Method and device for constructing carbonate rock core model, and storage medium

Abstract

The present disclosure provides a method and device for constructing a carbonate rock core model, and a storage medium, which belongs to the technical field of petroleum extraction. The construction method includes obtaining a computer tomography image of a rock sample; using a watershed algorithm to segment the computer tomography image to obtain a binary image, the binary image is composed of a first grayscale area and a second grayscale area, and the grayscale of the first grayscale area is different from the grayscale of the second grayscale area; using an ant colony algorithm to track the fracture skeleton of the computer tomography image, and establish a fracture skeleton line distribution map; according to the second grayscale area of ​​the binary image and the fracture skeleton line distribution map, establish a fracture distribution map; according to the second grayscale area of ​​the binary image and the fracture skeleton line distribution map, establish a hole distribution map; according to the fracture distribution map and the hole distribution map, establish a core model, and the core model can accurately reflect the fracture and cave development characteristics of multi-medium carbonate reservoirs.

Description

Technical Field

[0001] The present invention relates to the technical field of petroleum extraction, and in particular to a method and device for constructing a carbonate rock core model, and a storage medium. Background Art

[0002] As oil and gas development moves towards ancient, deep marine, high-temperature and high-pressure gas reservoirs, the objects faced are usually carbonate reservoirs with strong heterogeneity and multiple media characteristics. Compared with conventional sandstone reservoirs that are mainly porous, carbonate reservoirs have more developed fractures and caves, diverse spatial topological structures, and more complex fluid flow in them. In order to accurately understand the stratigraphic structure, it is usually necessary to obtain a certain number of cores for testing. However, due to the influence of reservoir conditions, coring becomes more difficult, the core recovery rate is greatly reduced, and the test is usually carried out under high temperature and high pressure conditions, which has high requirements for experimental instruments, high safety risks, long cycles, and the experiment is destructive to the core. It is difficult to obtain regular knowledge from limited experimental results.

[0003] In order to understand the stratigraphic structure more conveniently, core models, namely digital cores, have emerged. Digital images are used to characterize the microstructural information of real cores, and they have the same topological structure and characteristic parameters as real cores.

[0004] For multi-medium carbonate reservoirs, pores are the main storage space and fractures are important seepage channels. Only by establishing a core model that can finely characterize the fracture and cavity development characteristics inside the rock sample can we accurately understand the stratigraphic structure of multi-medium carbonate reservoirs. Summary of the invention

[0005] The disclosed embodiments provide a method and device for constructing a carbonate rock core model, and a storage medium, so as to establish a core model that accurately reflects the fracture-cavity development characteristics of a multi-medium carbonate reservoir.

[0006] In a first aspect, an embodiment of the present disclosure provides a method for constructing a carbonate rock core model, the method comprising: obtaining a computerized tomography image of a rock sample;

[0007] The electronic computer tomography image is segmented by a watershed algorithm to obtain a binary image, wherein the binary image is composed of a first grayscale area and a second grayscale area, the grayscale of the first grayscale area is different from the grayscale of the second grayscale area, the first grayscale area represents the matrix of the rock sample, and the second grayscale area represents the pores of the rock sample, and the pores include cracks and holes;

[0008] Using an ant colony algorithm to track the crack skeleton of the electronic computer tomography image and establish a crack skeleton line distribution map;

[0009] Establishing a crack distribution map according to the second grayscale area of ​​the binary image and the crack skeleton line distribution map;

[0010] Establishing a hole distribution map according to the second grayscale area of ​​the binary image and the crack skeleton line distribution map;

[0011] A core model is established according to the fracture distribution map and the hole distribution map.

[0012] Optionally, establishing a crack distribution map according to the second grayscale area of ​​the binary image and the crack skeleton line distribution map includes:

[0013] Separating a portion corresponding to the crack skeleton line from the second grayscale area according to the crack skeleton line distribution map;

[0014] The portion separated from the second grayscale area is superimposed on the crack skeleton line distribution map to obtain the crack distribution map.

[0015] Optionally, establishing a core model according to the fracture distribution map and the hole distribution map includes:

[0016] Establishing a pore distribution map according to the crack distribution map and the hole distribution map, wherein the pore distribution map includes cracks shown in the crack distribution map and holes shown in the hole distribution map;

[0017] The core model is established according to the multiple pore distribution maps of the rock sample.

[0018] Optionally, establishing a core model according to the fracture distribution map and the hole distribution map includes:

[0019] Establishing a fracture spatial distribution model according to the plurality of fracture distribution maps of the rock sample;

[0020] According to the fracture spatial distribution model, a fracture network model is established by using centerline extraction and maximum sphere algorithm;

[0021] Establishing a pore spatial distribution model according to the plurality of pore distribution maps of the rock sample;

[0022] According to the hole spatial distribution model, a hole network model is established by using a maximum sphere algorithm;

[0023] The core model is established according to the fracture network model and the pore network model.

[0024] Optionally, before segmenting the CT image using a watershed algorithm, the method further comprises:

[0025] The electronic computer tomography image is optimized, and the optimization processing includes at least one of filtering, noise reduction, sharpening, contrast adjustment, saturation adjustment, and brightness adjustment.

