Drawing method of pore-throat chart for tight reservoir microscopic model

Abstract

A method for drawing a pore-throat atlas of a tight reservoir microscopic model, which relates to the field of oil and gas field development. The method for drawing a pore-throat atlas of a tight reservoir microscopic model includes the following steps: cropping the cast image of the rock sample into a cast picture with an equal aspect ratio of length to width; cutting the cast picture into several picture units; outlining the pore-throat area on the picture unit and filling it with black; splicing the pore-throat areas of each picture unit together to obtain a pore-throat picture; correcting the pore-throat positions at the boundaries of each picture unit on the pore-throat picture to ensure that there are no sawteeth at the splicing points of the pore-throat areas; performing color inversion on the pore-throat picture to obtain the pore-throat atlas of the reservoir microscopic model. The method for drawing a pore-throat atlas of a tight reservoir microscopic model provided by this application reduces the amount of image processing information during manual drawing of the pore-throat structure, improves the accuracy of pore area description, can accurately depict the fine throats of tight reservoirs, and reduces the drawing cost.

Description

Technical Field

[0001] This application relates to the field of oil and gas field development, and more particularly, to a method for drawing pore-throat charts of a dense reservoir micro-model. Background Art

[0002] The microscopic displacement characteristics of oil, gas, and water in sandstone reservoirs are one of the important contents of oil and gas reservoir development research. Due to the special nature of the microscopic pore structure of the reservoir, the flow of oil, gas, and water in the reservoir is relatively complex. When conducting displacement physical model experiments, by truly restoring the microscopic pore structure characteristics of the reservoir, it is beneficial to analyze and explore the microscopic seepage characteristics of reservoir oil, gas, and water and the enrichment state of remaining oil and gas. At present, the three key steps in the production process of glass microscopic etching models are chart drawing, pore-throat etching, and glass slide bonding, and the degree of pore restoration in chart drawing determines the accuracy of the model. Currently, there is no method that can accurately depict the fine throat of a dense reservoir in a glass microscopic etching model. Summary of the Invention

[0003] The purpose of this application is to provide a method for drawing pore-throat charts of a dense reservoir micro-model, which reduces the amount of image processing information when manually drawing pore-throat structures, improves the accuracy of pore area description, can accurately depict the fine throat of a dense reservoir, and reduces the drawing cost.

[0004] The embodiments of this application are implemented as follows:

[0005] The embodiments of this application provide a method for drawing pore-throat charts of a dense reservoir micro-model, which includes the following steps:

[0006] Step 1: Crop the cast image of the rock sample into a cast picture with an equal aspect ratio of length to width;

[0007] Step 2: Cut the cast picture into several picture units;

[0008] Step 3: Outline the pore-throat area on the picture unit and fill it with black;

[0009] Step 4: Piece together the pore-throat areas of each picture unit to obtain a pore-throat picture;

[0010] Step 5: Correct the pore-throat positions at the boundaries of each picture unit on the pore-throat picture to ensure that there are no jagged edges at the joints of the pore-throat areas;

[0011] Step 6: Invert the color of the pore-throat picture to obtain the pore-throat chart of the reservoir micro-model.

[0012] In some alternative embodiments, when cropping the cast image of the rock sample into a picture with an equal aspect ratio of length to width, the pores on the image are retained.

[0013] In some optional embodiments, the cast image is adjusted to 8-bit color depth before cutting the cast image into a plurality of image units.

[0014] In some optional implementation schemes, when the casting image is cut into a plurality of image units, the cutting is performed in equal proportions according to 2 to the Nth power.

[0015] In some optional embodiments, when the pore throat regions are outlined on the picture units and filled with black, the picture units are respectively imported into the drawing software, and the pore throat regions are outlined and filled with black.

[0016] The beneficial effects of the present application are as follows: the method for drawing the pore throat plate of the microscopic model of the dense reservoir provided by the present application comprises the following steps: cutting the rock sample casting image into a casting image with equal aspect ratio; cutting the casting image into several image units; outlining the pore throat area on the image unit and filling it with black; splicing the pore throat areas of each image unit together to obtain a pore throat image; correcting the pore throat position at the boundary of each image unit on the pore throat image to ensure that no jagged edges are generated at the splicing of the pore throat area; and color-reversing the pore throat image to obtain a reservoir microscopic model pore throat plate. The method for drawing the pore throat plate of the microscopic model of the dense reservoir provided by the present application reduces the amount of image processing information when manually drawing the pore throat structure, improves the accuracy of the pore area depiction, can accurately depict the subtle throats of the dense reservoir, and reduces the drawing cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0018] Figure 1 A rock sample casting image of a tight reservoir in the method for drawing a pore throat plate of a tight reservoir micromodel provided in an embodiment of the present application;

[0019] Figure 2 A schematic diagram of cutting a rock sample casting image into image units in the method for drawing a pore throat plate of a tight reservoir micro-model provided in an embodiment of the present application;

[0020] Figure 3 A schematic diagram of the pore throat area in a picture unit in the method for drawing a pore throat map of a tight reservoir micromodel provided in an embodiment of the present application. DETAILED DESCRIPTION

[0021] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the following will clearly and completely describe the technical solutions in the embodiments of this application with reference to the accompanying drawings in the embodiments of this application. Obviously, the described embodiments are some, but not all, of the embodiments of this application. Usually, the components of the embodiments of this application described and illustrated in the accompanying drawings herein can be arranged and designed in various different configurations.

