A downhole dual-source driving distributed power supply system for drilling while measuring and a running method thereof

Abstract

The present disclosure provides a downhole dual-source driving distributed power supply system while drilling and a running method thereof, the system comprising: an external shell extending in an axial direction; a vortex street generating unit, a piezoelectric vibration energy harvesting unit and a distributed energy storage unit arranged in the external shell in an axial direction; the piezoelectric vibration energy harvesting unit comprising an internal shell, a base beam and a piezoelectric strain gauge; the outer wall of the internal shell is fixedly connected with the inner wall of the external shell; the fixed ends of a plurality of base beams are fixedly connected with the inner wall of the internal shell in a uniform manner in a circumferential direction, and the free ends have an inclination angle with the axis, for providing a flow-through space for drilling fluid; the piezoelectric strain gauges are loaded on the base beams; when the drilling tool is drilling and the drilling fluid is impacting, the base beams are used for receiving mechanical energy generated by drilling vibration and kinetic energy generated by vortex street disturbance, and the piezoelectric strain gauges are used for converting the mechanical energy and the kinetic energy into electric energy. During drilling, the electric energy is continuously generated with the continuous vibration of the drilling tool and the continuous impact of the drilling fluid, so as to realize the distributed collection and continuous supply of downhole electric energy.

Description

Technical Field

[0001] This invention relates to the field of downhole power supply technology, and in particular to a downhole dual-source driven distributed power supply system while drilling and its operation method. Background Technology

[0002] Logging while drilling (LoWWD) technology plays a crucial role in oil exploration and production, serving as the primary means of acquiring formation information and real-time drilling data. Due to the complex environment downhole characterized by high temperature, high pressure, and strong vibration, a stable, adaptable, and long-lasting power supply is required to ensure safe oil production and the normal operation of LoWWD instruments and equipment.

[0003] Currently, the main power supply methods include wired transmission, turbine generators, and high-temperature lithium batteries, which can meet the power requirements of different measuring instruments. However, all of these power supply methods have certain limitations, which are summarized as follows:

[0004] (1) Wired power transmission cables are prone to breakage when rotated, making them unusable in ultra-deep and large inclined wells;

[0005] (2) The power supply structure of mud turbine generators is complex and easily damaged, and cannot be used in the middle of the drilling site;

[0006] (3) Lithium batteries have short and unstable power supply time, and pose safety hazards such as data loss and explosion.

[0007] The aforementioned problems have become the main bottlenecks restricting the development of logging-while-drilling technology, and have also brought many limitations to the development of deep mining and deep earth exploration.

[0008] In addition, existing power supply systems are mostly integrated, with concentrated loads, making it impossible to flexibly adjust the power supply according to different situations. Furthermore, a fault will cause the entire power supply system to fail. At the same time, the plug-and-play power supply mode cannot meet the power demand under non-drilling conditions. Summary of the Invention

[0009] To address the problems existing in the prior art, this invention provides a downhole dual-source driven distributed power supply system for drilling and its operation method. The system can be installed at any position on the drill pipe and used in conjunction with logging instruments. During drilling, it fully harvests energy generated by both drilling fluid impact and drill string vibration, thereby providing stable and continuous power to the logging instruments and equipment, extending the service life of downhole power supply equipment or avoiding frequent replacements. Simultaneously, multi-stage piezoelectric vibration energy harvesting units and multiple base beams of different sizes within these units expand the power generation capacity, and connection to a distributed energy storage unit ensures flexible storage and retrieval of electrical energy.

[0010] To achieve the above objectives, the present invention adopts the following technical solution:

[0011] In a first aspect, the present invention provides a downhole dual-source driven distributed power supply system for drilling, comprising:

[0012] An outer shell extending along the axial direction;

[0013] The vortex street generating unit, piezoelectric vibration energy harvesting unit, and distributed energy storage unit are arranged axially within the outer shell. The piezoelectric vibration energy harvesting unit includes an inner shell, base beams, and piezoelectric strain gauges. The outer wall of the inner shell is fixedly connected to the inner wall of the outer shell. The fixed ends of multiple base beams are uniformly fixed to the inner wall of the inner shell along the circumference, and the free ends have an inclination angle with the axis to provide flow space for drilling fluid. Piezoelectric strain gauges are loaded on the base beams. During drilling and drilling fluid impact, the base beams are used to bear the mechanical energy generated by drilling vibration and the kinetic energy generated by vortex street disturbance, and the piezoelectric strain gauges are used to convert the mechanical energy and kinetic energy into electrical energy.

