Downhole adjustable while-drilling turbine mechanism

Abstract

The application provides a downhole adjustable while-drilling turbine mechanism, which comprises an outer cylinder shell, a guide vane and a turbine arranged in the inner part of the outer cylinder shell, and a transmission shaft for outputting rotary power, and further comprises a permanent magnetic force transmission assembly which comprises a driving permanent magnetic end and a driven permanent magnetic end arranged coaxially and radially spaced, the driving permanent magnetic end is fixedly connected with the turbine to rotate synchronously with the turbine. The application drives only the guide vane and the guide wheel cap with smaller driving quality to move axially through the fixed connection of the support and the transmission shaft, significantly reduces the driving force required by the adjusting mechanism, and improves the response speed of the shape memory alloy part. Since the moving part does not involve the rotating part, the slip ring brush assembly is not arranged, the electrical connection structure is completely simplified, the failure rate is reduced, and the erosion and wear of the rotary dynamic seal by the high-pressure mud are avoided, and the working reliability of the mechanism in the well is further improved.

Description

Technical Field

[0001] This invention belongs to the field of downhole drilling fluid power device technology, specifically relating to a downhole adjustable downhole turbine mechanism, which is suitable for power supply of downhole measurement and control systems, downhole power generation systems and downhole intelligent actuators in oil and gas drilling projects. Background Technology

[0002] Turbine drive mechanisms are core power units in intelligent downhole equipment for oil and gas drilling that rely on drilling mud to obtain fluid kinetic energy, provide power for downhole power generation and downhole actuators, and are widely used in various drilling monitoring and control systems and intelligent downhole drive systems.

[0003] However, in actual drilling operations, the input power requirements of downhole load equipment vary at different working stages, and the mud discharge rate fluctuates due to factors such as the operating conditions of the surface mud pump and changes in well depth. Fixed turbine mechanisms cannot adapt their power to load requirements, resulting in excess power under light load conditions and insufficient power under heavy load conditions.

[0004] To address the aforementioned issues, a few existing technologies have proposed adjustable turbine solutions, primarily employing hydraulic push rods or mechanical jacking structures. These solutions adjust the output power by changing the axial position of the guide impeller or turbine through external drive. However, these solutions have the following shortcomings in practical applications: First, it requires the addition of hydraulic pipelines or mechanical transmission components, which is cumbersome and occupies limited underground space. Secondly, the movement clearance of the adjustment mechanism is easily invaded by solid particles in a sandy mud environment, leading to blockage or jamming. Third, it involves dynamic sealing structures. Under the long-term scouring of high-temperature, high-pressure sand-containing mud downhole, the sealing pairs are prone to wear, leading to mud leakage and affecting the internal lubrication and electrical safety of the mechanism. Fourth, it requires an external power source to drive, which increases the complexity of the system.

[0005] A search revealed that there is currently no integrated speed-regulating turbine drive solution in the industry that utilizes shape memory alloy temperature control. Existing technologies struggle to achieve continuous and reliable power regulation of downhole turbine power mechanisms without adding external circuits or introducing easily clogged mechanical structures. Summary of the Invention

[0006] To address the aforementioned technical problems, this invention provides an adjustable downhole turbine mechanism to solve the problems of existing technologies that require the addition of hydraulic pipelines or mechanical transmission components, resulting in cumbersome structures, occupying limited downhole space, and the ease with which the movement clearance of the adjustment mechanism can be blocked or jammed by solid particles in sandy mud environments.

[0007] A downhole adjustable turbine-while-drilling mechanism includes an outer casing, a guide impeller and a turbine disposed inside the outer casing, and a drive shaft for outputting rotational power, and further includes: A permanent magnet drive assembly includes an active permanent magnet end and a driven permanent magnet end arranged coaxially and radially spaced apart. The active permanent magnet end is fixedly connected to the turbine to rotate synchronously with it, and the driven permanent magnet end is fixedly connected to the drive shaft. The active permanent magnet end and the driven permanent magnet end achieve non-contact torque transmission through magnetic coupling. A shape memory alloy drive assembly includes a shape memory alloy part, a heater, and a temperature sensor for detecting the temperature of the shape memory alloy part. The connecting bracket is fixedly installed on the inner wall of the outer cylinder shell. The connecting bracket rotatably supports the rear end of the drive shaft through a bearing, so that the turbine, the active permanent magnet end, the driven permanent magnet end, and the drive shaft are axially fixed relative to the outer cylinder shell. The guide impeller can be slidably disposed inside the outer cylinder shell along the axial direction, and the guide wheel cap is fixedly connected to the guide impeller and moves synchronously along the axial direction; One end of the shape memory alloy component is fixedly connected to the connecting bracket, and the other end of the shape memory alloy component is fixedly connected to the guide impeller or the guide wheel cap; The shape memory alloy component generates axial expansion and contraction displacement under the heating excitation of the heater, which pushes the guide impeller and the guide wheel cap to move axially reciprocally relative to the turbine, thereby changing the axial working distance between the guide impeller and the turbine.

