Method for constructing pore throat sections of rock pore network model by considering concavity and convexity

Abstract

The invention discloses a method for constructing pore throat sections of a rock pore network model by considering concavity and convexity in the technical field of image processing. The method comprises main steps of scanning a real rock core based on a CT technology and performing three-dimensional reconstruction; performing pore throat segmentation on the three-dimensional rock core, performing numbering and sorting on all pore throats, and making statistics on pore throat geometric parameter information; obtaining a relationship between a maximum inner angle of a quadrangle and a shape factor by utilizing a numerical experiment; determining the maximum inner angle of the quadrangle according to the concavity and convexity and the shape factor; making a diagonal line from a vertex of the angle, dividing the maximum inner angle into two parts, and determining the length of the diagonal line; establishing a section nonlinear feature equation and calculating the side length of the quadrangle with a Newton iteration method; and checking whether the feature equation has a positive solution and conforms to physical significance or not, and if not, performing reconstruction until all the pore throat sections are constructed. According to the method, the concavity and convexity of the cross section and the equivalency of the hydraulic radius of a porous medium are fully considered, so that the accuracy of representing the real porous medium by the pore network model is improved and a seepage parameter of the porous medium can be accurately predicted.

Description

technical field [0001] The invention relates to the technical field of image processing, in particular to a pore-throat section construction method of a rock pore network model considering concavo-convexity, which is suitable for porous medium reconstruction or microscopic seepage simulation based on the pore network model. Background technique [0002] The shape and connectivity of the pore space in porous media are extremely irregular, and the topological structure is complex. Its microstructure and physical properties determine many macroscopic seepage properties. In order to gain an in-depth understanding of the seepage mechanism and laws, people usually start from the pore level or even more microscopic level to study the complex seepage phenomena between pores. As a commonly used pore-level modeling method, the pore network model has the advantages of repeatability, controllability, and fast calculation speed. It is simple and easy to quantitatively study the seepage l...

AI Technical Summary

Problems solved by technology

This classical cross-section shape setting guarantees that the cross-section shape factor (the ratio of the square of the perimeter to the area) is equal, but it can only use convex polygons for shape equivalence, and cannot accurately characterize the concave cross-sections that exist in a large number of porous media

At the same time, the classic section setting scheme cannot fully guarantee that the perimeter and area of ​​the section are equal to the real pore throat section, resulting in inaccurate hydraulic radius (ratio of area to perimeter)

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