Drilling ground stress measuring device based on mechanical radial pressure application

Abstract

The invention relates to the technical field of stress measurement, in particular to a drilling ground stress measuring device based on mechanical radial pressure application, which comprises a device body, a plurality of radial pressure application units arranged along the axial direction of the device body, and a middle column arranged along the axial direction of the device body, the radial pressure applying unit comprises an expansion arm cavity, a plurality of abutting blocks distributed in the circumferential direction of the expansion arm cavity, and a stress detection sensor unit installed in the expansion arm cavity. The multiple expansion arm cavities are connected in series through the negative pressure unit and used for forming negative pressure through the negative pressure unit after measurement is finished, so that the expansion arm cavities retract synchronously. According to the device, the targets of one-time positioning well logging and multi-point synchronous measurement are achieved, the operation efficiency is greatly improved, pressurization is conducted in sequence from bottom to top, independent loading and radial pressure applying of each section are ensured, the expansion arm cavity is controlled to reset rapidly after measurement is completed, the contact force between the device body and the hole wall is effectively reduced, the risks of manual drawing, jamming and equipment damage are reduced, and safety is higher.

Description

Technical Field

[0001] This invention relates to the technical field of stress measurement, and more particularly to a borehole stress measurement device based on mechanical radial pressure. Background Technology

[0002] Geostress is widespread but difficult to obtain and reveal, yet it plays a crucial role in the planning, design, and decision-making of deep engineering projects. As humanity continues to explore the deeper crust of the Earth, the importance of geostress is increasingly evident, particularly its measurement in geotechnical engineering and earth science research. Currently, many countries have conducted geostress measurement work, employing more than ten methods and nearly one hundred types of measuring instruments.

[0003] In existing technologies, the borehole deformation method is relatively convenient to operate, with high accuracy and reliability, and can be used for deep and ultra-deep hole testing. However, existing borehole stress measurement equipment generally adopts a single-segment probe structure, which requires repeated probe movement in the borehole to perform multi-point measurements, resulting in low efficiency and cumbersome operation. At the same time, the simple structure is not suitable for long-distance, multi-point rapid stress acquisition, especially in complex stress fields or deep fractured rock masses, where repeated entry and exit from the borehole leads to large errors and high safety risks. Summary of the Invention

[0004] This invention provides a borehole stress measurement device based on mechanical radial pressure, achieving the goal of simultaneous multi-point measurement in a single well location logging operation, significantly improving operational efficiency. The pressure boosting process is performed sequentially to avoid interference between adjacent sections, ensuring independent loading and radial pressure application for each section. After measurement, the expansion chamber is quickly reset, effectively reducing the contact force between the device body and the borehole wall, minimizing the risk of human pulling, jamming, and equipment damage, thus enhancing safety. The specific solution is as follows: A borehole stress measurement device based on mechanical radial pressure includes a device body, multiple radial pressure units arranged along the axial direction of the device body, and a central column arranged along the axial direction of the device body. The radial pressure unit includes an expansion arm cavity, a plurality of abutment blocks distributed circumferentially along the expansion arm cavity, and a stress detection sensor unit installed in the expansion arm cavity, wherein the ends of the abutment blocks extend to the outside of the device body. The device body is equipped with a pressurization channel, and multiple expansion arm cavities are connected in series through the pressurization channel; The central column is installed in the pressurization channel, and a main passage cavity is opened through the middle of the central column. The main passage cavity is connected to each of the expansion arm cavities, and a check valve mechanism is provided at the connection between the two. Multiple expansion arm cavities are connected in series via a negative pressure unit, which is used to create negative pressure after the measurement is completed, so that each expansion arm cavity retracts synchronously.

[0005] Furthermore, a pressure control pipe is externally connected to the main body of the device, a hydraulic oil pump is installed at the end of the pressure control pipe, and a solenoid valve is installed on the pressurization channel.

[0006] Furthermore, the central column is used to divide each expansion arm cavity into multiple independent cavities corresponding to the abutment block, and each independent cavity is equipped with a stress detection sensor unit.

[0007] Furthermore, the check valve mechanism includes a one-way stop and a support spring installed at the bottom of the one-way stop, the one-way stop being used to restrict the upstream connection between the main passage and the expansion arm cavity in one direction.

[0008] Furthermore, the negative pressure unit includes a side passage cavity connected in series with multiple expansion arm cavities. The top of the side passage cavity is connected to the pressurization channel. Each expansion arm cavity is provided with a side stop block fixed to the outer wall of the central column. The side stop block is located at the top opening of the side passage cavity used to connect adjacent expansion arm cavities. The central column is vertically inserted into the pressurization channel.