[0008] Preferably, the turbine and the active permanent magnet end are integrated as a rotating unit, and their radial support is provided by a self-slipping bearing disposed between them, wherein the self-slipping bearing operates by a mud self-lubrication method.

[0009] Preferably, one end of the shape memory alloy part is fixedly installed to the turbine stator joint by a threaded fastening structure, and the turbine stator joint is fixedly connected to the guide impeller as a whole; the other end of the shape memory alloy part is fixedly installed to the connecting bracket by a threaded fastening structure.

[0010] Preferably, the heater is a resistance heating element, which is attached to or adjacent to the outer surface of the shape memory alloy part for controllable heating of the shape memory alloy part.

[0011] Preferably, the shape memory alloy part is a tubular or columnar structure, and a hollow cavity extending axially is formed between the connecting bracket and the drive shaft. The hollow cavity is used to accommodate the wires of the heater and the temperature sensor, and the wires are led out through the hollow cavity and connected to the slip ring brush assembly.

[0012] Preferably, the outer shell is made of non-magnetic titanium alloy or non-magnetic stainless steel, and the outer shell has a segmented assembly structure, with each segment being detachably fixedly connected by flanges and bolts.

[0013] Preferably, the guide impeller blades have a circumferential angle difference with the turbine blades, so that the slurry fluid flowing through the guide impeller acts on the turbine blades at a set impact angle, forming a tangential torque that drives the turbine to rotate.

[0014] Preferably, the sealing element is disposed at the fitting gap between the outer peripheral surface of the guide impeller and the inner wall surface of the outer cylinder shell, for maintaining a dynamic seal during the axial movement of the guide impeller and preventing mud from entering the rear chamber.

[0015] Preferably, a guide wheel cap is provided at the front end of the outer cylinder shell. The guide wheel cap is fixedly installed at the mud inlet of the outer cylinder shell and is fixedly connected to the guide impeller. The guide wheel cap is used to regulate the direction of the incoming flow at the front end and to provide protection for the internal parts.

[0016] Preferably, the shape memory alloy part generates a continuous axial elongation or contraction in relation to temperature under different heating powers of the heater. The real-time temperature of the shape memory alloy part is collected by the temperature sensor and fed back to an external controller. The external controller adjusts the heating power of the heater to achieve closed-loop continuous adjustment of the axial working distance between the guide impeller and the turbine, thereby enabling stepless control of the output speed and output power of the drive shaft.

[0017] Compared with the prior art, the present invention has the following beneficial effects: This invention, through a fixed connection bracket and drive shaft, drives only the less massive guide impeller and guide cap axially, significantly reducing the driving force required for the adjustment mechanism and improving the response speed of the shape memory alloy parts. Since the moving parts do not involve rotating components, there is no need for slip ring brush assemblies, thoroughly simplifying the electrical connection structure, reducing the failure rate, and avoiding the erosion and wear of the rotating dynamic seal by high-pressure mud, further enhancing the reliability of the mechanism in downhole operation.

[0018] This invention uses a permanent magnet drive assembly and a driven permanent magnet end to achieve non-contact power transmission, eliminating the rotary dynamic seal structure at the drive shaft. Combined with the mud self-lubrication method of the self-slip bearing, it eliminates the risk of mud leakage caused by dynamic seal wear, which is conducive to improving the long-term operational reliability of the mechanism in harsh downhole environments.

[0019] The adjustment mechanism of this invention is fully integrated inside the outer shell, eliminating the need for external hydraulic lines or additional drive motors. The shape memory alloy part itself is an integral structure with no moving gaps, thus avoiding the problem of particle intrusion and blockage. It has a compact structure, strong resistance to mud blockage, and good adaptability to limited downhole spaces.

[0020] This invention uses a temperature sensor to collect the temperature of the shape memory alloy component in real time and feeds it back to the controller, enabling closed-loop regulation of the heater's heating power and achieving precise control of the turbine displacement. Simultaneously, the slip ring brush assembly provides a reliable power supply and signal transmission channel for the internal heater and temperature sensor during rotation, supporting remote control and status monitoring of the mechanism.