[0014] Preferably, the vortex street generating unit includes a flow-around bluff body, a bluff body support frame, and a bluff body connecting frame;

[0015] The overall shape of the flow-around blunt body is a combination of a sphere and a cylinder. The flow-around blunt body is fixedly connected to the inside of the blunt body support frame. The blunt body connecting frame is evenly distributed between the inner wall of the blunt body support frame and the flow-around blunt body. The inner wall of the blunt body support frame is fixedly connected to one end of the blunt body connecting frame, and the outer wall is fixedly connected to the inner wall of the outer shell.

[0016] Preferably, after the upstream mud washes over the vortex street generating unit, a Karman vortex street is formed downstream, and the Karman vortex street generates a vortex street disturbance force perpendicular to the axis on the piezoelectric vibration energy harvesting unit.

[0017] Preferably, the two ends of the outer shell are fixedly connected to the upstream and downstream drilling tools, and generate axial vibration force with the drilling tools during drilling.

[0018] Preferably, the resultant force of the vortex street disturbance force and the axial vibration force acts on the piezoelectric strain gauge of the base beam.

[0019] Preferably, there are multiple piezoelectric vibration energy harvesting units, which are connected in series along the axial direction to form a piezoelectric annular stack.

[0020] Preferably, the plurality of base beams are of different sizes and are arranged sequentially along the circumference of the inner shell according to the external excitation frequency; piezoelectric strain gauges are loaded on the upper surface of the base beams, and the piezoelectric strain gauges are electrically connected to the distributed energy storage unit through wires.

[0021] Preferably, the distributed energy storage unit includes an energy management circuit and an energy storage management module;

[0022] The energy management circuit includes a rectifier circuit and a voltage doubler rectifier circuit. The rectifier circuit uses a multi-source input series synchronous switch circuit and a voltage doubler rectifier circuit. The multi-source input series synchronous switch circuit is used to realize real-time control and maximum power extraction of different piezoelectric vibration energy harvesting units at different times within a cycle. The voltage doubler rectifier circuit is used to amplify the circuit voltage and play a role in voltage stabilization.

[0023] The energy storage management module is used to provide power to the logging-while-drilling instruments.

[0024] Preferably, the downstream of the distributed energy storage unit is fixedly connected to a threaded end cap, and the threaded end cap is fixedly connected to a downstream drilling tool or measuring sub.

[0025] Secondly, the present invention provides an operation method for a downhole dual-source driven distributed power supply system while drilling, employing the downhole dual-source driven distributed power supply system while drilling described in the first aspect, comprising:

[0026] During drilling, the drilling fluid impacts the vortex street generating unit, generating a Karman vortex street, which in turn generates vortex street disturbance force on the piezoelectric vibration energy harvesting unit; the drill string drives the external shell to vibrate, generating axial vibration force on the piezoelectric vibration energy harvesting unit.

[0027] The piezoelectric vibration energy harvesting unit receives the resultant force of the vortex shedding force and the axial vibration force, converts it into electrical energy, and transmits the electrical energy to the distributed energy storage unit through the wire;

[0028] Distributed energy storage units manage, coordinate, store, and integrate received electrical energy to provide power for logging-while-drilling instruments and wireless repeaters.

[0029] Compared with the prior art, the beneficial effects of this disclosure are as follows:

[0030] (1) The present invention provides a downhole dual-source driven distributed power supply system for drilling, which can be applied in the field of oil drilling, such as logging-while-drilling technology, and used in conjunction with logging instruments to realize the collection and utilization of downhole energy. During the drilling process, multiple series-connected piezoelectric vibration energy harvesting units are used to convert drilling fluid impact and drill pipe vibration into usable electrical energy. This electrical energy is continuously generated with the continuous vibration of the drill string and the continuous impact of the drilling fluid during the drilling process, overcoming the shortcomings of wired power supply methods and achieving a continuous supply of downhole power. Thus, while ensuring the normal operation of the logging-while-drilling system, the potential of downhole environmental energy is fully utilized, developing a new green and low-carbon downhole power supply model, and providing new ideas, technologies, and methods for solving the power supply problem of logging-while-drilling instruments.

