A logging tool for measuring the borehole wall morphology of polar ice cap boreholes

Abstract

The present invention proposes a well logging instrument for measuring the borehole wall morphology of polar ice sheet boreholes, which belongs to the field of well logging technology and comprises a sliding part, a measuring arm support frame, a measuring arm, a force measuring leaf spring and a limit block. The number of measuring arms is nine. The well logging instrument abandons the traditional structure of using springs and adopts a more space-saving force measuring leaf spring design. While having sufficient accuracy, the structure of the well logging instrument is more streamlined, and the number of measuring arms can reach nine. At the same time, a measuring arm is proposed, which can achieve sufficiently high accuracy during measurement and has strong applicability, and can solve many problems in the measurement process. At the same time, the measuring arm is split into individuals, and each measuring arm is regarded as an independent system. Each measuring arm measures the data of a point. The more points there are, the more accurate the detection of the cross-sectional morphology of the borehole wall is, making it more meaningful to increase the number of measuring arms. At the same time, the well logging instrument is easy to repair and maintain and is not prone to self-locking.

Description

Technical Field

[0001] The present invention belongs to the field of well logging technology, and in particular, relates to a well logging instrument for measuring the morphology of borehole walls in polar ice caps. Background Art

[0002] The polar ice caps are formed by the gradual accumulation of snow that never melts all year round. The snow is also mixed with dust and suspended particles in the Earth's atmosphere, soluble chemical elements, etc. Therefore, through the ice layer, we can understand the important climate information contained in the polar ice caps that has been preserved with the snow for millions of years.

[0003] In addition to ice cores, boreholes in polar ice sheets also contain many features with important information. By detecting the cross-sectional morphology of the borehole wall, on the one hand, the strain of the ice layer can be calculated, and then the movement law of the glacier can be inverted, which is of great significance to the study of the changes and stability of the polar ice sheet. On the other hand, it can be observed whether there is any collapse of the borehole wall and irregular conditions of the borehole wall caused by brittle ice and warm ice inside the ice layer, reducing the occurrence of accidents such as drill jams; by measuring the temperature changes at different depths, the changes in ancient climate can be reconstructed and the geothermal flux can be studied; through the data of the hole depth, the thickness of the ice layer and the ice layer information can be determined.

[0004] Traditional geological petroleum logging mainly focuses on the measurement of aperture, and determines the amount of cement required for cementing according to the aperture size, and its measurement accuracy does not need to be too high. However, polar ice cap logging not only needs to measure the aperture, but also needs to characterize the shape of the cross-section of the borehole wall. Moreover, most of the wells measured in the polar ice cap have deformed under the stress of glacial movement, and most of them can be approximately regarded as ellipses. When measuring the borehole shape of the elliptical cross-section, at least five points are required to accurately fit the observed shape of the borehole. In addition, the low temperature conditions of polar ice cap logging make traditional geological drilling logging instruments unable to be applied to polar ice cap logging. For example, the patent document with announcement number CN201857958U discloses a six-arm caliper logging instrument, in which the measuring arm is in flat contact with the borehole wall, the description of the borehole wall is not accurate enough, and the measuring arm is ∧-shaped, which is relatively stable. Its contraction requires a large horizontal force. When encountering a groove or protrusion with a large aperture change, the vertical force is very large, so it is easy to get stuck in the hole and self-locking occurs. The patent document with publication number CN112878993A discloses a leaf spring type six-arm split-motion wellbore measuring instrument, whose measuring arms are composed of multiple curved steel plates. The force required for their retraction and extension is large, which can easily damage the hole wall. Moreover, the six measuring arms are all connected to a buffer spring, which is still a whole and cannot achieve true split motion. The patent document with publication number CN101131089B discloses a push-to-pull multi-arm straightening wellbore microelectrode logging instrument, in which the four measuring walls are connected to the same spring, which can only obtain the radius of the circle, but its measurement accuracy will be greatly reduced when measuring the morphology of the borehole with an elliptical cross section.

