A plunger-type drill string eccentric device and its control method

Abstract

This invention belongs to the field of drilling engineering technology and discloses a plunger-type drill string eccentric device and its control method capable of simulating the dynamic process of a drill string moving from the center of the wellbore to complete contact with the wellbore wall. The device includes: a transparent wellbore assembly comprising multiple transparent wellbores connected by a wellbore joint; a drill string assembly located within the transparent wellbore assembly, comprising multiple drill strings connected by threads; a lifting eccentric structure including an eccentric collar, the drill string assembly being rotatable within the eccentric collar, one end connected to the eccentric collar, and the other end sealed and passing through the wellbore joint and connected to a lead screw motor via a universal coupling; a plunger rod, the lead screw motor driving the plunger rod to vertically lift and lower via the universal coupling, thereby achieving eccentric adjustment of the drill string assembly within the transparent wellbore assembly by the eccentric collar; a limit sensing assembly including a limit sensor fixed to a fixed foundation and a sensing plate installed on the top of the lead screw of the lead screw motor for locating the eccentric origin; and a sensor module installed on the wellbore joint.

Description

Technical Field

[0001] This invention relates to the field of drilling engineering technology, specifically to a plunger-type drill string eccentric device and its control method. Background Technology

[0002] With the continuous increase in horizontal displacement and vertical-to-water ratio in extended reach wells, wellbore cleanliness has become increasingly prominent, becoming a key factor restricting drilling efficiency and safety. In deviated sections, especially near the horizontal (inclination angle > 60°), cuttings, due to their higher density than drilling fluid, are easily deposited on the annulus wall under gravity, forming cuttings beds. Cuttings beds can lead to stuck pipe, reduced rate of penetration (ROP), increased downhole equivalent circulating density (ECD), and even lost circulation or wellbore failure. Due to the complex downhole environment, the cuttings transport process cannot be directly observed; therefore, it is necessary to study its patterns using surface simulation experimental devices. However, during drilling operations, the drill pipe cannot maintain an ideal concentric state in the wellbore due to gravity. Therefore, surface simulation experimental devices need to have the function of adjusting the eccentricity of the drill pipe to study the impact of eccentricity on wellbore cleanliness.

[0003] However, existing ground simulation experimental devices have the following defects: 1) They cannot achieve continuous eccentricity adjustment from 0% to 100% (i.e., the distance of the drill string from the center of the well to the bottom of the well): Existing ground simulation experimental devices can only set a fixed eccentricity and cannot simulate the dynamic process of the drill string from the center of the well to being completely attached to the wall; 2) Single-segment structure limitation: Existing ground simulation experimental devices only support single-segment drill string eccentricity and cannot form multi-segment continuous eccentricity, making it difficult to simulate the cumulative effect of eccentricity in actual long wells; 3) Low adjustment accuracy: They lack a synchronous control mechanism, resulting in poor consistency during multi-segment eccentricity adjustment and large experimental data errors. Summary of the Invention

[0004] In order to simulate the dynamic process of the drill string moving from the center of the wellbore to being completely attached to the well wall, this invention proposes a plunger-type drill string eccentric device and its control method.

[0005] The plunger-type drill string eccentric device according to the present invention includes: a transparent wellbore assembly comprising a plurality of transparent wellbores, adjacent transparent wellbores being connected by a wellbore joint; a drill string assembly located within the transparent wellbore assembly, comprising a plurality of drill strings, adjacent drill strings being threadedly connected; and a lifting eccentric structure comprising a screw motor, a universal coupling, a plunger rod, and an eccentric collar, the eccentric collar being sleeved on the drill string assembly, the drill string assembly being rotatable within the eccentric collar, one end of the plunger rod being connected to the eccentric collar, and the other end being sealed and passing through the wellbore joint. The system is connected to a lead screw motor via a universal coupling. The lead screw motor drives the plunger rod to move vertically up and down through the universal coupling, thereby causing the eccentric collar to move vertically up and down, which in turn causes the drill string assembly to adjust its eccentricity within the transparent wellbore assembly. The system includes a limit sensor assembly, which consists of a limit sensor fixed to the motor bracket of the lead screw motor and a sensor plate installed on the top of the lead screw of the lead screw motor, for locating the eccentric origin. The system also includes a sensor module installed on the wellbore joint collar, for monitoring the pressure difference and temperature of the annulus between the transparent wellbore assembly and the drill string assembly.