[0031] (2) The dual-energy redundant design fully utilizes the existing resources provided by the drilling conditions themselves to ensure sufficient power for use and a certain amount of stored power; on the other hand, it effectively avoids the drawback of power supply cut-off when either energy source cannot be generated due to drill string vibration or drilling fluid impact.

[0032] (3) The present invention provides a downhole dual-source driven distributed power supply system for drilling, which can adjust the number level of the piezoelectric vibration energy harvesting unit, as well as the structural size and number of the base beam, according to the power supply requirements of the measurement sensing equipment, so that the piezoelectric annular stack formed by it can achieve the matching power of the measurement sub, and realize the real-time monitoring of drill pipe vibration, stress state, formation information and other data.

[0033] (4) The present invention provides a downhole dual-source driven distributed power supply system for drilling, wherein the distributed energy storage unit is connected to each piezoelectric vibration energy harvesting unit to realize the management, coordination, storage and integration of the electrical energy generated by the piezoelectric vibration energy harvesting unit; on the one hand, it provides power for logging-while-drilling instruments and equipment and wireless repeaters, etc.; on the other hand, the stored electrical energy can also provide continuous power for measuring sensors in non-drilling conditions, avoiding the problem of periodically replacing lithium batteries.

[0034] (5) The present invention provides a downhole dual-source driven distributed power supply system for drilling, which serves as hardware support and data transmission platform for logging data. It has a simple structure, can be distributed and installed at appropriate locations on the drill pipe, and its location is not limited. It can move with the drill pipe to any location downhole to realize distributed collection and utilization of electrical energy. It can be installed near the wireless relay of the smart drill pipe to receive test signals from measurement sensors, realize signal transmission between adjacent repeaters, improve downhole data transmission efficiency, and improve the downhole distributed power generation network. Attached Figure Description

[0035] The accompanying drawings, which form part of this disclosure, are used to provide a further understanding of this disclosure. The illustrative embodiments of this disclosure and their descriptions are used to explain this disclosure and do not constitute a limitation thereof.

[0036] Figure 1 This is a schematic diagram of a downhole dual-source driven distributed power supply system for drilling provided in this disclosure;

[0037] Figure 2 This is a schematic diagram of a piezoelectric vibration energy harvesting unit;

[0038] Figure 3 Schematic diagram of vortex street generating unit device

[0039] Figure 4 This is a schematic diagram of the forces acting on the base beam under dual-source excitation.

[0040] Figure 5This is a schematic diagram illustrating the working principle of a downhole dual-source driven distributed power supply system for drilling.

[0041] Among them, 1-vortex street generating unit; 2-piezoelectric vibration energy harvesting unit; 3-outer shell; 4-distributed energy storage unit; 5-threaded end cap; 6-inner shell; 7-base beam; 8-piezoelectric strain gauge; 9-flow-around blunt body; 10-blunt body connecting frame; 11-blunt body support frame. Detailed Implementation

[0042] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0043] Example 1

[0044] like Figure 1 As shown, this embodiment discloses a downhole dual-source driven distributed power supply system for drilling, including: an outer casing 3 extending along the axial direction.

[0045] Both ends of the outer casing 3 can be threaded to the upstream and downstream drilling tools, thus enabling standardized installation at any position on the drill pipe and realizing a distributed power generation mode downhole. Inside the outer casing 3, a vortex street generating unit 1, a piezoelectric vibration energy harvesting unit 2, and a distributed energy storage unit 4 are arranged along the axial direction.

[0046] The outer shell 3 is composed of two semi-cylindrical shells with their arc axes overlapping, their cross sections aligned and fixedly connected, and their outer diameter matching the dimensions of the upstream and downstream drilling tools.

