A downhole multi-parameter logging device

Abstract

The application discloses a downhole multi-parameter logging device and belongs to the technical field of logging while drilling, comprising a drill collar, a battery module and a circuit module are respectively arranged at the two ends of the inner cavity of the drill collar and are axially fixed through locking modules, a metal centralizer is fixedly arranged in the inner cavity of the drill collar, a plurality of independent centralizing blocks are arranged at the center of the metal centralizer, the drill collar comprises a drill collar body, an antenna housing, a strip-shaped magnetic core and a coil, and stable signal transmission is guaranteed, the battery module comprises annular batteries and butterfly springs, can be replaced on site and has a damping function, the circuit module comprises resistivity, azimuth gamma and inclination measurement modules, is integrally designed and has strong anti-interference performance, the metal centralizer realizes self-adaptive centralizing through centrifugal force and hydraulic damping, and the independent centralizing blocks can compensate temperature errors, the device is stable in structure, is suitable for complex well conditions, is convenient to maintain and can realize accurate and synchronous measurement of multiple parameters, thereby providing reliable data support for logging while drilling.

Description

Technical Field

[0001] This invention relates to the field of logging while drilling technology, and more specifically, to a downhole multi-parameter logging device. Background Technology

[0002] In the field of oil and gas exploration and development, logging while drilling (MWD) technology is a core technology for obtaining downhole formation and wellbore parameters in real time during the drilling process. It provides important data support for reservoir evaluation, wellbore trajectory control, and hydrocarbon determination, and is particularly suitable for complex well types such as horizontal wells, highly deviated wells, and deep wells. With the continuous increase in drilling workload for onshore horizontal and highly deviated wells, conventional wireline logging can no longer meet the requirements for real-time performance and adaptability. MWD and LWD systems have become indispensable core equipment in the field of oil drilling engineering. As a core component of the LWD system, the performance of downhole multi-parameter logging devices directly determines the accuracy of logging data, the stability of operations, and the convenience of maintenance.

[0003] Currently, traditional downhole multi-parameter logging devices suffer from numerous technical defects in practical applications, severely restricting the efficiency and quality of logging operations. Regarding the antenna and drill collar structure, traditional devices often employ a structure of "drill collar wound with a bottom layer of fiberglass – slotted enameled wire wound – a second layer of fiberglass wound – and a metal radome." This structure presents significant risks: the fiberglass has limited strength and is prone to collapse under high-pressure downhole conditions, directly causing damage to the enameled wire and resulting in instrument malfunction; the structure requires extremely high sealing, and inadequate sealing can lead to mud ingress, contaminating the coils and magnetic core, increasing maintenance difficulty; the fiberglass embedded in the radome window is susceptible to damage and failure due to long-term mud erosion and high temperatures, making radome replacement costly and cumbersome, impacting operational progress. Furthermore, the traditional drill collar material is prone to magnetic interference, affecting the accuracy of resistivity and other electromagnetic parameter measurements, making it unsuitable for high-precision logging requirements.

[0004] In terms of power supply and maintenance, the battery modules of traditional devices are mostly integrated fixed structures. After the battery is depleted, the entire instrument needs to be returned to the base for replacement by professional maintenance personnel. The round-trip transportation time is long and the labor cost is high, which seriously affects the rotation efficiency of the instruments on site and cannot meet the needs of rapid operation. Some devices use a single battery for power supply without redundancy backup. Battery failure can easily lead to loss of logging data and interruption of operation.

[0005] In terms of straightening performance, traditional drill collar straightening devices mostly adopt a fixed structure, making it difficult to eliminate straightening gaps. They also cannot adapt to changes in drill collar rotation speed and the high-temperature environment downhole. The severe vibrations generated when the drill collar rotates at high speed are easily transmitted to the battery module and circuit module through the device, leading to increased measurement errors and even causing component cracks or breaks. Some straightening devices are made of non-metallic materials, which have poor erosion and wear resistance. They are easily damaged by long-term mud erosion and cannot guarantee a long-term stable straightening effect. The flow channel design of the straightening device is unreasonable, resulting in poor mud flow, which easily leads to siltation and erosion wear, affecting the normal operation of the device. Summary of the Invention

[0006] 1. Technical problems to be solved

[0007] To address the problems existing in the prior art, the present invention aims to provide a downhole multi-parameter logging device that integrates resistance data measurement, azimuth gamma measurement, and well inclination measurement functions to meet the drilling resistivity monitoring needs of complex drilling scenarios such as horizontal wells and deep wells, and to provide technical support for oil and gas reservoirs.

[0008] 2. Technical Solution

[0009] To solve the above problems, the present invention adopts the following technical solution.