[0005] Since the cross-section of the borehole wall of the polar ice cap is mostly irregular, in order to characterize the irregular cross-section of the borehole wall, the multiple measuring arms of the logging instrument must be separated, and due to the influence of environmental factors and its high precision requirements, the structure of the logging instrument used for measuring the cross-section of the borehole wall of the polar ice cap is very high. However, the current logging instruments have problems such as being too complicated in structure to meet these requirements, and the number of measuring arms cannot be increased, resulting in the overall results not meeting expectations. Summary of the invention

[0006] In view of the above problems, the purpose of the present invention is to provide a logging instrument for measuring the morphology of borehole walls in polar ice caps. By means of a structure in which the force measuring leaf spring cooperates with the measuring arm to measure the aperture, it is possible for the nine measuring arms to independently and accurately complete the measurement of the aperture, thereby achieving accurate characterization of the cross-sectional morphology of the borehole wall and providing data support for understanding the internal conditions of the well.

[0007] The technical solution adopted by the present invention to achieve the above-mentioned purpose is: a logging instrument for measuring the morphology of borehole walls in polar ice caps, comprising: a sliding member, a measuring arm support frame, a measuring arm, a force measuring leaf spring and a limit block, the number of the measuring arms is nine, the nine measuring arms are evenly distributed along the circumference of the measuring arm support frame, and the upper ends of all the measuring arms are hingedly connected to the measuring arm support frame through pins, and the middle part of the measuring arm is connected to the pressure chamber located on the upper part of the logging instrument through a spring, and the spring is always in a stretched state and can always provide tension for the measuring arm; the logging instrument goes up When the measuring arm rotates around the pin shaft at different angles under the action of the spring tension, the elliptical arc surface on the upper part of the measuring arm contacts with the force measuring leaf spring and slides relatively; the measuring arm is in the shape of an elongated strip as a whole, and the lower end of the measuring arm has an arc protrusion, which protrudes from the surface of the measuring arm, so that the contact mode between the measuring arm and the borehole wall is always point contact, thereby accurately describing the shape of the borehole wall, and at the same time, the surface of the side of the lower end of the measuring arm facing away from the circular protrusion is an arc surface, which can prevent the logging instrument from being stuck at the uneven position of the borehole wall when it is moving upward; the upper end of the measuring arm The surface of one side of the end portion in contact with the force measuring leaf spring is an elliptical arc surface. When the measuring arm rotates around the pin shaft at different angles, the elliptical arc surface of the measuring arm will contact with the force measuring leaf spring and slide relatively. Due to the characteristics of its elliptical arc, the bending degree of the force measuring leaf spring will change with the rotation angle of the measuring arm, so that the drilling hole diameter can be judged according to the bending degree of the force measuring leaf spring; the sliding member is arranged inside the measuring arm support frame, and the upper part of the sliding member is connected to the driving motor so that the sliding member can move up and down under the drive of the driving motor; the limit block is fixed on the sliding member, and the limit block is fixed on the sliding member. The block cooperates with the measuring arm. During the downward movement of the logging instrument, the limit block is used to limit the measuring arm so that the position of the measuring arm is fixed relative to the limit block, so that the measuring arm is in a retracted state during the downward movement of the logging instrument. The number of the force measuring leaf springs is consistent with the number of the measuring arms and corresponds one to one. Each of the force measuring leaf springs is arranged along the axial direction of the sliding part and fixed on the outside of the sliding part, and each of the force measuring leaf springs is installed with a strain gauge. When the force measuring leaf spring is bent to different degrees, the resistance value of the strain gauge will change accordingly, and the bending degree of the force measuring leaf spring can be reflected according to the resistance value.

[0008] Furthermore, the sliding member is composed of an upper half and a lower half, and the upper half and the lower half are coaxially arranged and fixedly connected. The upper half of the sliding member is a round rod, which is used as a connecting rod to connect the driving motor. The lower half of the sliding member is a cylinder with a closed upper end and an open lower end. The side surface of the lower half of the sliding member is evenly distributed with nine grooves that are narrow on the top and wide on the bottom along the circumference. The lower part of the groove is an unpenetrated blind groove portion. The unpenetrated blind groove portion of the groove is fixed to the force measuring leaf spring by a pressure block and a screw. The other parts of the groove except the position of the blind groove portion are penetrated to form a through groove portion. The width of the narrow upper part of the groove is consistent with the width of the measuring arm. After the measuring arm is fixed by the pin shaft, the upper part of the measuring arm is in the narrow upper part of the groove, so that the sliding member can only slide up and down in the longitudinal direction, and a limit block is installed on the top of the groove.

[0009] Furthermore, the round rod and the cylinder in the sliding member are coaxially connected via a pin.

