Sample preparation method for deep geomechanics based on natural fracture plane reconstruction technology

Abstract

The application provides a deep earth rock mechanics sample preparation method based on a natural fracture surface reconstruction technology, and comprises the following steps: S1, preparing an original rock natural fracture surface sample; S2, performing XRD rock phase analysis on the original rock natural fracture surface sample, obtaining mineral components of the original rock, and determining an original rock type according to the mineral components of the original rock; S3, collecting a plurality of rock samples according to the original rock type to establish a base rock library; S4, matching the base rock closest to the mineral components of the original rock from the base rock library; S5, scanning the original rock natural fracture surface sample by using a three-dimensional scanning technology to obtain original rock natural fracture surface data; S6, carving the base rock by using a three-dimensional carving technology based on the original rock natural fracture surface data; and S7, completing reconstruction of the original rock natural fracture surface. The application can repeatedly prepare a sample with the same fracture surface morphology and mechanical characteristics as the original rock sample in a large quantity, and overcomes the problems of high cost, long cycle and low success rate caused by deep earth rock sampling.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of deep geology rock mechanics experiment sample preparation, in particular to a deep geology rock mechanics sample preparation method based on natural fracture surface reconstruction technology. BACKGROUND

[0002] Through rock mechanics experiments on samples taken from deep geology, the mechanical properties of rocks under different test conditions are understood from multiple angles, which is a necessary way to lead the development of deep geology engineering. However, the on-site sampling of deep geology faces the following challenges: high cost, long cycle and low success rate of available samples. This makes it difficult to carry out rock mechanics experiments for a long time due to the lack of experimental samples.

[0003] Fracture surface is a weak surface in mechanics, and the mechanical properties of deep geology are mainly determined by the development of its natural fracture surface. Therefore, to prepare a sample matching the mechanical properties of the original rock sample, reconstruction of the natural fracture surface of the original rock is the key to solving the problem. SUMMARY

[0004] The present application aims to provide a deep geology rock mechanics sample preparation method based on natural fracture surface reconstruction technology to solve the problems of high cost, long cycle and low success rate caused by deep geology sampling.

[0005] The present application provides a deep geology rock mechanics sample preparation method based on natural fracture surface reconstruction technology, comprising the following steps:

[0006] S1, preparing an original rock natural fracture surface sample;

[0007] S2, performing XRD rock phase analysis on the original rock natural fracture surface sample to obtain the mineral composition of the original rock, and determining the type of the original rock according to the mineral composition of the original rock;

[0008] S3, collecting a number of rock samples according to the type of the original rock to establish a base rock library;

[0009] S4, matching the base rock with the closest mineral composition to the original rock from the base rock library;

[0010] S5, scanning the original rock natural fracture surface sample using three-dimensional scanning technology to obtain the data of the original rock natural fracture surface;

[0011] S6, using three-dimensional carving technology to carve the base rock based on the data of the original rock natural fracture surface;

[0012] S7, completing the reconstruction of the original rock natural fracture surface.

[0013] Further, the original rock natural fracture surface sample prepared in step S1 needs to be processed as follows:

[0014] The cleaning tool is used to remove the muddy particles and impurities on the surface of the original rock, and a developing layer is coated on the surface of the original rock using a developing spray.

[0015] Further, the method for matching the base rock with the closest mineral composition to the original rock from the base rock library in step S4 comprises:

[0016] The XRD rock phase analysis is performed on the base rocks in the base rock library to obtain the mineral composition of each base rock;

[0017] The mineral composition of each base rock is matched with the mineral composition of the original rock, and the base rock with the closest mineral composition to the original rock is matched.

[0018] Further, the method for obtaining the original rock natural fracture surface data using the three-dimensional scanning technology in step S5 comprises:

[0019] The original rock natural fracture surface sample is scanned using the three-dimensional scanning technology to obtain a plurality of fracture surface point cloud data;

[0020] The plurality of fracture surface point cloud data is post-processed, including automatic splicing, data optimization and point cloud fusion, to obtain the point cloud data describing the undulating shape of the natural fracture surface, i.e., the required original rock natural fracture surface data.

[0021] Further, when the original rock natural fracture surface is scanned using the three-dimensional scanning technology, the height of the original rock natural fracture surface sample is raised and / or the angle of the original rock natural fracture surface sample is rotated to perform multiple scanning, thereby obtaining a plurality of fracture surface point cloud data.

[0022] Further, the method for carving the base rock based on the original rock natural fracture surface data using the three-dimensional carving technology in step S6 comprises:

[0023] The point cloud data describing the undulating shape of the natural fracture surface, i.e., the original rock natural fracture surface data, is digitally processed, and the mesh surface is encapsulated and synthesized to obtain a three-dimensional curved surface completely consistent with the surface shape of the original rock natural fracture surface sample; then the obtained three-dimensional curved surface is imported into the three-dimensional carving machine to be converted into a carving path recognizable by the three-dimensional carving machine, and the three-dimensional carving machine automatically completes the carving of the natural fracture surface of the base rock according to the carving path after the three-dimensional carving machine is started.

