A method for manufacturing a fine physical model of a target oil zone in a fracture-cavity oil and gas reservoir

Abstract

A method for manufacturing a fine physical model of a target oil zone in a fracture-vuggy oil and gas reservoir organically combines CT scanning technology, three-dimensional seismic imaging technology, and 3D printing technology. By establishing a library of single fracture images and a library of single hole images, and selecting appropriate single fracture images and / or single hole images for arrangement and combination in 3D image editing software, a simulated image of the target oil zone identical to the three-dimensional seismic model obtained by the three-dimensional seismic imaging technology is obtained. A fine physical model that can cover the entire target oil zone and even the entire regional underground strata of the fracture-vuggy oil and gas reservoir is then printed using a 3D printer. The fine physical model has a wide coverage area and can reflect the actual pore and fracture structure of the underground rock formations in the region. Various indoor displacement experiments are carried out on the model to obtain parameters such as crude oil recovery rate, residual oil saturation, and seepage characteristics. This has important guiding significance for later reservoir development, especially in the optimization of water injection methods and the structural design of injection-production well patterns.

Description

Technical Field

[0001] The present invention relates to the technical field of development of fracture-cavity oil reservoirs, and in particular to a method for manufacturing a fine physical model of a target oil zone in a fracture-cavity oil and gas reservoir. Background Art

[0002] Oil and natural gas resources are buried thousands of meters underground. For fracture-vuggy oil and gas reservoirs, pores and fractures serve as reservoir and migration pathways for oil and gas. Current research on the structural characteristics of fracture-vuggy reservoirs relies primarily on seismic interpretation, well logging data, and porosity and permeability analysis. These methods are inaccurate and lack detailed information on the distribution of fractures and cavities, resulting in unreliable research results and a true understanding of the actual fracture-vuggy reservoirs. Particularly in the mid-to-late stages of fracture-vuggy oil and gas field development, a lack of clear understanding of the remaining oil content and distribution after water flooding can significantly complicate the optimization of waterflooding methods and the construction of injection-production well patterns.

[0003] Current research on the fracture-cavity structure of fracture-cavity oil and gas reservoirs primarily involves building physical models of the fracture-cavity structure and etching the pore structure within the rock formation onto glass or acrylic plates using mechanical tools. This process is time-consuming, fails to capture the subtle structural features within the rock formation, and suffers from low accuracy.

[0004] 3D printing is a rapid prototyping technology that has emerged in recent years. Based on three-dimensional data, it uses solid powders, resins, plastics, and other materials to rapidly construct solid objects through layer-by-layer printing. This technology has been widely used in the medical, automotive, aviation, and construction industries. However, when applied to the physical modeling of the fracture-cavity structure of fracture-cavity oil and gas reservoirs, due to the limited scanning range and accuracy of 3D printing scanners, it is only possible to scan and restore the fracture-cavity structure of a single rock sample and cannot be applied to the physical modeling of an entire large area (such as an oilfield). Summary of the Invention

[0005] The present invention provides a method for manufacturing a fine physical model of a fracture-cavity oil and gas reservoir. By combining CT scanning technology, three-dimensional seismic imaging technology and 3D printing technology, a fine physical model that can truly reflect the structure of all fractures and caves in the underground strata of the entire oil field is produced. Various indoor displacement experiments are carried out on the fine physical model to accurately obtain parameters such as crude oil recovery rate, residual oil saturation and seepage characteristics. This has important guiding significance for the mid- and late-stage development of the fracture-cavity oil and gas reservoir, especially in the optimization of water injection methods and the structural design of injection-production well patterns.

[0006] The technical solutions of the present invention are as follows:

[0007] A method for manufacturing a fine physical model of a target oil zone in a fracture-cavity oil and gas reservoir comprises the following steps:

[0008] S1, in the target oil zone of the fracture-cavity oil and gas reservoir, a core sample with a typical fracture-cavity structure is selected, and a CT scanner is used to scan the core sample to obtain a set of two-dimensional projection images of the core sample;

[0009] S2, using reconstruction software with the Fieldcamp algorithm to perform three-dimensional reconstruction on a set of two-dimensional projection images of the core sample to obtain a 3D digital image of the core sample;

[0010] S3, analyzing the 3D digital image using 3D image analysis software to obtain a fracture-cavity characteristic image of the core sample, and exporting the fracture-cavity characteristic image as a fracture-cavity data volume;