[0006] Furthermore, the lifting eccentric structure also includes a base with a through hole and a motor bracket fixedly connected to the top of the base. The lead screw motor is fixed to the top of the motor bracket. A plunger sealing shaft hole component that is sealed and connected to the through hole is installed in the base. The bottom end of the plunger rod passes through the motor bracket and enters the shaft hole of the plunger sealing shaft hole component and is sealed and slidably connected with it. The top end of the plunger rod is connected to the lead screw of the lead screw motor through a universal coupling.

[0007] Furthermore, the lifting eccentric structure also includes a lifting ring connected between the plunger rod and the eccentric collar.

[0008] Furthermore, the drill string assembly is mounted in the eccentric collar via a bearing assembly. An installation groove for mounting the bearing assembly is formed on the outer peripheral wall of the connection between adjacent drill strings. The bearing assembly includes a first bearing located at the center of the installation groove and second bearings located at both ends of the installation groove, as well as a retaining ring for the bore installed between the first bearing and the second bearing. A first annular groove for cooperating with the first bearing and a second annular groove for cooperating with the second bearing are formed in the eccentric collar, as well as a third annular groove for cooperating with the retaining ring for the bore.

[0009] Furthermore, the wellbore clamp includes a clamp body and clamp flanges connected to opposite ends of the clamp body. Pressure rings for connecting to the clamp flanges are formed at opposite ends of the transparent wellbore. Silicone gaskets are provided between the pressure rings and the clamp flanges. The sensor module is mounted on the clamp body.

[0010] Furthermore, the well shaft coupling also includes a coupling adjustment base plate connected to the bottom of the coupling body and a coupling mounting base plate located below the coupling adjustment base plate, as well as an adjustment screw assembly connected between the coupling adjustment base plate and the coupling mounting base plate. The adjustment screw assembly is used to adjust the height of the well shaft coupling by adjusting the height of the coupling adjustment base plate relative to the coupling mounting base plate, so as to adjust the concentricity of the multi-section transparent well shaft.

[0011] Furthermore, the sensor module includes multiple pressure sensors disposed at the upper, middle and bottom of the throttle body, and at least one temperature sensor disposed at the middle of the throttle body.

[0012] The control method for the plunger-type drill string eccentric device according to the present invention is used to control the above-mentioned plunger-type drill string eccentric device, comprising the following steps: Step 1: drive each lead screw motor to return the induction plate on each lead screw motor to zero point; Step 2: stop the lead screw motor after the limit sensor captures the zeroing signal; Step 3: convert the target eccentricity into lifting distance through the controller and control the operation of the lead screw motor; Step 4: stop the operation after the lead screw motor drives the plunger rod to the lifting distance and start the drill string rotation.

[0013] Furthermore, the controller adjusts each lead screw motor through closed-loop feedback to ensure that the eccentricity error of each segment is less than 0.5mm.

[0014] Furthermore, each well section is designed to be able to adjust the same eccentricity synchronously or to adjust different eccentricities independently, in order to simulate the non-uniform working conditions of actual drilling.

[0015] Compared with existing technologies, the plunger-type drill string eccentric device and its control method of the present invention simultaneously achieve 0-100% continuous stepless eccentric adjustment, and can be adjusted synchronously or independently in dual modes. The simulated pipe section can be extended indefinitely. It has comprehensive advantages such as visualization, high precision, high scalability, and easy maintenance. It can realistically reproduce the complex eccentric working conditions of kilometer-level large-displacement wells, and provides unprecedented experimental means for the study of cuttings transport mechanism and the optimization of wellbore cleaning process. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the structure of the plunger-type drill string eccentric device according to an embodiment of the present invention;

[0017] Figure 2 for Figure 1 The diagram shows the structural schematic of the lifting eccentric structure.