[0047] There are multiple piezoelectric vibration energy harvesting units 2, which are connected in series along the axis of the shell to form a piezoelectric annular stack. The piezoelectric vibration energy harvesting units 2 are electrically connected to each other. Multiple rectangular cross-section grooves are designed along the circumference of the inner wall of the outer shell 3 for fixed connection with the piezoelectric vibration energy harvesting units 2. Specifically, the diameter of the rectangular cross-section grooves matches the outer diameter of the piezoelectric vibration energy harvesting unit 2, and the width of the rectangular cross-section grooves matches the width of the piezoelectric vibration energy harvesting unit 2.

[0048] like Figure 2 As shown, the piezoelectric vibration energy harvesting unit 2 includes an inner shell 6, base beams 7, and piezoelectric strain gauges 8. The outer wall of the inner shell 6 is fixedly connected to the inner wall of the outer shell 3. The fixed ends of the multiple base beams 7 are wider and are uniformly fixed to the inner wall of the inner shell 6 along the circumference. The free ends have an inclination angle with the axis to provide flow space for drilling fluid. Piezoelectric strain gauges 8 are loaded on the base beams 7. When the drill bit is drilling and the drilling fluid is impacting, the base beams 7 are used to receive the mechanical energy generated by drilling vibration and the kinetic energy generated by vortex street disturbance. The piezoelectric strain gauges 8 are used to convert the mechanical energy and kinetic energy into electrical energy.

[0049] In this specific embodiment, such as Figure 3As shown, the vortex street generating unit 1 has threads on its surface, which are used to fix it to the upstream drill pipe. The vortex street generating unit 1 includes a flow-around blunt body 9, a blunt body support frame 11, and a blunt body connecting frame 10. The overall shape of the flow-around blunt body 9 is a combination of a sphere and a cylinder. The flow-around blunt body 9 is fixedly connected to the inner side of the blunt body support frame 11. The blunt body connecting frames 10 are evenly distributed between the inner wall of the blunt body support frame 11 and the flow-around blunt body 9. The inner wall of the blunt body support frame 11 is fixedly connected to one end of the blunt body connecting frame 10, and its outer wall is fixedly connected to the inner wall of the outer shell 3. The outer wall of the blunt body support frame 11 has threads, with its upstream end fixedly connected to the upstream drill pipe and its downstream end fixedly connected to the outer shell 3. This achieves functional positioning of the flow-around blunt body 9, thereby reasonably controlling the effective distance between the flow-around blunt body 9 and the downstream piezoelectric vibration energy harvesting unit 2 to generate a Karman vortex street.

[0050] During drilling, the high-speed flowing drilling fluid or mud washes over the flow-around blunt body 9, generating vortex streets and eddies in its downstream direction, causing periodic velocity fluctuations, affecting the fluid properties of the drilling fluid behind the flow-around blunt body 9, and generating vortex street disturbances in the piezoelectric vibration energy harvesting unit 2 downstream of it.

[0051] When a Karman vortex street occurs, vortices are generated and detached alternately. According to the flow characteristics formula behind the object during the formation of a Karman vortex street:

[0052]

[0053] Where Re is the Reynolds number, representing the flow characteristics behind the object; u0 is the incoming flow velocity; d is the cylinder diameter, related to the structural dimensions of the vortex shedding unit; and v is the kinematic viscosity of the mud. The vortex shedding frequency f (Hz) can be further calculated.

[0054]

[0055] Therefore, in order to further improve power generation efficiency, by optimizing the structural dimensions of the vortex street generating unit and the structural dimensions of each base beam in the piezoelectric energy harvesting unit, the natural frequency of the base beam and the vortex street shedding frequency are made consistent with the external excitation frequency applied to the shell, that is, the frequency corresponding to the vibration generated during the rock breaking process of the drill bit, thereby exciting the system to generate resonance, so that the base beam 7 generates the maximum bending strain and improves the electromechanical conversion efficiency of the piezoelectric strain gauge 8.

[0056] The structural dimensions (such as length) of the base beams 7 in the piezoelectric vibration energy harvesting unit 2 vary, resulting in different stiffness or natural frequencies. Based on the power requirements of the logging-while-drilling instruments, a specific number and series of base beams of specific lengths are selected according to the load power demand. These base beams are arranged circumferentially according to the external excitation frequency and fixedly installed in the internal housing 6. Since the multiple base beams arranged sequentially have different natural frequencies or resonant frequencies, they can adaptably meet the drilling conditions of different operating frequency bands, thereby widening the operating frequency band through distributed power generation of multiple base beams.

