Drilling stress measuring device and manufacturing method

Abstract

The invention relates to the technical field of measurement, in particular to a borehole stress measuring device and a manufacturing method, and aims to solve the problem of insufficient monitoring precision and reliability caused by linear contact between an existing borehole stress meter and a borehole. The borehole stress measuring device provided by the invention comprises an oil bag pipe, a first blocking plate, a second blocking plate and an oil pipe, the two ends of the oil bag pipe are blocked by the first blocking plate and the second blocking plate to form a hollow cavity. One end of the oil pipe penetrates through the second blocking plate, communicates with the hollow cavity and is used for injecting hydraulic oil into the hollow cavity. According to the borehole stress measuring device provided by the invention, hydraulic oil is injected into the oil bag pipe to expand the oil bag pipe, so that the outer wall of the oil bag pipe is fully attached to the inner wall of the borehole to form surface contact, and the problem of insufficient monitoring precision and reliability caused by linear contact is avoided.

Description

Technical Field

[0001] The present invention relates to the field of measurement technology, and in particular to a borehole stress measurement device and a manufacturing method thereof. Background Art

[0002] In mine engineering, borehole stress monitoring is crucial for preventing disasters such as rock bursts. Compared with other methods, borehole stress monitoring can more directly and accurately reflect the stress state of the surrounding rock of the mine, providing an important basis for the safe mining and stability assessment of the mine.

[0003] The traditional oil pillow borehole stress gauge has poor coupling due to linear contact with the borehole, and it is difficult to comprehensively and accurately obtain the stress information around the borehole in practical applications, which limits the accuracy and reliability of borehole stress monitoring. Summary of the Invention

[0004] The purpose of the present invention is to provide a borehole stress measurement device and a manufacturing method thereof to solve the problem of insufficient monitoring accuracy and reliability caused by the linear contact between the existing borehole stress gauge and the borehole.

[0005] To solve the above technical problems, the technical solution provided by the present invention lies in:

[0006] The present invention provides a borehole stress measurement device, which is characterized by comprising an oil bladder tube, a first plug plate, a second plug plate and an oil pipe;

[0007] Both ends of the oil bladder tube are blocked by the first plug plate and the second plug plate to form a hollow cavity;

[0008] One end of the oil pipe passes through the second plug plate and communicates with the hollow cavity for injecting hydraulic oil into the hollow cavity.

[0009] In some alternative embodiments, the cross-section of the oil bladder tube is a regular polygon or a circle.

[0010] In some alternative embodiments, the number of sides of the regular polygon is a, and a ∈ [4, 12].

[0011] In some alternative embodiments, process grooves are provided on the sides of the regular polygon.

[0012] In some alternative embodiments, the ratio of the diameter of the circumscribed circle of the regular polygon to the wall thickness of the oil bladder tube is b, and b ∈ [25, 45];

[0013] The ratio of the diameter of the circumscribed circle of the regular polygon to the diameter of the borehole is c, and c ∈ [0.91, 0.98];

[0014] The ratio of the diameter of the circumscribed circle of the regular polygon to the diameter of the fully inflated oil bladder tube is d, and d ∈ [0.82, 0.93].

[0015] In some alternative embodiments, the oil bladder tube is in a spiral shape extending along the length direction.

[0016] In some alternative embodiments, the oil bladder tube is made of 12Cr1MoV.

[0017] In some alternative embodiments,

[0018] In some alternative embodiments, the oil bladder tube is twisted around the axis, and the twist angle along the length direction is α, where α ∈ [0°, 10°].

[0019] On the other hand, the present invention provides a method for manufacturing a borehole stress measurement device for manufacturing the above-mentioned borehole stress measurement device, including the following steps:

[0020] Weld the first plug plate and the second plug plate to both ends of the oil bladder tube respectively to form the hollow cavity;

[0021] Pass one end of the oil pipe through the second plug plate and fill the hollow cavity with hydraulic oil through the oil pipe;

[0022] Weld the second plug plate to the oil pipe and seal the gap between the oil pipe and the second plug plate.

