Push-arm mechanism and design method

Abstract

This invention provides a push-arm mechanism and its design method. The push-arm mechanism includes a rotating shaft, a pressure-resistant housing, a push-arm, a crank-slider mechanism, a lead screw and nut, and a DC motor. The rotating shaft passes through the pressure-resistant housing and mounts the push-arm onto it. One end of the crank-slider mechanism is connected to the rotating shaft, and the other end is connected to one end of the lead screw and nut. The DC motor rotates and outputs torque to drive the lead screw and nut, which in turn pushes the crank-slider mechanism to move, causing the push-arm to open and retract. This push-arm mechanism and its design method are located inside the pressure-resistant housing of a seismic acquisition instrument in a well, meeting the requirements of the high-temperature and high-pressure working environment in the well. It is responsible for realizing the coupling function between the seismic acquisition instrument in the wellbore (or casing wall), effectively improving the quality of wellbore seismic exploration and measurement operations.

Description

Technical Field

[0001] This invention relates to the field of seismic data acquisition technology for oil and gas exploration, and in particular to a push-arm mechanism and its design method. Background Technology

[0002] The method of measuring seismic signals by placing both the excitation system (source) and the receiving system (detector) simultaneously or one of them in the wellbore is generally referred to as wellbore seismic technology. With the development of wellbore seismic technology, the application of 3DVSP, inter-well seismic, and in-well microseismic fracturing monitoring technologies is becoming increasingly widespread, placing higher demands on the performance of in-well seismic signal acquisition equipment, primarily requiring multi-level, high sampling rates, and high sensitivity. Among these, the coupling effect between the in-well seismic acquisition instrument and the wellbore (or casing wall) is a key factor affecting the quality of wellbore seismic measurement operations, and currently, there is no complete solution available in China.

[0003] Chinese patent application CN114233222A discloses a six-arm pusher for small-diameter oil wells. The invention includes a cylindrical main body with a high-pressure oil chamber and an electric pump mounted at one end. Six axially spaced mounting grooves are evenly distributed on the outer surface of the main body. Each groove houses a pusher arm consisting of a main arm, an electrode plate, and a secondary arm. The main arm is connected to the piston via a push rod mounted on the main body. The six pushers are divided into two groups, front and rear, at 120-degree circumferential intervals. The main and secondary arms are parallel during opening. The connection ends of the six main arms to the main body are located on the same annular line. When the two groups of pushers are pushed open by the piston, the rear end of the electrode plate of the front group and the front end of the electrode plate of the rear group are close to the same annular line. This embodiment ensures that the electrode plates of the two groups of pushers are as close as possible to the same annular line after opening, resulting in similar measurement areas for each electrode plate and significantly improving measurement accuracy.

[0004] Chinese patent application CN111648760A discloses a downhole pusher. This application discloses a downhole pusher comprising: multiple push arms and a pusher unit; the multiple push arms are connected to the pusher unit; the pusher unit is connected to a surface system; the pusher unit controls the opening or closing of any one or more push arms, calculates the wellbore diameter based on the opening size of the push arms, collects the pressure transmitted by the push arms in real time, and transmits the wellbore diameter and pressure to the surface system. This embodiment achieves real-time surface control and real-time monitoring of pusher parameters, enabling flexible control of the push arms and exhibiting good maneuverability and practicality.

[0005] Chinese patent application CN113187421A discloses an adaptive wellbore shape pusher, comprising a cylindrical main body and a pusher arm disposed within a groove on the outer circumference of the main body. The pusher arm includes a main arm, an electrode plate, and a secondary arm connected in sequence. The two ends of the main arm are rotatably connected to one end of the main body and one end of the electrode plate, respectively, while the two ends of the secondary arm are rotatably connected to the other end of the electrode plate and the main body, respectively. An adjustment device is provided at the secondary arm to automatically adjust the contact angle between the electrode plate and the wellbore. This invention can be applied to any existing pusher with an expandable pusher arm, adjusting the existing pusher arm, which opens to a parallelogram shape, to form a quadrilateral with an arbitrary angle. By using an elastic component to make the extension of the secondary arm asynchronous with the main arm, the connected electrode plate can adjust its contact angle with the wellbore according to the change in the support height of the secondary arm. This allows the electrode plate to better conform to wellbore shapes with different inclinations, greatly improving the stability of the pusher after support.

