Positioning and holding device and downhole measuring instruments

Abstract

This invention provides a positioning and holding device and a downhole measuring instrument, belonging to the field of downhole logging instruments. The positioning and holding device, applied to a downhole measuring instrument, includes: a housing assembly, a power assembly, and a support assembly. The housing assembly includes: a sleeve with a guide hole; the power assembly and the support assembly are located inside the sleeve; the power assembly is used for axial movement within the sleeve; the support assembly includes: a support block, which moves radially under the drive of the power assembly until it passes through the guide hole on the sleeve and abuts against the inner wall of the instrument housing within the gap. This invention utilizes the power assembly to provide power to the support assembly, allowing the support assembly to pass through the sleeve and abut against the inner wall of the instrument housing, thereby fixing the probe mounting frame to the instrument housing. This prevents the probe mounting frame from shifting during downhole operations, ensuring that all functional modules and the instrument housing are aligned along the same axis, thus guaranteeing the probe's measurement accuracy.

Description

Technical Field

[0001] This invention relates to the field of downhole logging instruments, specifically to a positioning and holding device and a downhole measuring instrument. Background Technology

[0002] With the development of logging technology, the integration level of instruments has been continuously improved. Many originally independent functional modules have been integrated into the integrated circuit, shortening the system length. Due to the differences in the structure of different functional modules, multi-section skeleton structures connected in series have become a common design for highly integrated logging instruments. Multi-section skeleton structures with different measuring probes installed in series form the probe mounting skeleton, which is installed inside the instrument housing.

[0003] Structurally, assembly gaps and tolerances are unavoidable between the instrument housing and the probe mounting frame. During downhole operations, the probe mounting frame may tilt or rotate towards one side of the instrument housing, causing random angles between each functional module and the housing's axis, affecting the accuracy of the functional module's measurements and the instrument's stability. Although this variable is small, it can still produce significant errors for high-precision inclination measurement probes. Summary of the Invention

[0004] To address the aforementioned technical deficiencies, this invention provides a positioning and holding device and a downhole measuring instrument. The positioning and holding device is installed at both ends of the probe mounting frame. By utilizing a power component to provide power to the support component, the support component is protruded from the inside of the sleeve and abuts against the inner wall of the instrument housing, thereby fixing the probe mounting frame to the instrument housing. This prevents the probe mounting frame from shifting during downhole construction, ensuring that each functional module and the instrument housing are aligned on the same axis, thus guaranteeing the measurement accuracy of the probe.

[0005] The first aspect of the present invention provides a positioning and holding device for use in a downhole measuring instrument. The downhole measuring instrument includes an instrument housing and a probe mounting frame disposed inside the instrument housing. There is a gap between the probe mounting frame and the inner wall of the instrument housing. The positioning and holding device is disposed at both ends of the probe mounting frame. The positioning and holding device includes: a shell assembly, a power assembly, and a support assembly. The power assembly is connected to the support assembly. The outer casing assembly includes: a sleeve, the sleeve having a guide hole, and the power assembly and the support assembly being disposed inside the sleeve; The power component is capable of moving within the sleeve; The support assembly includes a support block that can move within the sleeve under the drive of the power assembly until it passes through a guide hole on the sleeve and abuts against the inner wall of the instrument housing within the gap.

[0006] In this embodiment of the invention, the power component includes: a drive motor, a lead screw, and a slider; The drive output shaft of the drive motor is connected to the first end of the lead screw and is used to drive the lead screw to rotate. The slider is sleeved on the lead screw, and moves axially within the sleeve as the lead screw rotates. The slider is fixedly connected to the support assembly, thereby driving the support block of the support assembly to move radially within the sleeve.

[0007] In this embodiment of the invention, the power assembly further includes: a key mechanism and a coupling; The drive output shaft of the drive motor is connected to one end of the coupling via the key mechanism; The other end of the coupling is connected to the first end of the lead screw.

[0008] In this embodiment of the invention, the power component further includes: a limiting block; The limiting block is circumferentially disposed on the outside of the lead screw, and the limiting block is located at a preset position inside the sleeve. The limiting block is used to restrict the movement of the slider.

[0009] In this embodiment of the invention, the support component further includes: a push block; The push block is fixedly connected to the slider and is used to move axially inside the sleeve under the drive of the slider; The push block and the support block are tapered together, and the contact surfaces of the push block and the support block are slidably connected by a sliding component to enable the push block to move axially inside the sleeve, thereby enabling the support block to move radially at the guide hole.