[0010] Furthermore, the outer contour of the measuring arm support frame is a stepped cylindrical shape as a whole, and nine accommodating grooves for accommodating the measuring arm are evenly distributed on the circumference of the measuring arm support frame, and each accommodating groove penetrates the measuring arm support frame radially, and the width of the accommodating groove is consistent with the width of the measuring arm.

[0011] Furthermore, a slot is provided at the upper end of the measuring arm to cooperate with the limit block, and the slot at the upper end of the measuring arm can cooperate with the limit block to make the measuring arm in a retracted state during the downward movement of the logging instrument. A protrusion is provided at the upper end of the measuring arm on the side facing away from the elliptical arc surface, and when the measuring arm is opened to a certain angle, the protrusion will abut against the limit block to prevent the measuring arm of the logging instrument from opening too much and causing self-locking. A pin shaft hole is provided in the middle of the upper end of the measuring arm for installing a pin shaft. A lifting ear for connecting a spring is provided in the middle of the measuring arm. The lifting ear and the circular protrusion are located on the same side of the measuring arm.

[0012] Furthermore, the force measuring leaf spring is in the shape of a rectangular sheet as a whole, is installed on the outside of the sliding member, and is fixed to the sliding member by screws and a pressing block.

[0013] Through the above design scheme, the present invention can bring the following beneficial effects:

[0014] 1. The force measuring leaf spring used in the present invention cooperates with the elliptical arc surface on the upper part of the measuring arm to reflect the aperture. Compared with the existing method of using a spring to reflect the aperture, the structure of the present invention is more streamlined, the measurement accuracy is also sufficiently high, and the occupied space is greatly reduced. This also enables the number of measuring arms of the present invention to reach nine, further improving the accuracy of the description of the cross-sectional morphology of the hole wall. In addition, each measuring arm has an independent force measuring leaf spring to cooperate with it, and they work independently without affecting each other, so that the logging instrument can more accurately describe the irregular-shaped hole wall section, and it is also more convenient for the maintenance and repair of the measuring arm.

[0015] 2. The measuring arm proposed by the present invention has a circular arc protrusion design at the lower end, which ensures that the contact mode between the measuring arm and the hole wall is always the most accurate point contact, so that the logging instrument can achieve a higher level of accuracy in describing the cross-sectional shape of the hole wall, and even if the logging instrument encounters a convex or concave part of the hole wall during the upward movement, the logging instrument can still measure accurately and will not get stuck in it and cause self-locking. In addition, the design of the upper end of the measuring arm is also very applicable. It can cooperate with the force measuring leaf spring to reflect the hole diameter, and can remain in a contracted state during the downward movement of the logging instrument, and then open after reaching the specified position, and can also prevent the self-opening angle from being too large and causing self-locking. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of the present application. The exemplary embodiments of the present invention and their descriptions are used to understand the present invention and do not constitute improper limitations of the present invention. In the drawings:

[0017] Figure 1 It is a three-dimensional schematic diagram of a logging instrument used for measuring the borehole wall morphology of a polar ice cap borehole according to an embodiment of the present invention;

[0018] Figure 2 This is a schematic diagram of the measuring arm support frame;

[0019] Figure 3 for Figure 2 AA section view;

[0020] Figure 4 A schematic diagram of a sliding member connecting a limit block and a force measuring leaf spring;

[0021] Figure 5 for Figure 4 AA section view;

[0022] Figure 6 This is a schematic diagram of the measuring arm;

[0023] Figure 7 This is the first state diagram of the cooperation between the measuring arm and the limit block;

[0024] Figure 8 This is the second state diagram of the cooperation between the measuring arm and the limit block;

[0025] Fig. 9 This is the third state diagram of the cooperation between the measuring arm and the limit block.

[0026] The marks in the figure are as follows: 1-sliding part; 2-measuring arm support frame; 3-measuring arm; 4-force measuring leaf spring; 5-pin shaft; 6-limiting block; 7-arc protrusion; 8-lifting ear; 9-protrusion; 10-pin shaft hole; 11-slot; 12-elliptical arc surface; 13-spring; 101-round rod; 102-cylinder. DETAILED DESCRIPTION

[0027] In order to explain the present invention more clearly, the present invention is further described below in conjunction with preferred embodiments and accompanying drawings. It should be understood by those skilled in the art that the content described below is illustrative rather than restrictive, and should not be used to limit the scope of protection of the present invention. Unless otherwise defined, the technical terms or scientific terms used herein should be the common meanings understood by people with ordinary skills in the field to which the present invention belongs.