[0057] The piezoelectric strain gauge 8 is attached and fixed to the surface of the base beam 7 and installed close to the fixed end of the base beam 7 to ensure that the maximum strain generated after the free end of the base beam 7 is excited can be directly transmitted to the piezoelectric strain gauge 8, so that it has the maximum electrical response.

[0058] The base beam 7 is subjected to the coupled excitation of vortex street disturbance and drill string axial force, which causes the piezoelectric strain gauge 8 attached to the surface of the base beam 7 to produce periodic strain. In this way, the fluid kinetic energy of the high-speed flow of drilling fluid and the mechanical energy of the outer shell caused by the strong vibration of the drill pipe are converted into electrical energy by the piezoelectric vibration energy harvesting unit 2. Multiple piezoelectric vibration energy harvesting units 2 are stacked to form a piezoelectric ring stack, and their respective electrical energy is transmitted to the distributed energy storage unit 4 through wires for collaborative management, thereby improving the system's energy collection efficiency and power generation capacity.

[0059] Specifically, the free end of the base beam 7 has a certain inclination angle α with the axis of the outer shell 3 to reserve a certain space, ensuring that there is enough annular space in the middle of the inner shell 6 to provide a flow channel for drilling fluid, and ensuring that all the multi-stage piezoelectric vibration energy harvesting units 2 are excited to generate vibration.

[0060] like Figure 4 As shown, the selection of the inclination angle α needs to comprehensively consider the influence of factors such as drilling fluid flow velocity, inner diameter of the inner shell 6, length of the base beam 7, and structural dimensions of the flow-around blunt body 9. By reasonably selecting the inclination angle, the resultant force of the vortex street disturbance force generated by the flow-around blunt body 9 and the axial force generated by the drill string vibration is perpendicular to the surface of the base beam 7, thereby achieving the optimal force-to-electric conversion efficiency of the piezoelectric vibration energy harvesting unit 2 and improving the maximum power generation efficiency in the limited downhole space.

[0061] After the upstream mud washes over the vortex street generating unit 1, a Karman vortex street is formed. The corresponding vortex street disturbance force is represented by F1, which is perpendicular to the axial direction. Both the inner shell 6 and the outer shell 3 are fixedly connected to the drill string. The drill string generates strong vibrations during drilling, and the resulting axial vibration force is represented by F2. The resultant force F of the above two forces, F1 and F2, acts on the surface of the base beam 7.

[0062] The piezoelectric strain gauge 8 is fixed to the upper surface of the base beam 7 to receive the vibration signal generated by the beam 7 under the action of force F, converting mechanical energy into electrical energy. The positive and negative terminals of the piezoelectric strain gauge 8 are connected to wires. Multiple wiring gaps and holes are provided on the inner shell 6 to protect and fix the wires. The wires are arranged in the wiring gaps through the pre-drilled holes on the inner shell 6. The piezoelectric strain gauge 8 is electrically connected to the distributed energy storage unit 4 via wires, transmitting electrical energy to the distributed energy storage unit 4.

[0063] The output force-electric response characteristics of different piezoelectric strain gauges 8 vary greatly. In order to improve the overall power conversion efficiency of the piezoelectric vibration energy harvesting unit 2 and to coordinate the force-electric response of different piezoelectric vibration energy harvesting units 2, the distributed energy storage unit 4 adopts a multi-source input series synchronous switching circuit. It independently designs a maximum power point tracking control algorithm and a corresponding extreme value detection and control unit circuit to adapt to each input energy source. It performs real-time control of the input of different piezoelectric strain gauges 8 and utilizes the long open-circuit time of the series synchronous switching inductor circuit to achieve the maximum power extraction of different piezoelectric vibration energy harvesting units 2 at different times within one cycle.

[0064] Specifically, the distributed energy storage unit 4 includes an energy management circuit and an energy storage management module, which are integrated and fixed inside the distributed energy storage unit 4.

[0065] The energy management circuit includes a rectifier circuit and a voltage doubler rectifier circuit. The rectifier circuit employs a multi-source input series synchronous switching circuit and a voltage doubler rectifier circuit. The multi-source input series synchronous switching circuit enables real-time control and maximum power extraction of different piezoelectric vibration energy harvesting units at different times within a cycle. The voltage doubler rectifier circuit amplifies the circuit voltage and acts as a voltage stabilizer when external excitation is weak, such as when the drilling speed is low.