[0006] Chinese patent application CN110374582A discloses a hydraulic pusher and logging tool. The hydraulic pusher includes a base and a pusher mechanism mounted on the base. The pusher mechanism includes a pusher arm and a piston assembly. The piston assembly includes a piston and a piston rod. The piston is slidably disposed within a cavity in the base, dividing the cavity into a first chamber and a second chamber. One end of the piston rod is connected to the piston, and the other end extends from the first chamber and connects to the pusher arm. Under hydraulic pressure, the piston rod reciprocates, causing the pusher arm to open and close. The hydraulic pusher of this application uses hydraulic pressure to control the pushing force, enabling high-force pusher operation. Furthermore, in the case of multiple pusher arms, the movement of each pusher arm can be independently hydraulically controlled, allowing for high-force release in the event of sticking.

[0007] The above-mentioned existing technologies are all quite different from the present invention and have failed to solve the technical problem we want to solve. Therefore, we have invented a new push arm mechanism and design method. Summary of the Invention

[0008] The purpose of this invention is to provide a push-arm mechanism and design method that is responsible for realizing the coupling function between the seismic acquisition instrument in the well and the wellbore (or casing wall), thereby effectively improving the quality of wellbore seismic exploration and measurement operations.

[0009] The objective of this invention can be achieved through the following technical measures: a push-arm mechanism, comprising a rotating shaft, a pressure-resistant housing, a push-arm, a crank-slider mechanism, a lead screw and nut, a reducer, and a DC motor. The rotating shaft passes through the pressure-resistant housing and mounts the push-arm onto it. One end of the crank-slider mechanism is connected to the rotating shaft, and the other end is connected to one end of the lead screw and nut. The DC motor rotates and outputs torque to drive the lead screw and nut, which in turn pushes the crank-slider mechanism to move, causing the push-arm to open and retract. The objective of this invention can also be achieved through the following technical measures:

[0010] The pressure-resistant housing is in the shape of a long cylinder, and there is a hole in the pressure-resistant housing. The rotating shaft is installed in the hole of the pressure-resistant housing.

[0011] The push arm mechanism also includes a rotary dynamic seal assembly, which is fitted onto the rotating shaft and installed in the hole of the pressure-resistant housing. The rotary dynamic seal assembly enables dynamic sealing between the rotating shaft and the pressure-resistant housing when the push arm rotates in a downhole high-pressure environment.

[0012] The push arm mechanism also includes an energy storage spring, a lead screw, a bearing, and a bearing housing. One end of the energy storage spring is connected to the other end of the lead screw nut, and the other end of the energy storage spring is connected to the lead screw. The input end of the lead screw and the bearing are installed in the bearing housing and then installed into the pressure-resistant housing.

[0013] The push-arm mechanism also includes a safety clutch and a speed reducer. One end of the safety clutch is connected to the lead screw, and the other end is connected to the speed reducer. The tail end of the speed reducer is connected to the DC motor. The speed reducer lowers the high speed output of the motor and increases the output torque.

[0014] The crank-slider mechanism includes a crank rod, a connecting rod, and a slider. One end of the crank rod is connected to the rotating shaft, and the other end is connected to one end of the connecting rod. The other end of the connecting rod is connected to one end of the slider, and the other end of the slider is connected to the lead screw nut.

[0015] After receiving the control signal to open the push arm, the DC motor rotates and outputs torque to drive the lead screw nut, which in turn pulls the crank-slider mechanism to move, thereby opening the push arm.