[0026] In a second aspect, the present disclosure also provides a device for constructing a carbonate rock core model, the device comprising:

[0027] An acquisition module, used for acquiring a computer tomography image of a rock sample;

[0028] A first processing module is used to segment the electronic computer tomography image by using a watershed algorithm to obtain a binary image, wherein the binary image is composed of a first grayscale area and a second grayscale area, the grayscale of the first grayscale area is different from the grayscale of the second grayscale area, the first grayscale area represents the matrix of the rock sample, and the second grayscale area represents the pores of the rock sample, and the pores include cracks and holes;

[0029] A second processing module is used to use an ant colony algorithm to perform crack skeleton tracking on the electronic computer tomography image to establish a crack skeleton line distribution map, establish a crack distribution map according to the second grayscale area of ​​the binary image and the crack skeleton line distribution map, and establish a hole distribution map according to the second grayscale area of ​​the binary image and the crack skeleton line distribution map;

[0030] A modeling module is used to establish a core model according to the fracture distribution map and the hole distribution map.

[0031] Optionally, the second processing module is used to establish the crack distribution map in the following manner:

[0032] Separating a portion corresponding to the crack skeleton line from the second grayscale area according to the crack skeleton line distribution map;

[0033] The portion separated from the second grayscale area is superimposed on the crack skeleton line distribution map to obtain the crack distribution map.

[0034] Optionally, the modeling module is used to establish the core model in the following manner:

[0035] Establishing a pore distribution map according to the crack distribution map and the hole distribution map, wherein the pore distribution map includes cracks shown in the crack distribution map and holes shown in the hole distribution map;

[0036] The core model is established according to the multiple pore distribution maps of the rock sample.

[0037] Optionally, the modeling module is used to establish the core model in the following manner:

[0038] Establishing a fracture spatial distribution model according to the plurality of fracture distribution maps of the rock sample;

[0039] According to the fracture spatial distribution model, a fracture network model is established by using centerline extraction and maximum sphere algorithm;

[0040] Establishing a pore spatial distribution model according to the plurality of pore distribution maps of the rock sample;

[0041] According to the hole spatial distribution model, a hole network model is established by using a maximum sphere algorithm;

[0042] The core model is established according to the fracture network model and the pore network model.

[0043] Optionally, the construction device also includes an optimization module for optimizing the CT scan image before segmenting the CT scan image using the watershed algorithm, wherein the optimization processing includes at least one of filtering, noise reduction, sharpening, contrast adjustment, saturation adjustment, and brightness adjustment.

[0044] In a third aspect, the present disclosure also provides a device for constructing a carbonate rock core model, including:

[0045] processor;

[0046] a memory for storing instructions executable by a processor;

[0047] Wherein, the processor is configured to execute the method for constructing a carbonate rock core model as described in the first aspect.

[0048] In a fourth aspect, an embodiment of the present disclosure further provides a storage medium, wherein the storage medium stores at least one instruction, and the instruction is loaded and executed by a processor to construct a carbonate rock core model as described in the first aspect.

[0049] The beneficial effects brought by the technical solution provided by the embodiments of the present disclosure include at least:

[0050] By using the watershed algorithm to segment the CT image, the CT image of the rock sample can be converted into a binary image. Each pixel in the binary image has only two possible grayscale values. The matrix and pores of the rock sample can be distinguished according to the grayscale. The crack skeleton line can be determined from the CT image by the ant colony algorithm, so as to establish a crack skeleton line distribution map. The crack skeleton line can show the distribution and morphology of the cracks. In this way, the crack distribution map can be established according to the second grayscale area in the binary image, that is, the pores, and the distribution and morphology of the cracks and the width of the cracks can be accurately reflected. After obtaining the crack skeleton line distribution map, the pore distribution map can also be established in combination with the second grayscale area in the binary image, which can accurately reflect the distribution and morphology of the pores and the size of the pores. Then, a core model is established according to the crack distribution map and the pore distribution map. The core model can accurately reflect the fracture and cave development characteristics of multi-medium carbonate reservoirs. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] In order to more clearly illustrate the technical solutions in the embodiments of the present disclosure, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present disclosure. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0052] Figure 1 is a flow chart of a method for constructing a carbonate rock core model provided by an embodiment of the present disclosure;

[0053] Figure 2 is a flow chart of another method for constructing a carbonate rock core model provided by an embodiment of the present disclosure;

[0054] Figure 3 It is a schematic diagram of a result of a rock sample scanned by a computer tomography provided by an embodiment of the present disclosure;

[0055] Figure 4 is a schematic diagram of a computer tomography image provided by an embodiment of the present disclosure;

[0056] Figure 5 is a schematic diagram of a binary image provided by an embodiment of the present disclosure;

[0057] Figure 6 is a schematic diagram of a crack skeleton line distribution diagram provided by an embodiment of the present disclosure;

[0058] Figure 7 is a schematic diagram of a process of separating a portion corresponding to a crack skeleton line from a second grayscale area provided by an embodiment of the present disclosure;

[0059] Figure 8 is a schematic diagram of a hole distribution diagram provided by an embodiment of the present disclosure;

[0060] Fig. 9 is a schematic diagram of a pore distribution diagram provided by an embodiment of the present disclosure;

[0061] Fig.10 is a schematic diagram of a core model provided by an embodiment of the present disclosure;