[0066] The energy storage module provides power to logging-while-drilling instruments, such as measurement sensors. Based on the maximum power point tracking algorithm, it adjusts the system's power output to the optimal state, making its actual output power close to the maximum output power.

[0067] The other end of the distributed energy storage unit 4 is fixedly connected to the threaded end cap 5. One end of the threaded end cap 5 has threads tapped on its inner wall surface, and is fixedly connected to the outer shell 3 through the threads. The other end has threads tapped on its outer wall surface, and is fixedly connected to the downstream drill rod or measuring sub through the threads.

[0068] like Figure 5 As shown, the working principle of this embodiment is as follows:

[0069] When the downhole dual-source driven distributed power supply system is working, the drilling fluid flows at high speed through the annular cavity inside the drill pipe. The rock breaking process of the drill string causes complex vibration behavior at different positions of the drill string, resulting in periodic relative motion between the drill string and the internal drilling fluid. The downhole dual-source driven distributed power supply system is fixedly connected to the drill string through the outer shell 3 and the threaded end cap 5, so that the system carries a certain amount of vibrational mechanical energy under the drive of the drill string.

[0070] As the drilling fluid flows through the internal cavity of the drill string, it first washes over the upstream vortex street generating unit 1. After flowing past the flow-around blunt body 9, it forms a Karman vortex street. The vortex street disturbance force generated by the shedding of the Karman vortex street periodically acts on the piezoelectric vibration energy harvesting unit 2. Under the coupled excitation of the vortex street disturbance force generated by the drilling fluid flow and the axial force generated by the vibration of the external shell, the base beam 7 generates forced vibration under the dual-source drive, quickly reaches the equilibrium position, and then performs periodic reciprocating motion. The piezoelectric strain gauge 8 is fixed to the upper surface of the fixed end of the base beam 7, receives the vibration signal generated by the base beam 7, and converts the mechanical energy into AC electrical energy through the piezoelectric material. The distributed energy storage unit 4 receives the electrical energy transmitted by each piezoelectric vibration energy harvesting unit 2, manages, coordinates, stores, and integrates the electrical energy, and provides continuous power to the logging-while-drilling instruments and wireless repeaters according to different operating conditions. It is understandable that the distributed energy storage unit's method of processing electrical energy is achievable with existing technology.

[0071] Because the downhole dual-source driven distributed power supply system provided in this embodiment is easy to install arbitrarily, and multiple piezoelectric vibration energy harvesting units 2 can be selectively set, the overall strategy of applying the downhole dual-source driven distributed power supply system provided in this embodiment to the downhole distributed power generation mode is summarized as follows:

[0072] (1) Distributed power generation using a single piezoelectric vibration energy harvesting unit:

[0073] For a single piezoelectric vibration energy harvesting unit 2, the base beams 7 of different lengths have different natural frequencies or resonant frequencies, adapting to multiple operating frequency bands corresponding to drill vibration. By employing a linear array structure with multiple base beams 7 of different structural parameters evenly distributed along the circumference, it is possible to superimpose multiple resonant frequencies and modes, forming a distributed power generation scheme for a single piezoelectric vibration energy harvesting unit 2. The open-circuit voltage v generated by a single base beam 7... p (t) can be calculated using the following formula:

[0074]

[0075] Among them, C p It is the internal capacitance of the strain gauge; R l It is external resistance; It is the electro-mechanical coupling coefficient, determined by the mode shape of the base beam; η r(t) represents the mechanical modal coordinates of the r-th order of the base beam.

[0076] (2) Distributed power generation using multi-stage piezoelectric vibration energy harvesting units:

[0077] For the piezoelectric ring stack formed by the multi-stage piezoelectric vibration energy harvesting units 2, the electrical response and energy output between different piezoelectric vibration energy harvesting units are transmitted to the distributed energy storage unit 4 through the positive and negative wires of the piezoelectric strain gauge 8 for coordinated management, thus widening the operating frequency band and achieving maximum power point tracking. The distributed energy storage unit 4 uses an internal integrated circuit to rectify and manage the signal and stores it in the energy storage module of the distributed energy storage unit 4. The voltage regulator circuit monitors the real-time output voltage and adjusts it to ensure that the output voltage is stable at the design state, thus solving the instability problem of the electrical signal generated by piezoelectric vibration.

