CN113776931B - Shale visual fracturing experiment device and method based on DIC technology - Google Patents
Shale visual fracturing experiment device and method based on DIC technology Download PDFInfo
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Abstract
The invention discloses a shale visual fracturing experimental device and method based on DIC technology, which are applied to the field of unconventional reservoir reconstruction and aim at the problem that the dynamic expansion process of shale hydraulic fracturing cracks cannot be effectively observed in the prior art; according to the invention, a special shale clamp is designed and the structure of the shale clamp is optimally designed, and the shale clamping mode is improved, so that a rock sample drilling and fixing mode adopted in the prior art is avoided; meanwhile, filling cracks with different approximation angles are manufactured for experiments, so that an interaction mechanism and key influence parameters of the hydraulic cracks and the natural cracks can be effectively obtained; the expansion condition of the crack in the hydraulic fracturing process is intuitively and continuously observed through the DIC, the expansion mode of the crack in the hydraulic fracturing process in a real rock stratum can be simulated, the interaction rule of the natural crack and the artificial crack is analyzed, and a reference is provided for engineering practice.
Description
Technical Field
The invention belongs to the field of petroleum exploration, and particularly relates to a shale oil gas unconventional reservoir reconstruction technology.
Background
Along with the progress of petroleum exploration and exploitation technology, the exploitation of unconventional oil gas becomes a hotspot of the petroleum industry nowadays, shale oil gas is also valued by vast scientific researchers due to the abundant reserves, and the development of related shale oil blocks is started in China. Therefore, research on the expansion rule of cracks in shale is of great significance to shale oil and gas exploitation. However, shale has the characteristics of low pore size and low permeability, the shale hydrocarbon generation mode is self-generated and self-stored, and the deep shale has large ground stress difference and higher temperature, so that the deep shale is difficult to achieve a better cracking effect in a complex environment. The shale layer is more heterogeneous, so that the characteristic that the expansion rule of the cracks in the shale is more complex than that in the conventional oil and gas exploitation process is determined, the crack formation mechanism of the complex cracks in the shale is ambiguous, and particularly the influence mechanism of the natural cracks on the hydraulic cracks is ambiguous. Conventional hydraulic fracturing experimental methods for researching shale fracture propagation rules cannot better analyze complex fractures in shale.
The digital image correlation technology (Digital Image Correlation, DIC) is internally provided with a digital image processing system and a numerical value computing system, and can convey the position information of the marked points in the experimental process to an automatic running program in the system for processing, so that the aim of crack expansion visualization in the rock sample is fulfilled. Each layer of rock in shale has complex properties, and the mechanical properties between layers are changeable, so that the crack forms are complex and various. A series of technical measures are used in engineering to improve the complexity of the fracture network, improve the fracture transformation volume of shale, achieve the purpose of improving the recovery ratio, but the obtained effect is poor, and the existing construction process for improving the fracture transformation volume of shale by improving the complexity of the fracture network is mainly established on the basis of experience, and cannot deeply analyze and study the complex fracture interaction mechanism and the hydraulic fracture formation mechanism, so that the existing construction process cannot be improved. Because of the specificity of deep shale, the current means for monitoring the hydraulic fracturing cracks in the field in real time has microseism, but the accuracy is not enough, and the method is also used for comprehensively detecting various cracks, so that the crack expansion condition can be accurately and truly restored, but the crack expansion rule cannot be analyzed due to the fact that a crack network is too complex, particularly the problem of interaction mode and rule of the hydraulic cracks and natural cracks cannot be analyzed, and the position relation between the hydraulic cracks and the artificial cracks cannot be accurately represented when a rock sample is selected, so that the experimental result is more fuzzy. In addition, the method for researching the interaction rule between the natural fracture and the artificial fracture is mainly used for predicting by analyzing the stress-strain relation through an indoor model experiment and a numerical simulation experiment, the accuracy is lack of persuasion, and the digital image correlation method (Digital image correlation, DIC) is a nondestructive, real-time, efficient and full-strain field surface deformation monitoring means, and can realize accurate position change information of the fracture at a real-time mark position, so that the DIC technology is applied to the research of the shale hydraulic fracture expansion rule, has profound research significance, and provides reference for the proposal of a new shale hydraulic fracturing method.