[0021] All functional components of this invention are integrated inside the outer shell, allowing for installation and use without significant modifications to existing downhole drilling tool structures, thus exhibiting excellent field adaptability. Shape memory alloys, permanent magnets, and self-lubricating bearings are all mature industrial products with controllable manufacturing costs, demonstrating good economic viability and scalability. Attached Figure Description

[0022] Figure 1 A schematic diagram of the A-flow inlet structure of a turbine power mechanism according to the present invention. Figure 2 A schematic diagram of the B-flow outlet structure of a turbine power mechanism according to the present invention.

[0023] Figure 3 A schematic diagram of the flow guide impeller and turbine of this invention.

[0024] Figure 4 A schematic diagram of the shape memory metal and heater of this invention.

[0025] Figure 5 A schematic diagram of the coupling transmission structure of the present invention.

[0026] Figure 6 A schematic diagram of the cross-sectional structure of the present invention.

[0027] 1. Guide impeller 2. Turbine 3. Permanent magnet coupling driving end 4. Permanent magnet coupling driven end 5. Self-slip bearing 6. Shape memory metal 7. Heater 8. Slip ring 9. Bearing 10. Housing 11. Drive shaft 12. Connecting bracket 13. Guide wheel cap 14. Sealing ring 15. Turbine stator joint. Detailed Implementation

[0028] The following will refer to the accompanying drawings in the embodiments of the present invention ( Figures 1 to 6 This document provides a clear and complete description of the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are merely a part of the embodiments of the present invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0029] In the description of this invention, the terms "axial," "radial," "front end," "rear end," "facing flow," and "back flow," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings or when the mechanism is operating normally. 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 "fixed connection," "rotatable connection," and "disposed of," etc., 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. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0030] like Figure 1 and Figure 2 As shown, the present invention provides an adjustable downhole turbine mechanism, which is fixedly installed inside the pipeline of the downhole drilling tool via an outer shell 10. The outer shell 10 is made of a non-magnetic material, preferably a non-magnetic titanium alloy or non-magnetic stainless steel, to prevent shielding or interference with the magnetic field of the internal permanent magnet drive components. To facilitate the assembly and maintenance of internal parts, the outer shell 10 preferably adopts a segmented assembly structure, with each segment being detachably fixedly connected by flanges and bolts, and O-rings are provided at the connection end faces to ensure overall sealing. The front end of the outer shell 10 has a mud inlet A, and the rear end has a mud outlet B. Drilling mud flows in through the inlet A, performs work inside the mechanism, and flows out through the outlet B.

[0031] The outer casing 10 has a guide cavity and a turbine mounting cavity coaxially arranged inside. A guide cap 13 and a guide impeller 1 are fixedly installed at the front end of the guide cavity. Figure 1 and Figure 3As shown, the guide vane 13 is located on the front side of the guide impeller 1, i.e., the front end. The guide vane 13 is fixedly connected to the guide impeller 1, and the outer periphery of the guide vane 13 is fixed to the inner wall of the outer cylinder shell 10. The guide vane 13 has a streamlined conical cap structure, and its function is to: firstly, rectify the mud fluid entering the mechanism, eliminate turbulence, and allow the fluid to enter the guide impeller 1 with a uniform flow velocity and direction; secondly, the guide vane 13 can provide physical protection for internal parts, preventing large rock fragments in the mud from directly impacting key parts and causing wear or damage. The blades of the guide impeller 1 are fixed at a set angle to adjust the flow direction of the mud fluid to an impact angle that matches the blades of the subsequent turbine 2. In this invention, the guide impeller 1, the guide vane 13, and the turbine stator joint 15 fixedly connected to the guide impeller 1 all remain stationary during operation and do not generate rotational motion.

[0032] like Figure 1 and Figure 5 As shown, a turbine 2 is rotatably mounted inside the turbine mounting cavity. The turbine 2 is located on the back flow side, i.e., behind, the guide impeller 1. The blades of the turbine 2 have a flow direction opposite to that of the blades of the guide impeller 1, so that the mud fluid guided by the guide impeller 1 acts on the blades of the turbine 2 at a set impact angle, forming a tangential rotational torque, driving the turbine 2 to rotate at high speed around its own axis.