[0028] To avoid obscuring the essence of the present invention, well-known methods, procedures, processes, components and circuits have not been described in detail.

[0029] like Figures 1 to 6 As shown, a logging instrument for measuring the borehole wall morphology of a polar ice cap borehole comprises a sliding member 1, a measuring arm support frame 2, a measuring arm 3, a force measuring leaf spring 4 and a limit block 6.

[0030] See also Figure 2 and Figure 3 The measuring arm support frame 2 is the main body, which is used to connect all parts. The measuring arm support frame 2 is connected to the measuring arm 3 through the pin 5, so that the measuring arm 3 can rotate around the pin 5 to a certain extent, and the measuring arm 3 can cooperate with the force measuring leaf spring 4 to slide relative to each other.

[0031] The outer contour of the measuring arm support frame 2 is a stepped cylindrical shape as a whole. During the logging process, the measuring arm support frame 2 is connected to the pressure chamber located on its upper part for storing the measuring elements of the logging instrument by screws, and the measuring arm support frame 2 is connected to the anti-torsion device located on its lower part for preventing the logging instrument from rotating by screws. Nine accommodating grooves for accommodating the measuring arm 3 are evenly distributed on the circumference of the measuring arm support frame 2, and each accommodating groove radially penetrates the measuring arm support frame 2, and the width of the accommodating groove is consistent with the width of the measuring arm 3. Since the measuring arm 3 needs to remain in a retracted state when the logging instrument is descending, the through groove on the measuring arm support frame 2 is used to place the measuring arm 3 when the logging instrument is descending, so that the measuring arm 3 will not protrude in the retracted state, and prevent the measuring arm 3 from protruding and hanging on the well wall when the logging instrument is descending. The large-diameter cylindrical space inside the measuring arm 3 is used to install the sliding part 1.

[0032] See also Figure 4 and Figure 5The upper half of the sliding member 1 is a round rod 101, which is used as a connecting rod to connect the drive motor and transmit the pulling force. The round rod 101 is coaxially connected to the lower half of the sliding member 1 through a pin. The lower half of the sliding member 1 is the main body of the sliding member 1, which is a cylinder 102 with a closed upper end and an open lower end. Nine grooves with narrow upper ends and wide lower ends are evenly distributed on its side. The lower half of the wide part of the groove is not penetrated. The unpenetrated part is fixed to the force measuring leaf spring 4 by a pressure block and a screw. The other parts of the groove are penetrated. The width of the narrow part of the upper part is consistent with the width of the measuring arm 3. After the measuring arm 3 is fixed by the pin 5, the upper part of the measuring arm 3 will be in the narrow part of the upper half of the groove, so that the sliding member 1 cannot rotate and can only slide up and down in the longitudinal direction. A limit block 6 is installed on the top of the groove to prevent the measuring arm 3 from opening too much and causing self-locking.

[0033] like Figure 6 As shown, the measuring arm 3 is in the shape of a long strip as a whole, and there is a large elliptical arc surface 12 on the upper part of the measuring arm 3. A slot 11 cooperating with the limit block 6 is provided at the upper end of the measuring arm 3. A protrusion 9 is provided on the side of the upper end of the measuring arm 3 facing away from the elliptical arc surface 12, and a pin hole 10 for installing the pin 5 is provided in the middle of the upper end of the measuring arm 3. The lower end of the measuring arm 3 has an arc protrusion 7 in the same direction as the lifting ear 8, and the circular protrusion 7 protrudes from the surface of the measuring arm 3, and the surface of the lower end of the measuring arm 3 facing away from the circular protrusion 7 is an arc surface. There are nine measuring arms 3 in total, and the nine measuring arms 3 are evenly distributed in the nine receiving grooves in the circumferential direction of the measuring arm support frame 2.

[0034] The force measuring leaf spring 4 is in the shape of a rectangular thin sheet as a whole, with a strain gauge in the middle, installed on the outside of the sliding member 1, and fixed on the sliding member 1 by screws and a pressure block.

