Turbine-driven radial vibration type resistance reduction centralizer

Abstract

The invention discloses a turbine-driven radial vibration type resistance-reducing centralizer, which relates to the technical field of oil and gas drilling and comprises a centralizer shell, a plurality of blades are arranged on the outer circumference of the centralizer shell, and a plurality of ellipsoidal rollers are axially mounted on the blades at intervals. A hydraulic power conversion module, an eccentric excitation generation module and a rigid excitation conduction module are arranged in the centralizer shell in the axial direction; the eccentric excitation generation module comprises a rotating shaft and an eccentric weight mounted on the rotating shaft; the hydraulic power conversion module comprises a turbine stator and a turbine rotor, the turbine stator is fixedly mounted in the centralizer shell, and the turbine rotor is mounted on the rotating shaft and is opposite to the turbine stator; the rigid excitation conduction module comprises rotating rings and bearings, the rotating rings are connected to the two ends of the rotating shaft in a sleeving mode, the outer diameters of the rotating rings are connected with the inner diameters of the bearings in a matched mode, and the outer rings of the bearings are fixedly connected into the centralizer shell. The friction resistance between the drilling tool and the well wall is reduced, and the drilling pressure transmission efficiency of the horizontal section is improved.

Description

Technical Field

[0001] This invention relates to the field of oil and gas drilling technology, and specifically to a turbine-driven radial vibration type drag-reducing centralizer. Background Technology

[0002] In oil and gas drilling engineering, especially in horizontal wells, extended reach wells, and deep well operations, the frictional resistance between the drill string and the wellbore is one of the key factors restricting the mechanical drilling rate and the efficiency of drilling pressure transmission. As the length of the horizontal section increases, the weight of the drill string causes it to adhere tightly to the lower wellbore, forming a large contact positive pressure. The presence of static friction makes it difficult for the drill string to slide smoothly, and in severe cases, it can even prevent the drilling pressure from being effectively transmitted to the drill bit, affecting drilling efficiency and wellbore trajectory control accuracy.

[0003] To reduce frictional resistance between the drill string and the wellbore, various drag-reducing centralizer structures have been proposed in the existing technology. For example, some centralizers have universal balls installed on the centralizer bars, utilizing the rolling characteristics of the balls to convert sliding friction into rolling friction; other structures install rollers on the centralizer shell, achieving drag reduction through the contact between the rollers and the wellbore.

[0004] However, although the omnidirectional ball structure has multi-directional rolling capability, it is prone to lateral slippage under high contact pressure, resulting in poor drill string trajectory stability. In addition, the ball and the well wall are in point contact, and the contact stress is concentrated, which can easily lead to local crushing of the ball or well wall mud cake. The roller structure is prone to blockage or wear in sandy or high-wear environments, and the drag reduction effect decreases significantly after long-term use.

[0005] Therefore, how to achieve stable and efficient drag reduction in complex wellbore environments while ensuring the accuracy of drill string trajectory control is a technical problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0006] The purpose of this invention is to overcome the above-mentioned shortcomings of the prior art and provide a turbine-driven radial vibration type drag-reducing stabilizer. This invention generates radial centrifugal force by driving the turbine and eccentric weight to rotate at high speed through drilling fluid, which actively breaks the static friction between the drill string and the well wall and transforms it into a dynamic friction state. Combined with the line contact rolling friction reduction of ellipsoidal rollers, it significantly reduces the friction between the drill string and the well wall and improves the drilling pressure transmission efficiency and trajectory control accuracy in the horizontal section.

[0007] To achieve the above objectives, the present invention adopts the following technical solution: A turbine-driven radial vibration type drag-reducing centralizer includes a centralizer housing, on the outer circumference of which multiple blades are provided, and multiple ellipsoidal rollers are embedded and installed at intervals along the axial direction on the blades. The major axis of the ellipsoidal rollers is consistent with the extension direction of the blades. Inside the centralizer housing, a hydraulic power conversion module, an eccentric excitation generation module, and a rigid excitation transmission module are arranged along the axial direction. The eccentric vibration generating module includes a rotating shaft and an eccentric weight. The eccentric weight is fixedly installed on the shaft body of the rotating shaft, and the center of mass of the eccentric weight is offset from the rotation center of the rotating shaft. The hydraulic power conversion module includes a turbine stator and a turbine rotor. The turbine stator is fixedly installed inside the centralizer housing, and the turbine rotor is mounted on a rotating shaft and is arranged opposite to the turbine stator. The rigid vibration transmission module includes a rotating ring and a bearing. The rotating ring is sleeved on both ends of the rotating shaft. The outer diameter of the rotating ring is connected to the inner diameter of the bearing by a spline fit. The outer ring of the bearing is fixedly connected inside the centralizer housing.