[0010] A downhole multi-parameter logging device includes a drill collar. A battery module and a circuit module are respectively installed at the left and right ends of the drill collar's inner cavity. The battery module and the circuit module are axially fixed by a locking module. A metal centralizer is also fixedly installed in the inner cavity of the drill collar. The metal centralizer is used to centralize the central axis at the end of the drill collar. Multiple circumferentially distributed independent centralizing blocks are installed at the center of the metal centralizer to eliminate centralizing gaps.

[0011] The drill collar includes a drill collar body, an antenna cover is fixedly fitted on the outer surface of the drill collar body, multiple sets of annular grooves are opened on the outer surface of the drill collar body, multiple circumferentially distributed windows are arranged in the annular grooves, a strip magnetic core is embedded in the window, and a coil is wound in the annular groove.

[0012] As a further improvement of the present invention, the battery module includes a spindle, on which two annular batteries are mounted, and an intermediate connecting disk is disposed between the two annular batteries, and the intermediate connecting disk is fixedly connected to the spindle.

[0013] As a further improvement of the present invention, a butterfly spring is installed on the mandrel, and the mandrel is anti-rotated by inserting an anti-rotation pin into a pin hole on the drill collar body. A guide head is fixedly installed at the end of the mandrel.

[0014] As a further improvement of the present invention, the circuit module includes a circuit core frame, on which a measuring module and a shock-absorbing ring are fixedly mounted. The circuit core frame is provided with a guide key and an anti-rotation pin. The guide key is inserted through a guide keyway on the drill collar body and anti-rotation is achieved by the anti-rotation pin.

[0015] As a further improvement of the present invention, a second guide head is fixedly installed at the end of the circuit core frame, and a second shock-absorbing ring is fixedly installed on the second guide head. The measurement module includes a resistivity measurement module, an azimuth gamma measurement module, and a near-end inclination measurement module.

[0016] As a further improvement of the present invention, the metal centralizer includes a pair of docking half-rings, the docking half-rings having multiple flow channels, and the pair of docking half-rings being fixed together as a ring by screws.

[0017] As a further improvement of the present invention, a pair of symmetrically distributed centrifugal chambers are provided near the outer edge of the inner cavity of the docking half-ring. An installation groove is provided at the center of the docking half-ring. The independent straightening block is slidably installed in the installation groove. A centrifugal counterweight is slidably installed in the centrifugal chamber. A limiting ring corresponding to the centrifugal counterweight is fixedly installed in the centrifugal chamber. The limiting ring is located in the inner direction of the centrifugal counterweight. A pre-tightening spring is fixedly installed between the centrifugal counterweight and the bottom wall of the centrifugal chamber. A T-shaped flow channel connects the installation groove and the pair of centrifugal chambers. A main piston is slidably installed at one end of the T-shaped flow channel near the centrifugal chamber. A secondary piston is slidably installed at one end of the T-shaped flow channel near the installation groove. The main piston is fixedly connected to the centrifugal counterweight. The secondary piston is fixedly connected to the independent straightening block.

[0018] As a further improvement of the present invention, hydraulic oil is filled between the main piston and the auxiliary piston, and a porous damping plate is fixedly installed at one end of the T-shaped flow channel near the mounting groove. The auxiliary piston is located between the porous damping plate and the independent straightening block.

[0019] As a further improvement of the present invention, the independent straightening block includes a base block, and a hidden groove is provided on the side of the base block away from the mounting groove. A matching fastening block is slidably installed in the hidden groove, and a thermal expansion bimetallic sheet is fixedly installed between the fastening block and the bottom wall of the hidden groove.

[0020] As a further improvement of the present invention, the outer surface of the locking module is provided with external threads, a sealing ring is provided at the end of the locking module near the battery module and the circuit module, and a slot is provided at the outer opening of the locking module.

[0021] 3. Beneficial Effects

[0022] Compared with the prior art, the advantages of this invention are:

[0023] (1) This device significantly improves the structural reliability and protection performance of downhole operations, effectively avoiding various hidden dangers of traditional structures. Compared with the traditional antenna structure that uses multi-layer fiberglass winding and metal radome with window, this device directly winds the coil around the circumference of the slotted drill collar and uses a ring radome welded to the drill collar body, which greatly simplifies the overall structure and provides maximum protection for the coil, avoiding problems such as collapse, enameled wire damage, and mud ingress caused by insufficient fiberglass strength and sealing failure. The ring design of the metal centralizer and the layout of the channel with the largest mud cross section reduce the scouring and loss of components by mud. The adaptive adjustment mechanism of the independent centralizer and the hydraulic damping shock absorption structure can effectively alleviate the adverse effects of downhole vibration and high temperature conditions, further ensuring the stable operation of the device in the harsh downhole environment.