[0023] Combining the above technical solutions, the technical effects that the present invention can achieve are as follows:

[0024] The borehole stress measurement device provided by the present invention includes an oil bladder tube, a first plug plate, a second plug plate, and an oil pipe; both ends of the oil bladder tube are blocked by the first plug plate and the second plug plate to form a hollow cavity; one end of the oil pipe passes through the second plug plate and communicates with the hollow cavity for injecting hydraulic oil into the hollow cavity.

[0025] The borehole stress measurement device provided by the present invention injects hydraulic oil into the oil bladder tube to expand the oil bladder tube, so that the outer wall of the oil bladder tube is fully attached to the inner wall of the borehole, forming a surface contact, and avoiding the problem of insufficient monitoring accuracy and reliability caused by linear contact. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for the description of the specific embodiments or the prior art. Obviously, the following drawings are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0027] Figure 1 It is a schematic structural diagram of the borehole stress measurement device provided by the embodiment of the present invention;

[0028] Figure 2 Cross-sectional schematic view of the oil bladder tube;

[0029] Figure 3 Structural schematic view of the oil bladder tube;

[0030] Figure 4 Top view of the oil bladder tube.

[0031] Icon: 100, oil bladder tube; 200, first plug plate; 300, second plug plate; 400, oil pipe; 110 - process groove. Detailed implementation manners

[0032] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. Generally, the components of the embodiments of the present invention described and illustrated in the drawings here can be arranged and designed in various different configurations.

[0033] The following will, with reference to the accompanying drawings, elaborate on some implementation manners of the present invention. Without conflict, the following embodiments and the features in the embodiments can be combined with each other.

[0034] Traditional oil pillow borehole stress gauges have a single monitoring direction and poor coupling due to linear contact with the borehole, making it difficult to comprehensively and accurately obtain stress information around the borehole in practical applications, which limits the accuracy and reliability of borehole stress monitoring.

[0035] In view of this, the present invention provides a borehole stress measurement device, including an oil bladder tube 100, a first plug plate 200, a second plug plate 300, and an oil pipe 400; both ends of the oil bladder tube 100 are blocked by the first plug plate 200 and the second plug plate 300 to form a hollow cavity; one end of the oil pipe 400 passes through the second plug plate 300 and communicates with the hollow cavity for injecting hydraulic oil into the hollow cavity.

[0036] The borehole stress measurement device provided by the present invention injects hydraulic oil into the oil bladder tube 100 to expand the oil bladder tube 100, so that the outer wall of the oil bladder tube 100 is fully attached to the inner wall of the borehole, forming a surface contact, avoiding the problem of insufficient monitoring accuracy and reliability caused by linear contact.

[0037] The following will, in combination with Figures 1 - 4 , elaborate on the structure and shape of the borehole stress measurement device provided in this embodiment.

[0038] In this embodiment, a through hole is provided on the second plug plate 300. The oil pipe 400 passes through the through hole and communicates with the hollow cavity, and is connected to the second plug plate 300 by welding.

[0039] In this embodiment, the oil bladder tube 100 is made of a thin-walled alloy tube, that is, made of alloy steel. Specifically, the material can be selected as 12Cr1MoV.

[0040] In an alternative embodiment of the present implementation, the cross-section of the oil bladder tube 100 is a regular polygon or a circle. The number of sides of the regular polygon is a. Considering the actual processing and application conditions, the preferred value range of a is a ∈ [4, 12]. Obviously, a is a positive integer. When a approaches infinity, it is a circle.

[0041] When the cross-section of the oil bladder tube 100 is a regular polygon, process grooves 110 are provided on the sides of the regular polygon, as Figure 2 shown. The process grooves 110 are used to improve the ability of the oil bladder tube 100 to resist external deformation when there is no oil pressure inside, and more importantly, to achieve expansion deformation during internal pressurization, so that the oil bladder tube 100 after expansion deformation can achieve good coupling contact with the inner wall of the drilling hole in the radial direction.

[0042] Similarly, when the cross-section of the oil bladder tube 100 is a circle, the process grooves 110 can be evenly distributed along the circumference.

[0043] It should be noted that when the cross-section of the oil bladder tube 100 is a circle, the practicality is relatively low. The reason is that a circle is not easy to expand, and when the size of the circular tube is small, poor coupling will occur, and when the size of the circular tube is large, it is difficult to install.