[0033] The rear end of the turbine 2 is preferably fixedly connected to the active permanent magnet end 3 of the permanent magnet drive assembly via a spline or bolt, so that the turbine 2 and the active permanent magnet end 3 form an integral rotating unit. The active permanent magnet end 3 has a cylindrical structure, and its inner wall or end face is embedded with N-pole and S-pole permanent magnets arranged alternately in the circumferential direction, preferably made of samarium cobalt magnets or neodymium iron boron magnets to withstand the high temperature environment downhole. A driven permanent magnet end 4 is coaxially arranged on the radial inner side of the active permanent magnet end 3, and a set air gap is maintained between the active permanent magnet end 3 and the driven permanent magnet end 4, and the two achieve non-contact magnetic coupling through the air gap magnetic field. The driven permanent magnet end 4 is also embedded with a permanent magnet corresponding to the active permanent magnet end 3, and the driven permanent magnet end 4 is preferably fixedly connected to the front end of the drive shaft 11 via a key or welding. When the active permanent magnet end 3 rotates, the magnetic field passes through the air gap and drives the driven permanent magnet end 4 and the transmission shaft 11 to rotate synchronously, thereby realizing the non-contact transmission of torque, completely eliminating the dynamic sealing structure, and fundamentally eliminating the risk of mud leakage along the transmission shaft 11.

[0034] The turbine 2 and the active permanent magnet end 3 form a single rotating unit, with radial and axial support provided by a self-lubricating bearing 5 disposed between them. The self-lubricating bearing 5 is preferably made of hard alloy material. During operation, the mud fluid enters the bearing gap and forms a hydrodynamic oil film, i.e., a mud film, during rotation, achieving self-lubrication without the need for additional lubricating media, thus adapting to the harsh working conditions of high temperature, high pressure, and high sand content in downhole environments.

[0035] The rear end of the drive shaft 11 is rotatably supported inside the connecting bracket 12 by a bearing 9. The bearing 9 is preferably a radial thrust combined bearing, which can simultaneously bear the radial and axial loads of the drive shaft 11. The rear end of the drive shaft 11 extends out of the connecting bracket 12 and serves as a power output end for connecting load equipment such as downhole generators and drilling tool actuators.

[0036] like Figure 1 , Figure 4 and Figure 6 As shown, the core adjustment component of this invention is a shape memory alloy part 6. The shape memory alloy part 6 is preferably made of a Ni-Ti based shape memory alloy with a two-way memory effect to adapt to the downhole temperature environment. The shape memory alloy part 6 has a tubular or columnar structure, preferably multiple columnar bars evenly distributed circumferentially, or it can be a single thin-walled cylinder.

[0037] One end of the shape memory alloy part 6 is threadedly connected to the turbine stator joint 15, which is integrally connected to the fixed guide impeller 1. Therefore, the front end of the shape memory alloy part 6 is relatively stationary in the axial direction. The other end of the shape memory alloy part 6 is also threadedly connected to the axially movable connecting bracket 12. The connecting bracket 12 is an annular bracket structure, and a sealing ring 14 is provided between its outer circumferential surface and the inner wall of the outer cylinder shell 10. The sealing ring 14 is preferably a Glyd ring or a V-shaped combination sealing ring, which can maintain good dynamic sealing performance during the axial movement of the connecting bracket 12, preventing external high-pressure mud from seeping into the bearing chamber and slip ring electrical connection area inside the mechanism through the fitting gap.

[0038] A heater 7 and a temperature sensor are attached or abutted near the shape memory alloy part 6. The heater 7 is preferably a resistance wire heater or a PTC ceramic heater, which wraps around or is attached to the outer surface of the shape memory alloy part 6 for controllable heating. The temperature sensor is preferably a thermocouple or a Pt100 platinum resistance temperature sensor, with its sensing end embedded in or in close contact with the surface of the shape memory alloy part 6, for real-time acquisition of the current temperature of the shape memory alloy part 6, providing feedback signals for closed-loop temperature control.

[0039] Since the drive shaft 11 rotates at high speed during operation, and power supply and signal transmission to the heater 7 and temperature sensor require connecting wires, the present invention assembles a slip ring brush assembly 8 on the drive shaft 11. Specifically, a hollow cylindrical cavity extending axially is formed between the shape memory alloy part 6, the connecting bracket 12, and the drive shaft 11. The wires of the heater 7 and the temperature sensor are led out to the external controller through a flexible cable channel or spiral cable reserved inside the outer shell 10.