[0024] As described above, due to the adoption of the above technical solutions, the present application has the following beneficial effects:

[0025] The present application can repeatedly prepare a large number of samples with the same fracture surface morphology and mechanical properties as the original rock sample, overcoming the problems of high cost, long cycle and low success rate caused by deep rock sampling. BRIEF DESCRIPTION OF DRAWINGS

[0026] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings in the embodiments will be briefly introduced as follows. It should be understood that the following drawings only show some of the embodiments of the present application, and therefore should not be considered as limiting the scope. For those skilled in the art, other related drawings can also be obtained without creative labor on the basis of the drawings.

[0027] Figure 1 The flow chart of the deep rock mechanics sample preparation method based on the natural fracture surface reconstruction technology of the embodiments of the present application;

[0028] Figure 2 The natural fracture surface sample preparation diagram of the embodiments of the present application;

[0029] Figure 3 The XRD rock phase analysis result display diagram of the bedrock library of the embodiments of the present application;

[0030] Figure 4 The XRD rock phase analysis result display diagram of the bedrock library of the embodiments of the present application;

[0031] Figure 5 The natural fracture surface point cloud data display diagram of the embodiments of the present application;

[0032] Figure 6 The natural fracture surface digital reconstruction surface diagram of the embodiments of the present application;

[0033] Figure 7 The reconstructed natural fracture surface sample diagram of the embodiments of the present application. DETAILED DESCRIPTION

[0034] In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are some of the embodiments of the present application, but not all the embodiments. The components of the embodiments of the present application described and shown in the drawings can be arranged and designed in various different configurations.

[0035] Therefore, the detailed description of the embodiments of the present application provided in the drawings below is not intended to limit the scope of the claimed present application, but only represents selected embodiments of the present application. All other embodiments obtained by those skilled in the art on the basis of the embodiments in the present application without creative labor are within the scope of protection of the present application.

[0036] EMBODIMENT

[0037] As Figure 1As shown, the embodiment proposes a deep geostatic rock mechanics sample preparation method based on natural fracture surface reconstruction technology, including the following steps:

[0038] S1, prepare the original rock natural fracture surface sample:

[0039] Use cleaning tools (such as brushes, etc.) to remove the muddy particles and impurities on the surface of the original rock, and use the developing spray to coat a layer of developing layer on the surface of the original rock, so that the relief form of the original rock natural fracture surface can be more accurately identified during three-dimensional scanning. The prepared original rock natural fracture surface sample in the embodiment is shown in Figure 2 , in which the numbers ① and ② are the positions of the two natural fracture surfaces in the sample.

[0040] S2, perform XRD rock phase analysis on the original rock natural fracture surface sample, obtain the mineral composition of the original rock, and determine the original rock type according to the mineral composition of the original rock;

[0041] The XRD rock phase analysis is to identify the phase of the crystal by using the different diffraction characteristics generated by the X-ray irradiation to the crystal, which is prior art and will not be described here. The diffraction peak spectrum and mineral composition results of the original rock natural fracture surface sample obtained by XRD rock phase analysis on the original rock natural fracture surface sample are shown in Figure 3 , it can be seen that the mineral composition of the original rock natural fracture surface sample is mainly 33% quartz, 34% plagioclase, and 7% microcline, and the original rock type can be determined as granodiorite, which belongs to the granite class.

[0042] S3, collect a number of rock samples to establish a bedrock library according to the original rock type:

[0043] According to the foregoing, the original rock type is determined as granodiorite, which belongs to the granite class, so 7 kinds of granite rock samples are collected to establish a bedrock library.

[0044] S4, match the bedrock with the most similar mineral composition to the original rock from the bedrock library; specifically:

[0045] Perform XRD rock phase analysis on the bedrocks in the bedrock library to obtain the mineral composition of each bedrock;

[0046] Match the mineral composition of each bedrock with the mineral composition of the original rock, and match the bedrock with the most similar mineral composition to the original rock.

[0047] Figure 4 The diffraction peak spectrum of the 5# bedrock in the bedrock library of the embodiment and the XRD rock phase analysis results of the 7 kinds of granite rock samples are shown. It can be seen that the mineral composition of the 5# bedrock is mainly 33% quartz, 44% plagioclase, and 15% microcline, which is most similar to the mineral composition of the original rock, and the 5# bedrock is selected for subsequent processing.

[0048] S5, scanning the original rock natural fracture surface sample by using three-dimensional scanning technology to obtain the original rock natural fracture surface data:

[0049] The three-dimensional scanning technology is used to scan the original rock natural fracture surface sample to obtain a plurality of fracture surface point cloud data. Optionally, when the three-dimensional scanning technology is used to scan the original rock natural fracture surface, the height of the original rock natural fracture surface sample is raised and / or the angle of the original rock natural fracture surface sample is rotated to perform multiple scans, thereby obtaining the plurality of fracture surface point cloud data.