[0018] Figure 3 This is a schematic diagram of the connection between adjacent drill string joints, which shows the three-dimensional structure of the bearing assembly;

[0019] Figure 4 for Figure 2Enlarged cross-sectional view of the bearing assembly shown;

[0020] Figure 5 This is a schematic diagram showing the connection between the transparent well casing and the well casing coupling;

[0021] Figure 6 This is a schematic diagram of the well shaft section collar;

[0022] Figure 7 This is a schematic diagram of the exploded structure of the well shaft coupling;

[0023] Figure 8 The left figure is a schematic diagram of the eccentric collar of the lifting eccentric structure located at the center position (0%), and the right figure is a schematic diagram of the eccentric collar of the lifting eccentric structure located at the maximum eccentric position (100%).

[0024] Figure 9 A schematic diagram showing the connection of multiple transparent well shafts;

[0025] Figure 10 A schematic diagram illustrating the lifting eccentricity principle of the lifting eccentricity structure;

[0026] Figure 11 A schematic diagram illustrating the principle of adjusting the height of the well shaft coupling;

[0027] Figure 12 This is a control principle diagram of the lifting eccentric structure. Detailed Implementation

[0028] To better understand the purpose, structure, and function of this invention, the invention will be described in further detail below with reference to the accompanying drawings.

[0029] Figure 1 The structure of a plunger-type drill string eccentric device 100 according to an embodiment of the present invention is shown. For example... Figure 1 As shown, the plunger-type drill string eccentric device 100 may include: a transparent wellbore assembly, including multiple transparent wellbores 1, adjacent transparent wellbores 1 being connected by wellbore clamps 2; a drill string assembly, located within the transparent wellbore assembly, including multiple drill strings 3, adjacent drill strings 3 being threadedly connected; and a lifting eccentric structure 4 (such as...). Figure 2 (As shown), it includes a lead screw motor 41, a universal coupling 42, a plunger rod 43, and an eccentric collar 44. The eccentric collar 44 is sleeved on the drill string assembly, allowing the drill string assembly to rotate within the eccentric collar 44. One end of the plunger rod 43 is connected to the eccentric collar 44, and the other end is sealed through the wellbore clamp 2 and connected to the lead screw motor 41 via the universal coupling 42. The lead screw motor 41 drives the plunger rod 43 to move vertically up and down through the universal coupling 42, thereby driving the eccentric collar 44 to move vertically up and down, thus adjusting the eccentricity of the drill string assembly within the transparent wellbore assembly. The limit sensing component includes a limit sensor 46 fixed to the motor bracket 45 of the lead screw motor 41 (fixed on...). Figure 2 The limit sensor mounting base 461 shown and the sensing plate 47 mounted on the top of the lead screw of the lead screw motor 41 are used to locate the eccentric origin; and the sensor module is mounted on the well section collar 2 to monitor the pressure difference and temperature of the annulus between the transparent well section assembly and the drill string assembly.

[0030] In the plunger-type drill string eccentric device 100 of this invention, multiple transparent wellbore sections 1 are connected end-to-end by wellbore clamps 2, enabling visual observation of the cuttings transport process. The length of the transparent wellbore assembly can be infinitely extended, simulating near-real kilometer-scale wellbores. Furthermore, the multiple transparent wellbore sections 1 can be modularly assembled and disassembled, increasing experimental efficiency. Multiple drill string sections 3 are threaded and located inside the transparent wellbore 1, ensuring that the connection method and strength of each drill string section 3 are consistent with a real drill string, transmitting real torque and increasing the reliability of the simulation results. Simultaneously, the drill string assembly is quick to assemble and disassemble, helping to reduce maintenance costs. In the lifting eccentric structure 4, the lead screw motor 41 drives the plunger rod 43 to move vertically up and down through the universal coupling 42, thereby causing the eccentric collar 44 to achieve 0-100% eccentricity with the drill string. This allows for continuous, stepless, and precisely quantifiable eccentricity adjustment of the drill string, covering all working conditions. The universal coupling 42 only allows the plunger rod 43 to move vertically up and down, eliminating lateral bending moments and making the lifting of the plunger rod 43 smoother. Figure 10 The working process of the lifting eccentric structure 4 is shown, combined with Figure 10 As shown, the lead screw motor 41 rotates (blue rotating arrow) and extends / retracts (blue vertical arrow), driving the plunger rod 43 to extend / retract (yellow vertical arrow), ultimately causing the eccentric collar 44 and drill string assembly to rise and fall (green vertical arrow), while the drill string assembly can rotate (red rotating arrow). Back Figure 1 The limit sensing component, through the combination of limit sensor 46 and sensing plate 47, can be used to locate the eccentric origin, ensure that all lifting eccentric structures 4 have the same synchronous reference, and at the same time avoid mechanical overshoot, thus playing a protective role for the equipment. Figure 8 The diagram illustrates the relative positions of the limit sensor 46 and the sensing element 47 when the drill string assembly is located at the center position (0%) and the maximum eccentric position (100%). The center position (0%) shown in the left figure can be considered as the eccentric origin. Monitoring the annular pressure differential in the sensor module can be used to obtain real-time annular pressure differential cloud maps to analyze the impact of cuttings transport on annular pressure loss. Simultaneously, temperature monitoring can be used for temperature compensation to improve pressure measurement accuracy and to study the effect of temperature on cuttings transport efficiency.