[0078] When logging-while-drilling instruments and equipment require power, the distributed energy storage unit 4 supplies power through the power supply circuit and adjusts the output voltage in real time according to the maximum power point tracking algorithm to obtain the maximum output power.

[0079] Meanwhile, since the distributed energy storage unit 4 can store electrical energy, it can also continuously supply power to related equipment in non-drilling conditions.

[0080] (3) Distributed installation of power supply system:

[0081] By connecting the threaded end cap 5 and the blunt body support frame 11 of the distributed power supply system provided in this embodiment to the drill pipe thread, standardized installation at any position of the downhole drill pipe can be achieved. The system can be installed near the drill bit or drill collar, at any position in the middle of the drill pipe, or near the wireless relay of the smart drill pipe, etc. It can also be used in combination with the measuring sub of the logging equipment, so as to follow the logging equipment to any position downhole and continuously supply power to the relevant equipment.

[0082] Distributed power supply overcomes the drawbacks of centralized power supply, which is susceptible to failure and can lead to the overall paralysis of the power supply system, thus ensuring a stable power supply. Furthermore, the power supply system provided in this embodiment has no external wiring, will not interfere with normal drilling operations, has high safety, occupies little space, has flexible installation location, and is simple and convenient to operate.

[0083] This embodiment provides a downhole dual-source driven distributed power supply system for drilling, which can be applied in the field of oil drilling, such as logging-while-drilling technology, and used in conjunction with logging instruments to realize the collection and utilization of downhole energy. During the drilling process, multiple series-connected piezoelectric vibration energy harvesting units are used to convert drilling fluid impact and drill string vibration into usable electrical energy. This electrical energy is continuously generated with the continuous vibration of the drill string and the continuous impact of the drilling fluid during drilling, overcoming the shortcomings of wired power supply methods. This achieves distributed collection and continuous supply of downhole electrical energy, solving the significant deficiencies of existing downhole power supply methods and filling the gaps in the fundamental theories of downhole mud-drill string coupled excitation vibration.

[0084] Example 2

[0085] like Figure 5 As shown, this embodiment provides an operation method for a downhole dual-source driven distributed power supply system while drilling, employing the downhole dual-source driven distributed power supply system while drilling described in Embodiment 1, including:

[0086] During drilling, the drilling fluid impacts the vortex street sound-generating unit, generating a Karman vortex street, which in turn generates vortex street disturbance force on the piezoelectric vibration energy harvesting unit; the drill string drives the external shell to vibrate, generating axial vibration force on the piezoelectric vibration energy harvesting unit.

[0087] The piezoelectric vibration energy harvesting unit receives the resultant force of the vortex shedding force and the axial vibration force, converts it into electrical energy, and transmits the electrical energy to the distributed energy storage unit through the wire;

[0088] Distributed energy storage units manage, coordinate, store, and integrate received electrical energy to provide power for logging-while-drilling instruments and wireless repeaters.

[0089] This specific embodiment provides an operation method for a downhole dual-source driven distributed power supply system while drilling. It utilizes multiple series-connected piezoelectric vibration energy harvesting units to convert drilling fluid impact and drill pipe vibration into usable electrical energy. The electrical energy can be continuously generated with the continuous vibration of the drill string and the continuous impact of the drilling fluid during the drilling process. The distributed energy storage unit manages and stores the electrical energy to ensure that electrical energy can still be provided in non-drilling conditions, thereby realizing the distributed and continuous supply of downhole power.

