CN118208229B - Visual hydraulic fracturing method ground stress test system and method - Google Patents

Abstract

The application relates to the technical field of a ground stress test system, in particular to a visual hydraulic fracturing ground stress test system and a visual hydraulic fracturing ground stress test method, wherein the visual hydraulic fracturing ground stress test system comprises a drilling hole, a test module connected with signals, an interaction module and a pressurizing module, the test module is arranged in the drilling hole during test, and the test module comprises a drill rod, a first packing unit, a first anchoring unit, an adjusting unit, a second anchoring unit and a second packing unit which are sequentially arranged along the drilling hole direction; the testing module is stretched into the drill hole, each item of quantized information is collected through the collecting unit in the testing module, each item of quantized information is calculated to obtain each item of measuring and calculating information, the digital display unit receives the measuring and calculating information and then carries out real-time processing, and a real-time picture, three-dimensional cylindrical coordinates of the crack, plane coordinates of the crack and a water pressure-time diagram display are output on the interaction module.

Description

A visual hydraulic fracturing ground stress testing system and testing method

Technical Field

The present application relates to the technical field of geostress testing systems, and specifically refers to a visualized hydraulic fracturing geostress testing system and testing method.

Background Art

Geostress testing is an important parameter for engineering rock mass stability analysis and engineering design, and is mainly obtained through actual measurement, especially in areas with strong tectonic activities and complex terrain. Since stress cannot be measured directly, it can only be measured by measuring the changes in physical quantities such as displacement and strain caused by stress changes, and then back-calculating the stress value based on certain assumptions. Therefore, all stress measurement methods used at home and abroad are to drill holes or grooves on the wall of the adit or the surface outcrop to cause stress disturbance, and then use probes to measure the changes in various physical quantities caused by stress disturbance.

The geostress testing method includes stress relief method, stress recovery method and hydraulic fracturing method. Taking hydraulic fracturing method as an example, hydraulic fracturing method is a geostress measurement method that uses the pressure of water to break the rock by applying a certain water pressure, thereby measuring the distribution of geostress. Some test devices in the prior art are simple camera monitoring, and the imaging of the cracks still depends on the role of the impression device. The measured geostress is the geostress of the entire pressure measuring section, and the stress value of the specific crack measurement point cannot be known; in some schemes, the data transmission of the camera depends on the data transmission line, and the data transmission line is exposed in the rock hole and is easily damaged by the falling of gravel, resulting in interruption of visualization; in some schemes, the drill rod length is fixed and cannot be temporarily adjusted according to the specific conditions on site.

In addition, although another part of the testing devices in the prior art adopts optical imaging, it needs to be coordinated with the traditional crack recording device impression device. The instrument still needs to be taken out and then put into the impression device. The testing steps are relatively complicated. The optical imaging principle in this scheme needs to rely on the light source. The position change and accidental drop of the light source will cause errors in the test.

Summary of the invention

The purpose of the present application is to provide a visualized hydraulic fracturing ground stress testing system and testing method, which is used to achieve two-dimensional planarization of crack morphology through visualized digital display scanning, thereby replacing traditional impression device imaging.

This application is implemented through the following technical solutions:

A visualized hydraulic fracturing ground stress testing system comprises a borehole, and also comprises a signal-connected test module, an interactive module and a pressurizing module. During testing, the test module is placed in the borehole. The test module comprises a drill rod, a first isolation unit, a first anchoring unit, an adjustment unit, a second anchoring unit and a second isolation unit arranged in sequence along the borehole direction. A collection unit connected to the interactive module signal is arranged on the side of the first anchoring unit close to the second anchoring unit. A digital display unit connected to the collection unit signal is also integrated in the test module. A hydraulic fracturing section for ground stress testing is formed between the first anchoring unit and the second anchoring unit. The collection unit is used to collect measurement information of the hydraulic fracturing section. The digital display unit performs digital processing on the received measurement information, and displays the output real-time picture, three-dimensional column coordinates of the fracture, plane coordinates of the fracture and a water pressure-time diagram in the interactive module.

A visualized method for testing ground stress by hydraulic fracturing includes the following steps: step 1, drilling and coring, drilling a borehole to be tested in an area to be tested; step 2, lowering the equipment, installing the test module into the borehole obtained in step 1; step 3, finding a section, finding a suitable pressure section without primary cracks through an interactive module, if there is no suitable pressure section, adjusting the length of the adjustment unit, and looping the steps until the suitable pressure section is found; step 4, fast anchoring, starting the first anchoring unit and the second anchoring unit, anchoring the anchor rods inside the two to the rock wall; step 5, isolation and fracturing, injecting fluid and pressurizing the first isolation unit and the second isolation unit through a pressurizing module to complete the expansion process of the two, and then injecting water and pressurizing the hydraulic fracturing section through the pressurizing module; step 6, cyclic pressurization, injecting fluid into the hydraulic fracturing section through the pressurizing module, and then Perform pressurization, unloading, and pressurization cycles for 3 to 5 cycles, and measure the re-tensioning pressure value; Step 7, digital display integration, scan the fracture measurement points on the borehole wall of the hydraulic fracturing section through the acquisition unit, and feedback and transmit it to the interactive module, the interactive module outputs and displays the real-time picture, the three-dimensional column coordinates of the fracture, the plane coordinates of the fracture, and the water pressure-time diagram; Step 8, data analysis, analyze and count the information displayed by the interactive module; Step 9, unloading operation, unloading the hydraulic fracturing section through the pressurization module; Step 10, close the isolation, unload the first isolation unit and the second isolation unit through the pressurization module and pump out the water; Step 11, remove the anchor, control the anchor rods inside the first anchor unit and the second anchor unit, and cancel their anchoring on the rock wall; Step 12, remove the equipment, and recycle and clean the test module in the borehole.