[0031] In this embodiment of the invention, the plunger-type drill string eccentric device 100 converts rotary motion into high-precision linear motion using a screw motor 41; a universal coupling 42 isolates lateral bending moments; and the plunger rod 43 and eccentric collar 44 form a linear push-pull chain, achieving 0-100% continuous, stepless, and quantifiable eccentricity of the drill string within the transparent wellbore assembly. The pressure gradient monitoring and temperature measurement of the sensor module help to construct an accurate cuttings transport model.

[0032] According to the present invention, in such Figure 2 In the preferred embodiment shown, the lifting eccentric structure 4 may further include a base 48 with a through hole and the aforementioned motor bracket 45 fixedly connected to the top of the base 48. The lead screw motor 41 is fixed to the top of the motor bracket 45. A plunger sealing shaft hole component 49, which is sealed and connected to the through hole, is installed inside the base 48. The bottom end of the plunger rod 43 passes through the motor bracket 45 and enters the shaft hole of the plunger sealing shaft hole component 49, where it is sealed and slidably connected. The top end of the plunger rod 43 is connected to the lead screw of the lead screw motor 41 via a universal coupling 42. This embodiment, by adding a base 48 and a modular sealing unit for the plunger sealing shaft hole component 49 located therein, enables the plunger rod 43 to rise and fall stably in the vertical direction, and the plunger sealing shaft hole component 49 can be quickly replaced, thus improving maintenance efficiency.

[0033] Preferably, such as Figure 2 As shown, a plunger seal ring 431 can be provided between the plunger rod 43 and the shaft hole, and a seal ring 491 can be provided between the base 48 and the plunger sealing shaft hole component 49. A dustproof ring 492 can be provided at the bottom of the inner wall of the shaft hole of the plunger sealing shaft hole component 49. The plunger seal ring 431 and the dustproof ring 492 between the plunger rod 43 and the shaft hole form a first seal, and the seal ring 491 between the base 48 and the plunger sealing shaft hole component 49 forms a second seal. The double seal can prevent rock debris from entering the base 48, avoid the plunger rod 43 from jamming, and extend the service life of the device.

[0034] In such Figure 2 In the preferred embodiment shown, the lifting eccentric structure 4 may further include a lifting ring 40 connected between the plunger rod 43 and the eccentric collar 44. The lifting ring 40 reduces the contact area with the drilling fluid, avoids damage from rock cuttings, and maintains the authenticity of fluid flow.

[0035] In such Figures 2 to 4In the preferred embodiment shown, the drill string assembly can be mounted within the eccentric collar 44 via a bearing assembly. An mounting groove 31 for mounting the bearing assembly can be formed on the outer peripheral wall of the connection between adjacent drill strings 3. The bearing assembly may include a first bearing 81 located at the center of the mounting groove 31 and second bearings 82 located at both ends of the mounting groove 31, as well as a retaining ring 83 for the bore installed between the first bearing 81 and the second bearing 82. A first annular groove for engaging with the first bearing 81, a second annular groove for engaging with the second bearing 82, and a third annular groove for engaging with the retaining ring 83 can be formed within the eccentric collar 44. This embodiment, through the design of a composite positioning structure of "double bearings + retaining ring + three-dimensional annular groove," ensures that the drill string does not experience axial movement even at high speeds; on the other hand, the distributed bearing of multiple bearings prevents the drill string from tilting or jamming during eccentric lifting, ensuring smooth movement; furthermore, it ensures assembly coaxiality and avoids the swaying problem of a single-bearing cantilever structure.