[0016] When the push arm opens and contacts the wellbore or casing wall, the lead screw nut compresses the energy storage spring, at which point the energy storage spring begins to store energy. When the DC motor stops working, the energy storage spring will always provide continuous elastic energy to the push arm, providing the coupling force required between the seismic acquisition instrument in the well and the wellbore or casing wall, thus realizing the coupling between the seismic acquisition instrument in the well and the wellbore or casing wall.

[0017] After receiving the control signal for the retraction of the push arm, the DC motor rotates and outputs torque to drive the lead screw nut, which in turn drives the crank-slider mechanism to move, thereby realizing the retraction of the push arm.

[0018] When the push arm cannot be retracted normally, the safety clutch will press the push arm under the action of the retraction force, which will then pull the screw nut in reverse, causing the safety clutch to slip and disengage, thereby realizing the retraction of the push arm and successfully recovering the seismic acquisition instrument in the well.

[0019] The objective of this invention can also be achieved through the following technical measures: a design method for a push-back arm mechanism, which designs the push-back arm mechanism, including:

[0020] Step 1: In the vertical casing well, the push arm of the logging instrument is in the open state. The entire push arm mechanism is regarded as a crank-slider mechanism. The gravity of the mechanism itself is ignored, and the casing wall and all parts of the push arm are regarded as rigid bodies.

[0021] Step 2: Establish a rectangular coordinate system for the push arm mechanism. Take the center point of the opening and closing rotation of the push arm as the origin O, and the instrument axis as the X-axis. The positive direction of the X-axis points from the origin to the direction of the lead screw and is parallel to the lead screw axis. The Y-axis passes through the origin and is opposite to the direction of the positive pressure N of the sleeve wall on the push arm.

[0022] Step 3: Take the entire pushing system as the research object and perform force analysis on the model.

[0023] The objective of this invention can also be achieved through the following technical measures:

[0024] In step 3, a rectangular coordinate system is established. Since the system is in equilibrium, the active forces acting on the entire system are the normal pressure N of the casing wall on the push arm and the tension F of the lead screw on the slider. N1 is the supporting force on the slider, and F2 is the tension of the connecting rod on the slider. The lengths of the connecting rods are L1, L2, L3, α1 (angle between the connecting rod and the horizontal), α2 (angle between the crank and the horizontal), α3 (opening angle of the push arm), ψ (angle between the push arm and the crank), h (slider offset), and ι (distance ι from the rotation point of the push arm to the well wall). A rectangular coordinate system is established by taking the center point O of the opening and closing rotation of the push arm. Since the system is in equilibrium, according to the necessary and sufficient condition for the equilibrium of a planar force system, the resultant torque M at point O is known. O If the value is zero, establish the equilibrium equation:

[0025] ∑M o =0

[0026] NL3cosα3=N1(L1cosα1+L2cosα2)+Fh.

[0027] Step 3 includes:

[0028] Step 31, taking the slider as the object of study, perform force analysis, where F2 is the tension force on the slider from the connecting rod, and establish the equilibrium equations:

[0029] ∑F x =0

[0030] F=F2cosα1

[0031] ∑F y =0

[0032] N = F2sinα1

[0033] have to:

[0034] N1=Ftanα1 Step 32, based on geometric relations, we get:

[0035]

[0036] L1sinα1+h=L2sinα2

[0037] Step 33, based on steps 31 and 32, yields:

[0038] NL3cosα3=Ftanα1(L1cosα1+L2cosα2)+Fh

[0039]

[0040] Substituting h = L2sinα2 - L1sinα1 into the above equation and rearranging, we get:

[0041]

[0042] Therefore, the analytical expression for the ratio of the lead screw's pulling force F on the slider to the normal force N is derived:

[0043]

[0044] Analyze the minimum value of K under the premise of satisfying the pushing force.