Compared with the prior art, this application has the following advantages and beneficial effects:

1. The present application extends the test module into the borehole, and then collects various quantitative information through the collection unit in the test module, and calculates various quantitative information to obtain various measurement information. After receiving the measurement information, the digital display unit performs real-time processing, and outputs real-time images, three-dimensional cylindrical coordinates of the cracks, plane coordinates of the cracks, and water pressure-time diagrams on the interactive module. Through the above process, the visualization of the cracks in the borehole can be effectively realized, and the three-dimensional coordinates of the crack measurement points can be obtained, and the three-dimensional coordinates can be losslessly transformed into two-dimensional coordinates, thereby completely replacing the traditional impression device imaging;

2. The digital processing process of the present application is capable of receiving complex data from multiple groups of measurement units (including cameras, rangefinders, and angle sensors), and performing efficient synchronous processing and real-time analysis; the above process can not only accurately convert and calibrate the raw data collected by the rangefinder, angle sensor, and camera, but also comprehensively consider the refractive index, wall thickness, and other factors affecting the measurement for correction to ensure the accuracy of the data. In addition, it is understandable that the process also has strong data processing capabilities and can intuitively display various measurement results in digital form, including but not limited to key parameters such as distance, angle, and optical path. This advanced digital processing capability significantly improves the readability and ease of use of the data, greatly reduces the errors and time costs of manual interpretation, and enhances the adaptability to complex measurement environments, thereby effectively improving the efficiency and accuracy of ground stress testing;

3. The transformation process of three-dimensional coordinates to two-dimensional coordinates in the present application can not only accurately map points in space to a two-dimensional plane through mathematical algorithms, but also take into account the errors and complex factors in actual measurements, such as surface unevenness and measurement errors of the equipment itself; through such processing, the digital display unit can provide users with an intuitive and easy-to-understand two-dimensional crack distribution map, which greatly simplifies the data interpretation process and improves the efficiency of understanding the development trend of cracks.

BRIEF DESCRIPTION OF THE DRAWINGS

The drawings described herein are used to provide a further understanding of the embodiments of the present application, constitute a part of the present application, and do not constitute a limitation on the embodiments of the present application. In the drawings:

FIG1 is a schematic diagram of a usage structure of the system of the present application;

FIG2 is another schematic diagram of the structure of the system of the present application;

FIG3 is a schematic diagram of the structure of the system of the present application;

FIG4 is a front view of the structure of the system of the present application;

FIG5 is an axial view of the first anchoring unit of the present application;

FIG6 is a perspective structural diagram of the first anchoring unit of the present application;

FIG7 is a schematic structural diagram of a salvage unit of the present application;

FIG8 is a schematic diagram of the process of the present application method;

FIG9 is a schematic diagram of the derivation of the correction process of the present application;

FIG10 is a schematic diagram of the derivation of the geometric distance from the rangefinder of the present application to the crack measurement point;

FIG11 is a schematic diagram of the derivation of the angle between the origin-crack measurement point connection line and the first isolation unit plane before correction in this application;

FIG12 is a schematic diagram of the derivation of the angle between the projection line of the origin-crack measurement point connection line on the first isolation unit plane and the initial direction of the plane before the correction of the present application;

FIG13 is a first schematic diagram of the derivation of the angle between the origin-crack measurement point connection line and the first isolation unit plane after correction in the present application;

FIG14 is a second schematic diagram of the derivation of the angle between the origin-crack measurement point connection line and the first isolation unit plane after correction in this application;

FIG15 is a schematic diagram of the derivation of the angle between the projection line of the origin-crack measurement point connection line on the first isolation unit plane and the initial direction of the plane after correction in this application;

FIG. 16 is a schematic diagram of the derivation of the coordinate transformation process of the present application.

Marks and corresponding parts names in the attached drawings:

1-Interaction module;

2- Palm surface;

3- Drill rod;

4- the first sealing unit;

5- second sealing unit;

6- Salvage unit;

61-fishing rod, 62-supporting end, 63-catch ball, 64-fishing joint;

7- Collection unit;

71-camera, 72-rangefinder, 73-integration of the first angle sensor and the second angle sensor, 74-collection unit integrated mass point;

8- first anchoring unit;

81 - anchor rod, 82 - motor, 83 - storage slot, 84 - first standard block, 85 - bottom surface of first anchoring unit;

9- second anchoring unit;

91-second standard block;

10- pressurization module;

11- regulating unit;

111-adjusting rod;

12-output 3D cylindrical coordinate origin, 121-2D plane coordinate origin, 122-drill pipe centerline, 123-initial position direction of the first anchoring unit;

13-protective cover, 131-inner wall of protective cover, 132-fracturing liquid environment, 133-gas environment inside protective cover;

14-crack measurement point, 15-output horizontal angle initial direction, 16-projection of the crack measurement point on the bottom surface of the first isolation unit.

DETAILED DESCRIPTION

In order to make the technical solution of the present application clearer, the terms in the present application are explained here, and some of them can be structurally limited in subsequent embodiments according to different usage environments.

The term "interaction module 1" in this application refers to the part that processes user input and output, and is used for interacting with the user and transmitting information, including but not limited to digital display instruments, display screens, etc.;

The term "pressurization module 10" in this application refers to the pressure device necessary for conducting hydraulic fracturing geostress testing, including but not limited to a water tank, a pressure pump, etc.;

The term "standard block" in this application refers to a standard block that is homogeneous and isotropic in the form of a tiny cube;

The term "correction" in this application includes both the length correction of the hydraulic fracturing stage adjustment unit 11 (correction of the effective length of the digital display Z coordinate) and the correction of the geometric distance from the rangefinder 72 to the fracture measurement point 14;

The term "correction" in this application includes completing the correction process of parameters by a corresponding algorithm.

The term "adjustment unit 11" in the present application refers to the "drill pipe 3" corresponding to the hydraulic fracturing stage, and its length can be adjusted.

The term "digital display unit" in this application refers to a dedicated processing unit capable of performing three-dimensional and two-dimensional coordinate transformation processing and image integration processing.

Embodiment 1:

Please refer to Figures 1 to 7, a visualized hydraulic fracturing ground stress testing system includes a borehole, a signal-connected test module, an interactive module 1 and a pressurizing module 10. During testing, the test module is placed in the borehole. The test module includes a drill rod 3, a first isolation unit 4, a first anchoring unit 8, an adjustment unit 11, a second anchoring unit 9 and a second isolation unit 5 arranged in sequence along the borehole direction. A collection unit 7 connected to the signal of the interactive module 1 is arranged on the side of the first anchoring unit 8 close to the second anchoring unit 9. A digital display unit connected to the signal of the collection unit 7 is also integrated in the test module. A hydraulic fracturing section for ground stress testing is formed between the first anchoring unit 8 and the second anchoring unit 9. The collection unit 7 is used to collect measurement information of the hydraulic fracturing section. The digital display unit digitizes the received measurement information and displays the output real-time picture, the three-dimensional column coordinates of the fracture, the plane coordinates of the fracture and the water pressure-time diagram in the interactive module 1.