[0062] Fig.11 is a schematic diagram of a fracture spatial distribution model provided by an embodiment of the present disclosure;

[0063] Fig.12 is a schematic diagram of a hole space distribution model provided by an embodiment of the present disclosure;

[0064] Fig.13 is a schematic diagram of a fracture network model provided by an embodiment of the present disclosure;

[0065] Fig.14 is a schematic diagram of a hole network model provided by an embodiment of the present disclosure;

[0066] Fig.15 is a schematic diagram of a core network model provided by an embodiment of the present disclosure;

[0067] Fig.16 It is a structural block diagram of a device for constructing a carbonate rock core model provided by an embodiment of the present disclosure;

[0068] Fig.17 A structural block diagram of a computer device provided by an exemplary embodiment of the present invention is shown. DETAILED DESCRIPTION

[0069] In order to make the objectives, technical solutions and advantages of the present disclosure more clear, the embodiments of the present disclosure will be further described in detail below with reference to the accompanying drawings.

[0070] Figure 1 1 is a flow chart of a method for constructing a carbonate rock core model provided by an embodiment of the present disclosure. Figure 1 As shown, the method includes:

[0071] S11: Obtain a computer tomography image of the rock sample.

[0072] S12: Use the watershed algorithm to segment the CT image to obtain a binary image.

[0073] The binary image is composed of a first grayscale area and a second grayscale area. The grayscale of the first grayscale area is different from the grayscale of the second grayscale area. The first grayscale area represents the matrix of the rock sample, and the second grayscale area represents the pores of the rock sample. The pores include cracks and holes.

[0074] S13: Using ant colony algorithm to track the crack skeleton of the electronic computer tomography image, and establish a crack skeleton line distribution map.

[0075] S14: Establishing a crack distribution map according to the second grayscale region of the binary image and the crack skeleton line distribution map.

[0076] S15: Establishing a hole distribution map according to the second grayscale region of the binary image and the crack skeleton line distribution map.

[0077] S16: Establish a core model according to the fracture distribution map and the hole distribution map.

[0078] By using the watershed algorithm to segment the CT image, the CT image of the rock sample can be converted into a binary image. Each pixel in the binary image has only two possible grayscale values. The matrix and pores of the rock sample can be distinguished according to the grayscale. The crack skeleton line can be determined from the CT image by the ant colony algorithm, so as to establish a crack skeleton line distribution map. The crack skeleton line can show the distribution and morphology of the cracks. In this way, the crack distribution map can be established according to the second grayscale area in the binary image, that is, the pores, and the distribution and morphology of the cracks and the width of the cracks can be accurately reflected. After obtaining the crack skeleton line distribution map, the pore distribution map can also be established in combination with the second grayscale area in the binary image, which can accurately reflect the distribution and morphology of the pores and the size of the pores. Then, a core model is established according to the crack distribution map and the pore distribution map. The core model can accurately reflect the fracture and cave development characteristics of multi-medium carbonate reservoirs.

[0079] Figure 2 FIG. 1 is a flow chart of another method for constructing a carbonate rock core model provided by an embodiment of the present disclosure. Figure 2 As shown, the method includes:

[0080] S21: Obtain a computer tomography image of the rock sample.

[0081] Computer tomography (CT) images (English: Computed Tomography, Chinese: Computer tomography) images can be obtained by performing CT scanning on rock samples to obtain multiple CT images.

[0082] The rock sample may be a core sample made from a rock core obtained from a formation.

[0083] For example, in this embodiment, the rock sample is a carbonate gas reservoir fracture-hole type plug rock sample, the diameter of the rock sample is 2.5 cm, and the height is 4.2 cm. The gas-measured porosity of the rock sample is 6.74%, and the permeability is 3.03 mD. Secondary pores such as microcracks, cracks, and holes can be clearly seen on the surface.

[0084] The multiple CT images may be multiple 16-bit grayscale images obtained by scanning along the height direction of the rock sample. Figure 3 FIG. 1 is a schematic diagram of a rock sample scanned by a computer tomography scan according to an embodiment of the present disclosure. Figure 3 As shown, a columnar three-dimensional rock sample model can be obtained by electronic computer tomography. The three-dimensional rock sample model is composed of multiple CT images. The diameter D of the rock sample is 2.5 cm and the height H is 4.2 cm. Figure 4 is a schematic diagram of a computer tomography image provided by an embodiment of the present disclosure. Figure 4 As shown, the electronic computer tomography image is Figure 3 A cross section of the 3D rock sample model in . Figure 4 The middle circular part is the cross section of the three-dimensional rock sample model, and the black part outside the circle is free of material.

[0085] For example, in this embodiment, the height of the rock sample is 4.2 cm. During the CT scanning of the rock sample, 1340 CT images are obtained, which are equivalent to 1340 cross sections of the three-dimensional rock sample model. The size of the CT image is 1530×1530, and the resolution is 7.83 μm.

[0086] The CT image obtained by performing electronic computed tomography scanning on the rock sample can be stored in a device with a storage function. In step S21, the electronic computed tomography image can be obtained from the device with a storage function, or the electronic computed tomography image can be obtained from the electronic computed tomography device during the process of performing the electronic computed tomography scanning.