[0011] S4, importing the fracture-hole data volume into 3D image editing software to obtain a single fracture image of each fracture and a single hole image of each hole in the core sample;

[0012] S5, repeating steps S1 to S4 to analyze a large number of rock samples with typical fracture-cavity structures in the target oil zone of the fracture-cavity oil and gas reservoir, obtaining a large number of single fracture images and single pore images, and forming a single fracture image library and a single pore image library;

[0013] S6, based on the 3D seismic model of the target oil zone of the fracture-vuggy oil and gas reservoir, selecting appropriate single fracture images and / or single hole images, and arranging and combining them in 3D image editing software to obtain a simulated image of the target oil zone identical to the 3D seismic model, and exporting the simulated image of the target oil zone as a pre-printed image data volume for a 3D printer;

[0014] S7, importing the pre-printed image data body into a 3D printer to print out a detailed physical model of the target oil area.

[0015] Preferably, in S6, the three-dimensional seismic model includes a visualized three-dimensional seismic image obtained by inverting the geological structure of the underground rock formations in the target oil field through three-dimensional seismic detection technology, and the visualized three-dimensional seismic image can at least display the distribution of underground pores and cracks in the target oil field.

[0016] Preferably, in S3, analyzing the 3D digital image by 3D image analysis software includes performing image area selection analysis and / or threshold setting analysis and / or denoising analysis and / or Boolean operation analysis on the 3D digital image; the 3D image analysis software is at least capable of calculating rock physical parameters and rock morphological characteristics, the rock physical parameters at least include pore diameter and crack width, and the rock morphological characteristics at least include pore morphological characteristics and crack morphological characteristics.

[0017] Preferably, in S6, suitable single fracture images and / or single hole images are selected and arranged and combined in 3D image editing software to form fracture unit bodies and / or hole unit bodies, and the fracture unit bodies and / or hole unit bodies are subjected to Boolean operation processing and / or correction processing and / or denoising processing to obtain a target oil field simulation image that is the same as the three-dimensional seismic model.

[0018] Preferably, in S2, the reconstruction software using the Fieldcamp algorithm is capable of transforming at least thousands of two-dimensional projection images from CT scans into 3D digital images. Preferably, the 3D image editing software includes at least repair, scaling, rotation, Boolean operations, merging components, converting shells to parts, and cutting functions.

[0019] Preferably, the 3D printer is a laser powder sintering 3D printer or a color multi-material 3D printer.

[0020] A fine physical model of a target oil zone of a fracture-cavity oil and gas reservoir is manufactured using the above-mentioned method for manufacturing a fine physical model of a target oil zone of a fracture-cavity oil and gas reservoir.

[0021] Preferably, the laser powder sintering 3D printer uses coated sand as printing material, and the fine physical model of the target oil area of ​​the fracture-cavity oil and gas reservoir produced can be used to carry out various indoor displacement experiments.

[0022] Preferably, the color multi-material 3D printer uses photosensitive resin as printing material to produce a display model of a fine physical model of a target oil zone of a fracture-cavity oil and gas reservoir, and the display model can perspectively display the pore information inside the target oil zone.

[0023] The advantages of the present invention over the prior art are: the method for manufacturing a fine physical model of a target oil zone of a fracture-vuggy oil and gas reservoir according to the present invention organically combines CT scanning technology, three-dimensional seismic imaging technology, and 3D printing technology. By establishing a single fracture image library and a single hole image library, and selecting appropriate single fracture images and / or single hole images from the single fracture image library and the single hole image library, and arranging and combining them in 3D image editing software, a simulation image of the target oil zone identical to the three-dimensional seismic model obtained by the three-dimensional seismic imaging technology is obtained. Then, a fine physical model that can cover the entire target oil zone and even the entire regional underground strata of the fracture-vuggy oil and gas reservoir is printed out using a 3D printer. The fine physical model has a wide coverage and can reflect the actual pore structure of the underground rock formations in the region. Various indoor displacement experiments are carried out on the model to obtain parameters such as crude oil recovery rate, residual oil saturation, and seepage characteristics. This has important guiding significance for later reservoir development, especially in the optimization of water injection methods and the structural design of injection-production well patterns. The fine physical model of the target oil zone of the fracture-cavity oil and gas reservoir obtained by the present invention is used for indoor experimental research, which saves costs, time and a lot of manpower and material resources compared to field experiments in the oil zone. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 The present invention is a flow chart of a method for manufacturing a fine physical model of a target oil zone in a fracture-cavity oil and gas reservoir. DETAILED DESCRIPTION

[0025] In order to facilitate understanding of the present invention, the present invention is described in more detail below with reference to specific embodiments.