It should be noted that some of the testing devices in the prior art are simple camera monitoring, and the imaging of the cracks still depends on the role of the impression device. The measured ground stress is the ground stress of the entire pressure measuring section, and the stress value of the specific crack measurement point 14 cannot be known; in this solution, the data transmission of the camera relies on the data transmission line, and the data transmission line is exposed in the rock hole and is easily damaged by the falling of gravel, resulting in interruption of visualization; in this solution, the length of the drill rod 3 is fixed and cannot be temporarily adjusted according to the specific conditions on site. Taking the Chinese patent application number 201610208284.2 as an example, it discloses a device and method for measuring ground stress based on visual uniformly distributed hydraulic fracturing. It can be understood that in this technical solution, the visualization process is a simple camera monitoring, and the imaging of the cracks still depends on the role of the impression device. The measured ground stress is the ground stress of the entire pressure measuring section, and the stress value of the specific crack measurement point 14 cannot be known; in this solution, the data transmission of the camera relies on the data transmission line, and the data transmission line is exposed in the rock hole and is easily damaged by the falling of gravel, resulting in interruption of visualization; in this solution, the length of the drill rod 3 is fixed and cannot be temporarily adjusted according to the specific conditions on site. Taking the Chinese patent with application number 201910982555.3 as an example, it discloses a locator for a water pressure-induced ground stress testing system. It is understandable that although this scheme adopts optical imaging, in its specific testing process, it still needs to cooperate with the traditional crack recording device impression device, and the instrument and equipment still need to be taken out and then put into the impression device. The testing steps are relatively complicated, and the optical imaging principle in this scheme relies on a light source. Changes in the position of the light source and accidental falling will cause errors in the test.

Based on the above problems, the applicant proposed a visualized hydraulic fracturing ground stress testing system, which extends the test module into the borehole, and then collects various quantitative information through the acquisition unit 7 in the test module, and calculates various quantitative information to obtain various measurement information. After receiving the measurement information, the digital display unit performs real-time processing and outputs the real-time picture, the three-dimensional cylindrical coordinates of the cracks, the plane coordinates of the cracks and the water pressure-time diagram on the interactive module 1. Through the above process, the visualization of the cracks in the borehole can be effectively realized, and the three-dimensional coordinates of the crack measurement point 14 can be obtained, and the three-dimensional coordinates can be losslessly transformed into two-dimensional coordinates, thereby completely replacing the traditional impression device imaging. It should also be noted that, through the integrated acquisition unit 7 and the digital display unit, the system can directly collect fracture data in the borehole, avoiding the cumbersome steps of obtaining fracture images with an external impression device in the traditional method, and reducing the errors that may be introduced by taking out and reinserting the instrument and equipment; compared with the traditional method relying on the external light source, the system can reduce the impact of the position change and falling of the light source, thereby improving the accuracy of imaging; through the visualization technology, it can monitor the formation and expansion of fractures in the hydraulic fracturing process in real time, providing more accurate input parameters for the calculation of ground stress, and enhancing the reliability of the test results and the accuracy of ground stress assessment.

It should be noted that the acquisition unit 7 includes a plurality of groups of cameras 71, a rangefinder 72 and an angle sensor that are evenly spaced. The angle sensor includes a first angle sensor and a second angle sensor. A first standard block 84 is provided on one side of the first anchoring unit 8 close to the hydraulic fracturing section. A second standard block 91 is provided on one side of the second anchoring unit 9 close to the hydraulic fracturing section.

The measurement information includes:

: During the water fracturing test phase, the distance between the first standard block 84 and the second standard block 91;

: During the water fracturing test phase, the distance from the rangefinder 72 to the first standard block;

: During the water fracturing test phase, the distance from the rangefinder 72 to the second standard block;

: The angle of rotation of the first angle sensor from the initial position to the first standard block 84 in the plane corresponding to the sealing unit;

: The angle of rotation of the first angle sensor from the initial position to the second standard block 91 in the plane corresponding to the sealing unit;

: The distance from the center of the standard block to the corresponding anchor unit plane;

: Digital display of effective length of Z axis;

: Refractive index of gas inside the protective cover 13;

: refractive index of protective cover 13;

: refractive index of fracturing fluid;

: The distance from the rangefinder 72 to the inner wall of the protective cover 13;

: Wall thickness of protective cover 13;

: The distance of the light from the rangefinder 72 from the outer wall of the protective cover 13 to the crack measuring point 14;

: The optical path measured by the rangefinder 72;

: Additional optical path;

: Correct the geometric distance from the rangefinder 72 to the crack measurement point 14;

: The distance from the origin to the crack measurement point 14 before correction;

: The minimum distance from the rotation center axis of the camera 71 to the center axis of the drill pipe 122;

: The distance from the rotation center of the camera 71 to the crack measurement point 14;

: The angle of rotation of the first angle sensor from the initial position to the crack measurement point 14 in the drill pipe plane;

: The angle between the line connecting the origin and the fracture measurement point 14 before correction and the plane of the first isolation unit 4;

: The angle between the origin-crack measurement point 14 connection line and the camera 71-crack measurement point 14 connection line on the isolation unit plane;

: The angle between the projection line of the line connecting the origin and the fracture measurement point 14 on the plane of the first isolation unit 4 and the initial direction of the plane before correction;

: Camera 71 integrates internal angle;

: The angle of rotation of the second angle sensor from the initial position to the crack measurement point 14 on the integrated plane of the camera 71;

: The distance from the origin to the crack measurement point 14 after correction;

: The distance between the camera 71 point and the plane of the first sealing unit 4;

: The distance from the integrated rotation center axis of camera 71 to the surface of rangefinder 72.