[0009] Furthermore, it also includes a stress measuring device, which is equipped with a measurement control module and a data detection module. The measurement control module is connected to the hydraulic oil pump, the solenoid valve and the pressure sensor respectively, and the data detection module is connected to the stress detection sensor unit.

[0010] Furthermore, each of the radial pressure units is provided with at least three abutment blocks, the outer ends of which are arc-shaped.

[0011] Furthermore, a mounting column is fixed to the top of the device body, and the mounting column is used to connect with the hoisting mechanism.

[0012] Compared with the prior art, the present invention can achieve at least the following beneficial effects: This invention achieves the goal of simultaneous multi-point measurement in a single positioning logging operation through multiple radial pressure units, significantly improving operational efficiency. It is particularly suitable for deep geostress detection. Each expansion arm cavity is pressure isolated by a check valve mechanism, and the pressurization process is carried out sequentially to avoid interference between adjacent sections, ensuring that each section is independently loaded and radially pressured. After the measurement is completed, the expansion arm cavity is controlled to quickly reset, effectively controlling the contact force between the device body and the borehole wall, reducing the risk of human pulling, jamming, and equipment damage, and improving safety. Attached Figure Description

[0013] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. Wherein: Figure 1 This is a schematic diagram of the overall structure of the present invention.

[0014] Figure 2 This is a schematic diagram of the structure when the abutment block of the present invention is extended.

[0015] Figure 3 This is a cross-sectional view of the device body of the present invention.

[0016] Figure 4 For the present invention Figure 3 Enlarged view of point A in the middle.

[0017] Figure 5 This is a top-view cross-sectional view of the device body of the present invention.

[0018] Figure 6 This is a schematic diagram of the structure of the device body of the present invention when the central column moves upward.

[0019] Figure 7 This is a block diagram illustrating the control principle of the stress measuring device of the present invention.

[0020] The reference numerals in the attached figures are as follows: 1. Device body; 2. Stress measuring instrument; 3. Mounting column; 4. Abutment block; 5. Pressurization channel; 6. Solenoid valve; 7. Central column; 8. Expansion arm cavity; 9. Main passage cavity; 10. One-way stop; 11. Stress detection sensor unit; 12. Side passage cavity; 13. Side stop block; 14. Pressure sensor. Detailed Implementation

[0021] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0022] Example 1, please refer to... Figures 1-6 As shown, the present invention provides a borehole stress measurement device based on mechanical radial pressure, including a device body 1, multiple radial pressure units arranged along the axial direction of the device body 1, and a central column 7 arranged along the axial direction of the device body 1; the radial pressure unit includes an expansion arm cavity 8, multiple abutment blocks 4 distributed circumferentially along the expansion arm cavity 8, and a stress detection sensor unit 11 installed in the expansion arm cavity 8. The ends of the abutment blocks 4 extend to the outside of the device body 1. By applying pressure, the pressure in the expansion arm cavity 8 is increased, causing the multiple abutment blocks 4 to extend and abut against the inner wall of the borehole, thereby fixing the device body 1 in the middle of the borehole. Conversely, by controlling the pressure reduction inside the expansion arm cavity 8, the multiple abutment blocks 4 are controlled to retract into the expansion arm cavity 8, making it easy to retract the device body 1. The stress of the abutment blocks 4 is detected by abutting against the inner wall of the borehole.

[0023] In addition, a pressurizing channel 5 is installed in the main body 1. Multiple expansion arm cavities 8 are connected in series through the pressurizing channel 5. A central column 7 is installed in the pressurizing channel 5, and a main passage 9 is opened through the middle of the central column 7. The main passage 9 is connected to each expansion arm cavity 8, and a check valve mechanism is provided at the connection point between the two. Multiple expansion arm cavities 8 are connected in series through a negative pressure unit. After the measurement is completed, the negative pressure unit is used to create negative pressure, so that each expansion arm cavity 8 retracts synchronously. The pressurizing channel 5 is pressurized, and the pressure is transmitted to each expansion arm cavity 8 sequentially through the main passage 9 in the central column 7. Due to the action of the check valve mechanism, during expansion... When the pressure inside the expansion arm cavity 8 increases to the preset value, that is, after the abutment block 4 extends, it fully abuts against the inner wall of the borehole. The check valve mechanism keeps the expansion arm cavity 8 independent. When pressurizing each expansion arm cavity 8 through the main passage 9, multiple expansion arm cavities 8 are pressurized sequentially from bottom to top, and the position of the device body 1 is limited sequentially from bottom to top, so that it is well maintained in the middle of the borehole. At the same time, the pressure between each expansion arm cavity 8 is kept independent, and pressure isolation is achieved during the pressurization process of different sections to prevent the upper section from interfering with the pressurization of the lower section. When a single expansion arm cavity 8 is damaged and depressurized, the adjacent expansion arm cavities 8 still maintain an independent measurement state.

