Self-driven along-drill-string measuring system based on friction nanometer generator

Abstract

The invention relates to the technical field of self-driven measurement-while-drilling tools, in particular to a self-driven measurement-while-drilling system based on a friction nano-generator. According to the technical scheme, the device comprises a friction nanometer generator, an energy management unit, a low-power-consumption wireless communication relay node and a ground control terminal, the friction nanometer generator is used for collecting vibration energy of a drill rod and converting the vibration energy into electric energy, and the friction nanometer generator is of a sliding type independent layer structure and comprises a rotor and a stator. The friction nanometer generator is deployed at each communication node, distributed self-driving is realized by using underground vibration energy, energy converted by the friction nanometer generator at the drill bit is enough to emit stronger communication signals, enough energy supply is ensured, the communication content and efficiency are enabled to be quickly responded, and the communication efficiency is improved. The information transmission technology with continuous power supply and low-power-consumption operation in the measurement while drilling process is developed, two-way communication of information is achieved, and remarkable engineering value is achieved for oil and gas resources difficult to exploit.

Description

Technical Field

[0001] The present invention relates to the technical field of self-driven measurement while drilling tools, and in particular to a self-driven measurement system along a drill string based on a friction nanogenerator. Background Art

[0002] In the exploration and development of oil and gas resources, measurement while drilling (MWD) technology is a key means of obtaining real-time downhole parameters such as well inclination, azimuth, tool face angle, temperature, pressure, and formation information. Traditional MWD systems rely primarily on battery power, downhole turbine power generation, or cable power supply, but these methods have significant drawbacks:

[0003] Battery power supply: High temperatures (>150°C) can easily cause battery capacity degradation, requiring frequent replacement, increasing maintenance costs and the risk of operational interruptions.

[0004] Turbine power generation: Relying on mud flow rate and viscosity, the mechanical structure is complex and prone to wear, making it difficult to adapt to small-diameter wellbore or deep well environments;

[0005] Cable power supply: The construction is complex and costly, and the cable is easily damaged by bending, stretching and friction underground.

[0006] In recent years, self-driving technology has become a research hotspot for solving underground energy supply problems, mainly including:

[0007] Turbine generator: Generates electricity through mud flow (Guo H et al., IET Electric Power Applications, 2013), but is sensitive to fluid parameters and has poor long-term reliability.

[0008] Piezoelectric generators: These use vibration to drive piezoelectric materials (e.g., ZnO nanowires, Wang ZL, Science, 2006). However, their output power is low (μW to mW), and their performance is susceptible to degradation in high-temperature environments.

[0009] Electromagnetic induction power generation: relies on magnetic field changes (Jiang D et al., Nano Energy, 2020), but requires large vibration drive, has a complex structure and is easily disturbed by the metal environment;

[0010] Thermoelectric power generation: This method uses underground temperature differences to generate electricity (Schnatzmeyer MA et al., Journal of Power Sources, 2004). However, the power density is low and the temperature difference is limited, making it difficult to meet the demand for continuous power supply.

[0011] Although triboelectric nanogenerators (TENGs) have shown potential in low-frequency vibration energy harvesting (Wang Zhonglin, NanoEnergy, 2013), existing technologies, such as the ring-shaped TENG proposed by Du T et al. (Advanced Materials Technologies, 2022), still have the following problems:

[0012] Insufficient energy supply stability: TENG output is affected by the material interface state and environmental humidity, and lacks efficient energy management strategies;

[0013] Low system integration: Existing solutions do not incorporate wireless communication technology and still require an external power supply to support data transmission;

[0014] Limited power density: The energy conversion efficiency is low under low-frequency vibration (1-10Hz), making it difficult to drive high-power sensors.

[0015] In summary, the existing self-driving technology cannot meet the requirements of downhole measurement systems for long-term stable energy supply, high data transmission rate and low-cost deployment. Therefore, this application proposes a self-driven along-drill string measurement system based on a friction nanogenerator. Summary of the Invention

[0016] The purpose of the present invention is to address the problem in the background technology that the existing self-driving technology cannot meet the requirements of the downhole measurement system for long-term stable energy supply, high data transmission rate and low-cost deployment, and to propose a self-driven along-drill string measurement system based on a friction nanogenerator.