[0008] Furthermore, the axial position of the turbine stator is defined within the centralizer housing by the first sleeve and the second sleeve, and the axial position of the turbine rotor is defined by the rotor limiting snap ring.

[0009] Furthermore, the axial position of the eccentric weight is limited by the weight limiting spring, the inner ring of the eccentric weight is provided with a rectangular groove, and the rotating shaft is provided with a shaft key. The shaft key cooperates with the rectangular groove to realize torque transmission.

[0010] Furthermore, the rotating ring has a thin-walled structure, with its inner and outer rings connected by multiple radial connecting ridges, forming a drilling fluid flow channel between adjacent connecting ridges. The inner ring of the rotating ring has a rectangular groove, which engages with the key on the rotating shaft to transmit torque.

[0011] Furthermore, the inner ring of the rotating ring has a single-sided opening structure, which facilitates the assembly of the rotating shaft; its other end is provided with a stepped structure to achieve axial positioning of the rotating shaft.

[0012] Furthermore, the blades have a spiral structure and are evenly distributed along the outer circumference of the centralizer shell.

[0013] Furthermore, the ellipsoidal rollers are in line contact with the well wall to disperse contact stress and reduce lateral slippage.

[0014] The beneficial effects of this invention are as follows: 1. This invention uses a turbine to drive an eccentric weight to rotate at high speed, generating a periodic radial centrifugal excitation force, which actively breaks the static friction between the drill string and the well wall and transforms it into a dynamic friction state. At the same time, the line contact rolling of the ellipsoidal rollers further reduces the travel resistance, realizing a dual resistance reduction mechanism of "actively breaking resistance + passive rolling friction reduction", which significantly improves the drilling pressure transmission efficiency and mechanical drilling speed in the horizontal section.

[0015] 2. The ellipsoidal roller of this invention has a line contact with the well wall, which effectively disperses the contact stress and avoids local crushing and mud cake damage compared to the point contact of the traditional spherical roller. At the same time, its long axis is consistent with the extension direction of the cutter blade, which restricts the lateral rolling of the roller and enhances the stability of the drill string trajectory. It is suitable for high dogleg well sections and complex formations.

[0016] 3. This invention generates high-frequency radial vibration driven by drilling fluid. The vibration acts on the surface of the stabilizer shell and cutter wings, which can effectively destroy the tendency of mud cake to accumulate, prevent mud packing of the stabilizer, assist in self-cleaning, extend tool life, reduce the number of trips, and reduce operating costs.

[0017] 4. The present invention has a compact structure and high transmission efficiency. The rigid excitation transmission module, which is composed of a rotating ring, bearing and spline connection, efficiently transmits the centrifugal force generated by the internal eccentric weight to the centralizer shell, avoiding energy loss. The drilling fluid flow channel set on the rotating ring ensures smooth flow of drilling fluid and does not affect hydraulic performance. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the external structure of the centralizer of the present invention; Figure 2 This is a cross-sectional view of the centralizer of the present invention; Figure 3 This is a schematic diagram of the turbine stator and turbine rotor of the present invention; Figure 4 This is an assembly diagram of the eccentric vibration generation module, the hydraulic power conversion module, and the rigid vibration transmission module of the present invention. Figure 5 This is a schematic diagram of the rotating ring structure of the present invention.

[0019] In the picture: 1-Center housing; 2-Blade blade; 3-Ellipsoidal roller; 4-Rotating shaft; 41-Shaft key; 5-Eccentric weight; 6-Turbine stator; 7-Turbine rotor; 71-Rotor rectangular slot; 8-Rotating ring; 81-Rotating ring rectangular slot; 82-Connecting ridge; 9-Bearing; 10-Weight limit circlip; 11-First sleeve; 12-Second sleeve; 13-Rotor limit circlip. Detailed Implementation

[0020] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention.