[0087] S22: Optimizing the CT scan image.

[0088] The optimization processing includes at least one of filtering, noise reduction, sharpening, contrast adjustment, saturation adjustment, and brightness adjustment.

[0089] The scope of optimization processing includes the entire area where the rock sample is located on the electronic computer tomography image, and the entire rock sample is taken as the research object. This is because carbonate rocks are highly heterogeneous. If only a part of the rock sample is taken as the processing and research object, the final core model is difficult to accurately express the overall fracture and cave development characteristics.

[0090] By optimizing the CT images, the quality of the CT images is improved, so that the boundary between the matrix and the pores of the rock sample is clearer on the CT images, which is beneficial to improving the accuracy of the core model finally established.

[0091] For example, the non-local mean filtering method is used to filter the CT scan image, which can filter out the system noise generated during the CT scan.

[0092] In a specific implementation, all acquired electronic computer tomography images can be imported into the image three-dimensional reconstruction software, and the entire plunger rock sample can be marked as a study area for processing.

[0093] S23: Use the watershed algorithm to segment the CT image to obtain a binary image.

[0094] The binary image is composed of a first grayscale area and a second grayscale area. The grayscale of the first grayscale area is different from the grayscale of the second grayscale area. The first grayscale area represents the matrix of the rock sample, and the second grayscale area represents the pores of the rock sample. The pores include cracks and holes. The cracks displayed in the binary image are mainly cracks with relatively large widths. For cracks with relatively small widths, it is usually difficult to display them in the binary image.

[0095] In a binary image, each pixel has only two possible grayscale states, that is, the grayscale value of any pixel in the image is either 0 or 255, representing black and white, respectively. For example, in the embodiment of the present disclosure, the grayscale of the first grayscale area is 255, which is white and represents the matrix, and the grayscale of the second grayscale area is 0, which is black and represents the pores. Figure 5 is a schematic diagram of a binary image provided by an embodiment of the present disclosure. Figure 5 In the figure, the white area 51 represents the first gray area, which shows the matrix in the rock sample, and the black area 52 represents the second gray area, which shows the pores in the rock sample, including cracks and holes.

[0096] The computed tomography image is a grayscale image. Through the watershed algorithm, the boundary between the matrix and the pores can be identified, and then expanded to its connected neighborhood, and the areas that are spatially adjacent and have similar grayscale values ​​are divided into one phase, thereby segmenting the matrix and pores.

[0097] The watershed algorithm uses the gradient image as the input image and is processed using the following formula:

[0098]

[0099] g(x,y)=max(grad(f(x,y)),gθ) (2)

[0100] Among them, f(x, y) represents the original image, grad() represents the gradient operation, and gθ represents the threshold.

[0101] By setting a threshold, excessive segmentation of the CT scan can be avoided.

[0102] S24: Using an ant colony algorithm to track the crack skeleton of the electronic computer tomography image, and establish a crack skeleton line distribution map.

[0103] The crack skeleton line can be obtained by tracing the crack skeleton of the electronic computed tomography image through the ant colony algorithm. Figure 6 It is a schematic diagram of a crack skeleton line distribution diagram provided in an embodiment of the present disclosure. Figure 6 The black line 61 in the figure represents the crack skeleton line, which shows the distribution position of the cracks and the shape of the cracks. The shape here refers to the extended shape, but cannot show the width of the cracks. The crack skeleton line distribution map shows all the crack skeleton lines and the relative position relationship between all the crack skeleton lines.

[0104] S25: Separating a portion corresponding to the crack skeleton line from the second grayscale area according to the crack skeleton line distribution map.

[0105] The second grayscale area in the binary image contains cracks and holes. The portion corresponding to the crack skeleton line refers to a section in the second grayscale area that extends along the crack skeleton line and whose end is aligned with the end of the crack skeleton line. Through step S25, cracks with relatively large width can be distinguished from the binary image.

[0106] Specifically, the crack skeleton line distribution map can be overlapped with the binary image, the distribution of the crack skeleton line can be determined in the binary image, and then the portion containing the crack skeleton line can be cut out from the binary image. The cut out portion represents a crack with a relatively large width.

[0107] Figure 7 1 is a schematic diagram of a process of separating a portion corresponding to a crack skeleton line from a second grayscale region provided by an embodiment of the present disclosure. The diagram is only for illustrating the separation process and does not represent a real binary image and a crack skeleton line distribution diagram. Figure 7 The dotted line in the figure represents the crack skeleton line, and the filled area represents the second grayscale area. Figure 7 As shown, after overlapping the crack skeleton line distribution map with the binary image, a part of the second grayscale area overlaps with the crack skeleton line, for example Figure 7In the figure, the second grayscale area overlaps with the crack skeleton line c and the crack skeleton line d, and overlaps with a part of the crack skeleton line b. In the second grayscale area, the part that overlaps with the crack skeleton line is marked, and the marked area is cut out from the second grayscale area (such as Figure 7 As shown in the figure below, a crack with a relatively large width is obtained.

[0108] S26: Superimposing the portion separated from the second grayscale area with the crack skeleton line distribution map to obtain a crack distribution map.

[0109] In step S25, the portion corresponding to the crack skeleton line separated from the second grayscale area is a crack with a larger width.