It should also be noted that the number of cameras 71, rangefinders 72 and angle sensors arranged in groups in the acquisition unit 7 is preferably 3 groups, and the corresponding numbers are 1, 2, and 3 respectively. Each group is responsible for the coordinate measurement and output within its own 120° range. The measurements do not interfere with each other and are output continuously. They are the corresponding data output by the first, second and third groups of acquisition units. Specifically, the system's built-in rangefinder 72 and angle sensor can accurately determine the position of the fracture measurement point 14, providing the spatial three-dimensional coordinates of the fracture, so that the shape, size and distribution of the fracture can be accurately described; during the hydraulic fracturing test phase, the system can monitor and record key distance and angle information in real time, such as the distance between standard blocks, the distance from the rangefinder 72 to the standard block, and the rotation angle of the angle sensor, etc. These data can be used to measure and analyze the dynamic development of the fracture; by accurately measuring and compensating for the refractive index of the gas and liquid inside and outside the camera 71 protective cover 13, the wall thickness of the protective cover 13, the additional optical path and other parameters, the accuracy of the measurement data is improved, making the test results more reliable; because the measurement processes of each group do not interfere with each other, the system has a strong adaptability to the development of fractures under complex geological conditions, and can provide stable and reliable data support in a changing geological environment.

It should also be noted that, in this embodiment, the acquisition unit 7 also includes a dual-axis sensor connected to the digital display unit signal, and the dual-axis sensor can be incorporated into a camera 71, a rangefinder 72 and an angle sensor arranged in a group, and is used for real-time position change monitoring of the first anchor unit 8. Specifically, in terms of position monitoring, the dual-axis sensor is connected to the digital display unit signal to form an accurate position monitoring system. The sensor can detect and record the real-time position changes of the camera 71, the rangefinder 72 and the first anchor unit 8 where the angle sensor is located. By measuring the displacement and tilt angle in two axial directions, the dual-axis sensor can provide dynamic data about the precise position of the anchor unit in space. These data are transmitted to the digital display unit in real time. Through real-time analysis of the data, the position changes between the anchor units can be accurately grasped, including but not limited to translation, rotation or any form of displacement, thereby ensuring the stability and safety of the monitored object.

In terms of fall warning, the application of biaxial sensors is also significant. Since they can monitor the position and angle changes of the first anchor unit in real time, once abnormal displacement or tilt angle exceeding the preset safety range is detected, the system can immediately trigger the warning mechanism; this early fall warning can provide a valuable time window for taking emergency measures, enhancing the safety and reliability of the overall system; through the monitoring and analysis of these real-time data, the biaxial sensor can not only effectively monitor position changes, but also provide timely warnings before potential fall events occur, thereby playing a preventive role. Similarly, the biaxial sensor can also be set on the salvage unit 6, including but not limited to the support end 62, the snap ball 63, the salvage joint 64, etc.

It should be noted that the digital display unit performs a digital processing of the received measurement information in a manner that satisfies: The digital display unit performs a digital processing of the received measurement information in a manner that satisfies:

;

;

;

in,

is the distance from the corrected origin to the crack measurement point 14;

is the angle between the line connecting the origin and the fracture measurement point 14 after correction and the plane of the first isolation unit 4;

It is the angle between the projection line of the line connecting the corrected origin and the fracture measurement point 14 on the plane of the first isolation unit 4 and the initial direction of the plane.

It should also be noted that, based on the above-mentioned digital processing process, it is able to receive complex data from multiple groups of measurement units (including camera 71, rangefinder 72 and angle sensor), and perform efficient synchronous processing and real-time analysis; the above process can not only accurately convert and calibrate the raw data collected by the rangefinder 72, angle sensor and camera 71, but also comprehensively consider the refractive index, wall thickness and other factors affecting the measurement for correction to ensure the accuracy of the data. In addition, it is understandable that the process also has a strong data processing capability, and can intuitively display various measurement results in digital form, including but not limited to key parameters such as distance, angle, and optical path. This advanced digital processing capability significantly improves the readability and ease of use of the data, greatly reduces the errors and time cost of manual interpretation, and enhances the adaptability to complex measurement environments, thereby effectively improving the efficiency and accuracy of ground stress testing.

It should be noted that the correction includes the length correction of the hydraulic fracturing section drill pipe 3 and the geometric distance correction from the rangefinder 72 to the fracture measurement point 14. It should also be noted that in the prior art ground stress visualization test system, the processing process of the fracturing section drill pipe 3 and the rangefinder 72 is not corrected, so there are partial errors. On this basis, the applicant proposes to correct the above two data, and the correction process includes the correction of the length of the fracturing section drill pipe 3 (digital display Z coordinate effective length correction) and the correction of the geometric distance from the rangefinder 72 to the fracture measurement point 14. Specifically, the former is to display the scanned data image on the interactive module 1 in real time. Different fracturing pressures are caused according to different surrounding rock conditions. This pressure value will affect the length of the hydraulic fracturing section drill pipe 3. Therefore, the length correction of the fracturing section drill pipe 3 (digital display Z coordinate effective length correction) is proposed, and its length in the pressurized liquid is displayed in real time (achieved by calculation correction), which also makes the subsequent fracture coordinates more accurate. The latter is to calibrate the accuracy of the rangefinder 72 working underwater to ensure that the data of the rangefinder 72 is the real data of spatial geometry, which is the first step to ensure accuracy. The subsequent data is based on the data of the rangefinder 72, that is, the data obtained by the rangefinder 72 is converted into spatial geometry data to remove the influence of the medium.

It should be noted that the digital display unit digitally processes the received measurement information and further includes transforming the three-dimensional cylindrical coordinate value of the crack into a two-dimensional plane coordinate value, and the transformation process satisfies:

;

;in,

is the x-coordinate value after transformation;

is the z coordinate value after transformation.

It should also be noted that the above-mentioned transformation process can not only accurately map points in space to a two-dimensional plane through mathematical algorithms, but also take into account errors and complex factors in actual measurements, such as surface unevenness and measurement errors of the equipment itself; through such processing, the digital display unit can provide users with intuitive and easy-to-understand two-dimensional crack distribution maps, which greatly simplifies the data interpretation process and improves the efficiency of cognition of crack development trends; compared with the existing technology, this transformation processing not only improves the accuracy of the results, but also makes the data presentation more in line with the analysis habits of geological engineers, thereby improving the scientificity and practicality of geostress testing and crack assessment.

It should be noted that the three-dimensional cylindrical coordinate range output in the digital processing process is divided according to the angle between the projection line of the corrected origin-crack measurement point 14 on the plane of the first isolation unit 4 and the initial direction of the plane. of partitions, where

.