[0035] The arc protrusion 7 at the lower end of each measuring arm 3 can not only make point contact with the borehole wall through the protruding part, accurately describe the borehole wall, but also prevent the logging instrument from being stuck by the uneven position of the borehole wall when ascending; the lifting ear 8 in the middle of the measuring arm 3 is used to connect with one end of the spring 13, and the other end of the spring 13 is connected to the pressure chamber. When it is not put into the borehole, the measuring arm 3 is manually retracted, and the spring 13 is also stretched at this time, and then the driving motor is driven forward to drive the sliding member 1 downward, and the measuring arm 3 is stuck through the limit block 6, and the measuring arm 3 is always in a retracted state during the descending process of the logging instrument, and the spring 13 is in a stretched state. After descending to the specified position, the driving motor is reversed to drive the sliding member 1 upward, and the limit block 6 set on the sliding member 1 is separated from the card slot 11 on the measuring arm 3, and the measuring arm 3 is released. Under the pulling force of the spring 13, the measuring arm 3 is opened to abut against the hole wall. Then the logging instrument moves upward and starts to work normally; when the measuring arm 3 rotates around the pin 5 at different angles, the elliptical arc surface 12 at the upper end of the measuring arm 3 will contact and slide relatively with the force measuring leaf spring 4. Due to the characteristics of its elliptical arc, the degree of bending of the force measuring leaf spring 4 will change with the rotation angle of the measuring arm 3, so that the aperture can be judged according to the degree of bending of the force measuring leaf spring 4.

[0036] like Figure 7 , Figure 8 and Fig. 9 As shown, the slot 11 at the upper end of the measuring arm 3, when the measuring arm 3 is not opened, the driving motor drives the sliding member 1 to move downward, and the slot 11 can cooperate with the limit block 6 on the sliding member 1, so that the limit block 6 is stuck in the slot 11, thereby fixing the measuring arm 3, so that the measuring arm 3 is in a retracted state during the downward movement of the logging instrument; after reaching the specified position, the driving motor drives the sliding member 1 to move it upward, release the measuring arm 3, and the measuring arm 3 starts to work; the protrusion 9 at the upper end of the measuring arm 3 will abut the limit block 6 when the measuring arm 3 is opened to a certain angle, so as to prevent the measuring arm 3 of the logging instrument from opening at an excessive angle and causing self-locking;

[0037] Working process of the present invention:

[0038] When using a logging instrument for measuring the borehole wall morphology of polar ice caps proposed in the present invention, first, the measuring arm 3 of the logging instrument needs to be in a retracted state during the downward process, so the measuring arm 3 needs to be manually retracted into the accommodating groove on the measuring arm support frame 2, and then the motor is driven to rotate forward, and the sliding member 1 is moved downward through the round rod 101 on the sliding member 1, and the limit block 6 is clamped in the clamping groove 11 of the measuring arm 3, ensuring that the measuring arm 3 is always in a retracted state during the process of descending to the corresponding position in the borehole.

[0039] After the logging instrument is lowered into the borehole, the driving motor is reversed through the ground computer to drive the sliding member 1 to move upward, and the limit block 6 is separated from the measuring arm 3. Because the spring 13 connected to the middle part of the measuring arm 3 is always in a stretched state and can provide pulling force for the measuring arm 3, the measuring arm 3 will open under the pulling force of the spring 13 after being separated from the limit block 6, and press against the borehole wall, and the logging instrument starts to move upward.

[0040] During the upward movement of the logging instrument, the lower end of the measuring arm 3 is close to the borehole wall, and the upper end will press the force measuring leaf spring 4 according to its opening degree while rotating around the pin shaft 5. The bending degree of the force measuring leaf spring 4 will change according to the hole size. The strain gauge on the force measuring leaf spring 4 can convert its bending degree into an electrical signal and transmit it to the surface. The cross-sectional shape of the hole wall can be understood based on the electrical signal.