[0024] (2) This device greatly simplifies the on-site operation and maintenance process and reduces maintenance and time costs. The battery module adopts a modular design and is easy to operate with the locking module. There is no need to return the instrument to the base or involve professional maintenance personnel. On-site personnel can directly pull out the battery module to complete the replacement, which significantly speeds up the rotation efficiency of the on-site instrument and solves the pain point of the cumbersome and time-consuming battery replacement process of traditional instruments. The circuit module adopts an integrated structure and is fixed and shock-absorbing through potting glue. The gamma sensor is designed with a multi-directional shock-absorbing protection structure, which not only facilitates daily maintenance but also reduces the probability of damage and replacement cost of vulnerable parts. At the same time, the simplification of the antenna structure also reduces the subsequent maintenance investment such as antenna cover replacement.

[0025] (3) This device effectively improves the measurement accuracy and continuity of logging data, ensuring the precision and efficiency of logging operations. The resistivity measurement section optimizes the module layout, placing the tuning function module close to the antenna to reduce signal attenuation, and embedding the core control module within the instrument core to avoid external interference, achieving stable and efficient signal transmission and reception. The azimuth gamma measurement section adopts a non-magnetic shell and alloy shielding layer design, effectively isolating external interference and ensuring detection accuracy. The near-end inclination measurement function of the inclination module solves the measurement lag problem, and continuous inclination measurement achieves fine control of the entire well section. Furthermore, the vibration-damping embedded installation method reduces the impact of vibration on the inclination data. In addition, the adaptive straightening structure effectively reduces measurement errors caused by vibration. With the synergistic effect of multiple modules, the accuracy, continuity, and reliability of the overall logging data are significantly improved. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the internal structure of the present invention.

[0027] Figure 2 This is a partial cross-sectional view of the battery module of the present invention.

[0028] Figure 3This is a partial cross-sectional view of the circuit module of the present invention.

[0029] Figure 4 This is a schematic diagram of the structure of the metal centralizer of the present invention.

[0030] Figure 5 This is a partial cross-sectional view of the locking module of the present invention.

[0031] Figure 6 This is a cross-sectional schematic diagram of the drill collar of the present invention.

[0032] Figure 7 This is a schematic diagram of the docking semi-ring structure of the present invention.

[0033] Figure 8 For the present invention Figure 7 Sectional view at point AA.

[0034] Figure 9 This is a schematic diagram of the disassembled structure of the independent straightening block of the present invention.

[0035] Figure 10 This is a schematic diagram of the external structure of the present invention.

[0036] Explanation of the labels in the diagram:

[0037] 1. Drill collar; 101. Drill collar body; 102. Antenna cover; 103. Bar magnetic core; 104. Coil; 2. Battery module; 201. Mandrel; 202. Toroidal battery; 203. Anti-rotation pin one; 204. Intermediate connecting plate; 205. Butterfly spring; 206. Guide head one; 3. Circuit module; 301. Circuit core frame; 302. Measurement module; 303. Shock-absorbing ring one; 304. Anti-rotation pin two; 305. Guide key; 306. Guide head two; 307. Shock-absorbing ring two; 4. Metal 401. Centralizer; 402. Connecting half-ring; 403. Flow channel; 404. Screw; 405. Centrifuge chamber; 406. Mounting slot; 407. Centrifugal counterweight; 408. Limiting ring; 409. Preload spring; 410. Main piston; 411. T-shaped flow channel; 412. Porous damping plate; 413. Secondary piston; 5. Locking module; 501. External thread; 502. Sealing ring; 503. Slot; 6. Independent centralizer; 601. Base block; 602. Thermal expansion bimetallic strip; 603. Adhesive block. Detailed Implementation

[0038] The following describes some embodiments of this application in detail with reference to the accompanying drawings.

[0039] Example 1: Please refer to Figures 1-6A downhole multi-parameter logging device includes a drill collar 1. A battery module 2 and a circuit module 3 are respectively installed at the left and right ends of the inner cavity of the drill collar 1. The battery module 2 and the circuit module 3 are axially fixed by a locking module 5. A metal centralizer 4 is also fixedly installed in the inner cavity of the drill collar 1. The metal centralizer 4 is used to straighten the central axis at the end of the drill collar 1.

[0040] The drill collar 1 includes a drill collar body 101. An antenna cover 102 is fixedly fitted on the outer surface of the drill collar body 101. Multiple sets of annular grooves are opened on the outer surface of the drill collar body 101. Multiple circumferentially distributed windows are provided in the annular grooves. A strip magnetic core 103 is embedded in the window. A coil 104 is wound in the annular groove.