It should also be noted that the above division basis can more accurately reflect the spatial distribution of the fracture position. By considering the angle between the projection of the line connecting the origin to the measurement point and the initial direction of the isolation unit plane, the process can better adapt to different geological structures and the complexity of fracture development, thereby providing more precise fracture positioning. Compared with the existing technology, this division method not only improves the accuracy of coordinate range division, but also makes the output data more targeted and operational, providing a more reliable basis for subsequent fracture analysis and evaluation work, and significantly improving the practical application value of geostress testing.

It should be noted that the two-dimensional plane coordinate range output by the transformation process is divided according to the x-coordinate value after transformation. of partitions, where

.

It should also be noted that the above division process provides a clear quantitative description of the lateral distribution of cracks, simplifies complex three-dimensional spatial information into two-dimensional plane information, and makes the distribution characteristics of cracks more intuitive and easy to understand; by focusing on the changes in the x-coordinate, the expansion trend of the cracks in a specific direction can be quickly identified, which helps to better understand the development pattern of the cracks and potential influencing factors; compared with the existing technology, this division method can more effectively reveal the extension of cracks in a specific direction, and provide geological engineers with a more accurate and practical basis for crack analysis, thereby improving the accuracy and efficiency of crack monitoring and evaluation.

As shown in FIG8 , a visual hydraulic fracturing method for geostress testing includes the following steps:

Step 1, drilling and coring, drilling the area to be tested to obtain a borehole;

Step 2, lowering the equipment and installing the test module into the drilled hole obtained in step 1;

Step 3, searching for a section, searching for a suitable pressure section without primary cracks through the interactive module 1, if there is no suitable pressure section, adjusting the length of the regulating unit 11, and repeating this step until a suitable pressure section is found;

Step 4: quick anchoring: start the first anchoring unit 8 and the second anchoring unit 9 to anchor the anchor rods 81 inside the two units to the rock wall;

Step 5, isolation and fracturing, the first isolation unit 4 and the second isolation unit 5 are pressurized by the pressurizing module 10 to complete the expansion process of the two, and then the hydraulic fracturing section is pressurized by the pressurizing module 10;

Step 6, cyclic pressurization, after the hydraulic fracturing section is infused with fluid through the pressurization module 10, pressurization, unloading, and pressurization cycle operations are performed, the number of cycles is 3 to 5 times, and the re-opening pressure value is measured;

Step 7, digital display integration, scanning the fracture measurement points 14 on the borehole wall of the hydraulic fracturing section through the acquisition unit 7, and transmitting the feedback to the interactive module 1, and the interactive module 1 outputs and displays the real-time picture, the three-dimensional cylindrical coordinates of the fracture, the plane coordinates of the fracture, and the water pressure-time diagram;

Step 8: data analysis, analyzing and counting the information displayed by the interactive module 1;

Step 9, unloading operation, unloading the hydraulic fracturing section through the pressurizing module 10;

Step 10, close the isolation, unload the first isolation unit 4 and the second isolation unit 5 through the pressurizing module 10 and pump out the water;

Step 11, remove the anchor, control the anchor rods 81 inside the first anchor unit 8 and the second anchor unit 9, and cancel their anchoring on the rock wall;

Step 12, take out the equipment, recover and clean the test module in the borehole.

It should be noted that the steps shown in Figure 8 only represent the general operation process of this application. In the actual test construction process, the construction personnel use drilling tools (impact drilling, rotary drilling, etc.) to drill the stratum or rock layer and take out the rock-soil-water mixture in the hole; the construction personnel rely on the external tripod to lower the test module to the designated area. The construction personnel turn on the interactive module 1, such as the camera 71 and the display screen, to observe the hole wall in real time, control the equipment to move back and forth in the hole wall, and find the suitable pressure section without primary cracks. If there is no suitable pressure section under this condition, the control equipment is disengaged from the borehole, and the length of the drill rod 3 is adjusted to perform a second lowering to find the suitable pressure section, and this cycle is repeated. After placing the device at the designated position of the borehole, the drill rod 3 of the test module is applied with a torque in a specified direction through the ground equipment, so as to realize the rapid rotation of the anchor rod 81 in the anchor unit at the outer end of the first isolation unit 4 and the second isolation unit 5, and firmly anchor it on the rock wall to complete the rapid anchoring. Through the surface water tank, reciprocating pressure pump, and isolation unit water channel device, the first isolation unit 4 and the second isolation unit 5 are infused and pressurized to complete the expansion of the isolation unit. Through the surface water tank, reciprocating pressure pump, and fracturing water channel device, water is infused and pressurized to the fracturing section. After the hydraulic fracturing section is infused through the surface water tank, reciprocating pressure pump, and fracturing water channel device, pressurization, unloading, and pressurization are cycled for 3 to 5 cycles to measure the re-tensioning pressure value. Through the camera 71, the rangefinder 72, and the angle sensor integration, the hole wall crack measurement point 14 in the fracturing stage is scanned, and real-time feedback is transmitted to the digital display, and the real-time picture, the three-dimensional column coordinates of the crack, the plane coordinates of the crack, and the water pressure-time diagram are output. The construction personnel can analyze the data in real time by outputting the real-time picture, the three-dimensional column coordinates of the crack, and the plane coordinates of the crack through the digital display integrated display. Unload the fracturing section through the surface water tank, the reciprocating pressure pump, and the fracturing water channel device. The first and second packers are unloaded and drained through the ground water tank, reciprocating pressure pump, and packer water channel device. After completing the above stages, the construction personnel control the ground equipment to apply a torque in a specified reverse direction to the drill rod 3 of the test module to quickly retract the anchor rod 81 in the anchor unit at the outer end of the first packer unit 4 and the second packer unit 5, and remove the anchor. The construction personnel use the external tripod to recover the device of the present invention to the designated area.

It should also be noted that by using the test module and the ground equipment to work together, accurate drilling of the formation or rock layer and the removal of the rock-soil-water mixture, as well as real-time observation of the cracks in the borehole and precise control of the fracturing operation are achieved. Compared with the prior art, the advantage of this process is that it integrates the camera 71, the rangefinder 72 and the angle sensor, which can accurately scan the crack measurement point 14 and transmit data in real time, thereby realizing the three-dimensional positioning and evaluation of the crack. In addition, through the use of a reciprocating pressure pump and a water channel device for the packer, the isolation unit can be accurately controlled to achieve efficient infusion, pressurization and unloading operations, thereby improving the accuracy and efficiency of hydraulic fracturing. The final rapid anchoring and removal of the anchoring process also optimizes the workflow, reduces the operation time and improves the reusability of the test system.