[0044] To reduce stress concentration during processing and expansion deformation, smooth fillet transitions are provided at the corners of the regular polygon, the process grooves 110, and the connections between each side and the process grooves 110.

[0045] When inflated with hydraulic oil, the oil bladder tube 100 expands into a circular tube and makes full contact with the drilling hole.

[0046] In some alternative embodiments, to ensure that the oil bladder tube 100 has the best deformation ability and anti-deformation ability, it is necessary to control the ratio b of the diameter of the circumscribed circle of the regular polygon to the wall thickness of the oil bladder tube 100, the ratio c of the diameter of the circumscribed circle of the regular polygon to the diameter of the drilling hole, and the ratio d of the diameter of the circumscribed circle of the regular polygon to the diameter of the fully expanded oil bladder tube 100.

[0047] Specifically, b ∈ [25, 45], c ∈ [0.91, 0.98], d ∈ [0.82, 0.93].

[0048] When the inside of the bladder tube is filled with oil and pressurized, the radial oil pressure causes the oil bladder tube 100 to expand outward. Since the radial force-bearing area is larger than the axial force-bearing area, the radial deformation occurs before the axial deformation and the deformation amount is larger than the axial deformation. When the wall thickness remains unchanged, the axial length shortens as the radial expansion deformation increases, and as a result, the oil bladder tube 100 moves away from the bottom of the drilling hole and cannot sense the axial stress change.

[0049] In this embodiment, in order to monitor the axial pressure and simultaneously monitor the radial stress and axial stress of the borehole, so as to more accurately reflect the stress state of the surrounding rock of the mine and provide an important basis for the safe mining and stability assessment of the mine, the oil bladder tube 100 is in a spiral shape extending along the length direction to compensate for the reduction of the axial length when the oil bladder tube 100 expands radially. That is, the oil bladder tube 100 twists around its own axis, and the twist angle along the length direction is α, α ∈ [0°, 10°], as Figure 3 , Figure 4 shown.

[0050] Obviously, the twist angle of the oil bladder tube 100 needs to be set according to actual needs as long as an appropriate compensation amount is ensured.

[0051] When hydraulic oil is injected into the oil bladder tube 100 and it expands, its axial dimension shortens, and the spiral shape forms a certain amount of redundancy. When expanding, the twist of the oil bladder tube 100 is eliminated and it elongates along the length direction, thereby making up for the length shortening caused by the radial expansion, ensuring the contact between the end of the oil bladder tube 100 and the bottom of the borehole, and thus enabling the simultaneous monitoring of the radial stress and axial stress. That is, during use, ensure the contact between the first plug plate 200 and the bottom of the borehole.

[0052] The spiral shape is achieved by twisting a certain angle on the basis of a straight shape. Through the spiral design, the axial oil pressure straightens and elongates the spiral oil bladder tube 100, making up for the axial shortening caused by the radial deformation. Ensure the contact between the axial direction of the oil bladder and the coal rock wall at the bottom of the borehole, and then realize the perception of the axial pressure.

[0053] In this embodiment, the oil pipe 400 is made of a stainless steel pipe, and the outer contours of the first plug plate 200 and the second plug plate 300 are consistent with the cross-sectional contour of the oil bladder tube 100 and are regular polygons with equal dimensions.

[0054] Compared with traditional oil pillows and multi-faceted oil bladders, the deformed polygon oil bladder tube 100 has a larger coupling area with the inner wall of the borehole and can more sensitively and accurately sense the pressure change. The spiral oil bladder tube 100 can realize the perception and monitoring of the axial stress of the borehole while sensing the radial pressure.

[0055] Based on the borehole stress measurement device provided in this embodiment, a method for manufacturing a borehole stress measurement device is proposed for manufacturing the above-mentioned borehole stress measurement device, including the following steps:

[0056] Weld the first plug plate 200 and the second plug plate 300 to both ends of the oil bladder tube 100 respectively to form a hollow cavity;

[0057] Pass one end of the oil pipe 400 through the second plug plate 300 and fill the hollow cavity with hydraulic oil through the oil pipe 400;

[0058] Weld the second plug plate 300 to the oil pipe 400 and seal the gap between the oil pipe 400 and the second plug plate 300.