Disclosure of Invention
In order to solve the technical problems, the invention provides a shale visual fracturing experimental device and method based on the DIC technology, a digital image correlation method (DIC) measurement system is used for observing the expansion condition of cracks in the hydraulic fracturing process, the expansion mode of the cracks in the hydraulic fracturing process in a real rock stratum can be simulated, the interaction rule of natural cracks and artificial cracks is analyzed, and a reference is provided for engineering practice.
One of the technical schemes adopted by the invention is as follows: shale visual fracturing experimental apparatus based on DIC technique includes: the device comprises a rock sample clamping system, a stress loading device, a hydraulic power applying device and a DIC measuring and analyzing system;
the rock sample clamping system is used for fixing the rock sample, and the rock sample clamping system includes: the device comprises two stainless steel pressing plates, two organic glass plates, a plurality of fastening devices, two enclosure components and a view window arranged on one stainless steel pressing plate; the two enclosure components are respectively arranged at the left side and the right side of the rock sample, and the front side and the rear side of the rock sample are sequentially provided with an organic glass plate and a stainless steel pressing plate from near to far; the two stainless steel pressing plates, the two organic glass plates and the two enclosure components are provided with reserved hole sites, and the fastening bolts are sequentially inserted into the stainless steel plates, the organic glass plates and the enclosure components, and are screwed and fixed;
the stress loading device is used for applying stress to the rock sample;
the hydraulic loading device is used for applying hydraulic power to the rock sample to perform fracturing;
the DIC measurement and analysis system is used for analyzing the fracture change in the hydraulic fracturing process.
Rectangular rubber sealing rings are also arranged between the two organic glass plates and the rock sample.
The stress loading device comprises: the device comprises a hydraulic piston and a fixed counterforce device, wherein the hydraulic piston is used for applying stress to a rock sample, and the fixed counterforce device is used for ensuring that the stress applied by the hydraulic piston fully acts on the rock sample.
The hydraulic power application device includes: the hydraulic fracturing device comprises a liquid injection port, a sealing clamping sleeve, a liquid storage device and a hydraulic pump, wherein the liquid injection port is used for injecting fracturing liquid required by hydraulic fracturing into a rock sample, the sealing clamping sleeve is used for preventing water from being scattered, the liquid storage device is used for storing the fracturing liquid, and the hydraulic pump is used for applying water injection power.
The DIC measurement and analysis system includes: the device comprises a displacement signal receiving device, a real-time image display device, a host, a strain analysis device and a crack identification and analysis device; the displacement signal receiving device is used for receiving the position information of the marking point in the hydraulic fracturing process, the real-time image display device is used for displaying the received position information of the marking point in a screen, the strain analysis device is used for converting the displacement information of the marking point into strain information, the crack identification and analysis device is used for drawing out the change condition of the crack according to the strain information and analyzing, and the host is used for controlling the operation of the displacement signal receiving device, the real-time image display device, the strain analysis device and the crack identification and analysis device.
The invention also provides a shale visual fracturing experimental method based on the DIC technology, which comprises the following steps:
s1: preparing a shale rock sample, and drilling a water hole in the center of the rock sample;
s2: placing the enclosure components on two sides of a rock sample, pre-clamping the rock sample provided with the enclosure components by adopting an organic glass plate, placing the pre-clamped rock sample between a front stainless steel pressing plate and a rear stainless steel pressing plate, and finally sequentially inserting a fastening device into the stainless steel plate, the organic glass plate, the rock sample enclosure components, the organic glass plate and the stainless steel plate, and screwing and fixing;
s3: starting a hydraulic piston by using the stress loading device, and applying required stress on the rock plate test piece through the hydraulic piston so as to load the boundary force of the rock plate test piece;
s4: starting a hydraulic pump through a hydraulic power application device, applying required hydraulic power through a hydraulic power Kong Xiangyan plate test piece, and performing a hydraulic fracturing experiment;
s5: the displacement signal receiving device is used for obtaining the displacement change of the marking point in the hydraulic fracturing process, the strain analysis device is used for obtaining the strain information in the experimental process, the crack identification and analysis device is used for analyzing and processing the strain information, and finally the image display device is used for displaying the crack information in the hydraulic fracturing process in the display, so that the purpose of visualizing the real-time change of the crack is achieved.