[0021] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "horizontal," "inner," "outer," and "one side," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for 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 limitations on the invention. The terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance. Furthermore, unless otherwise explicitly specified and limited, the terms "installed," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0022] Example 1

[0023] like Figure 1-5 As shown, the present invention provides a turbine-driven radial vibration type drag-reducing centralizer, which mainly includes a centralizer housing 1 and a hydraulic power conversion module, an eccentric excitation generation module and a rigid excitation transmission module disposed therein. The modules are arranged sequentially along the axial direction and work together to achieve the active drag reduction function.

[0024] like Figure 1 As shown, multiple blades 2 are arranged on the outer circumference of the centralizer housing 1. The blades 2 have a helical structure and are evenly distributed along the outer circumference of the centralizer housing 1. The helical blade design not only helps guide the flow of drilling fluid in the annulus but also enhances the centering effect of the centralizer in the wellbore. Multiple ellipsoidal rollers 3 are embedded and installed axially at intervals on each blade 2, with the major axis of the ellipsoidal rollers 3 aligned with the extension direction of the blade 2. The use of ellipsoidal rollers 3 instead of traditional spherical rollers aims to transform point contact into line contact, thereby effectively dispersing contact stress and preventing localized crushing under high load conditions. Simultaneously, the directional arrangement of the major axis of the ellipsoidal rollers 3 restricts their lateral rolling freedom, significantly reducing lateral slippage and improving the stability of the drill string trajectory.

[0025] like Figure 2 and Figure 4 As shown, the centralizer housing 1 is provided with a hydraulic power conversion module, an eccentric excitation generation module and a rigid excitation transmission module arranged sequentially along the axial direction.

[0026] Specifically, the eccentric vibration generating module includes a rotating shaft 4 and an eccentric weight 5. The eccentric weight 5 is fixedly mounted on the shaft of the rotating shaft 4, and its center of mass is offset from the rotation center of the rotating shaft 4. When the rotating shaft 4 drives the eccentric weight 5 to rotate at high speed, the eccentric mass generates a periodically changing centrifugal excitation force, serving as the original vibration source for the entire tool. The axial position of the eccentric weight 5 is limited by a weight limiting spring 10 to prevent axial movement during high-speed rotation. To reliably transmit torque, a rectangular groove is provided on the inner ring of the eccentric weight 5, and a shaft key 41 is provided on the rotating shaft 4. The shaft key 41 mates with the rectangular groove to ensure that the eccentric weight 5 rotates synchronously with the rotating shaft 4.

[0027] The hydraulic power conversion module includes a turbine stator 6 and a turbine rotor 7. The turbine stator 6 is fixedly installed inside the centralizer housing 1, and the turbine rotor 7 is mounted on the rotating shaft 4 and positioned opposite to the turbine stator 6. The turbine stator 6 guides the drilling fluid to impact the turbine rotor 7 at a certain angle, thereby driving the turbine rotor 7 to rotate at high speed. To ensure the axial positioning accuracy of the turbine stator 6 and the turbine rotor 7, the axial position of the turbine stator 6 is defined within the centralizer housing 1 by the first sleeve 11 and the second sleeve 12, and the axial position of the turbine rotor 7 is defined by the rotor limiting snap ring 13. The core function of this module is to convert the fluid kinetic energy of the drilling fluid into the mechanical rotational energy of the rotating shaft 4, providing a power source for subsequent excitation.

[0028] The rigid vibration transmission module includes a rotating ring 8 and a bearing 9. The rotating ring 8 is sleeved at both ends of the rotating shaft 4. The outer diameter of the rotating ring 8 is connected to the inner diameter of the bearing 9 via a spline fit. The outer ring of the bearing 9 is fixedly connected inside the centralizer housing 1. The function of this module is to transmit the centrifugal excitation force generated by the eccentric weight 5 to the centralizer housing 1 through the rotating shaft 4, rotating ring 8, and bearing 9, efficiently amplifying the internal micro-vibrations and transmitting them to the surface of the housing, thereby achieving the overall radial vibration of the centralizer.

[0029] As a preferred embodiment of the present invention, such as Figure 5 As shown, the rotating ring 8 adopts a thin-walled structure design. Its inner and outer rings are connected by multiple radial connecting ribs 82, forming drilling fluid flow channels between adjacent connecting ribs 82. This ensures smooth flow of drilling fluid inside the centralizer and avoids affecting hydraulic performance due to flow channel blockage. The inner ring of the rotating ring 8 has a rectangular groove 81, which mates with the key 41 on the rotating shaft 4 to achieve reliable torque transmission. To further optimize the assembly process, the inner ring of the rotating ring 8 is designed with a single-sided opening structure to facilitate the assembly of the rotating shaft 4; its other end has a stepped structure to achieve axial positioning of the rotating shaft 4, simplifying the overall structure and reducing the difficulty of processing and assembly.