Embodiment 2:

This embodiment only describes the parts that are different from the embodiment 1, specifically: As shown in Figures 5 and 6, the structures of the first anchoring unit 8 and the second anchoring unit 9 in this application are similar, and only the structure of the anchoring unit is specifically described here. It should be noted that the anchoring unit includes a seat body, and a plurality of storage grooves 83 are evenly spaced in the seat body. An anchor rod 81 is slidably arranged in the storage groove 83, and the end of the anchor rod 81 is connected to a motor 82 through a transmission component, and the first sealing unit 4 is provided with a salvage unit 6. It can be understood that the transmission component includes but is not limited to a gear set, a reduction box and other structures, and the motor 82 is connected to the interactive module 1 signal, that is, the speed and opening and closing of the motor 82 can be controlled by the interactive module 1. Based on the above structure, after determining the appropriate length of the fracturing section and the fracturing section drill pipe 3, the test is placed at the specified position of the borehole, and the torque in the specified direction is applied to the motor 82 through the interactive module 1 to achieve the rapid unscrewing of the anchor rod 81 in the anchoring unit at the outer end of the first isolation unit 4 and the second isolation unit 5, and firmly anchor it on the rock wall, so as to achieve the purpose of rapid anchoring, increasing the overall stiffness of the test device, reducing axial deformation, and reducing the generation of axial cracks. In this embodiment, it is preferred that the anchor rod 81 is centrally symmetrically arranged, and the anchor rod is rotated out of the original position by the motor 82. After the test is completed, the motor 82 applies a torque in the specified opposite direction to unscrew the anchor rod 81, and the anchor rod 81 moves from the end wall position to the initial position, which is convenient for removing the test equipment.

Embodiment 3:

This embodiment only describes the parts that are different from the embodiment 1, specifically: as shown in Figure 7, the salvage unit 6 includes a support end 62 arranged outside the first isolation unit 4, the end of the support end 62 is fixedly connected with a snap ball 63, the salvage unit 6 also includes a salvage joint 64 that cooperates with the snap ball 63, a salvage rod 61 is arranged on the salvage joint 64, a plurality of slots are arranged on the salvage joint 64, and convex rods that cooperate with the slots are evenly distributed on the snap ball 63. If at a certain stage, due to improper operation or other reasons, the top of the test module falls off from the ground equipment, the construction personnel put the salvage rod 61 into the borehole, connect it with the snap ball 63 through the salvage joint 64, and then rotate the salvage rod 61 to a certain angle, the preferred angle in this embodiment is 45°, rotate the convex rod on the snap ball 63 into the slot on the salvage joint 64, and become one, complete the subsequent operation and salvage, which can reduce property loss and equipment maintenance costs.

Embodiment 4:

This embodiment only describes the parts that are different from the embodiment 1, specifically: as shown in FIG4, the adjustment unit 11 includes a plurality of adjustment rods 111, and the two ends of each adjustment rod 111 can be connected to each other through threads. On the basis of the above embodiment, the construction personnel transmit image data in real time through the camera 71 to observe whether there are primary cracks on the inner wall of the borehole and the length of the section without cracks, and timely adjust the length of the hydraulic fracturing section drill pipe 3. Specifically, if there is no section suitable for fracturing in the borehole, the construction personnel will take the test module out of the borehole, and increase or decrease the adaptation length of the adjustment rod 111 by twisting the multi-section adjustment rod 111, so as to achieve the function of lengthening or shortening the length of the fracturing section, so as to match the pressure-appropriate section, so as to achieve the purpose of accurately measuring the ground stress, wherein the acquisition unit 7 can be connected by signal through star flash, Bluetooth, built-in data cable, etc.

Embodiment 5:

This embodiment only describes the parts that are different from the embodiment 1, specifically: as shown in Figure 9, it is a schematic diagram of the derivation process of the correction process of this application, specifically the derivation process of the length correction of the drill pipe 3 in the fracturing stage (digital display Z coordinate effective length correction), combined with the real-time size of the water pressure, the water pressure is The effective length of the Z axis is corrected in real time. The specific correction process is as follows: ;

in,

The distance between the first standard block 84 and the second standard block 91 during the water fracturing test phase (when there is pressure);

The distance from the rangefinder 72 to the first standard block 84 during the water fracturing test phase (when there is pressure);

The distance between the rangefinder 72 and the second standard block 91 during the water fracturing test phase (when there is pressure);

is the angle of rotation of the first angle sensor from the initial position to the first standard block 84 in the plane corresponding to the sealing unit (when there is pressure);

is the angle of rotation of the first angle sensor from the initial position to the second standard block 91 in the plane corresponding to the sealing unit (when there is pressure);

is the distance from the center of the standard block to the corresponding anchor unit plane (when there is no pressure);

It is the effective length of the digitally displayed Z axis under no pressure condition (no pressure);

is the axial deformation of the standard block;

is the elastic modulus of the standard block;

is the axial stress of the standard block;

is the lateral stress of the standard block 1;

is the lateral stress of the standard block 2;

is the standard block Poisson’s ratio;

It is the real-time water pressure;

is the area of each side of the standard block;

The water pressure is The effective length of the Z axis when

Embodiment 6:

This embodiment only describes the parts that are different from the embodiment 5, specifically: As shown in FIG. 10 , the geometric distance from the rangefinder 72 of the present application to the crack measurement point 14 is Derivation, the derivation process is:

;

in,

: Refractive index of gas inside the protective cover 13;

: refractive index of protective cover 13;

: refractive index of fracturing fluid;

: The distance from the rangefinder 72 to the inner wall of the protective cover 13;

: Wall thickness of protective cover 13;

: The distance of the light from the rangefinder 72 from the outer wall of the protective cover 13 to the crack measuring point 14;

: is the optical path measured by the rangefinder 72;

: is the additional optical path;

: To calibrate the geometric distance from the rangefinder 72 to the crack measuring point 14.