[0010] In this embodiment of the invention, the sliding component includes a T-shaped slide groove and a T-shaped locking block that cooperates with the T-shaped slide groove; The T-shaped groove is formed on the contact surface of the push block, and the T-shaped locking block is formed on the contact surface of the support block.

[0011] In this embodiment of the invention, the support component includes multiple sets of abutment units, each set of abutment units including: a push block and a support block, and the abutment width of the multiple support blocks in each set of abutment units is the same.

[0012] In this embodiment of the invention, the abutment width of the support block is determined based on the travel distance of the power component and the angle between the contact surface of the support block and the radial direction.

[0013] In this embodiment of the invention, the torque provided by the power component to the support component is determined based on the travel distance of the transmission component and the transmission efficiency of the transmission component.

[0014] In this embodiment of the invention, the sleeve includes a first sleeve and a second sleeve, the first sleeve and the second sleeve are internally connected, the power component is placed inside the first sleeve, the support component is placed inside the second sleeve, and the guide hole is formed on the second sleeve.

[0015] A second aspect of the present invention provides a downhole measuring instrument, the downhole measuring instrument comprising: an instrument housing, a probe mounting frame, a plurality of probes, and at least two positioning and holding devices, wherein the positioning and holding devices are as described above; The probe mounting frame, multiple probes, and multiple positioning and holding devices are all located inside the instrument housing; Multiple probes are mounted on the probe mounting frame; The positioning and holding device is installed at both ends of the probe mounting frame.

[0016] In this embodiment of the invention, the positioning and holding device is connected to the probe mounting skeleton screw, and the screw is circumferentially mounted on the sleeve. The positioning and holding device provided by the present invention is installed on both ends of the probe mounting frame. By using the power component to provide power to the support component, the support component is pushed out from the inside of the sleeve and abuts against the inner wall of the instrument housing, so as to fix the probe mounting frame to the instrument housing. This prevents the probe mounting frame from shifting during downhole construction, thereby ensuring that each functional module and the instrument housing are located on the same axis, thus guaranteeing the measurement accuracy of the probe.

[0017] Other features and advantages of the technical solution of the present invention will be described in detail in the following detailed embodiments section. Attached Figure Description

[0018] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this invention, illustrate exemplary embodiments of the invention and are used to explain the invention, but do not constitute an undue limitation of the invention. In the drawings: Figure 1 This is a schematic diagram of the tilting structure inside the housing of the highly integrated continuous inclination logging instrument provided in this embodiment of the invention; Figure 2 This is an overall assembly drawing of the positioning and holding device provided in an embodiment of the present invention; Figure 3 This is an axial cross-sectional view of the positioning and holding device provided in an embodiment of the present invention; Figure 4 This is a diagram illustrating the operational movements of the power assembly and support assembly provided in an embodiment of the present invention. Figure 5 This is a schematic diagram of the tapered fit between the push block and the support block provided in an embodiment of the present invention; Figure 6 This is a schematic diagram of the angle between the contact surface and the radial direction of the support block provided in an embodiment of the present invention; Figure 7 This is a schematic diagram of the structure of the positioning and holding device provided in the embodiment of the present invention when working in conjunction with the calibration table.

[0019] Explanation of reference numerals in the attached figures 1-Positioning and holding device, 2-Probe mounting frame, 3-Verification table, 101-Bearing, 102-Second sleeve, 103-Bearing sleeve, 104-Second flat key, 105-First flat key, 106-Drive motor, 107-First sleeve, 108-Coupling, 109-Lead screw, 110-Limit block, 111-Slider, 112-Push block, 113-Support block, 1131-Low support block, 1132-Middle support block, 1133-High support block. Detailed Implementation

[0020] To make the technical solutions and advantages of the embodiments of the present invention clearer, the exemplary embodiments of the present invention will be further described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not an exhaustive list of all embodiments. It should be noted that, unless otherwise specified, the embodiments and features in the embodiments of the present invention can be combined with each other.