[0040] The working method and power regulation principle of this invention are as follows: Drilling mud enters the mechanism through mud inlet A. It first passes through guide vane cap 13 for rectification, eliminating turbulence. Then, it flows through guide impeller 1, where its fixed blades adjust it into a swirling flow at a specific angle. The swirling mud impacts the blades of turbine 2. Because the guide impeller 1 and turbine 2 blades have opposite flow directions, the mud generates a tangential impact force on the turbine 2 blades, creating a rotational torque that drives turbine 2 to rotate. Turbine 2 drives the active permanent magnet end 3 to rotate synchronously. The active permanent magnet end 3 drives the driven permanent magnet end 4 and the drive shaft 11 to rotate in the same direction through the air gap magnetic field. Finally, mechanical power is output outward from the rear end of the drive shaft 11.

[0041] In this initial state, the axial working distance between the guide impeller 1 and the turbine 2 is the design rated distance. At this time, the turbine 2 can capture the kinetic energy of the mud fluid to the maximum extent and output rated torque and power.

[0042] When it is necessary to reduce the output power to adapt to light downhole operating conditions, the external controller issues a command to energize the heater 7 through the slip ring brush assembly 8. The heater 7 begins to heat up and heats the shape memory alloy part 6. When the temperature of the shape memory alloy part 6 rises above its phase transformation temperature point Af, the shape memory alloy undergoes a reverse phase transformation from martensite to austenite, generating a shape memory effect and elongating along the axial direction.

[0043] Since the connecting bracket 12 is fixed to the inner wall of the outer cylinder shell 10, the rear end of the shape memory alloy part 6 remains stationary in the axial direction, while the front end of it, which is fixed to the guide impeller 1, will extend towards the front end when heated and elongated, pushing the guide impeller 1 and the guide wheel cap 13 as a whole assembly to move axially towards the rear end, that is, towards the direction closer to the turbine 2.

[0044] During this process, the seal 14 between the outer circumferential surface of the guide impeller 1 and the inner wall of the outer cylinder shell 10 maintains a dynamic seal; while the axial positions of the turbine 2, the active permanent magnet end 3, the driven permanent magnet end 4, and the drive shaft 11 remain fixed.

[0045] After the guide impeller 1 moves backward, the axial working distance between it and the turbine 2 decreases. Throughout the displacement process, the self-slip bearing 5 continuously provides rotational support, the sealing ring 14 maintains a dynamic seal, and the slip ring brush assembly 8 continuously provides electrical connection to the heater 7 and the temperature sensor.

[0046] This axial displacement directly increases the axial working distance between the guide impeller 1 and the turbine 2. Since the position of the guide impeller 1 remains fixed, as the turbine 2 moves backward away from the guide impeller 1, the slurry fluid flowing from the guide impeller 1 has a longer diffusion path before reaching the turbine 2 blades. This results in a decrease in both the fluid's impact velocity and impact angle, thus reducing the tangential torque impacting the turbine 2 blades. According to fluid dynamics principles, the turbine input torque is proportional to the square of the fluid impact velocity. Therefore, with the increased distance, the output torque and speed of the turbine 2 decrease significantly, and the output power of the drive shaft 11 decreases accordingly.

[0047] When it is necessary to restore or increase the output power, the external controller reduces or cuts off the power supply current to the heater 7. The shape memory alloy part 6 gradually decreases in temperature under natural cooling or forced convection cooling by slurry fluid. When the temperature drops below the martensitic transformation temperature, the shape memory alloy undergoes a reverse austenite-to-martensite transformation and shrinks axially to return to its initial length.

[0048] When the shape memory alloy part 6 retracts, it pulls the connecting bracket 12 and the entire internal suspension assembly connected to it, including the turbine 2, the active permanent magnet end 3, the driven permanent magnet end 4, the drive shaft 11, etc., to move back to the front end. The axial distance between the guide impeller 1 and the turbine 2 gradually decreases and returns to the initial rated distance. At this time, the impact of the mud fluid on the turbine 2 blades is enhanced, and the output torque, speed and power are restored and increased to the rated values.

[0049] By continuously adjusting the heating power of heater 7 through an external controller and combining it with the real-time temperature signal of shape memory alloy part 6 fed back by a temperature sensor, closed-loop precise control of the elongation of shape memory alloy part 6 can be achieved. Since the elongation of shape memory alloy is approximately linearly related to temperature within the phase transition range, the axial working distance between guide impeller 1 and turbine 2 can be continuously and steplessly varied between the rated minimum and maximum distance by controlling the heating power, thereby achieving smooth and stepless adjustment of the output speed and output power of drive shaft 11.