Embodiment 7:

This embodiment only describes the parts that are different from the embodiment 6, specifically: as shown in FIG11, for the derivation of the distance from the origin to the fracture measurement point 14 before correction, specifically, the drill pipe center axis 122 is selected as the Z axis, the starting point (origin) is the intersection of the plane of the first isolation unit 4 and the drill pipe center axis 122, and the direction is along the axis to the second isolation unit 5. The derivation process is:

;

in,

The distance from the origin to the crack measurement point 14 before correction;

The minimum distance from the integrated rotation center axis of the camera 71 to the center axis of the drill pipe 122;

The distance from the integrated rotation center of the camera 71 to the crack measurement point 14;

is the angle that the angle sensor rotates from the initial position to the crack measurement point 14 in the plane of the drill pipe 3;

Embodiment 8:

This embodiment only describes the parts that are different from the embodiment 7, specifically: as shown in FIG11, the derivation of the angle between the line connecting the origin-crack measurement point 14 and the plane of the first isolation unit 4 before correction, the derivation process is:

;

in,

It is the angle between the line connecting the origin and the fracture measurement point 14 before correction and the plane of the first isolation unit 4.

Embodiment 9:

This embodiment only describes the parts that are different from the embodiment 8, specifically: as shown in FIG12, the angle between the projection line of the origin-crack measurement point 14 connecting line before correction and the initial direction of the plane of the first isolation unit 4 is derived, and the derivation process is:

;

in,

is the angle between the origin-crack measurement point 14 connection line and the camera 71-crack measurement point 14 connection line on the isolation unit plane;

The angle between the projection line of the line connecting the origin and the fracture measurement point 14 before correction and the initial direction of the plane of the first isolation unit 4;

Integrate internal angles for camera 71;

It is the angle that the second angle sensor rotates from the initial position to the crack measurement point 14 in the integrated plane of the camera 71.

Embodiment 10:

This embodiment only describes the parts that are different from the embodiment 9, specifically: as shown in Figures 13 and 14, the camera 71, the rangefinder 72, and the angle sensor integrated device are corrected, that is, the distance from the origin to the crack measurement point 14 after correction, and the derivation process is:

;

in,

is the distance from the corrected origin to the crack measurement point 14;

is the distance between the mass point of the camera 71 and the plane of the first sealing unit 4;

is the geometric distance from the rangefinder 72 to the crack measuring point 14;

The distance from the integrated rotation center axis of the camera 71 to the surface of the rangefinder 72.

Embodiment 11:

This embodiment only describes the parts that are different from the embodiment 10, specifically: as shown in Figures 13 and 14, it is the derivation of the angle between the corrected origin-crack measurement point 14 connection line and the plane of the first isolation unit 4, specifically:

.

Embodiment 12:

This embodiment only describes the parts that are different from the embodiment 11, specifically: as shown in FIG15, the angle between the projection line of the corrected origin-crack measurement point 14 connecting line on the plane of the first isolation unit 4 and the initial direction of the plane is derived, specifically:

.

Embodiment 13:

This embodiment only describes the parts that are different from the embodiment 12, specifically: as shown in FIG. 16, it is a derivation process of transforming the three-dimensional cylindrical coordinates into two-dimensional coordinates, wherein the two-dimensional coordinates are x-z coordinates, specifically:

;

;

in,

is the x-coordinate value after transformation;

is the z coordinate value after transformation.

It should also be noted that the formulas, symbols, etc. involved in the derivation process of the above-mentioned embodiments can be derived through the corresponding drawings, such as the output three-dimensional cylindrical coordinate origin 12, the two-dimensional plane coordinate origin 121, the drill pipe centerline 122, the initial position direction of the first anchoring unit 8, the protective cover 13, the inner wall 131 of the protective cover, the fracturing liquid environment 132, the gas environment 133 inside the protective cover, the fracture measurement point 14, the output horizontal angle initial direction 15, the projection 16 of the fracture measurement point on the bottom surface of the first isolation unit, the two-dimensional plane coordinate origin, etc., and their specific meanings and derivation process will not be repeated here.

The specific implementation methods described above further illustrate the purpose, technical solutions and beneficial effects of the present application in detail. It should be understood that the above description is only the specific implementation method of the present application and is not intended to limit the scope of protection of the present application. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present application should be included in the scope of protection of the present application.

Claims (8)