[0041] The drill collar body 101 is made of non-magnetic stainless steel, conforming to API standards. It possesses excellent high strength, corrosion resistance, and high-temperature resistance, and can withstand downhole high pressure, mud erosion, and severe vibration, avoiding the influence of magnetic interference on measurement data. The drill collar body 101 has standard threads at both ends, which can be precisely adapted to various drilling tools to meet the operational needs of different well types such as horizontal wells, highly deviated wells, and deep wells. An antenna cover 102 is fixedly fitted onto the outer surface of the drill collar body 101. The antenna cover 102 is made of non-magnetic stainless steel and is fixedly connected to the drill collar body 101 by welding. The connection is tight and has strong sealing, which can effectively prevent mud and impurities from entering the coil 104 area and prevent coil 104 from being damaged. Compared with the traditional fiberglass antenna cover structure, the welded metal antenna cover has higher strength, stronger anti-collapse ability, longer service life, and lower maintenance and replacement costs.

[0042] Multiple annular grooves are formed on the outer surface of the drill collar body 101. These grooves are equidistantly distributed along the axial direction of the drill collar, providing a stable winding carrier for the coil 104. Multiple circumferentially distributed windows are provided within the annular grooves. These windows extend axially and are used to embed and install the bar magnetic core 103. The bar magnetic core 103 is made of a high-permeability soft magnetic material, which can enhance the intensity of electromagnetic signals transmitted and received by the coil 104, improve the stability and efficiency of signal transmission, reduce signal attenuation and interference, and provide a basic support for high-precision resistivity measurement. After the bar magnetic core 103 is embedded in the window, it is integrally encapsulated with fiberglass to further improve the sealing performance and structural stability, and prevent mud from entering the window and damaging the bar magnetic core 103 and the coil 104. A coil 104 is wound inside the annular groove. The coil 104 is made of high-strength enameled wire and is directly attached to the drill collar body 101 after winding. Compared with the traditional "double-layer fiberglass wrapping" structure, the coil 104 is more directly protected, avoiding damage to the coil 104 caused by the collapse of the fiberglass. At the same time, it simplifies the structural design and reduces the difficulty of processing and maintenance.

[0043] The battery module 2 includes a spindle 201, on which two ring-shaped batteries 202 are mounted. An intermediate connecting disk 204 is provided between the two ring-shaped batteries 202, and the intermediate connecting disk 204 is fixedly connected to the spindle 201.

[0044] A butterfly spring 205 is installed on the spindle 201. The spindle 201 is anti-rotated by inserting an anti-rotation pin 203 into a pin hole on the drill collar body 101. A guide head 206 is fixedly installed at the end of the spindle 201.

[0045] The mandrel 201 is made of high-strength non-magnetic stainless steel, with strong structural rigidity, which can stably support components such as the ring battery 202, and also has good corrosion resistance. Two ring batteries 202 are installed on the mandrel 201. The ring batteries 202 are high-efficiency lithium batteries with sufficient capacity to ensure that the continuous data storage time of the memory meets the needs of long-term logging operations. The dual-battery design forms a redundancy backup to avoid operation interruption due to the failure of a single battery.

[0046] An intermediate connecting plate 204 is provided between the two annular batteries 202. The intermediate connecting plate 204 is made of insulating and high-temperature resistant material and is fixedly connected to the spindle 201. It is used to separate the two annular batteries 202 to prevent short circuits between the batteries and also plays an axial positioning role to ensure stable battery installation. A butterfly spring 205 is installed on the spindle 201. The butterfly spring 205 is made of high-strength elastic material and has excellent axial shock absorption performance. It can buffer the impact of severe downhole vibration on the battery module 2, prevent the battery from being damaged by vibration, and ensure power supply stability. The spindle 201 is anti-rotated by inserting an anti-rotation pin 203 into the pin hole on the drill collar body 101 to prevent the battery module 2 from rotating during the rotation of the drill collar and avoid problems such as wire entanglement and poor contact. A guide head 206 is fixedly installed at the end of the spindle 201. The guide head 206 is made of wear-resistant and corrosion-resistant material, which can guide the downhole mud to flow smoothly through the battery module 2 area, reduce the scouring and wear of the module by the mud, and at the same time play a sealing and protective role to prevent the mud from entering the module.

[0047] The circuit module 3 includes a circuit core frame 301, on which a measurement module 302 and a shock-absorbing ring 303 are fixedly installed. The circuit core frame 301 is provided with a guide key 305 and an anti-rotation pin 304. The guide key 305 is inserted through the guide keyway on the drill collar body 101, and anti-rotation is achieved by the anti-rotation pin 304.

[0048] A second guide head 306 is fixedly installed at the end of the circuit core frame 301. A second shock absorber ring 307 is fixedly installed on the second guide head 306. The measurement module 302 includes a resistivity measurement module, an azimuth gamma measurement module, and a near-end inclination measurement module. Both the first shock absorber ring 303 and the second shock absorber ring 307 are PEEK shock absorber rings, which are used to buffer the impact of vibration on the circuit module 3 and protect the precision circuit board and sensor.