[0050] The plurality of fracture surface point cloud data is post-processed, including automatic splicing, data optimization and point cloud fusion, to obtain point cloud data describing the undulating morphology of the natural fracture surface, i.e. the required original rock natural fracture surface data.

[0051] Figure 5 Two point cloud data of natural fracture surfaces obtained by scanning the original rock natural fracture surface sample in this embodiment are shown. From Figure 5 the undulating changes of the surface morphology of the natural fracture surface sample can be clearly distinguished.

[0052] S6, carving the bedrock based on the original rock natural fracture surface data using three-dimensional carving technology:

[0053] The original rock natural fracture surface data, i.e. the point cloud data of the undulating morphology of the two natural fracture surfaces, is digitally processed to encapsulate and synthesize a mesh surface, thereby obtaining two three-dimensional surfaces that are completely consistent with the surface morphology of the original rock natural fracture surface sample; Figure 6 Two three-dimensional surfaces, i.e. digital reconstruction surfaces, that are completely consistent with the surface morphology of the natural fracture surface sample in this embodiment are shown.

[0054] The obtained two three-dimensional surfaces are then imported into a three-dimensional carving machine and converted into carving paths recognizable by the three-dimensional carving machine. After starting the three-dimensional carving machine, the three-dimensional carving machine automatically completes the carving of the natural fracture surface of the bedrock according to the carving paths.

[0055] S7, reconstruction of the original rock natural fracture surface is completed, and the obtained bedrock sample is shown in Figure 7 The prepared bedrock has a natural fracture surface with a surface morphology consistent with that of the original rock and similar mineral components, and can be used to better replace the original rock for related rock mechanics tests.

[0056] The above only describes the preferred embodiments of the present application and is not intended to limit the present application. For those skilled in the art, the present application can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A method for preparing deep-earth rock mechanics samples based on natural fracture surface reconstruction technology, characterized in that, Includes the following steps: S1. Prepare samples of natural fracture surfaces in the original rock. S2. Perform XRD rock phase analysis on the samples of natural fracture surfaces of the original rock to obtain the mineral composition of the original rock, and determine the type of original rock based on the mineral composition of the original rock. S3. Collect several rock samples based on the original rock type to establish a bedrock repository; S4. Match the bedrock with the mineral composition most similar to the original rock from the bedrock pool; S5. Use three-dimensional scanning technology to scan the original rock natural fracture surface sample and obtain the original rock natural fracture surface data; S6. Based on the original rock's natural fracture surface data, three-dimensional carving technology is used to carve the bedrock; S7. Complete the reconstruction of the original rock's natural fracture surface.

2. The method for preparing deep-earth rock mechanics samples based on natural fracture surface reconstruction technology according to claim 1, characterized in that, The original rock natural fracture surface sample prepared in step S1 needs to be treated as follows: Use cleaning tools to remove mud particles and debris from the surface of the original rock, and then apply a developing layer to the surface of the original rock using a developing spray.

3. The method for preparing deep-earth rock mechanical samples based on natural fracture surface reconstruction technology according to claim 1, characterized in that, The method for matching the bedrock with the mineral composition most similar to the protorock from the bedrock pool in step S4 includes: XRD rock phase analysis was performed on the bedrock in the bedrock pool to obtain the mineral composition of each bedrock. The mineral composition of each bedrock is matched with that of the original rock to identify the bedrock with the closest mineral composition to the original rock.

4. The method for preparing deep-earth rock mechanics samples based on natural fracture surface reconstruction technology according to claim 1, characterized in that, The method for obtaining natural fracture surface data of the original rock using three-dimensional scanning technology in step S5 includes: Three-dimensional scanning technology was used to scan the original rock natural fracture surface sample to obtain multiple fracture surface point cloud data; Post-processing, including automatic stitching, data optimization, and point cloud fusion, is performed on multiple fracture surface point cloud data to obtain point cloud data describing the undulating morphology of natural fracture surfaces, which is the required original rock natural fracture surface data.

5. The method for preparing deep-earth rock mechanical samples based on natural fracture surface reconstruction technology according to claim 4, characterized in that, When using 3D scanning technology to scan the natural fracture surface of the original rock, multiple scans are performed by raising and lowering the height of the natural fracture surface sample and / or rotating the angle of the natural fracture surface sample, thereby obtaining multiple fracture surface point cloud data.

6. The method for preparing deep-earth rock mechanics samples based on natural fracture surface reconstruction technology according to claim 4 or 5, characterized in that, The method for carving bedrock using 3D carving technology based on the original rock's natural fracture surface data in step S6 includes: The point cloud data of the natural fracture surface of the original rock, i.e. the undulating shape of the natural fracture surface, is digitally processed and encapsulated into a mesh surface to obtain a three-dimensional surface that is completely consistent with the surface shape of the original rock natural fracture surface sample. The obtained three-dimensional surface is then imported into a three-dimensional engraving machine and converted into an engraving path that the three-dimensional engraving machine can recognize. After the three-dimensional engraving machine is started, it automatically completes the engraving of the natural fracture surface of the bedrock according to the engraving path.

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