[0045] In step 33, the analysis revealed that the minimum value of K is significantly affected by L3 and L2, while h and L1 have little impact on the minimum value of K. The crank-slider mechanism is constrained by the outer diameter and the mechanism components; L2 takes its maximum value within its range. Considering the unknown conditions inside the sleeve and the need for safe and smooth recovery, the range of the push arm deployment angle α3 is [value missing]. During actual downhole operations, the extension angle of the push arm The length of the push arm is affected by the inner diameter of the casing. Given the inner diameter Φd, the push arm length L3 = lsinα3 within the optimal working angle can be obtained. Then, using α2 as the independent variable, the minimum point is found, yielding the minimum value of K. The push arm mechanism and design method in this invention emphasize ease of use, safety, and automatic retraction upon power failure. This includes: controlling the motor output torque under the command of the ground controller to open the push arm; and controlling the motor output torque under the command of the ground controller to retract the push arm from the seismic acquisition instrument in the wellbore. The main design components include the push arm, crank-slider mechanism, elastic energy storage device, safety clutch, pressure-resistant outer shell structure, and rotary dynamic seal assembly design. This invention is located inside the pressure-resistant outer shell of the seismic acquisition instrument in the wellbore and meets the requirements of the high-temperature and high-pressure working environment in the well. It is responsible for realizing the coupling function between the seismic acquisition instrument in the wellbore (or casing wall), effectively improving the quality of wellbore seismic exploration and measurement operations. Attached Figure Description

[0046] Figure 1 This is a structural diagram of the pushing system in a specific embodiment of the pushing arm mechanism of the present invention;

[0047] Figure 2 This is a static balance diagram of the push-arm system in a specific embodiment of the present invention;

[0048] Figure 3 This is a mechanical model diagram of the push-to-close system actuator in a specific embodiment of the present invention;

[0049] Figure 4 This is a force analysis diagram of the slider of the pushing system in a specific embodiment of the present invention;

[0050] In the diagram, 1-pressure resistant housing; 2-rotary seal assembly; 3-rotating shaft; 4-push arm; 5-crank rod; 6-connecting rod; 7-slider; 8-lead screw nut; 9-energy storage spring.

[0051] 10-Screw 11-Bearing housing 12-Safety clutch 13-Reducer

[0052] F: The pulling force of the lead screw on the sleeve slider

[0053] N: Positive pressure of the well wall on the push arm

[0054] L1: Link length

[0055] L2: Crank length

[0056] L3: Push arm length

[0057] α1: Angle between the connecting rod and the horizontal

[0058] α2: Angle between crank and horizontal

[0059] ψ: Angle between the push arm and the crank

[0060] h: Offset between the slider and the crank rotation center

[0061] ι: Distance from the rotating point of the push arm to the well wall

[0062] F2: The tension force on the slider

[0063] O: Center point of the opening and closing rotation of the push arm

[0064] M O :Resultant torque at point O. Detailed Implementation

[0065] It should be noted that the following detailed descriptions are exemplary and intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which the present invention belongs.

[0066] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments of the present invention. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, and / or combinations thereof.

[0067] The push-back arm mechanism mainly includes: a DC motor and reducer, a safety clutch, a lead screw and nut, an energy storage spring, a crank-slider mechanism, a rotary dynamic seal assembly, and a push-back arm.

[0068] The pressure-resistant shell is generally cylindrical. The circular cross-section improves the overall pressure resistance of the shell, reduces manufacturing difficulty, and increases manufacturing economy.

[0069] The rotating shaft passes through the pressure-resistant housing and mounts the push arm onto the pressure-resistant housing. The rotating shaft is installed inside the bore of the pressure-resistant housing, and the rotating sealing assembly is fitted onto the rotating shaft and installed inside the bore. The rotating sealing assembly achieves dynamic sealing between the rotating shaft and the pressure-resistant housing when the push arm rotates in the downhole high-pressure environment.