The rock sample is prepared by drilling a preformed hole in the center of the rock sample and preparing a vertical crack vertically penetrating the preformed hole as an artificial crack.
When the rock sample is prepared, the method further comprises the step of spraying white paint on one side of the rock sample, which is required to observe displacement information of the rock sample, and spraying black speckles after the white paint is fully dried.
The rock sample height is greater than the rock sample clamping system.
Including preparing a plurality of rock samples with different angles of approach to fill the fracture.
The invention has the beneficial effects that: the experimental device, in particular to a sample clamp, adopts a unique plane sealing mode, designs a special rectangular sealing ring clamping groove on the front glass panel, and has the highest withstand voltage of 20MPa; secondly, introducing a DIC test system to dynamically observe the crack expansion process in real time; finally, the experimental device is used for quantitatively analyzing the mutual interference mechanism of the hydraulic fracture and the natural fracture; the invention has the following advantages:
1. according to the invention, a rock sample clamping mode is innovated, and compared with the mode of fixing the rock sample drilling in the prior art, the rock sample clamping device can be used for fixing the rock sample more firmly and ensuring that the mechanical property of the rock sample is not disturbed;
2. the height of the rock sample prepared by the method is larger than that of the clamping device assembly, so that the problem that the rock sample cannot be continuously applied with pressure due to deformation lower than that of the clamping device assembly caused by compression of the rock sample is avoided;
3. the method adopts a linear cutting mode to manufacture clear filling cracks on the shale sample, adopts different fillers to fill, and fills the cracks through manufacturing different approach angles to perform experiments, so as to obtain the interaction mode and the interaction rule of the hydraulic cracks and the natural cracks and the factors influencing the interaction mode and the interaction rule of the hydraulic cracks and the natural cracks;
4. in the rock sample clamping process, a transparent organic glass plate is adopted for pre-clamping, so that the observation is convenient, and the deformation condition of a sample in the crack expansion process is captured in real time through a front camera; a rectangular rubber sealing ring is arranged between the sample and the front glass panel, so that higher sealing and buffering effects can be achieved;
5. the invention provides a shale hydraulic fracture expansion real-time visual observation method, which is used for observing the expansion condition of a fracture in the hydraulic fracturing process by utilizing a digital image correlation method (DIC) measurement system; the method can simulate the expansion mode of the crack in the hydraulic fracturing process in the real rock stratum, analyze the interaction rule of the natural crack and the artificial crack, and provide reference for engineering practice.
Drawings
FIG. 1 is an experimental set-up of the present invention provided in an embodiment of the present invention;
FIG. 2 is a diagram of a rock sample clamping system provided by an embodiment of the present invention;
FIG. 3 is a diagram illustrating a stress loading device according to an embodiment of the present invention;
FIG. 4 is a schematic illustration of a hydraulic power application apparatus according to an embodiment of the present invention;
FIG. 5 is a block diagram of a DIC measurement and analysis system according to an embodiment of the invention;
FIG. 6 is a detailed view of a 45-degree rock sample at an approach angle provided by an embodiment of the present invention;
FIG. 7 is a detailed view of a 30 DEG angle of approach rock sample provided by an embodiment of the present invention;
FIG. 8 is a detailed view of a 15 DEG angle of approach rock sample provided by an embodiment of the present invention;
FIG. 9 is a maximum principal strain cloud obtained by the device when the rock sample approach angle provided by the embodiment of the invention is 45 degrees;
FIG. 10 is a maximum principal strain cloud obtained by the device when the rock sample approach angle provided by the embodiment of the invention is 30 degrees;
FIG. 11 is a maximum principal strain cloud obtained by the device when the rock sample approach angle provided by the embodiment of the invention is 15 degrees;