[0110] For cracks with smaller width, it may be difficult to distinguish them in the binary image, e.g. Figure 7 In the figure, the crack skeleton line a does not overlap with the second grayscale area, and part of the crack skeleton line b does not overlap with the second grayscale area. This shows that the crack width at the crack skeleton line a is small, and the crack at the crack skeleton line b has a small lower width, and both cannot be distinguished in the binary image. For this part of the crack with a smaller width, an approximate treatment can be made and replaced by the crack skeleton line.

[0111] By superimposing the portion separated from the second grayscale area with the crack skeleton line distribution map, the resulting image can distinguish cracks with larger widths as well as cracks with smaller widths. Thus, a crack distribution map is obtained, from which not only the distribution and morphology of the cracks can be obtained, but also the width of the cracks with larger widths can be measured.

[0112] S27: Establishing a hole distribution map according to the second grayscale region of the binary image and the separated portion in the region corresponding to the crack skeleton line.

[0113] The second grayscale area in the binary image contains cracks and holes with larger widths. The part separated from the second grayscale area in step S25 represents the cracks with larger widths. This part is removed from the binary image, and the remaining area in the second grayscale area represents the holes. Figure 8 is a schematic diagram of a hole distribution diagram provided by an embodiment of the present disclosure. Figure 8 In the figure, the black area 81 represents the holes, and the hole distribution map can reflect the distribution and shape of the holes and the size of the holes.

[0114] S28: Establish a core model based on the fracture distribution map and the hole distribution map.

[0115] In one possible implementation, the core model may be established in the following manner:

[0116] A pore distribution map is established based on the crack distribution map and the hole distribution map.

[0117] A core model is established based on multiple pore distribution maps of the rock sample.

[0118] The pore distribution map includes cracks shown in the crack distribution map and holes shown in the hole distribution map.

[0119] Fig. 9 is a schematic diagram of a pore distribution diagram provided by an embodiment of the present disclosure. Fig. 9 As shown, the crack distribution map and the hole distribution map can be superimposed so that the cracks and holes are distributed on the same map, that is, the pore distribution map is obtained. Since the pore distribution map is obtained through the crack distribution map and the hole distribution map, the cracks 91 and the holes 92 can be distinguished according to the pore distribution map.

[0120] As mentioned above, in the embodiment of the present disclosure, there are a total of 1340 CT images. By processing each CT image in sequence through steps S22 to S27, 1340 pore distribution maps can be established in step S28. The 1340 pore distribution maps correspond to 1340 cross-sections of the rock sample spaced apart in the height direction. Fig.10 Schematic diagram of a core model provided by an embodiment of the present disclosure. Fig.10 As shown, by superimposing these 1340 pore distribution maps and reconstructing them in three dimensions, a three-dimensional model of the rock sample, also known as the core model, is established. Fig.10 The black areas 101 in FIG. 1 represent cracks or holes.

[0121] The core model can be converted into a grid model after digital processing to facilitate the study of the core.

[0122] In another possible implementation, the core model may be established in the following manner:

[0123] A fracture spatial distribution model is established based on multiple fracture distribution maps of rock samples.

[0124] According to the fracture spatial distribution model, the fracture network model is established by using centerline extraction and maximum sphere algorithm.

[0125] A pore spatial distribution model is established based on multiple pore distribution maps of rock samples.

[0126] According to the spatial distribution model of holes, the maximum sphere algorithm is used to establish the hole network model.

[0127] The core model is established based on the fracture network model and the pore network model.

[0128] As mentioned above, in the embodiment of the present disclosure, there are a total of 1340 CT images, and by processing each CT image in steps S22 to S27 in sequence, 1340 crack distribution maps and 1340 hole distribution maps can be obtained. The 1340 crack distribution maps and the 1340 hole distribution maps correspond to 1340 cross sections of the rock sample spaced in the height direction. Fig.11 Schematic diagram of a fracture spatial distribution model provided by an embodiment of the present disclosure. Fig.11 As shown in the figure, 1340 fracture distribution maps are superimposed and reconstructed in three dimensions to establish a three-dimensional model reflecting the fractures in the rock sample, that is, a fracture spatial distribution model. Fig.11 The black portion 111 in FIG. 1 represents a crack. Fig.12 Schematic diagram of a hole space distribution model provided by an embodiment of the present disclosure. Fig.12 As shown in the figure, 1340 hole distribution maps are superimposed and reconstructed in three dimensions to establish a three-dimensional model reflecting the holes in the rock sample, that is, the hole spatial distribution model. Fig.12 The black portion 121 in FIG. 1 represents a hole.

