present invention, unless otherwise specified or limited, the terms "installed," "connected," "connect," "fixed," etc. should be understood in a broad sense. For example, they can refer to fixed connection, detachable connection, or integration; mechanical connection, electrical connection; direct connection, or indirect connection through an intermediate medium; internal communication between two components, or interaction between two components, unless otherwise specified. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0054] In the present invention, unless otherwise expressly specified or limited, when a first feature is "above" or "below" a second feature, it may mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediary. Furthermore, when a first feature is "above," "above," or "above" a second feature, it may mean that the first feature is directly above or diagonally above the second feature, or simply means that the first feature is at a higher level than the second feature. When a first feature is "below," "below," or "below" a second feature, it may mean that the first feature is directly below or diagonally below the second feature, or simply means that the first feature is at a lower level than the second feature.

[0055] In the description of this specification, the reference terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification and features of different embodiments or examples without contradiction.

[0056] Although the embodiments of the present invention have been shown and described above, it will be understood that the above embodiments are illustrative and are not to be construed as limitations on the present invention. A person skilled in the art may change, modify, replace and modify the above embodiments within the scope of the present invention.

Claims

1. An axial oscillation drag reduction tool based on flow control, characterized by: The invention comprises a connecting pipe (1), a primary sleeve (2), a secondary sleeve (3) and an anti-drop sleeve (4) which are sequentially connected in a sealing manner along the longitudinal direction, wherein the primary sleeve (2) is sealed with a primary piston (21) which can move along its axial direction, the outer periphery of the primary piston (21) is provided with a flow channel (211) which extends axially to both ends thereof, the end of the primary piston (21) away from the connecting pipe (1) is coaxially connected with a primary piston rod (22) having a smaller diameter than the primary piston rod, the primary piston (21) and the primary piston rod (22) are provided with a first drainage channel (23) which axially penetrates the first drainage channel (21). 3) The diameter of a section away from the first-stage piston (21) is reduced, a first elastic member (24) is connected between the first-stage piston (21) and one end of the second-stage sleeve (3), a second-stage piston (31) movable along its axial direction is sealed in the second-stage sleeve (3), the end of the second-stage piston (31) away from the first-stage sleeve (2) is coaxially connected to a second-stage piston rod (32) having a smaller diameter than the first-stage piston rod (32), the second-stage piston rod (32) extends into the anti-drop sleeve (4), and a second drainage channel (33) is provided in the second-stage piston (31) and the second-stage piston rod (32) which axially penetrates the two. The first-stage piston rod (22) can be axially moved to a sealed position and inserted into the second leakage channel (33) near the port thereof. A second elastic member (34) is connected between the second-stage piston (31) and one end of the anti-drop sleeve (4). A connecting core shaft (5) that can be moved along its axial direction is sealed in the anti-drop sleeve (4). The connecting core shaft (5) is provided with a third leakage channel (51) that axially passes through it. One end of the connecting core shaft (5) is sealed and connected to the end of the second-stage piston rod (32) that extends into the anti-drop sleeve (4). One end of the connecting pipe (1) is provided with a coaxially inserted into the A tubular first connection sealing portion (11) is provided at one end of the first-stage sleeve (2), and the first connection sealing portion (11) is threadedly connected to the inner wall of one end of the first-stage sleeve (2); the end of the first connection sealing portion (11) is provided as a conical surface, and the end of the first-stage piston (21) close to the first connection sealing portion (11) is provided as a conical sealing surface adapted to the conical surface; and a tubular second connection sealing portion (35) is provided at one end of the second-stage sleeve (3) and inserted into the other end of the first-stage sleeve (2), and the second connection sealing portion (35) is threadedly connected to the inner wall of the other end of the first-stage sleeve (2).

2. The flow-controlled axial oscillation drag reduction tool according to claim 1, characterized in that: A plurality of flow channels (211) are provided and are evenly spaced and distributed along the circumference of the first-stage piston (21).

3. The flow-controlled axial oscillation drag reduction tool according to claim 1, characterized in that: The first elastic member (24) is connected between the first-stage piston (21) and the second connecting sealing portion (35).

4. The flow-controlled axial oscillation drag reduction tool according to claim 1, characterized in that: One end of the anti-drop sleeve (4) is provided with a tubular third connection sealing portion (41) inserted into the other end of the secondary sleeve (3), and the third connection sealing portion (41) is threadedly connected to the inner wall of the other end of the secondary sleeve (3).

5. The flow-controlled axial oscillation drag reduction tool according to claim 4, characterized in that: The second elastic member (34) is connected between the secondary piston (31) and the third connecting sealing portion (41).

6. The flow-controlled axial oscillation drag reduction tool according to any one of claims 1 to 5, characterized in that: One end of the connecting core shaft (5) is sleeved on the outside of one end of the secondary piston rod (32) extending into the anti-drop sleeve (4), and the two are threadedly connected to each other.

7. The flow-controlled axial oscillation drag reduction tool according to any one of claims 1 to 5, characterized in that: An extension pipe section (221) having a smaller diameter than the first-stage piston rod (22) is integrally formed and coaxially provided at one end of the first-stage piston rod (22) away from the first-stage piston (21). The first-stage piston rod (22) can be axially moved to the extension pipe section (221) and sealedly inserted into a port of the second leakage channel (33) close thereto. The first leakage channel (23) has a section within the extension pipe section (221) with a reduced diameter.

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