[0049] The installation and protection design of each component in circuit module 3 is meticulous: the transmitter board and control board of the circuit are fixed to the circuit core frame 301 with screws. After fixing, potting compound is poured to form an overall fixation and shock absorption protection, preventing vibration from causing the circuit board to loosen or be damaged. The gamma sensor is integrated into the azimuth gamma measurement module. Due to the higher cost, a separate shock absorption structure can be designed. Radial shock absorption is achieved using O-rings, axial shock absorption pads are used, and circumferential anti-rotation structure is used. Finally, the gamma cover plate is tightened with screws to reduce the impact of vibration on the gamma sensor from all directions, prevent sensor damage, and ensure the accuracy of azimuth gamma measurement. The resistivity measurement module adopts a 4-transmit 2-receive compensated measurement scheme, including a main control unit, a transmitter unit, and a receiver unit. The transmitter and receiver tuning function modules are installed near the transmitter and receiver antennas to shorten the signal transmission distance and reduce signal attenuation. The MCU, transmitter and receiver control modules are installed inside the circuit core frame 301, effectively protecting the circuit board from external environmental interference and facilitating maintenance. The acquisition and processing unit and probe of the azimuth gamma measurement module are mounted at the lower end of the circuit core frame. The probe uses a non-magnetic material shell and a tungsten copper-nickel alloy shielding layer to effectively isolate external magnetic and electromagnetic interference. The inclinometer module uses a high-precision MEMS gravity accelerometer, which is embedded in the circuit core frame 301 with a vibration-damping module structure. It incorporates temperature compensation and zero-drift self-correction algorithms to dynamically correct errors and ensure the accuracy of inclinometer data.

[0050] The metal centralizer 4 includes a pair of mating half-rings 401, each with multiple flow channels 402. The pair of mating half-rings 401 are fixed together as a single ring by screws 403, reducing the swaying of the drill collar during rotation and preventing vibration from impacting the battery module 2 and circuit module 3, thus ensuring measurement accuracy. The metal centralizer 4 is made of 17-4PH high-strength stainless steel, which is erosion-resistant, wear-resistant, and high-strength, suitable for the high-speed scouring and severe vibration environment of downhole mud. The metal centralizer 4 includes a pair of mating half-rings 401, which are fixed together as a single ring by screws 403, facilitating easy assembly and disassembly and on-site maintenance. The multiple flow channels 402 on the mating half-rings 401 are evenly distributed circumferentially along the mating half-rings 401, employing a maximum mud flow cross-section design to reduce mud scouring of components while ensuring smooth mud flow and preventing mud accumulation from affecting the normal operation of the device.

[0051] The outer surface of the locking module 5 is provided with an external thread 501. The external thread 501 adopts a short-tooth Acrylic thread with a thread angle of 29°, which conforms to the imperial standard. It has high friction and good self-locking performance, and can resist external impact and vibration to ensure the reliability of the fixation. A sealing ring 502 is provided at the end of the locking module 5 near the battery module 2 and the circuit module 3. The sealing ring 502 is made of high-temperature resistant and corrosion-resistant elastic rubber material, which can achieve a tight seal between the locking module and the end of the module, prevent mud from entering the module and protect the internal components and circuits. A slot 503 is provided at the outer opening of the locking module 5. The slot 503 is adapted to a special tooling, which allows the on-site operator to quickly tighten or loosen the locking module 5. The tightening torque meets the operation standard, ensuring the fixation strength, and at the same time, it is convenient to replace the battery on-site without returning the instrument to the base.

[0052] It should be noted that the electrical components mainly include battery module 2, the measurement module 302 of circuit module 3, and related circuit boards. The power supply is centered on battery module 2, with two ring batteries 202 connected in series via an intermediate connecting plate 204 to provide a stable DC power supply for the entire device. The dual-battery redundancy design can prevent operation interruption due to the failure of a single battery. The battery module can be quickly replaced on-site. After the operator uses special tools to disassemble and lock module 5, the battery module 2 can be pulled out of the inner cavity of drill collar 1, the ring battery 202 can be replaced, and then it can be reinstalled and locked. There is no need to return to the base for maintenance by professional personnel, which greatly improves the efficiency of operation. The control system is centered on the MCU main control unit of circuit module 3, which coordinates the operation of various measurement modules and transmitting and receiving units. The MCU sends control signals to the transmitting and receiving units of the resistivity measurement module via preset programs or external commands, adjusting parameters such as signal transmission frequency and phase, and receiving and processing formation reflection signals. It also sends control commands to the azimuth gamma measurement module to simultaneously acquire gamma intensity and azimuth signals, ensuring signal accuracy through shielding and anti-interference design. Furthermore, it sends control signals to the inclinometer module to acquire near-end and continuous inclinometer data in real time, dynamically correcting errors through temperature compensation and zero-drift self-correction algorithms. Signal transmission between modules is achieved through dedicated lines made of high-temperature resistant and anti-interference materials, fixed inside the circuit core frame 301 to prevent vibration from causing loosening or damage, thus ensuring the stability of control and signal transmission.