[0070] The crank-slider mechanism consists of three parts: a crank rod, a connecting rod, and a slider. One end of the crank rod is connected to the shaft, and the other end is connected to the connecting rod. The other end of the connecting rod is connected to the slider. The lead screw nut is connected to the energy storage spring and the slider.

[0071] The lead screw's input end is mounted in a bearing housing and then inserted into a pressure-resistant housing. One end of the safety clutch is connected to the lead screw, and the other end is connected to the reducer. The reducer's tail end is connected to a DC motor.

[0072] The safety clutch is used when the push arm cannot be retracted normally due to obstruction or motor failure during instrument retrieval. Under the action of the retrieval pull force, the push arm is compressed, which in turn pulls the screw nut in reverse, causing the safety clutch to slip and disengage, thus enabling the push arm to be retracted and the seismic acquisition instrument in the well to be successfully retrieved.

[0073] The following are several specific embodiments of the application of the present invention.

[0074] Example 1

[0075] In a specific embodiment 1 of the present invention, such as Figure 1 As shown, during installation, the pressure-resistant housing 1 has a hole, and the rotating shaft 3 passes through the pressure-resistant housing 1 to install the push arm 4 onto the pressure-resistant housing 1. The rotating shaft 3 is installed inside the hole of the pressure-resistant housing 1.

[0076] The rotary sealing assembly 2 is fitted onto the rotary shaft 3 and installed inside the hole. The rotary sealing assembly 2 enables dynamic sealing between the rotary shaft 3 and the pressure-resistant housing 1 when the push arm 4 rotates in the downhole high-pressure environment.

[0077] The crank-slider mechanism consists of three parts: crank rod 5, connecting rod 6, and slider 7. One end of crank rod 5 is connected to the rotating shaft 3, and the other end is connected to the connecting rod 6. The other end of connecting rod 6 is connected to slider 7.

[0078] The other end of the slider 7 is connected to the lead screw nut 8, and the other end of the lead screw nut 8 is connected to the energy storage spring 9.

[0079] The other end of the energy storage spring 9 is connected to the lead screw 10, and the input end of the lead screw 10 is installed in the bearing housing 11 with the bearing.

[0080] One end of the safety clutch 12 is connected to the lead screw 10 via the bearing housing 11, and the other end is connected to the reducer 13. The tail end of the reducer 13 is connected to the DC motor.

[0081] The above components are connected in sequence and then installed into the pressure-resistant housing 1.

[0082] Example 2

[0083] In a specific embodiment 2 of the present invention, the working process is as follows: under the command of the ground controller, the DC motor (not shown) is controlled by the winch cable. The DC motor rotates and outputs torque to drive the lead screw nut 8, which in turn pulls (pushes) the crank-slider mechanism. The crank-slider mechanism is composed of crank rod 5, connecting rod 6, and slider 7 connected in sequence, thereby realizing the opening of the push arm 4. When the push arm 4 opens and contacts the wellbore (or casing wall), the lead screw nut 8 compresses the energy storage spring 9. At this time, the energy storage spring 9 begins to store energy. When the DC motor stops working, the energy storage spring 9 continuously provides elastic energy to the push arm 4, providing the necessary coupling force between the seismic acquisition instrument and the wellbore (or casing wall), thus achieving coupling between the seismic acquisition instrument and the wellbore (or casing wall). After the seismic acquisition instrument completes its measurement work, under the command of the ground controller, it controls the DC motor to rotate and output torque to drive the lead screw nut 8. The lead screw nut 8 then pushes (pulls) the crank-slider mechanism (composed of crank rod 5, connecting rod 6, and slider 7 connected in sequence) to move, thereby realizing the retraction of the push arm 4. If the seismic acquisition instrument encounters obstruction during retrieval or the DC motor malfunctions, causing the push arm 4 to fail to retract normally, the safety clutch 12, under the action of the retrieval pull force, will compress the push arm 4, which will then pull the lead screw nut 8 in reverse, causing the safety clutch 12 to slip and disengage, thus realizing the retraction of the push arm 4 and successfully recovering the seismic acquisition instrument.

