Digital core and pore network model reconstruction method based on random fractal theory

Abstract

The invention discloses a digital core and pore network model reconstruction method based on random fractal theory. Based on the multi-fractal characteristics of porous media, the capillary pressure curve obtained by the conventional mercury injection method is fractally characterized, and the random distribution is derived by using the random distribution theory. The fractal expression of density function, mean value and variance, stochastic theory and multi-fractal theory are combined to construct a digital core, and a three-dimensional micro-network model is conveniently established based on this. Low cost, can save cost. Mercury porosimetry is used to measure the capillary pressure curve, and the whole core is used in the experiment, which can fully display the microscopic pore structure. The calculation method of the present invention is simple and convenient, and the method is advanced. The microscopic pore structure of the reservoir rock is complex and irregular. It is difficult for the traditional classical theory to accurately describe a very complex system. The method described in this aspect combines the multi-fractal theory and The combination of random distribution theory can accurately characterize the microscopic pore structure, and the method is easy to program.

Description

technical field [0001] The invention relates to a method for constructing a three-dimensional quantitative description of the microscopic pore structure of a porous medium, in particular to a method for constructing a digital rock core based on a pore network model. Background technique [0002] In the past, the microscopic mechanism of fluid seepage in porous media was mostly studied qualitatively through experiments, and the research results mostly stayed on the macroscopic scale, so it was difficult to have a more in-depth and detailed understanding of the microscopic mechanism. In order to quantitatively describe the seepage problem on the microscopic scale, the first problem to be solved is to describe the microscopic pore structure finely. In recent years, scholars at home and abroad have carried out a lot of research work in this field. In conclusion, the research ideas are mainly in the following two categories: 1. Based on digital cores, the flow simulation is carri...

AI Technical Summary

Problems solved by technology

The technical requirements for core imaging are not only high, but also the obtained cores are thin slices, which are small in scale, costly for testing, and difficult to popularize and apply.

Numerical reconstruction method A variety of reconstruction methods developed so far rely on various statistical methods or simulate the formation process of the core to establish a digital core, the typical ones are Gaussian simulation method, simulated annealing method, process simulation method, multi-point simulation method, Multi-point statistical method and Markov stochastic reconstruction method, but the digital cores established based on these methods are isotropic and cannot quantitatively characterize complex pore systems

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