[0090] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. 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 dual-source driven distributed power supply system for drilling, characterized in that, include: An outer shell extending along the axial direction; The vortex street generating unit, piezoelectric vibration energy harvesting unit, and distributed energy storage unit are arranged axially within the outer shell. The piezoelectric vibration energy harvesting unit includes an inner shell, base beams, and piezoelectric strain gauges. The outer wall of the inner shell is fixedly connected to the inner wall of the outer shell. The fixed ends of multiple base beams are uniformly fixed to the inner wall of the inner shell along the circumference, and the free ends have an inclination angle with the axis to provide flow space for drilling fluid. Piezoelectric strain gauges are loaded on the base beams. During drilling and drilling fluid impact, the base beams are used to bear the mechanical energy generated by drilling vibration and the kinetic energy generated by vortex street disturbance, and the piezoelectric strain gauges are used to convert the mechanical energy and kinetic energy into electrical energy.

2. The downhole dual-source driven distributed power supply system for drilling as described in claim 1, characterized in that, The vortex street generating unit includes a flow-around bluff body, a bluff body support frame, and a bluff body connecting frame; The overall shape of the flow-around blunt body is a combination of a sphere and a cylinder. The flow-around blunt body is fixedly connected to the inside of the blunt body support frame. The blunt body connecting frame is evenly distributed between the inner wall of the blunt body support frame and the flow-around blunt body. The inner wall of the blunt body support frame is fixedly connected to one end of the blunt body connecting frame, and the outer wall is fixedly connected to the inner wall of the outer shell.

3. The downhole dual-source driven distributed power supply system for drilling as described in claim 1, characterized in that, After the upstream mud washes over the vortex street generating unit, a Karman vortex street is formed downstream. The Karman vortex street generates a vortex street disturbance force perpendicular to the axis on the piezoelectric vibration energy harvesting unit.

4. The downhole dual-source driven distributed power supply system for drilling as described in claim 3, characterized in that, The outer shell is fixedly connected to the upstream and downstream drilling tools at both ends, and generates axial vibration force with the drilling tools during drilling operations.

5. A downhole dual-source driven distributed power supply system for drilling as described in claim 4, characterized in that, The combined force of the vortex street disturbance and the axial vibration force acts on the piezoelectric strain gauge of the base beam.

6. The downhole dual-source driven distributed power supply system for drilling as described in claim 1, characterized in that, The piezoelectric vibration energy harvesting unit is multiple, and the multiple piezoelectric vibration energy harvesting units are connected in series along the axial direction to form a piezoelectric annular stack.

7. A downhole dual-source driven distributed power supply system for drilling as described in claim 1, characterized in that, The multiple base beams are of different sizes and are arranged sequentially along the circumference of the inner shell according to the external excitation frequency; piezoelectric strain gauges are loaded on the upper surface of the base beams, and the piezoelectric strain gauges are electrically connected to the distributed energy storage unit through wires.

8. The downhole dual-source driven distributed power supply system for drilling as described in claim 1, characterized in that, The distributed energy storage unit includes an energy management circuit and an energy storage management module; The energy management circuit includes a rectifier circuit and a voltage doubler rectifier circuit. The rectifier circuit uses a multi-source input series synchronous switch circuit and a voltage doubler rectifier circuit. The multi-source input series synchronous switch circuit is used to realize real-time control and maximum power extraction of different piezoelectric vibration energy harvesting units at different times within a cycle. The voltage doubler rectifier circuit is used to amplify the circuit voltage and play a role in voltage stabilization. The energy storage management module is used to provide power to the logging-while-drilling instruments.

9. A downhole dual-source driven distributed power supply system for drilling as described in claim 1, characterized in that, The downstream of the distributed energy storage unit is fixedly connected to the threaded end cap, and the threaded end cap is fixedly connected to the downstream drilling tool or measuring sub.

10. A method for operating a downhole dual-source driven distributed power supply system while drilling, comprising the downhole dual-source driven distributed power supply system while drilling as described in any one of claims 1-9, characterized in that, During drilling, the drilling fluid impacts the vortex street generating unit, generating a Karman vortex street, which in turn generates vortex street disturbance force on the piezoelectric vibration energy harvesting unit; the drill string drives the external shell to vibrate, generating axial vibration force on the piezoelectric vibration energy harvesting unit. The piezoelectric vibration energy harvesting unit receives the resultant force of the vortex shedding force and the axial vibration force, converts it into electrical energy, and transmits the electrical energy to the distributed energy storage unit through the wire; Distributed energy storage units manage, coordinate, store, and integrate received electrical energy to provide power for logging-while-drilling instruments and wireless repeaters.

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