[0041] Finally, it should be noted that the above are only preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or replace some of the technical features therein with equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A logging tool for measuring the morphology of borehole walls in polar ice caps, characterized in that: include: A sliding member (1), a measuring arm support frame (2), a measuring arm (3), a force measuring leaf spring (4) and a limit block (6); the number of the measuring arms (3) is nine, and the nine measuring arms (3) are evenly distributed along the circumference of the measuring arm support frame (2); the upper ends of all the measuring arms (3) are hingedly connected to the measuring arm support frame (2) through a pin shaft (5); at the same time, the middle part of the measuring arm (3) is connected to a pressure chamber located at the upper part of the well logging instrument through a spring (13); when the well logging instrument moves upward, under the tension of the spring (13), when the measuring arm (3) rotates around the pin shaft (5) to different angles, the upper end of the measuring arm (3) contacts with the force measuring leaf spring (4) and slides relatively; the measuring arm (3) is in the shape of a long strip as a whole, and the lower end of the measuring arm (3) has a circular protrusion (7), which protrudes from the surface of the measuring arm (3), and at the same time, the lower end of the measuring arm (3) is in contact with the circular protrusion (7). The side surface of the shaped protrusion (7) facing away is an arc surface, so that the contact mode between the measuring arm (3) and the borehole wall is always point contact, and the side surface of the upper end of the measuring arm (3) in contact with the force measuring leaf spring (4) is an elliptical arc surface (12); the sliding member (1) is arranged inside the measuring arm support frame (2), and the upper part of the sliding member (1) is connected to the driving motor, so that the sliding member (1) can move up and down under the drive of the driving motor; the limit block (6) is fixed on the sliding member (1), and the limit block (6) cooperates with the measuring arm (3) so that the measuring arm (3) is in a retracted state during the downward movement of the logging instrument; the number of the force measuring leaf springs (4) is consistent with the number of the measuring arms (3) and corresponds one to one, each of the force measuring leaf springs (4) is arranged along the axial direction of the sliding member (1) and fixed on the outer side of the sliding member (1), and each of the force measuring leaf springs (4) is installed with a strain gauge.

2. The logging tool for measuring the borehole wall morphology of polar ice cap boreholes according to claim 1, characterized in that: The sliding member (1) is composed of an upper part and a lower part, which are coaxially connected. The upper part of the sliding member (1) is a round rod (101), which is used as a connecting rod to connect the drive motor. The lower part of the sliding member (1) is a cylinder (102) with a closed upper end and an open lower end. Nine grooves that are narrow at the top and wide at the bottom are evenly distributed on the side surface of the lower part of the sliding member (1) along the circumferential direction. The lower part of the groove is a blind groove part that is not penetrated. The blind groove part that is not penetrated by the groove is used to fix the force measuring leaf spring (4) through a pressure block and a screw. The other parts of the groove except the position of the blind groove part are penetrated to form a through groove part. The width of the narrow part of the upper part of the groove is consistent with the width of the measuring arm (3). After the measuring arm (3) is fixed by the pin (5), the upper part of the measuring arm (3) is located in the narrow part of the upper part of the groove, so that the sliding member (1) can only slide up and down in the longitudinal direction. A limit block (6) is installed at the top of the groove.

3. The logging tool for measuring the borehole wall morphology of polar ice cap boreholes according to claim 2, characterized in that: The round rod (101) and the cylinder (102) in the sliding member (1) are connected by a pin.

4. The logging tool for measuring the borehole wall morphology of polar ice cap boreholes according to claim 1, characterized in that: The outer contour of the measuring arm support frame (2) is in the shape of a stepped cylinder as a whole, and nine accommodating grooves for accommodating the measuring arm (3) are evenly distributed in the circumferential direction of the measuring arm support frame (2), and each accommodating groove radially penetrates the measuring arm support frame (2), and the width of the accommodating groove is consistent with the width of the measuring arm (3).

5. The logging tool for measuring the borehole wall morphology of polar ice cap boreholes according to claim 1, characterized in that: The upper end of the measuring arm (3) is provided with a slot (11) that cooperates with the limit block (6).

6. The logging instrument for measuring the borehole wall morphology of polar ice cap boreholes according to claim 1 or 5, characterized in that: The upper end of the measuring arm (3) has a protrusion (9) on the side facing away from the elliptical arc surface (12).

7. The logging tool for measuring the borehole wall morphology of polar ice cap boreholes according to claim 1, characterized in that: A pin hole (10) for mounting a pin (5) is provided in the middle of the upper end of the measuring arm (3).

8. The logging tool for measuring the borehole wall morphology of polar ice cap boreholes according to claim 1, characterized in that: A lifting lug (8) for connecting a spring (13) is provided in the middle of the measuring arm (3).

9. The logging tool for measuring the borehole wall morphology of polar ice cap boreholes according to claim 8, characterized in that: The lifting ear (8) and the circular protrusion (7) are located on the same side of the measuring arm (3).

10. The logging tool for measuring the borehole wall morphology of polar ice cap boreholes according to claim 1, characterized in that: The force measuring leaf spring (4) is in the shape of a rectangular thin sheet as a whole, is installed on the outside of the sliding member (1), and is fixed to the sliding member (1) by means of screws and a pressing block.

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