[0026] A method for manufacturing a fine physical model of a target oil zone in a fracture-vuggy oil and gas reservoir comprises the following steps:

[0027] S1. Within the target oil zone of a fracture-cavity oil and gas reservoir, a core sample with a typical fracture-cavity structure is selected and scanned using a CT scanner to obtain a set of two-dimensional projection images of the core sample. The CT scanner is a SkyScan 1173 model manufactured by Bruker. It features an X-ray source with a maximum voltage of 130 kV, can scan samples with a maximum diameter of 14 cm and a length of 20 cm, and has a maximum pixel resolution of 5 μm. The CT scanner includes a tube that generates X-rays, a sample stage (rotatable 360°), and a monitor that detects X-rays and generates projections. The CT scanner is connected to a computer and can be controlled using operating software provided by the CT scanner manufacturer. The CT scanner performs non-destructive scanning of the rock sample, detecting the internal pores and fractures and skeletal structure of the rock sample. The set of two-dimensional projection images of the core sample obtained here includes at least thousands of 2D projection images from the CT scan.

[0028] S2, using reconstruction software (NRecon) with the Feldkamp algorithm to perform three-dimensional reconstruction on the two-dimensional projection image of the core sample to obtain a 3D digital image of the core sample;

[0029] S3, analyzing the 3D digital image using 3D image analysis software (such as CTAn), obtaining a fracture-cavity characteristic image of the core sample through image region selection analysis, threshold setting analysis, denoising analysis, and Boolean operation analysis, and exporting the fracture-cavity characteristic image in STL format to obtain a fracture-cavity data volume;

[0030] S4, importing the fracture-hole data volume into 3D image editing software (such as Magics), and after repairing, converting the fracture-hole data volume into parts using the shell-to-part function to obtain a fracture-hole image of the core sample. The fracture-hole image of the core sample is cut using a cutting function to obtain a single fracture image of each fracture and a single hole image of each hole in the core sample;

[0031] S5, repeating steps S1 to S4 to analyze a certain amount of rock samples with typical fracture-cavity structures in the target oil zone of the fracture-cavity oil and gas reservoir to obtain sufficient single fracture images and single pore images to form a single fracture image library and a single pore image library;

[0032] S6, based on the 3D seismic model of the target oil zone of the fracture-vuggy oil and gas reservoir, selecting appropriate single fracture images and single hole images, and using the merging component function of the 3D image editing software to arrange and combine them, to obtain a target oil zone fracture-vuggy structure simulation image having the same fracture-vuggy structure characteristics as the 3D seismic model of the target oil zone, and subjecting the target oil zone fracture-vuggy structure simulation image to Boolean operation processing, correction processing, and denoising processing to obtain a pre-printed image data volume in STL format;

[0033] S7: Importing the pre-printed image data volume into the 3D printing software of the 3D printer, adjusting the 3D printer settings, and printing a detailed physical model of the target oil zone containing a fine fracture-cavity structure. This detailed physical model of the target oil zone has a wide coverage and can reflect the actual pore-fracture structure within the underground rock formations of the target oil zone. Conducting various indoor displacement experiments on this detailed physical model of the target oil zone can determine parameters such as crude oil recovery factor, residual oil saturation, and seepage characteristics. This provides important guidance for later reservoir development, particularly in optimizing water injection methods and designing injection-production well patterns.

[0034] It should be noted that the above-described specific embodiments can enable those skilled in the art to more fully understand the present invention, but do not limit the present invention in any way. Therefore, although this specification has described the present invention in detail with reference to the drawings and embodiments, those skilled in the art should understand that the present invention can still be modified or replaced by equivalents. In short, all technical solutions and changes that do not depart from the spirit and scope of the present invention should be included in the scope of protection of the patent of this invention.