[0129] Fig.13 Schematic diagram of a fracture network model provided by an embodiment of the present disclosure. Fig.13 As shown in the figure, based on the fracture spatial distribution model, the fracture network model established by using centerline extraction and maximum sphere algorithm is a grid model. Fig.13 The black portion 131 in FIG. 1 represents a crack. Fig.14 is a schematic diagram of a hole network model provided by an embodiment of the present disclosure. Fig.14 As shown in the figure, based on the hole space distribution model, the hole network model established by using the maximum sphere algorithm is a grid model. Fig.14 The black portion 141 in FIG. 1 represents a crack. Fig.15 Schematic diagram of a core network model provided by an embodiment of the present disclosure. Fig.15 As shown, according to Fig.13 The fracture network model and Fig.14The core model established by the pore network model is also a grid model, that is, a core network model. By integrating the fracture network model that reflects the fractures in the rock sample and the pore network model that reflects the holes in the rock sample, a three-dimensional model can be obtained. The three-dimensional model is the core model, which reflects both the fractures in the rock sample and the holes in the rock sample. This method does not require digitization again. Compared with the aforementioned method, it is beneficial to reduce the number of grids, reduce the modeling time, and simplify the model. After the core model is established, the core model can be used to determine the number of pores, fracture opening and other information. For example, in this embodiment, through the core model, it is determined that the number of pores is 12344, the pore radius is distributed in the range of 0.06 to 74.97 μm, the average is 2.64 μm, the number of fracture balls and sticks is 39385, and the fracture opening is distributed in the range of 2.71 to 109.92 μm, with an average of 11.92 μm. The details are as follows in Table 1:

[0130] Table 1 Parameters of the three-dimensional fracture-hole model of the rock sample in the embodiment

[0131]

[0132] Fig.16 is a structural block diagram of a carbonate rock core model construction device provided by an embodiment of the present disclosure, such as Fig.16 As shown, the carbonate rock core model construction device includes an acquisition module 10, a first processing module 20, a second processing module 30 and a modeling module 40.

[0133] The acquisition module 10 is used to acquire a computer tomography image of the rock sample.

[0134] The first processing module 20 is used to segment the electronic computer tomography image using a watershed algorithm to obtain a binary image, which is composed of a first grayscale area and a second grayscale area. The grayscale of the first grayscale area is different from the grayscale of the second grayscale area. The first grayscale area represents the matrix of the rock sample, and the second grayscale area represents the pores of the rock sample, and the pores include cracks and holes.

[0135] The second processing module 30 is used to use an ant colony algorithm to track the crack skeleton of the electronic computer tomography image, establish a crack skeleton line distribution map, establish a crack distribution map based on the second grayscale area of ​​the binary image and the crack skeleton line distribution map, and establish a hole distribution map based on the second grayscale area of ​​the binary image and the crack skeleton line distribution map.

[0136] The modeling module 40 is used to establish a core model according to the fracture distribution map and the hole distribution map.

[0137] By using the watershed algorithm to segment the CT image, the CT image of the rock sample can be converted into a binary image. Each pixel in the binary image has only two possible grayscale values. The matrix and pores of the rock sample can be distinguished according to the grayscale. The crack skeleton line can be determined from the CT image by the ant colony algorithm, so as to establish a crack skeleton line distribution map. The crack skeleton line can show the distribution and morphology of the cracks. In this way, the crack distribution map can be established according to the second grayscale area in the binary image, that is, the pores, and the distribution and morphology of the cracks and the width of the cracks can be accurately reflected. After obtaining the crack skeleton line distribution map, the pore distribution map can also be established in combination with the second grayscale area in the binary image, which can accurately reflect the distribution and morphology of the pores and the size of the pores. Then, a core model is established according to the crack distribution map and the pore distribution map. The core model can accurately reflect the fracture and cave development characteristics of multi-medium carbonate reservoirs.

[0138] The acquisition module 10 can acquire the computer tomography image of the rock sample according to the aforementioned step S11 or step S21, which will not be described in detail here.

[0139] The first processing module 20 can obtain a binary image according to the aforementioned step S12 or step S23, which will not be described in detail here.

[0140] The second processing module 30 can establish a crack skeleton line distribution map according to the aforementioned step S13 or step S24, can establish a crack distribution map according to the aforementioned step S14 or steps S25 to S26, and can establish a hole distribution map according to the aforementioned step S15 or step S27, which will not be described in detail here.

[0141] The modeling module 40 may establish a crack skeleton line distribution map according to the aforementioned step S16 or step S28, which will not be described in detail herein.

[0142] Optionally, the construction device may further include an optimization module 50. The optimization module 50 is used to optimize the CT image before segmenting the CT image using the watershed algorithm, and the optimization includes at least one of filtering, noise reduction, sharpening, contrast adjustment, saturation adjustment, and brightness adjustment. By optimizing the CT image, the quality of the CT image is improved, so that the boundary between the matrix and the pores of the rock sample on the CT image is clearer, which is conducive to improving the accuracy of the core model finally established.

[0143] The optimization module 50 can optimize the CT scan image according to the aforementioned step S22, which will not be described in detail here.

[0144] Optionally, the second processing module 30 may be used to establish a crack distribution map in the following manner:

[0145] A portion corresponding to the crack skeleton line is separated from the second grayscale area according to the crack skeleton line distribution map.

[0146] The portion separated from the second grayscale area is superimposed on the crack skeleton line distribution map to obtain a crack distribution map.

[0147] The second processing module 30 can obtain a crack distribution map according to the aforementioned steps S25 and S26, which will not be described in detail here.

[0148] In a possible implementation, the modeling module 40 can establish a pore distribution map based on the fracture distribution map and the hole distribution map, and establish a core model based on multiple pore distribution maps of the rock sample, wherein the pore distribution map includes fractures shown in the fracture distribution map and holes shown in the hole distribution map.