[0017] The technical solution of the present invention is a self-driven along-drill string measurement system based on a triboelectric nanogenerator, comprising:

[0018] A triboelectric nanogenerator, deployed in the cavity of the drill pipe wall, is used to convert high-frequency, high-energy vibration energy downhole into electrical energy. The triboelectric nanogenerator adopts a sliding independent layer structure, including a mover and a stator. The mover surface is covered with copper foil, and the stator is composed of a plasma-treated polytetrafluoroethylene layer and copper electrodes.

[0019] An energy management and storage module, connected to the triboelectric nanogenerator, comprising a full-wave rectifier circuit, a high-temperature resistant capacitor energy storage unit, and a voltage stabilization circuit, for converting the high-voltage pulse power output by the triboelectric nanogenerator into a stable 3.3V DC power;

[0020] Low-power wireless communication relay nodes, each independently integrated with a triboelectric nanogenerator and an energy management storage module, are deployed on each drill pipe and include a CC1101 radio frequency module for wireless data transmission between adjacent drill pipes and an RS485 serial communication module for wired data transmission within the drill pipe. The CC1101 radio frequency module uses Gaussian frequency shift keying (GFSK) modulation technology and supports a data transmission rate of 115kbps.

[0021] A gamma-ray geosteering measurement module is integrated near the drill bit and is used to collect gamma-ray values, well inclination and azimuth data at the drill bit in real time, and upload the data to the ground control terminal through the relay node.

[0022] The ground control terminal receives and analyzes gamma data and well trajectory parameters in real time, and dynamically adjusts the drilling direction to ensure that the drill bit is located within the reservoir.

[0023] Optionally, the rotor of the friction nanogenerator adopts an FR-4 epoxy glass cloth laminate substrate with a thickness of 1.5-1.7 mm, preferably 1.6 mm, a surface copper foil thickness of 50 μm, and the polytetrafluoroethylene layer is plasma treated.

[0024] Optionally, the high-temperature resistant supercapacitor energy storage unit of the energy management storage module adopts a stacked structure with an operating temperature range of -40°C to 200°C. The high-frequency voltage stabilization circuit is configured with an undervoltage lockout mechanism, which automatically cuts off the load power supply when the input voltage is lower than 2.7V.

[0025] Optionally, the gamma-ray geosteering measurement module includes a scintillation crystal detector and a photomultiplier tube, with a sampling frequency ≥10 Hz and a measurement blind area ≤0.5 m, and is capable of identifying mud interlayers in real time and triggering wellbore trajectory adjustment instructions.

[0026] Optionally, the distribution density of the relay nodes is 3-5 per drill pipe to form a redundant communication network.

[0027] Optionally, the ground control terminal has a built-in geological modeling algorithm, which combines gamma data and well inclination to dynamically generate a three-dimensional wellbore trajectory map, and sends real-time adjustment instructions to the downhole steering tool through the relay node.

[0028] Optionally, the buffer layer of the friction nanogenerator uses a foam tape with a thickness of 1.5 mm to maintain interface contact pressure under high-frequency vibration.

[0029] Optionally, the data transmitted by the system includes near-bit gamma value, real-time well inclination, azimuth and formation lithology identification results, with a data upload delay of ≤100ms, which is used for dynamic tracking of reservoir boundaries during horizontal drilling.

[0030] Compared with the prior art, this application has at least one of the following beneficial technical effects:

[0031] 1. By deploying triboelectric nanogenerators at each communication node, the system leverages downhole vibration energy to achieve distributed self-drive, eliminating reliance on traditional batteries or external power supplies and significantly improving the stability and sustainability of energy supply. Adequate energy support enables the communication system to respond quickly and transmit data efficiently, resolving the communication delays and signal interruptions caused by insufficient energy in traditional measurement while drilling (MWD) operations. Furthermore, by combining optimized energy management with low-power communication technologies, the system maintains real-time, reliable signal transmission in complex downhole environments, providing instant data support for dynamic well trajectory adjustment and formation identification, significantly improving the accuracy and efficiency of drilling operations.

[0032] 2. TENG uses high-temperature resistant materials and optimized structure, and can operate stably for a long time under high temperature, high pressure and strong vibration environments, with an output power attenuation rate of less than 5%.

[0033] 3. Combining the low-power CC1101 radio frequency module with RS485 serial port communication, a wireless-wired hybrid transmission network is constructed. The data transmission rate is three orders of magnitude higher than that of traditional mud pulse telemetry, meeting the needs of high-precision real-time monitoring.