[0053] Example 2: Please refer to Figures 7-9Based on Example 1, multiple circumferentially distributed independent straightening blocks 6 are installed at the center of the metal straightener 4 to eliminate straightening gaps. A pair of symmetrically distributed centrifugal chambers 404 are opened near the outer edge of the inner cavity of the docking half-ring 401 for installing centrifugal counterweights 406 and other components. An installation groove 405 is opened at the center of the docking half-ring 401 for sliding installation of the independent straightening blocks 6. The independent straightening blocks 6 are used to eliminate straightening gaps and achieve high-precision straightening. A centrifugal counterweight 406 is slidably installed inside the centrifugal chamber 404. The centrifugal counterweight 406 is made of high-density material and can generate a large centrifugal force when the drill collar rotates. A limiting ring 407 corresponding to the centrifugal counterweight 406 is fixedly installed inside the centrifugal chamber 404. The limiting ring 407 is located on the inner side of the centrifugal counterweight 406 and is used to limit the reverse movement of the centrifugal counterweight 406. A preload spring 408 is fixedly installed between the centrifugal counterweight 406 and the bottom wall of the centrifugal chamber 404. The preload spring 408 is made of high-strength elastic material and can apply a continuous preload force to the centrifugal counterweight 406, pushing it to move outward.

[0054] A T-shaped flow channel 410 connects the mounting slot 405 and a pair of centrifugal chambers 404 to transmit hydraulic force. A main piston 409 is slidably mounted on one end of the T-shaped flow channel 410 near the centrifugal chamber 404. The main piston 409 is fixedly connected to the centrifugal counterweight 406 and can move synchronously with the centrifugal counterweight 406. A secondary piston 412 is slidably mounted on the other end of the T-shaped flow channel 410 near the mounting slot 405. The secondary piston 412 is fixedly connected to the independent straightening block 6 and can push the independent straightening block 6 along... The mounting groove slides; hydraulic oil is filled between the main piston 409 and the auxiliary piston 412. The hydraulic oil has good fluidity and damping characteristics, which can realize the smooth transmission of force and buffer vibration by using the damping effect; a porous damping plate 411 is also fixedly installed at one end of the T-shaped flow channel 410 near the mounting groove 405. The porous damping plate 411 has multiple evenly distributed channels, which can further improve the damping force of the hydraulic oil, enhance the vibration buffering effect, and not hinder the continuous transmission of preload and centrifugal force.

[0055] Multiple circumferentially distributed independent straightening blocks 6 are installed at the center of the metal straightener 4 to eliminate straightening gaps and achieve adaptive high-precision straightening; the independent straightening block 6 includes a base block 601, a thermally expanding bimetallic sheet 602 and a clamping block 603. The base block 601 is made of high-strength wear-resistant material and has a robust structure, which can stably support the thermal expansion bimetallic strip 602 and the clamping block 603. A hidden groove is opened on the side of the base block 601 away from the mounting groove for installing the clamping block 603 and the thermal expansion bimetallic strip 602. The clamping block 603 is slidably installed in the hidden groove and is made of wear-resistant material. It can tightly abut against the drill collar mandrel to achieve the straightening effect. The thermal expansion bimetallic strip 602 is fixedly installed between the clamping block 603 and the bottom wall of the hidden groove. The thermal expansion bimetallic strip 602 is made of iron-nickel-chromium-nickel-chromium material, which is composed of two alloy layers with significantly different thermal expansion coefficients. It can work stably in the downhole high-temperature range from room temperature to 150 degrees Celsius. It accurately senses temperature changes and generates directional expansion deformation, pushing the clamping block 603 to move outward, compensating for the error gap caused by the thermal expansion and contraction of materials under high temperature environment, and ensuring the continuous and stable straightening effect.

[0056] Working principle:

[0057] Before operation, assemble and debug each module. Insert two ring-shaped batteries 202 onto the spindle 201 of battery module 2, using the intermediate connecting plate 204 for positioning, and ensure the butterfly spring 205 is installed correctly. Install battery module 2 into the left end of the drill collar 1's inner cavity, using anti-rotation pin 203 inserted into the pin hole of the drill collar body 101 to prevent rotation, and use guide head 206 to guide mud flow. Fix the measurement module 302 and circuit board of circuit module 3 onto the circuit core frame 301, and apply potting compound for shock absorption and protection, especially ensuring the shock absorption structure of the gamma sensor is installed correctly. Install circuit module 3 into the right end of the drill collar's inner cavity using guide key 305, engaging with the guide keyway of the drill collar body 101. Use anti-rotation pin 304 engaging with the pin hole of the drill collar body 101 to prevent rotation. Guide head 306, along with shock-absorbing rings 303 and 307, provide protection and shock absorption. A pair of mating half-rings 401 are fixed into a ring shape by screws 403 to form a metal centralizer 4 and installed into the corresponding position in the inner cavity of the drill collar, ensuring that the independent centralizer 6 is installed in the mounting groove 405 and slides smoothly; the locking module 5 is tightened by special tooling, and axial fixation is achieved by external thread 501, and sealing ring 502 ensures sealing performance, thus completing the overall assembly of the device.