[0024] The negative pressure unit generates negative pressure to control the synchronous retraction of multiple expansion arm cavities 8, which quickly retracts the abutment block 4 into the expansion arm cavity 8. After the measurement is completed, all expansion arm cavities 8 are driven to return to their initial state, making it easy to retrieve the device body 1.

[0025] Through the above structural design, multiple radial pressure units are used to achieve the goal of one-time positioning logging and multi-point synchronous measurement, which greatly improves the efficiency of operation. It is especially suitable for deep geostress detection. Each expansion arm cavity 8 is pressure isolated by a check valve mechanism. The pressurization process is carried out sequentially to avoid interference between adjacent sections and ensure that each section is independently loaded and radially pressured. After the measurement is completed, the expansion arm cavity 8 is controlled to quickly reset, effectively reducing the contact force between the device body 1 and the borehole wall, reducing the risk of human pulling, jamming and equipment damage, and making it safer.

[0026] The stress detection sensor unit 11 is composed of an acceleration sensor and a stress sensor. The movement of the contact block 4 reflects the change of stress in different directions. The stress detection sensor unit 11 monitors the stress change and realizes all-round stress measurement. It can achieve accurate layer stress identification and data decoupling, significantly improve measurement accuracy, and improve the efficiency of ground stress measurement.

[0027] In this embodiment, a pressure control pipe is externally connected to the device body 1, and a hydraulic oil pump is installed at the end of the pressure control pipe. A solenoid valve 6 is installed on the pressurization channel 5. The hydraulic oil pump increases or decreases the hydraulic oil pressure to the pressurization channel 5 through the pressure control pipe, so as to flexibly control the oil pressure according to the measurement requirements.

[0028] In addition, the central column 7 is used to divide each expansion arm cavity 8 into multiple independent cavities corresponding to the abutment blocks 4. Each independent cavity is equipped with a stress detection sensor unit 11, and each radial pressure unit is provided with at least three abutment blocks 4. The outer end of the abutment block 4 has an arc-shaped structure, which can independently measure the stress in multiple directions of the expansion arm cavity 8, providing measurement accuracy. Three or more abutment blocks 4 can improve the fixation of the device body 1, keep it in the middle of the borehole, and balance the force on the outer ring of the device body 1, thereby improving measurement accuracy.

[0029] Please see Figures 3-4 The check valve mechanism includes a one-way stopper 10 and a support spring installed at the bottom of the one-way stopper 10. The one-way stopper 10 is used to restrict the upstream connection between the main passage 9 and the expansion arm cavity 8 in one direction. The pressure is transmitted to each expansion arm cavity 8 through the main passage 9. Due to the action of the one-way stopper 10 and the support spring at the bottom, the pressure only enters the expansion arm cavity 8 of the current working section, so that it first undergoes corresponding radial pressure to complete the radial limit of the borehole inner wall of this section. Then the pressure rises sequentially to the next level expansion arm cavity 8. The pressure is loaded sequentially in a similar manner to ensure that each section applies pressure independently and does not interfere with each other.

[0030] The top of the device body 1 is fixed with a mounting column 3, which is used to connect with the hoisting mechanism so that the device body 1 can be easily sent to a specified depth through the hoisting mechanism.

[0031] Example 2 further optimizes the borehole stress measurement device based on mechanical radial pressure provided in Example 1. The difference from Example 1 is that... (See also: [link to example 1]). Figures 3-7 The negative pressure unit includes a side passage cavity 12 connected in series with multiple expansion arm cavities 8. The top of the side passage cavity 12 is connected to the pressurization channel 5. Each expansion arm cavity 8 is provided with a side stop block 13 fixed to the outer wall of the central column 7. The side stop block 13 is located at the top opening of the side passage cavity 12 used to connect adjacent expansion arm cavities 8. The central column 7 is vertically inserted into the pressurization channel 5. After the measurement is completed, the hydraulic oil pump controls the pressurization channel 5 to generate negative pressure. Due to the limiting effect of the check valve mechanism, the pressurization channel 5 is located in the upper space of the central column 7. Under negative pressure, the central column 7 moves upward due to the negative pressure. The upward movement of the central column 7 drives the side stop block 13 to release the blockage of the side passage 12. At this time, multiple expansion arm cavities 8 are interconnected through the side passage 12 and directly connected to the top of the pressurization channel 5, so that the fluid in the expansion arm cavity 8 is quickly extracted. This allows the control block 4 to quickly return to its original position and retract, detaching from the borehole wall, improving recovery efficiency, and preventing safety issues such as device jamming, wall adhesion, and forced pull-out. After the retraction is completed, the device is extracted as a whole through the lifting system, completing the entire logging process.