[0030] In summary, this invention utilizes a turbine-driven eccentric weight to generate high-frequency radial vibration, actively breaking the static friction between the drill string and the wellbore. Then, low-friction travel is achieved through line-contact rolling of ellipsoidal rollers, forming a composite drag-reduction mechanism of "active vibration breaking static friction + passive rolling reducing dynamic friction." The modules are compact and reliably connected, ensuring efficient vibration transmission while also considering drilling fluid flow performance and tool assembly convenience, making it suitable for long horizontal drilling operations under complex well conditions.

[0031] While the specific embodiments of the present invention have been described above in conjunction with the accompanying drawings, this is not intended to limit the scope of protection of the present invention. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art without creative effort based on the technical solutions of the present invention are still within the scope of protection of the present invention.

Claims

1. A turbine-driven radial vibration type drag-reducing centralizer, characterized in that, The device includes a centralizer housing (1), on which multiple blades (2) are provided on the outer circumference. Multiple ellipsoidal rollers (3) are embedded and installed on the blades (2) at intervals along the axial direction. The long axis of the ellipsoidal rollers (3) is consistent with the extension direction of the blades (2). The centralizer housing (1) is provided with a hydraulic power conversion module, an eccentric vibration generation module and a rigid vibration transmission module along the axial direction inside. The eccentric vibration generating module includes a rotating shaft (4) and an eccentric weight (5). The eccentric weight (5) is fixedly installed on the shaft of the rotating shaft (4), and the center of mass of the eccentric weight (5) is offset from the rotation center of the rotating shaft (4). The hydraulic power conversion module includes a turbine stator (6) and a turbine rotor (7). The turbine stator (6) is fixedly installed inside the centralizer housing (1), and the turbine rotor (7) is installed on the rotating shaft (4) and is arranged opposite to the turbine stator (6). The rigid vibration transmission module includes a rotating ring (8) and a bearing (9). The rotating ring (8) is sleeved on both ends of the rotating shaft (4). The outer diameter of the rotating ring (8) and the inner diameter of the bearing (9) are connected by a spline fit. The outer ring of the bearing (9) is fixedly connected inside the centralizer housing (1).

2. The turbine-driven radial vibration type drag-reducing centralizer according to claim 1, characterized in that, The axial position of the turbine stator (6) is defined within the centralizer housing (1) by the first sleeve (11) and the second sleeve (12), and the axial position of the turbine rotor (7) is defined by the rotor limiting snap ring (13).

3. A turbine-driven radial vibration type drag-reducing centralizer according to claim 1, characterized in that, The axial position of the eccentric weight (5) is limited by the weight limiting spring (10). The inner ring of the eccentric weight (5) is provided with a rectangular groove. The rotating shaft (4) is provided with a shaft key (41). The shaft key (41) cooperates with the rectangular groove to realize torque transmission.

4. A turbine-driven radial vibration type drag-reducing centralizer according to claim 1, characterized in that, The rotating ring (8) is a thin-walled structure. Its inner ring and outer ring are connected by multiple radial connecting ribs (82). A drilling fluid flow channel is formed between adjacent connecting ribs (82). The inner ring of the rotating ring (8) is provided with a rotating ring rectangular groove (81). The rotating ring rectangular groove (81) cooperates with the shaft key (41) on the rotating shaft (4) to transmit torque.

5. A turbine-driven radial vibration type drag-reducing centralizer according to claim 4, characterized in that, The inner ring of the rotating ring (8) has a single-sided opening structure, which facilitates the assembly of the rotating shaft (4); the other end of the rotating ring (8) has a stepped structure, which is used to achieve axial positioning of the rotating shaft (4).

6. A turbine-driven radial vibration type drag-reducing centralizer according to claim 1, characterized in that, The blade (2) has a spiral structure and is evenly distributed along the outer circumference of the centralizer shell (1).

7. A turbine-driven radial vibration type drag-reducing centralizer according to claim 1, characterized in that, The ellipsoidal roller (3) is in line contact with the well wall to disperse contact stress and reduce lateral slippage.

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