[0058] The assembled device is connected to the drilling tool via API standard threads at both ends of the drill collar 1 and lowered into the downhole working area along with the drilling tool. After the device is lowered into the well, the toroidal battery 202 of the battery module 2 starts to supply power, and the current is transmitted to the circuit module 3 through the line. The MCU main control unit starts and completes the initialization and debugging of each measurement module 302. The resistivity measurement module, azimuth gamma measurement module, and inclination measurement module enter the working ready state. The drill collar 1 rotates synchronously with the drilling tool, laying the foundation for subsequent adaptive centering and multi-parameter measurement.

[0059] During the rotation of the drill collar 1, the centrifugal counterweight 406 of the metal stabilizer 4 moves outward under the preload of the preload spring 408, pushing the main piston 409 to slide along the centrifugal chamber 404. The main piston transmits the force to the auxiliary piston 412 through the hydraulic oil in the T-shaped flow channel 410. The auxiliary piston pushes the independent stabilizer 6 outward along the mounting groove 405, pressing it against the spindle of the drill collar 1, eliminating assembly gaps, and achieving initial stabilization. As the drill collar rotation speed increases, the centrifugal force on the centrifugal counterweight 406 increases, further pushing the main piston 409 to move. The hydraulic oil strengthens the thrust on the independent stabilizer 6, making the independent stabilizer 6 press more tightly against the spindle. The stabilization force adaptively increases with the rotation speed, effectively suppressing drill collar swaying and vibration. In the high-temperature environment downhole, the thermal expansion bimetallic strip 602 of the independent centralizing block 6 senses temperature changes and generates directional expansion, pushing the sticking block 603 to move outward, compensating for the error gap caused by the thermal expansion and contraction of the material, and ensuring the continuous and stable centralizing effect; at the same time, the hydraulic oil in the T-shaped flow channel 410 works with the porous damping plate 411 to buffer the violent vibration downhole by using the damping effect, reducing the impact of vibration on the battery module 2 and the circuit module 3, and ensuring the stable operation of each module.

[0060] After each module starts, it simultaneously acquires and processes resistivity, azimuth gamma, and inclination parameters. In the resistivity measurement module, the MCU main control unit sends a control signal to the transmitting unit. The transmitting unit generates and tunes an electromagnetic wave signal, which is transmitted to the formation through the coil 104 in the annular groove of the drill collar 1. The bar magnetic core 103 enhances the signal strength and stability. The electromagnetic wave signal reflected from the formation is received by the coil and transmitted to the receiving unit. The receiving unit filters, tunes, and converts the signal, transforming it into a processable electrical signal and transmitting it to the MCU. The MCU calculates the formation resistivity parameters using a compensation algorithm. In the azimuth gamma measurement module, the gamma probe acquires the formation gamma signal, and the azimuth positioning unit simultaneously acquires azimuth information. The acquisition and processing unit amplifies, filters, and digitizes the signal, simultaneously transmitting the gamma intensity and corresponding azimuth data to the MCU, achieving synchronous and accurate acquisition of gamma and azimuth signals. In the inclination measurement module, a MEMS high-precision gravity accelerometer collects wellbore attitude signals. Near-end inclination measurement solves the measurement lag problem and reduces interference from factors such as drilling fluid and wellbore enlargement. Continuous inclination measurement reflects changes in the wellbore trajectory in real time. The collected signals are corrected by temperature compensation and zero drift self-correction algorithms before being transmitted to the MCU to obtain accurate wellbore trajectory parameters, providing a basis for drilling engineers to adjust the drill bit trajectory.

[0061] After integrating and encoding the parameters collected from each module, the data is uploaded to the ground control system via a dedicated transmission channel, providing real-time formation and wellbore information to on-site personnel. Simultaneously, the device's built-in memory backs up the data to prevent loss. During operation, operators can monitor the device's status in real time via the ground system. If the battery runs out, operation can be stopped, the device removed from the wellhead, and the locking module 5 disassembled using specialized tools. The battery module 2 can then be pulled out, replaced with the toroidal battery 202, and reassembled without returning the device to the base, significantly reducing maintenance time. Similarly, if maintenance of the circuit module 3 is required, it can be disassembled and removed for targeted repair or component replacement. After maintenance, it is reinstalled into the drill collar 1 cavity and locked, allowing the device to be put back into operation.