reference numerals: 1 is a rock sample clamping system, 101 is a stainless steel pressing plate, 102 is an organic glass plate, 103 is a view window, 104 is a fastening device, 105 is a containment component, 106 is a rock sample, 2 is a stress loading device, 201 is a hydraulic piston, 202 is a fixed counterforce device, 3 is a hydraulic force applying device, 301 is a liquid injection port, 302 is a sealing clamping sleeve, 303 is a liquid storage device, 304 is a hydraulic pump, 4 is a DIC measuring and analyzing system, 401 is a displacement signal receiving device, 402 is a real-time image display device, 403 is a strain analyzing device, 404 is a crack identifying and analyzing device, 405 is a control computer, 406 is a high-speed camera, 5 is a rock sample detailed graph with an approach angle of 45 degrees, and 501 is a maximum stress sigma 1 502 is the maximum stress sigma 2 503 is filling crack, 504 is hydraulic hole, 505 is hydraulic crack, 6 is detailed graph of rock sample with approach angle of 30 DEG, 601 is maximum stress sigma 1 602 is the maximum stress sigma 2 603 is the filling fracture, 604 is the hydraulic hole, 7 is the 15 degree rock sample detail drawing of the approach angle, 701 is the maximum stress sigma 1 702 is the maximum stress sigma 2 703 is a filled fracture, 704 is a hydraulic hole, and 705 is a hydraulic fracture.
Detailed Description
The present invention will be further explained below with reference to the drawings in order to facilitate understanding of technical contents of the present invention to those skilled in the art.
As shown in fig. 1, the shale hydraulic fracturing experimental apparatus of the invention comprises: a rock sample clamping system 1, a stress loading device 2, a hydraulic power applying device 3 and a DIC measuring and analyzing system 4.
As shown in fig. 2, the rock sample clamping system 1 includes: stainless steel press plate 101, plexiglass plate 102, view window 103, fastening means 104, enclosure assembly 105. The stainless steel platen 101 is configured to protect and secure a rock sample 106, the plexiglass plate 102 is configured to protect the rock sample 106 from external interference, the view window 103 is configured to facilitate viewing of macroscopic manifestations of the rock sample 106 during hydraulic fracturing, the fastening means 104 is configured to secure the various components, and the containment assembly 105 is configured to protect the rock sample 106.
As shown in fig. 3, the stress loading device 2 includes: a hydraulic piston 201, and a reaction force device 202. The hydraulic piston 201 is configured to apply a stress. The fixed reaction force device 202 is configured to ensure that the force exerted by the hydraulic piston on the rock sample 106 is sufficiently acting in the rock sample 106.
As shown in fig. 4, the hydraulic power applying device 3 includes: a liquid injection port 301, a sealing clamping sleeve 302, a liquid storage device 303 and a hydraulic pump 304. The injection port 301 is configured to inject a fracturing fluid required for hydraulic fracturing into the rock sample 106, in particular through a hydraulic bore of the rock sample, the sealing ferrule 302 is configured to prevent water loss, the reservoir 303 is configured to store the fracturing fluid, the hydraulic pump 304 is configured to apply a water injection motive force, and to control a water injection rate.
The DIC measurement and analysis system 4, as shown in fig. 5, comprises: a displacement signal receiving device 401, a real-time image display device 402, a host, a strain analysis device 403 and a crack identification and analysis device 404. The displacement signal receiving device 401 is configured to receive the position information of the marking point in the hydraulic fracturing process, the real-time image display device 402 is configured to display the received position information of the marking point in a screen, so as to realize the purpose of visualization, the host computer is configured to control the computer to coordinate and work with each other, the strain analysis device 403 is configured to convert the displacement information of the marking point into strain information, and the crack recognition and analysis device 404 is configured to trace the change condition of the crack according to the strain information and analyze the change condition.
The specific working process of the displacement signal receiving device 401 is as follows: the position information of the black speckles obtained by the high-speed camera is transmitted to the displacement signal receiving device 401, the black speckles are artificial mark points, the high-speed camera compares the displacement change conditions of the black speckles on 2 continuous pictures, and the deformation condition of the whole sample is reproduced by a built-in algorithm.