[0022] Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of this application that is claimed, but merely represents selected embodiments of this application. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of this application without creative efforts fall within the scope of protection of this application.

[0023] The following further describes in detail the features and performance of the method for drawing the pore-throat atlas of the tight reservoir micro-model of this application in combination with embodiments.

[0024] As Figure 1 、 Figure 2 and Figure 3 shown, the embodiments of this application provide a method for drawing the pore-throat atlas of a tight reservoir micro-model, which includes the following steps:

[0025] Step 1: Crop the cast image of the rock sample into a cast picture with an equal aspect ratio of length to width; optionally, when cropping the cast image of the rock sample into a picture with an equal aspect ratio of length to width, retain the pores on the cast image of the rock sample as much as possible.

[0026] Step 2: Cut the cast picture into several picture units; optionally, before cutting the cast picture into several picture units, adjust the cast picture to an 8-bit color depth. Optionally, when cutting the cast picture into several picture units, cut it in equal proportions according to the Nth power of 2.

[0027] Step 3 、 Trace the pore-throat area on the picture unit and fill it with black; optionally, when tracing the pore-throat area on the picture unit and filling it with black, import the picture units into the drawing software respectively, trace the pore-throat area and fill it with black.

[0028] Step 4 、 Stitch the pore-throat areas of the individual picture units together to obtain a pore-throat picture;

[0029] Step 5: Correct the pore-throat positions at the boundaries of the individual picture units on the pore-throat picture to ensure that there are no jagged edges at the joints of the pore-throat areas;

[0030] Step 6: Invert the color of the pore-throat picture to obtain the pore-throat atlas of the reservoir micro-model;

[0031] Step 7: Print the pore-throat plate of the reservoir microscopic model into a film for use in making a glass etching model.

[0032] The method for drawing the pore-throat plate of the tight reservoir microscopic model provided by the embodiment of the present application divides the cast image of the rock sample into several picture units, outlines the pore-throat regions respectively and fills them with black, and then stitches the picture units to form a pore-throat picture and processes the sawteeth at the edges of the pore-throat regions to obtain the pore-throat plate of the reservoir microscopic model. This not only reduces the capital investment in using professional pore-throat recognition software, avoids the loss of pore regions caused by threshold segmentation in software processing when the cast color and particle color in the tight reservoir sample are relatively close, but also can reduce the amount of image processing information when manually drawing the pore-throat structure by the method of first dividing and then stitching the cast image of the rock sample. It can accurately depict the fine throat channels in the tight reservoir and effectively improve the accuracy of pore region description.

[0033] The embodiments described above are some, but not all, of the embodiments of the present application. The detailed description of the embodiments of the present application is not intended to limit the scope of the present application claimed, but merely represents selected embodiments of the present application. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present application without creative efforts fall within the scope of protection of the present application.

Claims

1. A method for drawing pore-throat charts of a dense reservoir microscopic model, characterized in that It includes the following steps: Step 1: Crop the rock sample cast image into a cast picture with an equal aspect ratio of length to width; Step 2: Cut the cast picture into several picture units; Step 3: Outline the pore-throat area on the picture unit and fill it with black; Step 4: Piece together the pore-throat areas of each picture unit to obtain a pore-throat picture; Step 5: Correct the pore-throat positions at the boundaries of each picture unit on the pore-throat picture to ensure that there are no jagged edges at the joints of the pore-throat areas; Step 6: Perform color inversion on the pore-throat picture to obtain a pore-throat plate of the reservoir microscopic model.

2. The method for drawing the pore-throat atlas of the tight reservoir microscopic model according to claim 1, wherein When cropping the rock sample cast image into a picture with an equal aspect ratio of length to width, retain the pores on the image.

3. The method for drawing the pore throat chart of the tight reservoir microscopic model according to claim 1, wherein Before cutting the cast picture into several picture units, adjust the cast picture to an 8-bit color depth.

4. The method for drawing the pore-throat atlas of the tight reservoir microscopic model according to claim 1, characterized in that When cutting the cast picture into several picture units, cut it in equal proportion according to the Nth power of 2.

5. The method for drawing the pore-throat atlas of the tight reservoir microscopic model according to claim 1, wherein When outlining the pore-throat area on the picture unit and filling it with black, import the picture unit into the drawing software respectively, outline the pore-throat area and fill it with black.

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