[0021] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0022] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0023] In this invention, unless otherwise explicitly specified and limited, terms such as "installation," "connection," "linking," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0024] In developing this invention, the inventors discovered that with the development of logging technology, the integration level of instruments is constantly improving. Many originally independent functional modules have been integrated into a comprehensive circuit, shortening the system length. Due to the differences in the structure of different functional modules, multi-section skeleton structures connected in series have become a common design for highly integrated logging instruments. Multi-section skeleton structures, which house different functional modules, are connected in series to form the internal structural components of the instrument, installed within the instrument housing, and serve as the skeleton for mounting the probe.

[0025] Structurally, assembly gaps and tolerances are unavoidable between the instrument housing and the probe mounting frame. During downhole operations, the probe mounting frame may tilt or rotate towards one side of the instrument housing, causing random angles between each functional module and the housing's axis, affecting the accuracy of the functional module's measurements and the instrument's stability. Although this variable is small, it can still produce significant errors for high-precision inclination measurement probes.

[0026] Figure 1 This is a schematic diagram of the tilted structure inside the housing of the highly integrated continuous inclination logging instrument provided in this embodiment of the invention. Figure 1As shown, taking a highly integrated continuous inclination logging instrument as an example, in the axial section, the upper and lower ends of the frame are supported on both sides of the inner wall of the outer shell, creating a bending angle; in the radial section, the installation gap between the positioning pin and the inner wall of the outer shell causes the instrument core to twist. At this time, the internal probe and the actual inclination and azimuth of the outer shell are both angled. Taking the continuous inclination logging instrument of the drilling tool series as an example, the probe is the Dalian Huatian continuous inclination logging probe. The design assembly gap between the inner cavity of the outer shell and the instrument core frame is 0.5mm on one side, and the length of the continuous inclination probe is 500mm. The measurement accuracy of the continuous inclination probe of this instrument is: inclination angle measurement range: 0~180°, error: ±0.2°; azimuth angle measurement range: 0~360°, error: ±2°. Analysis of the instrument mounting frame's different postures within the housing reveals that, in the longitudinal section, the upper and lower ends of the frame are supported on opposite sides of the inner wall of the housing, resulting in a bending angle between the mounting frame and the housing, with a maximum angle of ±0.12°. In the cross-section, the mounting holes in the locating pins and the inner wall of the housing have a design clearance, causing axial oscillation when the mounting frame rotates, with a maximum reciprocating angle of ±1.98°. Calculations show that the lack of locating support within the housing causes bending or oscillation of the instrument core, increasing the well inclination angle measurement error to ±0.32° and the azimuth angle measurement error to ±3.98°, representing increases of 60% and 99% respectively. In reality, the cumulative machining and assembly errors of the connector components, along with the elastic deformation of the metal material, may further amplify the impact on the results.

[0027] To address the aforementioned problems, this invention provides a positioning and holding device applied to a downhole measuring instrument. The downhole measuring instrument includes an instrument housing and a probe mounting frame disposed inside the instrument housing. A gap exists between the probe mounting frame and the inner wall of the instrument housing. The positioning and holding device is located at both ends of the probe mounting frame. The positioning and holding device includes: a shell assembly, a power assembly, and a support assembly. The shell assembly includes: a sleeve with a guide hole. The power assembly and the support assembly are disposed inside the sleeve. The power assembly is used for axial movement within the sleeve. The support assembly includes: a support block that moves radially under the drive of the power assembly, passes through the guide hole from inside the sleeve, and abuts against the inner wall of the instrument housing. The positioning and holding device is installed on both ends of the probe mounting frame. By using the power component to provide power to the support component, the support component is pushed out from the inside of the sleeve and abuts against the inner wall of the instrument housing, so as to fix the probe mounting frame to the instrument housing. This prevents the probe mounting frame from shifting during downhole construction, thus ensuring that each functional module and the instrument housing are in the same axis, guaranteeing the measurement accuracy of the probe.

[0028] Figure 2This is an overall assembly drawing of the positioning and holding device provided in an embodiment of the present invention. Figure 2 As shown, the positioning and holding device provided in this embodiment is installed at both ends of the probe mounting frame 2, and the probe mounting frame 2 includes multiple sections of frame on which measuring probes are mounted. The positioning and holding device 1 and the probe mounting frame 2 are disposed inside the instrument housing of the downhole measuring instrument, and there is a gap between the inner wall of the instrument housing and the probe mounting frame 2. Figure 3 This is an axial cross-sectional view of the positioning and holding device provided in an embodiment of the present invention, as shown below. Figure 3 As shown, the positioning and holding device 1 provided in this embodiment includes: a housing assembly, a power assembly, and a support assembly, wherein the power assembly is connected to the support assembly. The housing assembly includes: a sleeve with a guide hole; the sleeve includes a first sleeve 107 and a second sleeve 102. The power assembly includes: a drive motor 106, a lead screw 109, a slider 111, a key mechanism, a coupling 108, and a limiting block 110. The support assembly includes: multiple sets of abutment units, each set of abutment units containing a pushing block and a supporting block 113, wherein the supporting block 113 of each set of abutment units extends out of the guide hole with the same abutment width.