[0084] Example 3

[0085] In a specific embodiment 3 of the present invention, the present invention provides a design method for optimizing the dimensional parameters of each component of the push-arm system.

[0086] A force analysis of the push arm shows that when the push arm opens downhole and forms a reliable coupling with the casing wall, the entire push system can be considered to be in a state of static equilibrium. Figure 2 As shown. The push-arm system is simplified as follows: Figure 3 The mechanical model shown is simplified as shown in the figure.

[0087] 1. Taking the entire pushing system as the research object, perform a force analysis on the model as follows: Figure 3 :

[0088] Establish a rectangular coordinate system at point O, since the system is in equilibrium.

[0089] ΣM o =0

[0090] NL3cosα3=N1(L1cosα1+L2cosα2)+FhF: The tension of the lead screw on the sleeve slider

[0091] N: Positive pressure of the well wall on the push arm

[0092] L1: Link length

[0093] L2: Crank length

[0094] L3: Push arm length; α1: Angle between connecting rod and horizontal; α2: Angle between crank and horizontal; ψ: Angle between push arm and crank; h: Offset between slider and crank rotation center; ι: Distance from push arm rotation point to well wall.

[0095] F2: The slider is subjected to the tension of the connecting rod.

[0096] O: Center point of the opening and closing rotation of the push arm

[0097] M O :Resultant torque at point O.

[0098] 2. Taking the slider as the object of study, perform force analysis and establish equilibrium equations:

[0099] ∑F x =0

[0100] F=F2cosα1

[0101] ∑F y =0

[0102] N = F2sinα1

[0103] have to:

[0104] N1=F tanα1

[0105] 3. Based on geometric relationships, we get:

[0106]

[0107] L1sinα1+h=L2sinα2

[0108] According to 1.2:

[0109] NL3cosα3=Ftanα1(L1cosα1+L2cosα2)+Fh

[0110]

[0111] Substituting h = L2sinα2 - L1sinα1 into the above equation and rearranging, we get:

[0112]

[0113] Therefore, the analytical expression for the ratio of the lead screw's pulling force F on the slider to the normal force N is derived:

[0114]

[0115] Analyze the minimum value of K under the premise of satisfying the pushing force.

[0116] Analysis revealed that the minimum value of K is significantly influenced by L3 and L2, while h and L1 have little impact on it. The crank-slider mechanism is constrained by factors such as the outer diameter and the mechanism's components. L2 takes its maximum value within its range. Considering the unknown conditions inside the sleeve and ensuring safe and smooth recovery, the range of the push arm deployment angle α3 is [insert range here]. During actual downhole operations, the extension angle of the push arm The length of the push arm is affected by the inner diameter of the sleeve. When the inner diameter of the sleeve Φd is known, the length of the push arm within the optimal working angle is L3 = lsinα3. At this time, the minimum point is found with α2 as the independent variable, and the minimum value of K is obtained.

[0117] In actual use, the appropriate length of push arm can be replaced according to the casing diameter of the working well to provide the required pushing force.

[0118] Finally, it should be noted that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

[0119] Except for the technical features described in the specification, all other technologies are known to those skilled in the art.