[0149] In another possible implementation, the modeling module 40 can establish a fracture spatial distribution model based on multiple fracture distribution maps of the rock sample, establish a fracture network model based on the fracture spatial distribution model using centerline extraction and the maximum sphere algorithm, establish a hole spatial distribution model based on multiple hole distribution maps of the rock sample, establish a hole network model based on the hole spatial distribution model using the maximum sphere algorithm, and establish a core model based on the fracture network model and the hole network model.

[0150] The modeling module 40 can establish a core model according to the aforementioned step S28, which will not be described in detail here.

[0151] Fig.17 FIG. 1 shows a block diagram of a computer device provided by an exemplary embodiment of the present invention. Fig.17 As shown, the computer device 300 includes a central processing unit (CPU) 301, a system memory 304 including a random access memory (RAM) 302 and a read-only memory (ROM) 303, and a system bus 305 connecting the system memory 304 and the central processing unit 301. The computer device 300 also includes a basic input / output system (I / O system) 306 that helps to transfer information between various components in the computer, and a large-capacity storage device 307 for storing an operating system 313, application programs 314, and other program modules 315.

[0152] The basic input / output system 306 includes a display 308 for displaying information and an input device 309 such as a mouse and a keyboard for user inputting information. The display 308 and the input device 309 are connected to the central processing unit 301 through an input / output controller 310 connected to the system bus 305. The basic input / output system 306 may also include an input / output controller 310 for receiving and processing inputs from a plurality of other devices such as a keyboard, a mouse, or an electronic stylus. Similarly, the input / output controller 310 also provides output to a display screen, a printer, or other types of output devices.

[0153] The mass storage device 307 is connected to the central processing unit 301 through a mass storage controller (not shown) connected to the system bus 305. The mass storage device 307 and its associated computer readable media provide non-volatile storage for the computer device 300. That is, the mass storage device 307 may include a computer readable medium (not shown) such as a hard disk or a CD-ROM drive.

[0154] Without loss of generality, computer readable media may include computer storage media and communication media. Computer storage media include volatile and non-volatile, removable and non-removable media implemented in any method or technology for storing information such as computer readable instructions, data structures, program modules or other data. Computer storage media include RAM, ROM, EPROM, EEPROM, flash memory or other solid-state storage technologies, CD-ROM, DVD or other optical storage, cassettes, magnetic tapes, disk storage or other magnetic storage devices. Of course, those skilled in the art will appreciate that computer storage media are not limited to the above. The above-mentioned system memory 304 and mass storage device 307 can be collectively referred to as memory.

[0155] According to various embodiments of the present invention, the computer device 300 can also be connected to a remote computer on the network through a network such as the Internet. That is, the computer device 300 can be connected to the network 312 through the network interface unit 311 connected to the system bus 305, or the network interface unit 311 can be used to connect to other types of networks or remote computer systems (not shown).

[0156] The memory also includes one or more programs, which are stored in the memory and configured to be executed by the CPU. The one or more programs include instructions for performing the method for constructing a carbonate core model as described above in an embodiment of the present invention.

[0157] The embodiment of the present invention also provides a non-transitory computer-readable storage medium, when the instructions in the storage medium are executed by the processor of the carbonate rock core model construction device, the carbonate rock core model construction device can execute Figures 1-2 A method for constructing a carbonate rock core model provided in any one of the items.

[0158] A computer program product containing instructions that, when executed on a computer, causes the computer to perform Figures 1-2 Any one of the items provides instructions for a method of constructing a carbonate core model.

[0159] The present disclosure also provides a non-transitory computer-readable storage medium. When the instructions in the storage medium are executed by a processor of a carbonate rock core model construction device, the carbonate rock core model construction device can execute Figures 1-2 A method for constructing a carbonate rock core model provided in any one of the items.

[0160] A computer program product containing instructions that, when executed on a computer, causes the computer to perform Figures 1-2 Any one of the items provides instructions for a method of constructing a carbonate core model.

[0161] It should be noted that: the carbonate rock core model construction device provided in the above embodiment only uses the division of the above functional modules as an example when constructing the carbonate rock core model. In actual applications, the above functions can be assigned to different functional modules as needed, that is, the internal structure of the device is divided into different functional modules to complete all or part of the functions described above. In addition, the carbonate rock core model construction device provided in the above embodiment and the carbonate rock core model construction method embodiment belong to the same concept, and the specific implementation process is detailed in the method embodiment, which will not be repeated here.

[0162] A person skilled in the art will understand that all or part of the steps to implement the above embodiments may be accomplished by hardware, or by a program to instruct the relevant hardware, and the program may be stored in a computer-readable storage medium, and the above-mentioned storage medium may be a read-only memory, a disk or an optical disk, etc.

[0163] The above description is only an optional embodiment of the present disclosure and is not intended to limit the present disclosure. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present disclosure shall be included in the protection scope of the present disclosure.