[0059] Specifically, the oil bladder tube 100 adopts a cold drawing process. First, it is necessary to carry out pretreatment work such as annealing, straightening, and pickling for multiple times; then pass the alloy steel semi-finished tube through the forming die and cold draw it to obtain a spiral regular polygon oil bladder tube 100; subsequently, perform recrystallization annealing treatment on the cold-drawn and formed oil bladder tube 100 to eliminate the internal stress and work hardening during cold drawing and fully restore its plasticity; finally, straighten, pickle, and surface treat it again to obtain the finished oil bladder tube 100.

[0060] The traditional oil bladder is designed with a gas release valve at the other end of the oil injection side, which is convenient for exhausting the internal gas when the oil bladder tube 100 is filled with oil and reducing the oil injection resistance. Since the size of the gas release valve is small, its diameter is less than 10 mm, and it cannot effectively contact the inner wall of the drill hole, resulting in a small radial contact area between the measuring device and the inner wall of the drill hole. In order to increase the radial contact area between the oil bladder tube 100 and the inner wall of the drill hole, the gas release valve is cancelled in the borehole stress measuring device provided in this embodiment.

[0061] During actual operation, first align the first plug plate 200 and the second plug plate 300 with the oil bladder tube 100 respectively and weld them firmly to form a hollow cavity, then pass the oil pipe 400 through the through hole on the second plug plate 300, fill the hollow cavity with hydraulic oil through the oil pipe 400. When injecting oil, the gas in the hollow cavity can be discharged through the gap between the oil pipe 400 and the through hole on the second plug plate 300 without using a gas release valve. Finally, weld the oil pipe 400 and the second plug plate 300 together from the outside of the second plug plate 300 to seal the gap between the oil pipe 400 and the through hole on the second plug plate 300 by welding.

[0062] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A borehole stress measurement device, characterized in that, It includes an oil bladder tube (100), a first plug board (200), a second plug board (300) and an oil pipe (400); Both ends of the oil bladder tube (100) are sealed by the first plug board (200) and the second plug board (300) to form a hollow cavity; One end of the oil pipe (400) passes through the second plug board (300) and communicates with the hollow cavity, and is used to inject hydraulic oil into the hollow cavity.

2. The borehole stress measurement device according to claim 1, characterized in that, The cross-section of the oil bladder tube (100) is a regular polygon or a circle.

3. The borehole stress measurement device according to claim 2, characterized in that, The number of sides of the regular polygon is a, and a ∈ [4, 12].

4. The borehole stress measurement device according to claim 2, characterized in that Process grooves (110) are provided on the sides of the regular polygon.

5. The borehole stress measurement device according to claim 4, characterized in that, Smooth fillet transitions are provided at the corners of the regular polygon, the process grooves (110) and the connections between the sides and the process grooves (110).

6. The borehole stress measurement device according to claim 2, wherein The ratio of the diameter of the circumscribed circle of the regular polygon to the wall thickness of the oil bladder tube (100) is b, and b ∈ [25, 45]; The ratio of the diameter of the circumscribed circle of the regular polygon to the diameter of the drill hole is c, and c ∈ [0.91, 0.98]; The ratio of the diameter of the circumscribed circle of the regular polygon to the diameter of the fully inflated oil bladder tube (100) is d, and d ∈ [0.82, 0.93].

7. The borehole stress measurement device according to any one of claims 1-6, characterized in that, The oil bladder tube (100) is in a spiral shape extending along the length direction.

8. The borehole stress measurement device according to any one of claims 1-6, characterized in that, The oil bladder tube (100) is made of 12Cr1MoV.

9. The borehole stress measurement device according to any one of claims 1-6, characterized in that, The oil bladder tube (100) is twisted around the axis, and the twisting angle along the length direction is α, and α ∈ [0°, 10°].

10. A manufacturing method of a borehole stress measurement device for manufacturing the borehole stress measurement device according to any one of claims 1-9, characterized in that, It includes the following steps: Weld the first plug board (200) and the second plug board (300) to the two ends of the oil bladder tube (100) respectively to form the hollow cavity; Pass one end of the oil pipe (400) through the second plug board (300) and fill the hollow cavity with hydraulic oil through the oil pipe (400); Weld the second plug board (300) and the oil pipe (400) to seal the gap between the oil pipe (400) and the second plug board (300).

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