[0034] 4. The modular design allows the TENG network to be expanded on demand and can be embedded in the cavity of the drill pipe wall without interfering with drilling operations; distributed wireless relay nodes realize data cascade transmission and adapt to different well depths.

[0035] 5. TENG uses low-cost materials, and its manufacturing cost is much lower than that of turbine generators or cable power supply systems; its battery-free design reduces the risk of environmental pollution and is in line with the trend of green energy technology.

[0036] 6. The energy management unit converts the high-voltage, low-current output of TENG into stable direct current through ultracapacitor energy storage, switch voltage regulation, and undervoltage lockout mechanisms, ensuring that the sensor and communication module continue to operate reliably under power supply fluctuations.

[0037] This communication is achieved through the use of vibration-converting triboelectric nanogenerators, which are far more powerful than traditional energy sources and can be deployed on every communication node. Due to the sufficient energy supply, communication content and efficiency are relatively fast and responsive.

[0038] In summary, the present invention deploys a friction nanogenerator at each communication node and uses downhole vibration energy to achieve distributed self-drive. The energy converted by the friction nanogenerator at the drill bit is sufficient to transmit a stronger communication signal, ensuring sufficient energy supply, enabling rapid response of communication content and efficiency. It develops information transmission technology with continuous power supply and low power consumption during the measurement while drilling process, and realizes two-way communication of information, which has significant engineering value for difficult-to-exploit oil and gas resources. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 This is the overall architecture diagram of a self-driven along-drillstring measurement system based on a triboelectric nanogenerator;

[0040] Figure 2 This is an architectural diagram of a low-power wireless communication system;

[0041] Figure 3 This is a flowchart of downhole data transmission;

[0042] Figure 4 The figure summarizes the characteristics of different measurement while drilling information transmission technologies. DETAILED DESCRIPTION

[0043] The following is a detailed description of the specific embodiments of the present invention in conjunction with the accompanying drawings. It should be noted that the embodiments of the present invention are not limited thereto, and those skilled in the art can make reasonable adjustments within the scope of the technical concept of the present invention.

[0044] Embodiment: This embodiment provides a self-driven along-drill string measurement system based on a friction nanogenerator. The various parts of the system are described in detail below.

[0045] 1. Overall system architecture

[0046] like Figure 1 As shown, the self-driven along-drill-string measurement system of the present invention includes the following core modules:

[0047] Triboelectric nanogenerator (TENG): Deployed in the cavity of the drill pipe wall, it is used to convert the vibration energy of the drill pipe into electrical energy;

[0048] Energy management unit (EMU): connected to the TENG, used to rectify, store and stabilize electrical energy;

[0049] Low-power wireless communication relay node: integrated into each drill pipe, including CC1101 radio frequency module and RS485 serial communication module;

[0050] Ground control terminal: receives and processes data transmitted from underground;

[0051] Distributed sensor network: collects downhole parameters (tool face angle, well inclination angle, pressure, temperature, etc.).

[0052] 2. Specific implementation of triboelectric nanogenerator (TENG)

[0053] 2.1 Structural design

[0054] The TENG adopts a sliding independent layer structure, specifically comprising:

[0055] Mover (moving part): uses high-temperature resistant FR-4 epoxy glass cloth laminate (thickness 0.5mm) as the base material, and the surface is covered with copper foil (Cu) (thickness 50μm);

[0056] Stator (fixed part): composed of polytetrafluoroethylene (PTFE) membrane (thickness 100μm) and copper electrodes. The PTFE membrane is plasma treated to enhance the surface roughness and increase the triboelectric charge density.

[0057] 2.2 Working Mode

[0058] The vibration of the drill rod drives the mover to slide axially, causing the copper foil and PTFE membrane to periodically contact and separate, generating alternating current through triboelectric effect and electrostatic induction. At low-frequency vibrations of 1-10 Hz, a single TENG can achieve an open-circuit voltage of 300 V and a short-circuit current of 5 μA.

[0059] 3. Specific implementation of the Energy Management Unit (EMU), such as Figure 2 shown.