[0032] The measuring device also includes a stress measuring instrument 2, which is equipped with a measurement control module and a data detection module. The measurement control module is connected to the hydraulic oil pump, the solenoid valve 6, and the pressure sensor 14, respectively. The data detection module is connected to the stress detection sensor unit 11. When it is necessary to inject high-pressure fluid into the pressurization channel 5, the measurement control module controls the hydraulic oil pump to work and the solenoid valve 6 to open. The pressure sensor 14 detects the fluid pressure in the pressurization channel 5. When the preset value is reached, the hydraulic oil pump is stopped and the solenoid valve 6 is closed. The data detection module receives the measurement data fed back by the stress detection sensor unit 11, obtains the borehole stress measurement data, and sends the measurement results to the terminal device of the testing personnel through wired or wireless transmission, so that they can quickly understand the measurement results and achieve the purpose of automated measurement.

[0033] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A borehole in-situ stress measurement device based on mechanical radial pressure, characterized in that, It includes a device body (1), multiple radial pressure units arranged along the axial direction of the device body (1), and a central column (7) arranged along the axial direction of the device body (1). The radial pressure unit includes an expansion arm cavity (8), a plurality of abutment blocks (4) distributed circumferentially along the expansion arm cavity (8), and a stress detection sensor unit (11) installed in the expansion arm cavity (8), the ends of the abutment blocks (4) extending to the outside of the device body (1); A pressurization channel (5) is installed in the main body (1) of the device, and multiple expansion arm cavities (8) are connected in series through the pressurization channel (5); The central column (7) is installed in the pressurization channel (5). A main passage cavity (9) is opened through the middle of the central column (7). The main passage cavity (9) is connected to each of the expansion arm cavities (8), and a check valve mechanism is provided at the connection between the two. Multiple expansion arm cavities (8) are connected in series through a negative pressure unit, which is used to generate negative pressure through the negative pressure unit after the measurement is completed, so that each expansion arm cavity (8) retracts synchronously.

2. The borehole stress measuring device based on mechanical radial pressure as described in claim 1, characterized in that: The device body (1) is externally connected to a pressure control pipe, and a hydraulic oil pump is installed at the end of the pressure control pipe. A solenoid valve (6) is installed on the pressurization channel (5).

3. The borehole stress measuring device based on mechanical radial pressure as described in claim 1, characterized in that: The central column (7) is used to divide each expansion arm cavity (8) into multiple independent cavities corresponding to the abutment block (4), and each independent cavity is equipped with a stress detection sensor unit (11).

4. The borehole stress measuring device based on mechanical radial pressure as described in claim 1, characterized in that: The check valve mechanism includes a one-way stop (10) and a support spring installed at the bottom of the one-way stop (10). The one-way stop (10) is used to restrict the upstream connection between the main passage (9) and the expansion arm cavity (8).

5. The borehole stress measuring device based on mechanical radial pressure as described in claim 2, characterized in that: The negative pressure unit includes a side passage cavity (12) connected in series with multiple expansion arm cavities (8). The top of the side passage cavity (12) is connected to the pressurization channel (5). Each expansion arm cavity (8) is provided with a side stop block (13) fixed to the outer wall of the central column (7). The side stop block (13) is located at the top opening of the side passage cavity (12) used to connect adjacent expansion arm cavities (8). The central column (7) is vertically inserted into the pressurization channel (5).

6. The borehole stress measuring device based on mechanical radial pressure as described in claim 5, characterized in that: It also includes a stress measuring device (2), which is equipped with a measurement control module and a data detection module. The measurement control module is connected to the hydraulic oil pump, the solenoid valve (6) and the pressure sensor (14) respectively, and the data detection module is connected to the stress detection sensor unit (11).

7. The borehole stress measurement device based on mechanical radial pressure as described in claim 1, characterized in that: Each radial pressure unit is provided with at least three abutment blocks (4), the outer ends of which are arc-shaped.

8. The borehole stress measuring device based on mechanical radial pressure as described in claim 1, characterized in that: The top of the device body (1) is fixed with a mounting column (3), which is used to connect with the hoisting mechanism.

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