[0029] The power assembly and the support assembly are located inside the sleeve; the power assembly can move axially within the sleeve; the support block 113 can move radially under the drive of the power assembly until it passes through the guide hole on the sleeve and abuts against the inner wall of the instrument housing within the gap.

[0030] Specifically: the drive motor 106 is located inside the first sleeve 107; the drive output shaft of the drive motor 106 is connected to the first end of the lead screw 109, and is used to drive the lead screw 109 to rotate; the slider 111 is sleeved on the lead screw 109, and the slider 111 moves axially inside the sleeve as the lead screw 109 rotates; the slider 111 is fixedly connected to the support assembly, and is used to drive the support block 113 of the support assembly to pass through the guide hole from inside the sleeve and abut against the inner wall of the instrument housing.

[0031] Furthermore, the key mechanism includes a first key 105 and a second key 104, with the first key 105 and coupling 108 also disposed within the first sleeve 107. The drive output shaft of the drive motor 106 is connected to one end of the coupling 108 via the first key 105; the other end of the coupling 108 is connected to the first end of the lead screw 109 via the second key 104. The drive motor 106, connected to the coupling 108 via the first key 105, transmits power to the lead screw 109, causing the lead screw 109 to rotate, thereby moving the slider 111 on the lead screw 109.

[0032] In this embodiment, the power assembly further includes a bearing unit, which includes a bearing 101 and a bearing sleeve 103. The second end of the lead screw 109 is connected to the bearing 101 via the bearing sleeve 103. The bearing unit is disposed within the second sleeve 102. The lead screw 109 passes through the first sleeve 107 and the second sleeve 102, and the slider 111 moves within the second sleeve 102.

[0033] In this embodiment, the limiting block 110 is circumferentially disposed on the outside of the lead screw 109. The limiting block 110 is located at a preset position inside the sleeve, and the limiting block 110 is used to restrict the movement of the slider 111. More specifically, the limiting block 110 and the bearing sleeve 103 together constrain the stroke of the slider 111 on the lead screw 109.

[0034] Figure 4 This is a diagram illustrating the operational movements of the power assembly and support assembly provided in an embodiment of the present invention, such as... Figure 4 As shown, the push block 112 is fixedly connected to the power assembly and is used to move axially inside the sleeve under the drive of the power assembly. The push block 112 is taperedly engaged with the support block 113, and the contact surfaces of the push block 112 and the support block 113 are slidably connected through a sliding assembly to realize the axial movement of the push block 112 inside the sleeve, thereby causing the support block 113 to move radially at the guide hole. Specifically, the push block 112 is fixedly connected to the slider 111 of the power assembly. When the lead screw 109 rotates in the forward direction, the slider 111 moves downward, thereby driving the push block 112 to move downward. During the downward movement of the push block 112, it drives the support block 113 to pass through the guide hole from inside the sleeve and move towards the inner wall of the instrument housing. Figure 5 This is a schematic diagram of the tapered fit between the push block and the support block provided in an embodiment of the present invention, as shown below. Figure 5 As shown, the sliding component includes a T-shaped groove and a T-shaped locking block that mates with the T-shaped groove; the T-shaped groove is formed on the contact surface of the push block 112, and the T-shaped locking block is formed on the contact surface of the support block 113. Furthermore, in this embodiment, the T-shaped locking block and the support block 113 are integrally designed, that is, the cross-section of the support block 113 is T-shaped.

[0035] Under the action of the power assembly, the support block 113 can also move from the inner wall of the instrument housing into the sleeve, achieving a return along the original path. Specifically, the drive motor 106 in the power assembly drives the lead screw 109 to rotate in the opposite direction. The slider 111 on the lead screw 109 moves upward as the lead screw 109 rotates in the opposite direction, and the push block also moves upward with the slider 111. Under the action of the sliding assembly, the upward movement of the push block drives the support block 113 back into the sleeve. When the support block 113 returns to the sleeve, the multiple frames in the probe mounting frame 2 can be pulled out at any time, that is, probes with different measurement functions can be assembled at will.