[0036] In such Figure 6 In the preferred embodiment shown, the wellhead clamp 2 may include a clamp body 21 and clamp flanges 22 connected to opposite ends of the clamp body 21, in combination with... Figure 5 As shown, pressure rings 11 are formed at opposite ends of the transparent wellbore 1 for connection with the clamp flange 22. Silicone gaskets 6 (such as...) can be provided between the pressure rings 11 and the clamp flange 22. Figure 1 As shown, the sensor module is mounted on the clamp body 21. This configuration makes the connection between the transparent well tubes 1 more stable and leak-free. The transparent well tubes 1 can withstand cyclic thermal shock, and the silicone gaskets 6 can elastically compensate for thermal expansion and contraction, preventing the acrylic tubes from cracking.

[0037] In such Figures 5 to 7 In the preferred embodiment shown, the well shaft clamp 2 may further include a clamp adjustment base plate 71 connected to the bottom of the clamp body 21 and a clamp mounting base plate 72 located below the clamp adjustment base plate 71, as well as an adjustment screw assembly 73 connected between the clamp adjustment base plate 71 and the clamp mounting base plate 72. The adjustment screw assembly 73 is used to adjust the height of the well shaft clamp 2 by adjusting the height of the clamp adjustment base plate 71 relative to the clamp mounting base plate 72, so as to adjust the concentricity of the multi-section transparent well shaft 1, and to solve the problem of axial deviation of the splicing of the multi-section transparent well shaft 1, so as to ensure that the inner wall forms a continuous concentric cylinder.

[0038] Preferably, such as Figure 6 and Figure 7 As shown, the adjusting screw assembly 73 may include multiple double-ended bolts, each of which can be adjusted independently. Preferably, there are four double-ended bolts, located at the four corners of the clamp adjusting base plate 71. (Combined with...) Figure 11 As shown, the lifting or left-right balance adjustment of the well section hoop 2 can be achieved by adjusting the height of each double-headed bolt.

[0039] In such Figure 5 and Figure 6 In the preferred embodiment shown, the sensor module may include multiple pressure sensors 51 disposed at the upper, middle, and bottom of the hoop body 21, and at least one temperature sensor 52 disposed at the middle of the hoop body 21. The arrangement of multiple pressure sensors 51 allows for real-time acquisition of the annular pressure gradient, which can be used to study the impact of rock cuttings transport on annular pressure loss. The experiment can continue even if any sensor fails, resulting in higher system reliability.

[0040] In such Figure 9 In the preferred embodiment shown, multiple plunger-type drill string eccentric devices 100 described above can be used to simulate a long wellbore.

[0041] The control method for the plunger-type drill string eccentric device according to an embodiment of the present invention, used to control the plunger-type drill string eccentric device 100, may include the following steps: Step 1: Drive each lead screw motor 41 to return the sensing plate 47 on each lead screw motor 41 to zero; Step 2: Stop the lead screw motor 41 after the limit sensor 46 captures the zeroing signal; Step 3: Convert the target eccentricity into a lifting distance through the controller and control the lead screw motor 41 to run; Step 4: The lead screw motor 41 drives the plunger rod 43 to the lifting distance and then stops running, starting the drill string rotation. The control method for the plunger-type drill string eccentric device of the present invention, after closed-loop zeroing, calculates the stroke according to the target eccentricity, achieving one-click fully automatic calibration with zero manual intervention; it also has small repeatability errors and high comparability of experimental data; it can use open software algorithms and can be integrated with PID self-tuning.

[0042] Preferably, the controller can adjust each lead screw motor 41 through closed-loop feedback to ensure that the eccentricity error of each section of the drill string is less than 0.5mm.