Claims

1. A design method for a push-and-hold arm mechanism, characterized in that, This method designs a push-arm mechanism, which includes a rotating shaft, a pressure-resistant housing, a push-arm, a crank-slider mechanism, a lead screw nut, and a DC motor. The rotating shaft passes through the pressure-resistant housing and mounts the push-arm onto the housing. One end of the crank-slider mechanism is connected to the rotating shaft, and the other end is connected to one end of the lead screw nut. The DC motor rotates and outputs torque to drive the lead screw nut, which in turn pushes the crank-slider mechanism to move, causing the push-arm to open and retract. The push arm mechanism also includes an energy storage spring, a lead screw, a bearing, and a bearing housing. One end of the energy storage spring is connected to the other end of the lead screw nut, and the other end of the energy storage spring is connected to the lead screw. The input end of the lead screw and the bearing are installed in the bearing housing and then installed into the pressure-resistant housing. The crank-slider mechanism includes a crank rod, a connecting rod, and a slider. One end of the crank rod is connected to the rotating shaft, and the other end is connected to one end of the connecting rod. The other end of the connecting rod is connected to one end of the slider, and the other end of the slider is connected to the lead screw nut. The specific design steps include: Step 1: In the vertical casing well, the push arm of the logging instrument is in the open state. The entire push arm mechanism is regarded as a crank-slider mechanism. The gravity of the mechanism itself is ignored, and the casing wall and all parts of the push arm are regarded as rigid bodies. Step 2: Establish a rectangular coordinate system for the push arm mechanism. Take the center point of the opening and closing rotation of the push arm as the origin O, and the instrument axis as the X-axis. The positive direction of the X-axis points from the origin to the direction of the lead screw and is parallel to the lead screw axis. The Y-axis passes through the origin and is opposite to the direction of the positive pressure N of the sleeve wall on the push arm. Step 3: Take the entire pushing system as the research object and perform force analysis on the model; In step 3, a rectangular coordinate system is established. Since the system is in equilibrium, the active forces acting on the entire system are the normal pressure N of the casing wall on the push arm and the tension F of the lead screw on the slider. N1 is the supporting force on the slider, and F2 is the tension of the connecting rod on the slider. The lengths of the connecting rods are L1, L2, L3, α1 (angle between the connecting rod and the horizontal), α2 (angle between the crank and the horizontal), α3 (opening angle of the push arm), ψ (angle between the push arm and the crank), h (slider offset), and ι (distance ι from the rotation point of the push arm to the well wall). A rectangular coordinate system is established by taking the center point O of the opening and closing rotation of the push arm. Since the system is in equilibrium, according to the necessary and sufficient condition for the equilibrium of a planar force system, the resultant torque M at point O is known. o If the value is zero, establish the equilibrium equation: ΣM o =0 NL3cosα3=N1(L1cosα1+L2cosα2)+Fh.

2. The design method of the push-arm mechanism according to claim 1, characterized in that, include: Step 31, taking the slider as the object of study, perform force analysis, where F2 is the tension force on the slider from the connecting rod, and establish the equilibrium equations: ∑F x ＝0 F=F2cosα1 ∑F y ＝0 N = F2sinα1 have to: N1=F tanα1 Step 32, based on geometric relationships, we get: L1sinα1+h=L2sinα2 Step 33, based on steps 1 and 2, we get: NL3cosα3=Ftanα1(L1cosα1+L2cosα2)+Fh Substituting h = L2sinα2 - L1sinα1 into the above equation and rearranging, we get: Therefore, the analytical expression for the ratio of the lead screw's pulling force F on the slider to the normal force N is derived: Analyze the minimum value of K under the premise of satisfying the pushing force.

3. The design method of the push-arm mechanism according to claim 2, characterized in that, In step 33, the analysis revealed that the minimum value of K is significantly affected by L3 and L2, while h and L1 have little impact on the minimum value of K. The crank-slider mechanism is constrained by the outer diameter and the mechanism components; L2 takes its maximum value within its range. Considering the unknown conditions inside the sleeve and the need for safe and smooth recovery, the range of the push arm deployment angle α3 is [value missing]. During actual downhole operations, the extension angle of the push arm The length of the push arm is affected by the inner diameter of the sleeve. When the inner diameter of the sleeve Φd is known, the length of the push arm within the optimal working angle is L3 = lsinα3. At this time, the minimum point is found by taking α2 as the independent variable, and the minimum value of K is obtained.

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