Claims

1. A method for manufacturing a fine physical model of a target oil zone in a fracture-vuggy oil and gas reservoir, characterized in that: The following steps are involved: S1, in the target oil zone of the fracture-cavity oil and gas reservoir, a core sample with a typical fracture-cavity structure is selected, and a CT scanner is used to scan the core sample to obtain a set of two-dimensional projection images of the core sample; S2, using reconstruction software with the Fieldcamp algorithm to perform three-dimensional reconstruction on a set of two-dimensional projection images of the core sample to obtain a 3D digital image of the core sample; S3, analyzing the 3D digital image using 3D image analysis software to obtain a fracture-cavity characteristic image of the core sample, and exporting the fracture-cavity characteristic image as a fracture-cavity data volume; S4, importing the fracture-hole data volume into 3D image editing software to obtain a single fracture image of each fracture and a single hole image of each hole in the core sample; S5, repeating steps S1 to S4, analyzing a large number of rock samples with typical fracture-cavity structures in the target oil zone of the fracture-cavity oil and gas reservoir, obtaining a large number of single fracture images and single pore images, and establishing a single fracture image library and a single pore image library; S6, based on the 3D seismic model of the target oil zone of the fracture-vuggy oil and gas reservoir, selecting appropriate single fracture images and / or single hole images from the single fracture image library and the single hole image library, and arranging and combining them in a 3D image editing software to obtain a simulated image of the target oil zone identical to the 3D seismic model, and exporting the simulated image of the target oil zone as a pre-printed image data volume for a 3D printer; S7, importing the pre-printed image data body into a 3D printer to print out a detailed physical model of the target oil area.

2. The method for manufacturing a fine physical model of a target oil zone in a fracture-vuggy oil and gas reservoir according to claim 1, characterized in that: In S6, the three-dimensional seismic model includes a visualized three-dimensional seismic image obtained by inverting the geological structure of the underground rock formations in the target oil field through three-dimensional seismic detection technology, and the visualized three-dimensional seismic image can at least show the distribution of underground pores and fractures in the target oil field.

3. The method for manufacturing a fine physical model of a target oil zone in a fracture-vuggy oil and gas reservoir according to claim 1, characterized in that: In S3, analyzing the 3D digital image by 3D image analysis software includes performing image area selection analysis and / or threshold setting analysis and / or denoising analysis and / or Boolean operation analysis on the 3D digital image; the 3D image analysis software is capable of at least calculating rock physical parameters and rock morphological characteristics, wherein the rock physical parameters include at least pore diameter and fracture width, and the rock morphological characteristics include at least pore morphological characteristics and fracture morphological characteristics.

4. The method for manufacturing a fine physical model of a target oil zone in a fracture-vuggy oil and gas reservoir according to claim 1, characterized in that: In S6, suitable single fracture images and / or single hole images are selected and arranged and combined in 3D image editing software to form fracture-hole unit bodies and / or hole unit bodies, and the fracture-hole unit bodies and / or hole unit bodies are subjected to Boolean operation processing and / or correction processing and / or denoising processing to obtain a target oil zone simulation image identical to the 3D seismic model.

5. The method for manufacturing a fine physical model of a target oil zone in a fracture-vuggy oil and gas reservoir according to claim 1, characterized in that: In S2, the reconstruction software with the Fieldcamp algorithm can at least transform thousands of two-dimensional projection images of CT scans into 3D digital images.

6. The method for manufacturing a fine physical model of a target oil zone in a fracture-vuggy oil and gas reservoir according to claim 1, characterized in that: The 3D image editing software at least includes a repair function, a zoom function, a rotation function, a Boolean operation function, a component merging function, a shell-to-part conversion function, and a cutting function.

7. The method for manufacturing a fine physical model of a target oil zone in a fracture-vuggy oil and gas reservoir according to claim 1, characterized in that: The 3D printer is a laser powder sintering printer.

8. A fine physical model of the target oil zone of a fracture-vuggy oil and gas reservoir, characterized by: The method for manufacturing a fine physical model of a target oil zone in a fracture-cavity oil and gas reservoir is used as claimed in any one of claims 1 to 7.

9. The fine physical model of the target oil zone of the fracture-vuggy oil and gas reservoir according to claim 8 is characterized in that: The 3D printer uses coated sand as printing material to produce a detailed physical model of the target oil zone capable of carrying out various indoor flooding operations.

10. The fine physical model of target oil zone of fracture-vuggy oil and gas reservoir according to claim 8, characterized in that: The 3D printer uses photosensitive resin as printing material to produce a display model of a fine physical model of a target oil zone in a fracture-cavity oil and gas reservoir.

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