[0043] Furthermore, each wellbore section 2 can be configured to synchronously adjust the same eccentricity or independently adjust different eccentricities to simulate the non-uniform working conditions of actual drilling. The synchronous mode can be used to study the effects of uniform eccentricity, while the independent mode simulates real random eccentricity downhole. The same equipment covers both research needs, greatly saving costs.

[0044] Combination Figure 8 , Figure 9 as well as Figure 12 As shown, the complete working process of controlling the plunger-type drill string eccentric device 100 using the control method of the present invention is as follows, taking a single experiment of "70% eccentricity, three-section transparent wellbore 1, synchronous control" as an example:

[0045] Phase 1: Equipment Assembly and Zero-Point Calibration

[0046] First, the transparent wellbore 1 is leveled: the three sections of transparent wellbore 1 are connected end to end by wellbore clamps 2; the four double-ended bolts are rotated to raise and lower the clamp adjustment base plate 71 until the laser level shows that the straightness of the entire length meets the requirements, completing the coarse adjustment of concentricity. Then, the three sections of drill string 3 are screwed together into a single piece and passed through the bearing assembly in each eccentric ring 44; the first bearing 81 and the second bearing 82 in the bearing assembly are respectively embedded in the annular groove of the eccentric ring 44, and the hole is locked with a retaining ring 83, so that the drill string can rotate but is axially positioned. Finally, zero-point calibration is performed: the controller issues a command to make all lead screw motors 41 retract synchronously; after the induction plate 47 triggers the limit sensor 46, the lead screw motor 41 stops rotating, and the system records the 0% eccentric origin; the controller drives the lead screw motor 41 to extend to the end of the stroke, and the system records 100% eccentricity; the software linearly calibrates the stroke 0-R (R is the wellbore radius) corresponding to 0-100%.

[0047] Phase 2: Setting Target Bias

[0048] First, input "70% eccentricity" on the control interface; the controller converts the stroke L=0.7R and sends pulse commands to the three lead screw motors 41; closed-loop feedback ensures that the deviation of the three eccentricities is <0.5mm.

[0049] Phase 3: Eccentric Lifting Execution

[0050] The lead screw motor 41 rotates, driving its lead screw to move linearly. The universal coupling 42 eliminates angular displacement, causing the plunger rod 43 to descend vertically. The lifting ring 40 transmits thrust to the eccentric collar 44, driving the drill string to descend as a whole until it reaches a 70% eccentric position. The limit sensor 46 monitors in real time to prevent overshoot.

[0051] Phase 4: Drilling Fluid Circulation and Drill String Rotation

[0052] The surface pump is started, and drilling fluid enters the annulus from the wellhead; the drill string is driven to rotate at a set speed under the support of the bearing assembly; the pressure sensor and temperature sensor sample once per second, and the data is uploaded to the host computer; and the morphology of the cuttings bed is recorded by a high-speed camera.

[0053] Phase 5: End of Experiment and Reset

[0054] After the experiment is completed, the controller executes "return to zero" with one key: all lead screw motors 41 retract synchronously to the limit triggered by the induction plate 47 to 0% eccentricity; then the pump is turned off, the drill string rotation is stopped, and the drill string can be disassembled.

[0055] Phase 6: Mode Switching

[0056] To simulate "non-uniform eccentricity", you can switch to "independent mode" in the software and input different eccentricity rates (such as 30%, 50%, and 70%) for the three segments respectively, and repeat stages 2-5.

[0057] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. These modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be covered within the scope of the claims and specification of the present invention. In particular, as long as there is no structural conflict, the various technical features mentioned in the embodiments can be combined in any way. The present invention is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A plunger-type eccentric drill string device, characterized in that, include: A transparent wellbore assembly includes multiple transparent wellbores, with adjacent transparent wellbores connected by wellbore clamps; A drill string assembly, located within the transparent wellbore assembly, includes multiple drill strings, with adjacent drill strings being threadedly connected. The lifting eccentric structure includes a lead screw motor, a universal coupling, a plunger rod, and an eccentric collar. The eccentric collar is sleeved on the drill string assembly, which can rotate within the eccentric collar. One end of the plunger rod is connected to the eccentric collar, and the other end is sealed through the wellbore clamp and connected to the lead screw motor via the universal coupling. The lead screw motor drives the plunger rod to lift vertically through the universal coupling, thereby driving the eccentric collar to lift vertically, and thus adjusting the eccentricity of the drill string assembly within the transparent wellbore assembly. The limit sensing assembly includes a limit sensor fixed to the motor bracket of the lead screw motor and a sensing plate installed on the top of the lead screw of the lead screw motor, used for locating the eccentric origin; and A sensor module, installed on the wellbore joint, is used to monitor the pressure difference and temperature of the annulus between the transparent wellbore assembly and the drill string assembly.