Claims

1. A method for constructing a carbonate rock core model, characterized in that: The method comprises: Obtaining computerized tomography images of rock samples; The electronic computer tomography image is segmented by a watershed algorithm to obtain a binary image, wherein the binary image is composed of a first grayscale area and a second grayscale area, the grayscale of the first grayscale area is different from the grayscale of the second grayscale area, the first grayscale area represents the matrix of the rock sample, and the second grayscale area represents the pores of the rock sample, and the pores include cracks and holes; Using an ant colony algorithm to track the crack skeleton of the electronic computer tomography image and establish a crack skeleton line distribution map; Establishing a crack distribution map according to the second grayscale area of ​​the binary image and the crack skeleton line distribution map; Establishing a hole distribution map according to the second grayscale area of ​​the binary image and the crack skeleton line distribution map; A core model is established according to the fracture distribution map and the hole distribution map.

2. The method for constructing a carbonate rock core model according to claim 1, characterized in that: The step of establishing a crack distribution map according to the second grayscale area of ​​the binary image and the crack skeleton line distribution map comprises: Separating a portion corresponding to the crack skeleton line from the second grayscale area according to the crack skeleton line distribution map; The portion separated from the second grayscale area is superimposed on the crack skeleton line distribution map to obtain the crack distribution map.

3. The method for constructing a carbonate rock core model according to claim 1, characterized in that: The establishing of the core model according to the fracture distribution map and the hole distribution map comprises: Establishing a pore distribution map according to the crack distribution map and the hole distribution map, wherein the pore distribution map includes cracks shown in the crack distribution map and holes shown in the hole distribution map; The core model is established according to the multiple pore distribution maps of the rock sample.

4. The method for constructing a carbonate rock core model according to claim 1, characterized in that: The establishing of the core model according to the fracture distribution map and the hole distribution map comprises: Establishing a fracture spatial distribution model according to the plurality of fracture distribution maps of the rock sample; According to the fracture spatial distribution model, a fracture network model is established by using centerline extraction and maximum sphere algorithm; Establishing a pore spatial distribution model according to the plurality of pore distribution maps of the rock sample; According to the hole spatial distribution model, a hole network model is established by using a maximum sphere algorithm; The core model is established according to the fracture network model and the pore network model.

5. The method for constructing a carbonate rock core model according to any one of claims 1 to 4, characterized in that: Before segmenting the CT image using the watershed algorithm, the method further includes: The electronic computer tomography image is optimized, and the optimization processing includes at least one of filtering, noise reduction, sharpening, contrast adjustment, saturation adjustment, and brightness adjustment.

6. A device for constructing a carbonate rock core model, characterized in that: The construction device comprises: An acquisition module, used for acquiring a computer tomography image of a rock sample; A first processing module is used to segment the electronic computer tomography image by using a watershed algorithm to obtain a binary image, wherein the binary image is composed of a first grayscale area and a second grayscale area, the grayscale of the first grayscale area is different from the grayscale of the second grayscale area, the first grayscale area represents the matrix of the rock sample, and the second grayscale area represents the pores of the rock sample, and the pores include cracks and holes; A second processing module is used to use an ant colony algorithm to perform crack skeleton tracking on the electronic computer tomography image to establish a crack skeleton line distribution map, establish a crack distribution map according to the second grayscale area of ​​the binary image and the crack skeleton line distribution map, and establish a hole distribution map according to the second grayscale area of ​​the binary image and the crack skeleton line distribution map; A modeling module is used to establish a core model according to the fracture distribution map and the hole distribution map.

7. The device for constructing a carbonate rock core model according to claim 6, characterized in that: The second processing module is used to establish the crack distribution map in the following manner: Separating a portion corresponding to the crack skeleton line from the second grayscale area according to the crack skeleton line distribution map; The portion separated from the second grayscale area is superimposed on the crack skeleton line distribution map to obtain the crack distribution map.

8. The device for constructing a carbonate rock core model according to claim 6, characterized in that: The modeling module is used to establish the core model in the following manner: Establishing a pore distribution map according to the crack distribution map and the hole distribution map, wherein the pore distribution map includes cracks shown in the crack distribution map and holes shown in the hole distribution map; The core model is established according to the multiple pore distribution maps of the rock sample.

9. The device for constructing a carbonate rock core model according to claim 6, characterized in that: The modeling module is used to establish the core model in the following manner: Establishing a fracture spatial distribution model according to the plurality of fracture distribution maps of the rock sample; According to the fracture spatial distribution model, a fracture network model is established by using centerline extraction and maximum sphere algorithm; Establishing a pore spatial distribution model according to the plurality of pore distribution maps of the rock sample; According to the hole spatial distribution model, a hole network model is established by using a maximum sphere algorithm; The core model is established according to the fracture network model and the pore network model.

10. The device for constructing a carbonate rock core model according to claim 6, characterized in that: The construction device also includes an optimization module, which is used to optimize the electronic computer tomography image before the watershed algorithm is used to segment the electronic computer tomography image, and the optimization processing includes at least one of filtering, noise reduction, sharpening, contrast adjustment, saturation adjustment, and brightness adjustment.

11. A device for constructing a carbonate rock core model, characterized in that: include: processor; a memory for storing instructions executable by a processor; Wherein, the processor is configured to execute the method for constructing a carbonate rock core model as described in any one of claims 1 to 5.

12. A storage medium, characterized in that: The storage medium stores at least one instruction, and the instruction is loaded by the processor and executed by the method for constructing a carbonate rock core model according to any one of claims 1 to 5.

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