A core image processing method and system based on matlab

Abstract

The invention relates to the technical field of image processing, in particular to a rock core picture processing method and system based on an MATLAB. The rock core picture processing method includes the steps of finding out color change rules of pixel points in a rock core color image to be processed and carrying out color channel converting according to the color change rules. The specific method includes the steps of carrying out color channel converting on red casting bodies through the function of d=mod((R-B),255), carrying out color channel converting on blue casting bodies through the function of d=mod((B-R),255), and converting the rock core image into a binary image through the function of BW=im2bw(d)t), wherein the t is a comparison threshold value, the BW is an image data body after binaryzation, and the im2bw is an application program for carrying out binary image converting based on a true color image of the comparison threshold value. According to the rock core picture processing method and system, rock matrixes and holes in the rock core image can be accurately separated, and modeling basis data are provided for building digital rock core and rock physical numerical simulation.

Description

technical field

[0001] The invention relates to the technical field of image processing, and is mainly applicable to a method and system for processing rock core images based on MATLAB. Background technique

[0002] Unconventional oil and gas reservoirs, such as gas-bearing shale, tight sandstone, carbonate rock, oil sand, etc., are the main targets of exploration and development at present and in the future. In the process of carrying out conventional petrophysical experiments on these reservoirs, many difficulties have been encountered, such as the difficulty of core displacement with low porosity and low permeability, and the difficulty of coring carbonate reservoirs with well-developed fractures. Moreover, petrophysical experiments cannot quantitatively study the influence of reservoir microscopic parameters on rock macroscopic physical properties, and reflect the pore model of rock microstructure. The digital core technology is based on the digital core and takes the n...

Examples

Embodiment 1

[0055] Select an oilfield core casting thin section, the size of which is 768*1024 pixels. The color that fills the pores of the cast body is red, and the rest is regarded as the skeleton. The specific image processing steps include:

[0056] 1) Use the image reading program package in MATLAB software to digitally read the color image of the rock core to be processed, and then extract the three primary color values ​​of the color channels R, G, and B of each pixel in the color image of the rock core to be processed; Then select 100 target pixels and 100 non-target pixels, respectively, and obtain the color change rules of the target pixels and non-target pixels through comparative analysis. In this embodiment, the color change law of the target pixel is that the difference between R and B values ​​is larger than the difference between other primary color values, and the color change law of non-target pixel points is that the difference between R and B values ​​is larger than ...

Embodiment 2

[0064] Select an oilfield core casting thin section, the size is 740*540 pixels. The color that fills the pores of the cast is blue, and everything else is considered a skeleton. The specific image processing steps include:

[0065] 1) Use the image reading program package in MATLAB software to digitally read the color image of the rock core to be processed, and then extract the three primary color values ​​of the color channels R, G, and B of each pixel in the color image of the rock core to be processed; Then select 100 target pixels and 100 non-target pixels, respectively, and obtain the color change rules of the target pixels and non-target pixels through comparative analysis. In this embodiment, the color change law of the target pixel is that the difference between R and B values ​​is larger than the difference between other primary color values, and the color change law of non-target pixel points is that the difference between R and B values ​​is larger than the differ...

technical field

[0001] The invention relates to the technical field of image processing, and is mainly applicable to a method and system for processing rock core images based on MATLAB. Background technique

[0002] Unconventional oil and gas reservoirs, such as gas-bearing shale, tight sandstone, carbonate rock, oil sand, etc., are the main targets of exploration and development at present and in the future. In the process of carrying out conventional petrophysical experiments on these reservoirs, many difficulties have been encountered, such as the difficulty of core displacement with low porosity and low permeability, and the difficulty of coring carbonate reservoirs with well-developed fractures. Moreover, petrophysical experiments cannot quantitatively study the influence of reservoir microscopic parameters on rock macroscopic physical properties, and reflect the pore model of rock microstructure. The digital core technology is based on the digital core and takes the n...

Examples

Embodiment 1

[0055] Select an oilfield core casting thin section, the size of which is 768*1024 pixels. The color that fills the pores of the cast body is red, and the rest is regarded as the skeleton. The specific image processing steps include:

[0056] 1) Use the image reading program package in MATLAB software to digitally read the color image of the rock core to be processed, and then extract the three primary color values ​​of the color channels R, G, and B of each pixel in the color image of the rock core to be processed; Then select 100 target pixels and 100 non-target pixels, respectively, and obtain the color change rules of the target pixels and non-target pixels through comparative analysis. In this embodiment, the color change law of the target pixel is that the difference between R and B values ​​is larger than the difference between other primary color values, and the color change law of non-target pixel points is that the difference between R and B values ​​is larger than ...

Embodiment 2

[0064] Select an oilfield core casting thin section, the size is 740*540 pixels. The color that fills the pores of the cast is blue, and everything else is considered a skeleton. The specific image processing steps include:

[0065] 1) Use the image reading program package in MATLAB software to digitally read the color image of the rock core to be processed, and then extract the three primary color values ​​of the color channels R, G, and B of each pixel in the color image of the rock core to be processed; Then select 100 target pixels and 100 non-target pixels, respectively, and obtain the color change rules of the target pixels and non-target pixels through comparative analysis. In this embodiment, the color change law of the target pixel is that the difference between R and B values ​​is larger than the difference between other primary color values, and the color change law of non-target pixel points is that the difference between R and B values ​​is larger than the differ...

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