2. The plunger-type eccentric drill string device according to claim 1, characterized in that, The lifting eccentric structure also includes a base with a through hole and a motor bracket fixedly connected to the top of the base. The lead screw motor is fixed to the top of the motor bracket. A plunger sealing shaft hole component is installed in the base and sealed to the through hole. The bottom end of the plunger rod passes through the motor bracket and enters the shaft hole of the plunger sealing shaft hole component and is sealed and slidably connected to it. The top end of the plunger rod is connected to the lead screw of the lead screw motor through the universal coupling.

3. The plunger-type eccentric drill string device according to claim 2, characterized in that, The lifting eccentric structure also includes a lifting ring connected between the plunger rod and the eccentric collar.

4. The plunger-type eccentric drill string device according to any one of claims 1 to 3, characterized in that, The drill string assembly is mounted in the eccentric collar via a bearing assembly. An installation groove for mounting the bearing assembly is formed on the outer peripheral wall of the connection between adjacent drill strings. The bearing assembly includes a first bearing located at the center of the installation groove and second bearings located at both ends of the installation groove, as well as a retaining ring for the bore installed between the first bearing and the second bearing. The eccentric collar has a first annular groove for cooperating with the first bearing, a second annular groove for cooperating with the second bearing, and a third annular groove for cooperating with the retaining ring for the bore.

5. The plunger-type eccentric drill string device according to any one of claims 1 to 3, characterized in that, The wellbore clamp includes a clamp body and clamp flanges connected to opposite ends of the clamp body. Pressure rings for connecting to the clamp flanges are formed at opposite ends of the transparent wellbore. A silicone gasket is provided between the pressure ring and the clamp flange. The sensor module is disposed on the clamp body.

6. The plunger-type eccentric drill string device according to claim 5, characterized in that, The well shaft coupling also includes a coupling adjustment base plate connected to the bottom of the coupling body and a coupling mounting base plate located below the coupling adjustment base plate, as well as an adjustment screw assembly connected between the coupling adjustment base plate and the coupling mounting base plate. The adjustment screw assembly is used to adjust the height of the well shaft coupling by adjusting the height of the coupling adjustment base plate relative to the coupling mounting base plate, so as to adjust the concentricity of the multiple transparent well shaft sections.

7. The plunger-type eccentric drill string device according to claim 5, characterized in that, The sensor module includes multiple pressure sensors disposed at the upper, middle and bottom of the throttle body, and at least one temperature sensor disposed at the middle of the throttle body.

8. A control method for a plunger-type drill string eccentric device, used to control the plunger-type drill string eccentric device according to any one of claims 1 to 7, characterized in that, Includes the following steps: Step 1: Drive each of the lead screw motors to return the induction plates on each of the lead screw motors to zero; Step 2: The limit sensor stops the lead screw motor after capturing the zeroing signal; Step 3: Convert the target eccentricity into lifting distance using the controller, and control the operation of the lead screw motor; Step 4: The lead screw motor drives the plunger rod to the specified lifting distance and then stops running, starting the drill string rotation.

9. The control method for the plunger-type drill string eccentric device according to claim 8, characterized in that, The controller adjusts each lead screw motor through closed-loop feedback to ensure that the eccentricity error of each segment is less than 0.5mm.

10. The control method for the plunger-type drill string eccentric device according to claim 8, characterized in that, Each of the aforementioned wellbore sections is designed to be able to be adjusted synchronously with the same eccentricity or to be adjusted independently with different eccentricities, in order to simulate the non-uniform working conditions of actual drilling.

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