Different samples with the approximation angles of 45 degrees, 30 degrees and 15 degrees are prepared, and the following description is given by the approximation angle of 45 degrees:
the rock sample required for the experiment shown in fig. 6 was prepared, the size of the rock sample 5 was 240×150×30mm, a hydraulic hole 504 with a diameter of 3mm was drilled at the center of the test piece using a high-precision drill, and a hydraulic fracture with a half-fracture length of 10mm and a width of 0.5mm was prepared using wire cutting. Two through cracks 20mm long by 1.5mm wide and 45 ° from the horizontal were symmetrically cut at 25mm in the hydraulic hole 504 by wire cutting, and gypsum was filled therein to simulate filling cracks 503.
The filling material is mainly used for simulating natural cracks with different cementing strength characteristics, and the common filling material can also be cement mortar, high-grade cement and the like.
And (3) placing the prepared rock sample 106 into a high-temperature oven, drying at a high temperature of 120 ℃ for 24 hours until the sample is sufficiently dried, spraying white paint on one side of the rock sample, which is required to observe displacement information, and spraying black specks which are easy to be shot by a high-speed camera after the white paint is sufficiently dried.
The organic glass plates 102 are pre-fixed on two sides of the prepared rock sample 106, the alignment of the organic glass plate hole sites and the rock sample enclosure assembly 105 hole sites is guaranteed, then the assembly is placed between the front stainless steel pressing plate 101 and the rear stainless steel pressing plate 101, the alignment of the hole sites is also satisfied, the fastening devices 104 are sequentially inserted into the stainless steel pressing plate 101, the organic glass plates 102, the rock sample enclosure assembly 105, the organic glass plates 102 and the stainless steel pressing plate 101, and the fastening and fixing are carried out, so that the fastening and the combination of all parts are guaranteed.
The hydraulic piston 201 is fully contacted with the rock sample 106, the hydraulic piston 201 is absolutely vertical to the side surface of the rock sample 106, the contact end is positioned at the center of the stress surface of the rock sample 106 so as to ensure uniform stress, the hydraulic piston 201 is started by the stress loading device 2, and the required maximum stress and minimum stress are applied to the rock plate test piece through the hydraulic piston 201, so that the loading of the boundary force of the rock plate test piece can be realized.
By activating the hydraulic pump 304 by means of the hydraulic application device 3, the hydraulic pump 304 gives a certain pressure to the fracturing fluid stored in the reservoir 303 and applies the required hydraulic pressure to the rock sample 106 through the injection port 301, which ensures that the flow rate is uniform and that the flow rate per unit time is kept uniform. So that the device enters a hydraulic fracturing stage to prepare for further fracturing experiments.
The displacement signal receiving device 401 can obtain the displacement change of the marking point in the hydraulic fracturing process, the strain analysis device 403 can obtain the strain information in the experimental process, the strain information can be analyzed and processed by the fracture identification and analysis device 404, and finally the fracture information in the hydraulic fracturing process is displayed in a display by the real-time image display device 402, so that the purpose of visualizing the real-time change of the fracture is realized.