[0060] 3.1 Circuit Design

[0061] EMU includes the following functional modules:

[0062] Full-wave rectifier bridge: composed of four Schottky diodes (model 1N5819), converting the AC power output by the TENG into DC power;

[0063] Energy storage circuit: uses a 22mF supercapacitor (withstand voltage 400V) to store electrical energy, and smoothes the output voltage through a parallel tantalum capacitor (100μF / 35V);

[0064] Voltage stabilization circuit: Use the TPS62150 switching regulator to convert the voltage of the energy storage capacitor into a stable 3.3V DC power for the wireless communication module;

[0065] Undervoltage lockout (UVLO) mechanism: When the storage capacitor voltage is lower than 2.7V, the power supply is cut off to protect the system.

[0066] 4. Specific implementation of low-power wireless communication systems, such as Figure 3 shown.

[0067] 4.1 Hardware Configuration

[0068] CC1101 RF module: operates in the 433MHz frequency band, supports GFSK modulation, has a maximum transmit power of +10dBm, a receive sensitivity of -110dBm, and a data transmission rate of 115kbps;

[0069] RS485 serial communication module: uses MAX3485 chip, supports full-duplex communication, and has a transmission rate of 9.6kbps to 1Mbps;

[0070] Microcontroller: MSP430F5529 low-power MCU is used to manage data acquisition, caching, and routing.

[0071] 4.2 Data Transmission Protocol

[0072] Time Division Multiple Access (TDMA): Each relay node is allocated a fixed time window (e.g., 10ms) and sends data through CC1101 during the window period to avoid signal conflicts.

[0073] Data hierarchical routing:

[0074] Downhole sensor data is transmitted to the relay node inside the drill pipe via the RS485 bus;

[0075] The relay node transmits wirelessly to the relay node of the adjacent drill pipe via CC1101;

[0076] The data is uploaded to the ground control terminal step by step, forming a cascade transmission network.

[0077] 5. System deployment and operation example

[0078] Taking a 3,000-meter deep well as an example, the specific implementation steps are as follows:

[0079] TENG deployment: Three sets of TENG modules are embedded in the wall cavity of each drill pipe (9.5m in length) (more sets can be placed as needed);

[0080] Energy management unit integration: Each TENG group is connected to an independent EMU and outputs a stable 3.3V voltage;

[0081] Relay node configuration: One relay node is deployed in each drill pipe, including CC1101 module and RS485 bus interface;

[0082] Ground terminal connection: The ground control terminal receives data transmitted from the wellhead drill pipe wirelessly and displays parameters such as well inclination angle and tool face angle in real time.

[0083] 6. Technical effect verification

[0084] Through laboratory simulation tests (vibration frequency 5Hz, temperature 150℃), this system achieves the following performance:

[0085] Energy supply stability: The total output power of the TENG network reaches 6mW, which can continuously power the wireless communication module;

[0086] Data transmission rate: The end-to-end data transmission rate is stable at 115kbps, and the bit error rate is less than 10-6;

[0087] Environmental adaptability: After 500 hours of continuous operation under high temperature (200°C) and high pressure (100MPa) conditions, the output power attenuation rate of TENG was less than 5%.

[0088] The present invention is based on the TENG self-driven while-drilling communication system, which consists of self-driven while-drilling communication relay nodes deployed on each drill pipe. The number of deployed nodes is determined by the drill pipe specifications and drilling depth. Downhole data, such as tool face angle, well inclination, azimuth, and rock formation information, are collected by downhole measurement / logging while drilling instruments (MWD / LWD tools) and then transmitted to the ground control end through multiple self-driven while-drilling communication relay nodes. Each while-drilling communication relay node plays a connecting role. The ground control end then processes the data in a timely manner and transmits the command to the ground in the same way.

[0089] The present invention realizes distributed self-driving by deploying friction nanogenerators at each communication node and utilizing downhole vibration energy. The energy converted by the friction nanogenerator at the drill bit is sufficient to transmit a stronger communication signal, while others may only send a few kb of information due to their relatively low performance. For example, the data rate of the mud pulse telemetry technology currently commonly used in oil and gas production is only 5-40 bit / s. The self-driven downhole communication system based on friction nanogenerators, friction nanogenerators, energy management units and downhole communication relay nodes constitute relay nodes, and multiple relay nodes are distributed on each drill pipe to form a self-driven downhole communication system. During the downhole process, the self-driven downhole communication system can transmit information in both directions, and the data transmission rate is increased by 3 orders of magnitude compared with the traditional method. The energy transmission efficiency reaches 2.22J / bit. The transmission speed of other drill pipes is given in the figure below. Figure 4 As shown, ensuring sufficient energy supply enables rapid response of communication content and efficiency, developing information transmission technology with continuous power supply and low power consumption during measurement while drilling, and realizing two-way communication of information, which has significant engineering value for difficult-to-extract oil and gas resources.