[0062] The above description is merely a preferred embodiment of the present invention; however, the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and its improved concepts, should be covered within the scope of protection of the present invention.

Claims

1. A downhole multi-parameter logging device, comprising a drill collar (1), characterized in that: The drill collar (1) has a battery module (2) and a circuit module (3) installed at the left and right ends of its inner cavity, respectively. The battery module (2) and the circuit module (3) are axially fixed by a locking module (5). A metal stabilizer (4) is also fixedly installed in the inner cavity of the drill collar (1). The metal stabilizer (4) is used to stabilize the central axis at the end of the drill collar (1). Multiple circumferentially distributed independent stabilizing blocks (6) are installed at the center of the metal stabilizer (4) to eliminate stabilizing gaps. The drill collar (1) includes a drill collar body (101), an antenna cover (102) is fixedly fitted on the outer surface of the drill collar body (101), and multiple sets of annular grooves are opened on the outer surface of the drill collar body (101). Multiple circumferentially distributed windows are provided in the annular grooves, and a strip magnetic core (103) is embedded in the window. A coil (104) is wound in the annular groove. The metal stabilizer (4) includes a pair of docking half-rings (401), each with multiple flow channels (402). The pair of docking half-rings (401) are fixed together as a ring by screws (403). A pair of symmetrically distributed centrifugal chambers (404) are provided near the outer edge of the inner cavity of each docking half-ring (401). A mounting groove (405) is provided at the center of each docking half-ring (401). The independent stabilizer block (6) is slidably installed in the mounting groove (405). A centrifugal counterweight block (406) is slidably installed in each centrifugal chamber (404). A centrifugal counterweight block (406) is fixedly installed in each centrifugal chamber (404). A limiting ring (407) is corresponding to the block (406). A pre-tightening spring (408) is fixedly installed between the centrifugal counterweight block (406) and the bottom wall of the centrifugal chamber (404). A T-shaped flow channel (410) is connected between the mounting groove (405) and a pair of centrifugal chambers (404). A main piston (409) is slidably installed at one end of the T-shaped flow channel (410) near the centrifugal chamber (404). A secondary piston (412) is slidably installed at one end of the T-shaped flow channel (410) near the mounting groove (405). The main piston (409) is fixedly connected to the centrifugal counterweight block (406). The secondary piston (412) is fixedly connected to the independent straightening block (6).

2. The downhole multi-parameter logging device according to claim 1, characterized in that: The battery module (2) includes a spindle (201), on which two annular batteries (202) are mounted. An intermediate connecting disk (204) is provided between the two annular batteries (202), and the intermediate connecting disk (204) is fixedly connected to the spindle (201).

3. The downhole multi-parameter logging device according to claim 2, characterized in that: A butterfly spring (205) is installed on the mandrel (201). The mandrel (201) is anti-rotated by inserting an anti-rotation pin (203) into a pin hole on the drill collar body (101). A guide head (206) is fixedly installed at the end of the mandrel (201).

4. The downhole multi-parameter logging device according to claim 3, characterized in that: The circuit module (3) includes a circuit core frame (301), on which a measurement module (302) and a shock-absorbing ring (303) are fixedly installed. The circuit core frame (301) is provided with a guide key (305) and an anti-rotation pin (304). The guide key (305) is inserted through the guide keyway on the drill collar body (101) and anti-rotation is achieved through the anti-rotation pin (304).

5. A downhole multi-parameter logging device according to claim 4, characterized in that: The circuit core frame (301) is fixedly installed with a flow guide head two (306) at its end, and a shock absorber ring two (307) is fixedly installed on the flow guide head two (306). The measurement module (302) includes a resistivity measurement module, an azimuth gamma measurement module and a near-end inclination measurement module.

6. The downhole multi-parameter logging device according to claim 1, characterized in that: Hydraulic oil is filled between the main piston (409) and the auxiliary piston (412). A porous damping plate (411) is fixedly installed at one end of the T-shaped flow channel (410) near the mounting groove (405). The auxiliary piston (412) is located between the porous damping plate (411) and the independent straightening block (6).

7. A downhole multi-parameter logging device according to claim 6, characterized in that: The independent straightening block (6) includes a base block (601), the outer surface of the base block (601) is provided with a hidden groove, a matching fastening block (603) is slidably installed in the hidden groove, and a thermal expansion bimetallic sheet (602) is fixedly installed between the fastening block (603) and the bottom wall of the hidden groove.

8. The downhole multi-parameter logging device according to claim 1, characterized in that: The locking module (5) has an external thread (501) on its outer surface. A sealing ring (502) is provided at one end of the locking module (5) near the battery module (2) and the circuit module (3). A slot (503) is provided at the outer opening of the locking module (5).

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