The invention also provides a specific experimental method, which comprises the following steps:
s1: preparing a shale rock sample with the size of 240 multiplied by 150 multiplied by 30mm, drilling a hydraulic hole penetrating through the rock sample in the center of the rock sample, preparing a vertical crack vertically penetrating through the reserved hole as an artificial crack, spraying white paint on one side of the rock sample, which is required to observe displacement information, and spraying black dispersion spots which are easy to be shot by a high-speed camera after the white paint is fully dried;
s2: placing the enclosure components on two sides of a rock sample to play a role of protection, placing organic glass plates on two sides of the rock sample and the enclosure components, paying attention to aligning the organic glass plates with reserved holes of the enclosure components, then installing stainless steel plates on the outer sides of the organic glass plates, sequentially inserting fastening bolts into the stainless steel plates, the organic glass plates and the enclosure components, screwing the organic glass plates and the stainless steel plates, and ensuring that all components are fastened and combined together;
s3: starting a hydraulic piston by using the stress loading device, and applying required stress on the rock plate test piece through the hydraulic piston so as to load the boundary force of the rock plate test piece;
s4: starting a hydraulic pump through a hydraulic power application device, and applying required hydraulic power through a hydraulic power Kong Xiangyan plate test piece, so that the device enters a hydraulic fracturing stage and can continue a fracturing experiment; the center of the view window 103 is provided with a hole site matched with the hydraulic hole;
s5: the displacement signal receiving device can obtain the change of displacement of the marking point in the hydraulic fracturing process, then the strain analysis device can obtain the strain information in the experimental process, and further the strain information can be analyzed and processed through the fracture identification and analysis device, and finally the fracture information in the hydraulic fracturing process is displayed in the display through the image display device, so that the purpose of visualizing the real-time change of the fracture is realized.
Fig. 9 is a maximum principal strain cloud obtained by the device when the rock sample approach angle is 45 degrees, and as can be seen from fig. 9, the central fracture is first cracked, the hydraulic fracture extends to the filling fracture after the cracking, the hydraulic fracture extends to deflect before the hydraulic fracture and the filling fracture meet, and the hydraulic fracture and the filling fracture meet in a nearly vertical form. After the hydraulic fracture intersects the filling fracture, the hydraulic fracture continues to extend, but the hydraulic fracture continues to deflect in a direction opposite to that before the hydraulic fracture intersects the filling fracture.
Fig. 10 is a maximum principal strain cloud obtained by the device when the rock sample approach angle is 30 °, and as can be seen from fig. 10, the hydraulic fracture is first cracked at both ends and uniformly spread horizontally over Time, but the right fracture propagation speed is significantly higher than the left, when the right hydraulic fracture is propagated to the right filling fracture position at time= 68.43s, the filling fracture starts to be significantly strained, then the left filling fracture is strained, and finally the hydraulic fracture penetrates the filling fracture to a lower extent.
Fig. 11 is a graph of the maximum principal strain cloud obtained by the device when the rock sample approach angle is 15 °, and it can be seen from time= 233.67s and time= 276.27s that, at the initial stage of fracturing, the left filling fracture is subjected to obvious strain, and as the hydraulic force continues to be applied, the right side is subjected to obvious tensile strain, but as the Time passes, the right side hydraulic fracture reaches the filling fracture first, but none of the hydraulic fracture penetrates the filling fracture.
The invention can analyze the influence of natural cracks on the artificial crack expansion rule by obtaining the maximum tensile strain cloud pictures with different approximation angles as shown in figures 9-11.
Those of ordinary skill in the art will recognize that the embodiments described herein are for the purpose of aiding the reader in understanding the principles of the present invention and should be understood that the scope of the invention is not limited to such specific statements and embodiments. Various modifications and variations of the present invention will be apparent to those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention should be included in the scope of the claims of the present invention.
Claims (8)
1. Shale visual fracturing experimental apparatus based on DIC technique, its characterized in that includes: the device comprises a rock sample clamping system, a stress loading device, a hydraulic power applying device and a DIC measuring and analyzing system;
the rock sample clamping system is used for fixing the rock sample, and the rock sample clamping system includes: the device comprises two stainless steel pressing plates, two organic glass plates, a plurality of fastening devices, two enclosure components and a view window arranged on one stainless steel pressing plate; the two enclosure components are respectively arranged at the left side and the right side of the rock sample, and the front side and the rear side of the rock sample are sequentially provided with an organic glass plate and a stainless steel pressing plate from near to far; the two stainless steel pressing plates, the two organic glass plates and the two enclosure components are provided with reserved hole sites, and the fastening bolts are sequentially inserted into the stainless steel plates, the organic glass plates, the enclosure components, the organic glass plates and the stainless steel plates and screwed and fixed to fasten and combine the components together; rectangular rubber sealing rings are also arranged between the two organic glass plates and the rock sample;
the stress loading device is used for applying stress to the rock sample;
the hydraulic loading device is used for applying hydraulic power to the rock sample to perform fracturing;
the DIC measurement and analysis system is used for analyzing the fracture change in the hydraulic fracturing process.