[0036] In this embodiment, a push block 112 and a support block 113 form a set of abutting units. The positioning and holding device 1 in this embodiment has 3 sets of abutting units. The push block in the 3 sets of abutting units is driven by the slider 111 on the lead screw 109 to push the support block 113 together to move towards the inner wall of the instrument housing until the instrument housing is clamped to fix the probe mounting frame 2 inside the instrument housing.

[0037] In other embodiments of the present invention, the positioning and holding device 1 is composed of 4 or 6 sets of abutment units.

[0038] In other embodiments of the present invention, the support assembly has one and only one push block 112, which is sleeved on the lead screw 109 and fixedly connected to the slider 111. The push block 112 has multiple T-shaped grooves. Correspondingly, there is one and only one guide hole, which allows multiple support blocks 113 to be pushed out.

[0039] In this embodiment, the support block 113 and the push block 112 are detachably connected through the sliding component, and the support block 113 and the push block 112 with different abutment widths can be replaced according to actual needs.

[0040] In this embodiment, the contact width of the support block 113 is determined by the stroke distance of the power assembly and the angle between the contact surface of the support block 113 and the radial direction. Specifically, the power assembly uses a drive motor 106 to drive the lead screw 109 to rotate, adjust the push block 112 to move up and down, and push the support block 113 to extend and retract. Figure 6 This is a schematic diagram of the angle between the contact surface and the radial direction of the support block provided in an embodiment of the present invention, as shown below. Figure 6 As shown, the pushing stroke of the support block 113 is controlled by the limit block 110 of the lead screw 109 and the motor control system. Let the pitch of the lead screw 109 be P, the number of rotations be n, the track angle between the pushing block 112 and the support block 113 be α, and the unidirectional extension distance of the support block 113 (i.e., the abutment width of the support block 113) be L, then we can obtain: L = P × n × tanα; At the same time, the spacing K of the limit block 110 should ensure that: K≥P*n.

[0041] In this embodiment, the torque provided by the power component to the support component is determined by the travel distance of the transmission component and the transmission efficiency of the transmission component.

[0042] Specifically, when the downhole measuring instrument is in a horizontal position, the support block 113 will experience unilateral support stress. Therefore, the power transmission of the drive motor 106 should satisfy: T = F × p × η × μ, where T represents the torque, F represents the force applied to the lead screw, p represents the lead screw pitch, η represents the transmission efficiency, and μ represents the coefficient of friction. Assuming the total mass of the probe mounting frame 2 is N, in the case of two support points, the torque formula should be: T = N × g × p × η × μ / 2tanα.

[0043] In this embodiment, the support assembly realizes the centering and pushing of the probe mounting frame 2 and the probe. By uniformly designing multiple support blocks 113 in the circumferential direction, the probe mounting frame 2 is stably and evenly pushed towards the axis. Each support block 113 is connected to the pushing block 112 through a slide rail, realizing synchronous pushing in multiple directions. This ensures that the pushing process and force are synchronized and uniform, ensuring that the instrument can achieve the same pushing force and centering effect under different angles and postures.

[0044] Figure 7 This is a schematic diagram of the structure of the positioning and holding device provided in this embodiment of the invention working in conjunction with the calibration table, as shown below. Figure 7 As shown, when the downhole measuring instrument performs azimuth calibration, it is achieved by replacing the support block 113 with different contact widths, such as low support block 1131, medium support block 1132, and high support block 1133, to adapt to calibration tables 3 from different manufacturers.

[0045] The second aspect of this embodiment provides a downhole measuring instrument, which includes: an instrument housing, a probe mounting frame 2, multiple probes, and at least two positioning and holding devices 1, wherein the positioning and holding device is the positioning and holding device 1 as described above; The probe mounting frame 2, multiple probes, and multiple positioning and holding devices 1 are all located inside the instrument housing; Multiple probes are mounted on the probe mounting frame 2; The positioning and holding device 1 is installed at both ends of the probe mounting frame 2.

[0046] In this embodiment, the positioning and holding device 1 is screwed to the probe mounting frame 2, and the screw is circumferentially mounted on the sleeve.