[0090] The above specific embodiments are merely several optional embodiments of the present invention. Based on the technical solutions of the present invention and the relevant inspirations of the above embodiments, those skilled in the art may make various alternative improvements and combinations to the above specific embodiments.

Claims

1. A self-driven along-drillstring measurement system based on a triboelectric nanogenerator, characterized in that: include: A triboelectric nanogenerator, deployed in the cavity of the drill pipe wall, is used to convert high-frequency, high-energy vibration energy downhole into electrical energy. The triboelectric nanogenerator adopts a sliding independent layer structure, including a mover and a stator. The mover surface is covered with copper foil, and the stator is composed of a plasma-treated polytetrafluoroethylene layer and copper electrodes. An energy management and storage module, connected to the triboelectric nanogenerator, comprising a full-wave rectifier circuit, a high-temperature resistant capacitor energy storage unit, and a voltage stabilization circuit, for converting the high-voltage pulse power output by the triboelectric nanogenerator into a stable 3.3V DC power; Low-power wireless communication relay nodes, each independently integrated with a triboelectric nanogenerator and energy management storage module, are deployed on each drill pipe and include a CC1101 radio frequency module for wireless data transmission between adjacent drill pipes and an RS485 serial communication module for wired data transmission within the drill pipe. A gamma-ray geosteering measurement module is integrated near the drill bit and is used to collect gamma-ray values, well inclination and azimuth data at the drill bit in real time, and upload the data to the ground control terminal through the relay node. The ground control terminal receives and analyzes gamma data and well trajectory parameters in real time, and dynamically adjusts the drilling direction to ensure that the drill bit is located within the reservoir.

2. The self-driven along-drillstring measurement system based on a triboelectric nanogenerator according to claim 1, characterized in that: The rotor of the friction nanogenerator adopts an FR-4 epoxy glass cloth laminate substrate with a thickness of 1.5-1.7 mm, a surface copper foil thickness of 50 μm, and the polytetrafluoroethylene layer is treated with argon plasma.

3. The self-driven along-drill-string measurement system based on a triboelectric nanogenerator according to claim 1, characterized in that: The high-temperature resistant supercapacitor energy storage unit of the energy management storage module adopts a stacked structure with an operating temperature range of -40°C to 200°C. The high-frequency voltage stabilization circuit is equipped with an undervoltage lockout mechanism, which automatically cuts off the load power supply when the input voltage is lower than 2.7V.

4. The self-driven along-drill-string measurement system based on a triboelectric nanogenerator according to claim 1, characterized in that: The gamma-ray geosteering measurement module includes a scintillation crystal detector and a photomultiplier tube, has a sampling frequency of ≥10 Hz, a measurement blind area of ≤0.5 m, and can identify mud interlayers in real time and trigger wellbore trajectory adjustment instructions.

5. The self-driven along-drill-string measurement system based on a triboelectric nanogenerator according to claim 1, characterized in that: The distribution density of the relay nodes is 3-5 per drill pipe, forming a redundant communication network.

6. The self-driven along-drillstring measurement system based on a triboelectric nanogenerator according to claim 1, characterized in that: The ground control terminal has a built-in geological modeling algorithm, which dynamically generates a three-dimensional wellbore trajectory map by combining gamma data and well inclination angle, and sends real-time adjustment instructions to the downhole steering tool through the relay node.

7. The self-driven along-drill-string measurement system based on a triboelectric nanogenerator according to claim 1, characterized in that: The buffer layer of the friction nanogenerator uses a foam tape with a thickness of 1.5 mm to maintain interface contact pressure under high-frequency vibration.

8. The self-driven along-drill-string measurement system based on a triboelectric nanogenerator according to claim 1, characterized in that: The data transmitted by the system includes near-bit gamma value, real-time well inclination, azimuth and formation lithology identification results. The data upload delay is ≤100ms and is used for dynamic tracking of reservoir boundaries during horizontal drilling.

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