2. The DIC technology based shale visual fracturing experiment apparatus of claim 1, wherein the stress loading apparatus comprises: the device comprises a hydraulic piston and a fixed counterforce device, wherein the hydraulic piston is used for applying stress to a rock sample, and the fixed counterforce device is used for ensuring that the stress applied by the hydraulic piston fully acts on the rock sample.
3. The DIC technology based shale visual fracturing experiment apparatus of claim 1, wherein the hydraulic power applying apparatus comprises: the hydraulic fracturing device comprises a liquid injection port, a sealing clamping sleeve, a liquid storage device and a hydraulic pump, wherein the liquid injection port is used for injecting fracturing liquid required by hydraulic fracturing into a rock sample, the sealing clamping sleeve is used for preventing water from being scattered, the liquid storage device is used for storing the fracturing liquid, and the hydraulic pump is used for applying water injection power.
4. The visual fracturing experimental apparatus of shale based on DIC technology of claim 1, wherein the DIC measurement and analysis system comprises: the device comprises a displacement signal receiving device, a real-time image display device, a host, a strain analysis device and a crack identification and analysis device; the displacement signal receiving device is used for receiving the position information of the marking point in the hydraulic fracturing process, the real-time image display device is used for displaying the received position information of the marking point in a screen, the strain analysis device is used for converting the displacement information of the marking point into strain information, the crack identification and analysis device is used for drawing out the change condition of the crack according to the strain information and analyzing, and the host is used for controlling the operation of the displacement signal receiving device, the real-time image display device, the strain analysis device and the crack identification and analysis device.
5. The DIC technology-based shale visual fracturing experiment method of the DIC technology-based shale visual fracturing experiment device, which is characterized by comprising the following steps:
s1: preparing a shale rock sample, and drilling a water hole in the center of the rock sample; during preparation of the rock sample, drilling a preformed hole in the center of the rock sample and preparing a vertical crack vertically penetrating through the preformed hole as an artificial crack;
s2: placing the enclosure components on two sides of a rock sample, pre-clamping the rock sample provided with the enclosure components by adopting an organic glass plate, placing the pre-clamped rock sample between a front stainless steel pressing plate and a rear stainless steel pressing plate, and finally sequentially inserting a fastening device into the stainless steel plate, the organic glass plate, the rock sample enclosure components, the organic glass plate and the stainless steel plate, and screwing and fixing;
s3: starting a hydraulic piston by using the stress loading device, and applying required stress on the rock plate test piece through the hydraulic piston so as to load the boundary force of the rock plate test piece;
s4: starting a hydraulic pump through a hydraulic power application device, applying required hydraulic power through a hydraulic power Kong Xiangyan plate test piece, and performing a hydraulic fracturing experiment;
s5: the displacement signal receiving device is used for obtaining the displacement change of the marking point in the hydraulic fracturing process, the strain analysis device is used for obtaining the strain information in the experimental process, the crack identification and analysis device is used for analyzing and processing the strain information, and finally the image display device is used for displaying the crack information in the hydraulic fracturing process in the display, so that the purpose of visualizing the real-time change of the crack is achieved.
6. The visual fracturing experimental method of shale based on DIC technology of claim 5, wherein the rock sample is prepared by spraying white paint on one side of the rock sample, which is required to observe displacement information, and spraying black specks after the white paint is fully dried.
7. The visual fracturing experimental method of shale based on DIC technology of claim 6, wherein the heights of rock samples are all larger than that of a rock sample clamping system.
8. The method of claim 7, comprising preparing a plurality of rock samples with different angles of approach to fill the fracture.
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| CN116163697A (en) * | 2022-12-15 | 2023-05-26 | 山东大学 | Visual multi-perforation fracturing flow dynamic allocation control experiment system and working method |
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| CN108952659B (en) * | 2018-07-11 | 2020-06-05 | 中国石油大学(北京) | Visual supercritical carbon dioxide fracturing physical simulation test method |
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