1. A visualized hydraulic fracturing ground stress testing system, comprising a borehole, characterized in that it also comprises a signal-connected testing module, an interactive module (1) and a pressurizing module (10); during testing, the testing module is placed in the borehole; the testing module comprises a drill rod (3), a first isolation unit (4), a first anchoring unit (8), an adjusting unit (11), a second anchoring unit (9) and a second isolation unit (5) arranged in sequence along the borehole direction; a first anchoring unit (8) is provided on one side of the first anchoring unit (8) close to the second anchoring unit (9) with a The interactive module (1) includes a collection unit (7) connected to the collection unit (7) by signals, the test module also includes a digital display unit connected to the collection unit (7) by signals, a hydraulic fracturing section for ground stress testing is formed between the first anchor unit (8) and the second anchor unit (9), the collection unit (7) is used to collect measurement information of the hydraulic fracturing section, the digital display unit performs digital processing on the received measurement information, and displays the output real-time picture, three-dimensional column coordinates of the fracture, plane coordinates of the fracture, and a water pressure-time diagram in the interactive module (1); The acquisition unit (7) comprises a plurality of groups of cameras (71) evenly spaced apart, a rangefinder (72) and an angle sensor, the angle sensor comprising a first angle sensor and a second angle sensor, a first standard block (84) being arranged on a side of the first anchoring unit (8) close to the hydraulic fracturing section, and a second standard block (91) being arranged on a side of the second anchoring unit (9) close to the hydraulic fracturing section; The measurement information includes: : During the water fracturing test phase, the distance between the first standard block (84) and the second standard block (91); : During the water fracturing test phase, the distance from the rangefinder (72) to the first standard block; : During the water fracturing test phase, the distance from the rangefinder (72) to the second standard block; : the angle of rotation of the first angle sensor from the initial position to the first standard block (84) in the plane corresponding to the sealing unit; : the angle of rotation of the first angle sensor from the initial position to the second standard block (91) in the plane corresponding to the sealing unit; : The distance from the center of the standard block to the corresponding anchor unit plane; : Digital display of effective length of Z axis; : refractive index of the gas inside the protective cover (13); : refractive index of the protective cover (13); : refractive index of fracturing fluid; : The distance from the rangefinder (72) to the inner wall of the protective cover (13); : wall thickness of protective cover (13); : The distance of the light of the rangefinder (72) from the outer wall of the protective cover (13) to the crack measuring point (14); : the optical path measured by the distance meter (72); : Additional optical path; : Correction of the geometric distance from the distance meter (72) to the crack measurement point (14); : The distance from the origin to the crack measurement point (14) before correction; : The minimum distance from the rotation center axis of the camera (71) to the center axis of the drill pipe (122); : The distance from the rotation center of the camera (71) to the crack measurement point (14); : The angle of rotation of the first angle sensor from the initial position to the fracture measurement point (14) on the drill pipe plane; : Angle between the line connecting the origin and the fracture measurement point (14) before correction and the plane of the first isolation unit (4); : The angle between the line connecting the origin-fracture measurement point (14) and the line connecting the camera (71)-fracture measurement point (14) on the plane of the isolation unit; : the angle between the projection line of the line connecting the origin and the fracture measurement point (14) before correction and the initial direction of the plane on the plane of the first isolation unit (4); : Camera (71) integrated internal angle; : the angle of rotation of the second angle sensor from the initial position to the crack measurement point (14) on the integrated plane of the camera (71); : The distance from the origin to the crack measurement point (14) after correction; : the distance between the camera (71) mass point and the plane of the first sealing unit (4); : The distance from the integrated rotation center axis of the camera (71) to the surface of the rangefinder (72); The digital display unit performs digital processing of the received measurement information in a manner that satisfies: ; ; ; in, is the distance from the corrected origin to the crack measurement point (14); is the angle between the corrected origin-fracture measurement point (14) connecting line and the plane of the first isolation unit (4); The angle between the projection line of the line connecting the corrected origin and the fracture measurement point (14) on the plane of the first sealing unit (4) and the initial direction of the plane; The protective cover (13) is arranged outside the acquisition unit (7); the number of groups of cameras (71), rangefinders (72) and angle sensors arranged in groups in the acquisition unit (7) is 3, and the groups are numbered 1, 2, and 3 respectively, and each group is responsible for coordinate measurement and output within a range of 120°, wherein: These are the corresponding data output by the 1st, 2nd and 3rd groups of acquisition units respectively. 2. A visualized hydraulic fracturing geostress testing system according to claim 1, characterized in that: the correction includes the length correction of the hydraulic fracturing section drill pipe (3) and the geometric distance correction from the rangefinder (72) to the fracture measurement point (14). 3. A visualized hydraulic fracturing ground stress testing system according to claim 1, characterized in that: the digital display unit digitally processes the received measurement information and further comprises transforming the three-dimensional cylindrical coordinate value of the crack into a two-dimensional plane coordinate value, and the transformation process satisfies: ; ;in, is the x-coordinate value after transformation; is the z coordinate value after transformation. 4. A visualized hydraulic fracturing ground stress testing system according to claim 2, characterized in that: the three-dimensional cylindrical coordinate range output during the digital processing is divided according to the angle between the projection line of the corrected origin-fracture measurement point (14) on the plane of the first isolation unit (4) and the initial direction of the plane of partitions, where . 5. A visual hydraulic fracturing ground stress testing system according to claim 3, characterized in that: the two-dimensional plane coordinate range output by the transformation process is divided according to the transformed x-coordinate value of partitions, where . 6. A visualized hydraulic fracturing ground stress testing system according to claim 1, characterized in that: the first anchoring unit (8) and the second anchoring unit (9) have the same structure and both include a seat body, a plurality of storage grooves (83) are evenly spaced in the seat body, an anchor rod (81) is slidably arranged in the storage groove (83), the end of the anchor rod (81) is connected to a motor (82) through a transmission component, and a salvage unit (6) is arranged on the first isolation unit (4). 7. A visualized hydraulic fracturing ground stress testing system according to claim 6, characterized in that: the salvage unit (6) includes a support end (62) arranged outside the first isolation unit (4), the end of the support end (62) is fixedly connected to a snap ball (63), the salvage unit (6) also includes a salvage joint (64) that cooperates with the snap ball (63), a salvage rod (61) is arranged on the salvage joint (64), a plurality of slots are arranged on the salvage joint (64), and convex rods that cooperate with the slots are evenly spaced on the snap ball (63); the adjustment unit includes a plurality of sections of drill rod (3) that are detachably connected. 8. A method for testing ground stress by a visualized hydraulic fracturing method, characterized in that: based on a system for testing ground stress by a visualized hydraulic fracturing method according to any one of claims 1 to 7, the method comprises the following steps: Step 1, drilling and coring, drilling the area to be tested to obtain a borehole; Step 2, lowering the equipment and installing the test module into the drilled hole obtained in step 1; Step 3, searching for a section, searching for a suitable pressure section without primary cracks through the interactive module (1), if there is no suitable pressure section, adjusting the length of the regulating unit (11), and repeating this step until a suitable pressure section is found; Step 4: quick anchoring, activating the first anchoring unit (8) and the second anchoring unit (9) to anchor the anchor rods (81) inside the two units to the rock wall; Step 5, isolation and fracturing, the first isolation unit (4) and the second isolation unit (5) are pressurized by injecting liquid through the pressurizing module (10) to complete the expansion process of the two, and then the hydraulic fracturing section is pressurized by injecting water through the pressurizing module (10); Step 6, cyclic pressurization, after injecting fluid into the hydraulic fracturing section through the pressurization module (10), pressurization, unloading, and pressurization cycle operations are performed, the number of cycles is 3 to 5 times, and the re-opening pressure value is measured; Step 7, digital display integration, scanning the fracture measurement points (14) on the borehole wall of the hydraulic fracturing section through the acquisition unit (7), and transmitting the feedback to the interactive module (1), and the interactive module (1) outputs and displays the real-time picture, the three-dimensional cylindrical coordinates of the fracture, the plane coordinates of the fracture, and the water pressure-time diagram; Step 8: data analysis, analyzing and counting the information displayed by the interactive module (1); Step 9, unloading operation, unloading the hydraulic fracturing section through the pressurizing module (10); Step 10, closing the isolation, unloading the first isolation unit (4) and the second isolation unit (5) through the pressurizing module (10) and pumping out water; Step 11, removing the anchor, controlling the anchor rods (81) inside the first anchor unit (8) and the second anchor unit (9), and cancelling their anchoring on the rock wall; Step 12, take out the equipment, recover and clean the test module in the borehole.