[0050] The embodiments of the present invention are given for the purposes of illustration and description. Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A downhole adjustable turbine-while-drilling mechanism, comprising an outer casing (10), a guide impeller (1) and a turbine (2) disposed inside the outer casing (10), and a drive shaft (11) for outputting rotational power, characterized in that, Also includes: A permanent magnet drive assembly includes an active permanent magnet end (3) and a driven permanent magnet end (4) arranged coaxially and radially spaced apart. The active permanent magnet end (3) is fixedly connected to the turbine (2) to rotate synchronously with it. The driven permanent magnet end (4) is fixedly connected to the drive shaft (11). The active permanent magnet end (3) and the driven permanent magnet end (4) achieve non-contact torque transmission through magnetic coupling. A shape memory alloy drive assembly includes a shape memory alloy part (6), a heater (7), and a temperature sensor for detecting the temperature of the shape memory alloy part (6). The connecting bracket (12) is fixedly installed on the inner wall of the outer cylinder shell (10). The connecting bracket (12) rotatably supports the rear end of the drive shaft (11) through a bearing (9), so that the turbine (2), the active permanent magnet end (3), the driven permanent magnet end (4), and the drive shaft (11) are axially fixed relative to the outer cylinder shell (10). The guide impeller (1) is slidably disposed inside the outer cylinder shell (10) along the axial direction, and the guide wheel cap (13) is fixedly connected to the guide impeller (1) and moves synchronously along the axial direction; One end of the shape memory alloy part (6) is fixedly connected to the connecting bracket (12), and the other end of the shape memory alloy part (6) is fixedly connected to the guide impeller (1) or the guide wheel cap (13). The shape memory alloy part (6) generates axial extension and retraction displacement under the heating excitation of the heater (7), which pushes the guide impeller (1) and the guide wheel cap (13) to move axially and reciprocally relative to the turbine (2), thereby changing the axial working distance between the guide impeller (1) and the turbine (2).

2. The downhole adjustable turbine mechanism according to claim 1, characterized in that, The turbine (2) and the active permanent magnet end (3) are integrated rotating units, and their radial support is provided by a self-slip bearing (5) located between them. The self-slip bearing (5) operates by mud self-lubrication.

3. The downhole adjustable turbine mechanism according to claim 1, characterized in that, One end of the shape memory alloy part (6) is fixedly installed on the turbine stator joint (15) by a threaded fastening structure, and the turbine stator joint (15) is fixedly connected to the guide impeller (1) as a whole; the other end of the shape memory alloy part (6) is fixedly installed on the connecting bracket (12) by a threaded fastening structure.

4. The downhole adjustable drilling turbine mechanism according to claim 1, characterized in that, The heater (7) is a resistance heating element, which is attached to or adjacent to the outer surface of the shape memory alloy part (6).

5. The downhole adjustable turbine mechanism according to claim 1, characterized in that, The shape memory alloy part (6) is a tubular or columnar structure. A hollow cavity extending along the axial direction is formed between the connecting bracket (12) and the transmission shaft (11). The hollow cavity is used to accommodate the heater (7) and the wires of the temperature sensor.

6. The downhole adjustable turbine mechanism according to claim 1, characterized in that, The outer shell (10) is made of non-magnetic titanium alloy or non-magnetic stainless steel. The outer shell (10) is a segmented assembly structure, and the segments are detachably fixed together by flanges and bolts.

7. The downhole adjustable drilling turbine mechanism according to claim 1, characterized in that, The blades of the guide impeller (1) have a circumferential angle difference with the blades of the turbine (2).

8. The downhole adjustable turbine mechanism according to claim 1, characterized in that, The sealing element (14) is disposed at the fitting gap between the outer peripheral surface of the guide impeller (1) and the inner wall surface of the outer cylinder shell (10).

9. The downhole adjustable turbine mechanism according to claim 1, characterized in that, The outer cylinder shell (10) is provided with a guide wheel cap (13) at the front end. The guide wheel cap (13) is fixedly installed at the mud inlet (A) of the outer cylinder shell (10), and the guide wheel cap (13) is fixedly connected to the guide impeller (1).

10. The downhole adjustable turbine drilling mechanism according to any one of claims 1 to 9, characterized in that, The shape memory alloy part (6) generates a continuous axial elongation or contraction that corresponds to the temperature under different heating powers of the heater (7).

Images