[0047] Although preferred embodiments of the invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including both the preferred embodiments and all changes and modifications falling within the scope of the invention.

[0048] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

[0049] The optional embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the embodiments of the present invention are not limited to the specific details described above. Within the scope of the technical concept of the embodiments of the present invention, various simple modifications can be made to the technical solutions of the embodiments of the present invention, and these simple modifications all fall within the protection scope of the embodiments of the present invention. Furthermore, it should be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. As long as such combination does not violate the spirit of the embodiments of the present invention, it should also be considered as the content disclosed by the embodiments of the present invention.

Claims

1. A positioning and holding device applied to a downhole measuring instrument, the downhole measuring instrument comprising an instrument housing and a probe mounting skeleton arranged inside the instrument housing, a gap existing between the probe mounting skeleton and an inner wall of the instrument housing, characterized in that, The positioning and holding device is located at both ends of the probe mounting frame. The positioning and holding device includes: a housing assembly, a power assembly, and a support assembly. The power assembly is connected to the support assembly. The outer casing assembly includes: a sleeve, the sleeve having a guide hole, and the power assembly and the support assembly being disposed inside the sleeve; The power component is capable of moving within the sleeve; The support assembly includes a support block that can move within the sleeve under the drive of the power assembly until it passes through a guide hole on the sleeve and abuts against the inner wall of the instrument housing within the gap.

2. The positioning and retaining device of claim 1, wherein, The power components include: a drive motor, a lead screw, and a slider; The drive output shaft of the drive motor is connected to the first end of the lead screw and is used to drive the lead screw to rotate. The slider is sleeved on the lead screw, and moves axially within the sleeve as the lead screw rotates. The slider is fixedly connected to the support assembly, thereby driving the support block of the support assembly to move radially within the sleeve.

3. The positioning and retaining device of claim 2, wherein, The power assembly also includes: a key mechanism and a coupling; The drive output shaft of the drive motor is connected to one end of the coupling via the key mechanism; The other end of the coupling is connected to the first end of the lead screw.

4. The positioning and retaining device of claim 2, wherein, The power assembly also includes: a limiting block; The limiting block is circumferentially disposed on the outside of the lead screw, and the limiting block is located at a preset position inside the sleeve. The limiting block is used to restrict the movement of the slider.

5. The positioning and retaining device of claim 2, wherein, The support components also include: a push block; The push block is fixedly connected to the slider and is used to move axially inside the sleeve under the drive of the slider; The push block and the support block are tapered together, and the contact surfaces of the push block and the support block are slidably connected by a sliding component to enable the push block to move axially inside the sleeve, thereby enabling the support block to move radially at the guide hole.

6. The positioning and retaining device of claim 5, wherein, The sliding component includes a T-shaped slide groove and a T-shaped locking block that mates with the T-shaped slide groove; The T-shaped groove is formed on the contact surface of the push block, and the T-shaped locking block is formed on the contact surface of the support block.

7. The positioning and retaining device of claim 5, wherein, The support component includes multiple sets of abutment units, each set of abutment units including: a push block and a support block, and the abutment width of the multiple support blocks in each set of abutment units is the same.

8. The positioning and retaining device of claim 5, wherein, The contact width of the support block is determined based on the travel distance of the power assembly and the angle between the contact surface of the support block and the radial direction.

9. The positioning and retaining device of claim 5, wherein, The torque provided by the power component to the support component is determined based on the travel distance of the transmission component and the transmission efficiency of the transmission component.

10. The positioning holding device according to claim 1, characterized in that, The sleeve includes a first sleeve and a second sleeve, the first sleeve and the second sleeve are internally connected, the support assembly is placed inside the second sleeve, and the guide hole is formed on the second sleeve.

11. A downhole measuring instrument characterized by The downhole measuring instrument includes: an instrument housing, a probe mounting frame, multiple probes, and at least two positioning and holding devices, wherein the positioning and holding devices are the positioning and holding devices according to any one of claims 1-10; The probe mounting frame, multiple probes, and multiple positioning and holding devices are all located inside the instrument housing; Multiple probes are mounted on the probe mounting frame; The positioning and holding device is installed at both ends of the probe mounting frame.

12. The downhole measuring instrument of claim 11, wherein, The positioning and holding device is connected to the probe mounting frame screw, and the screw is circumferentially mounted on the sleeve.

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