Method for analyzing shale fracturing mode based on digital image

Abstract

The invention provides a method for analyzing a shale fracturing mode based on a digital image. The method comprises the following steps: characterizing the heterogeneity of shales caused by the shape, size and distribution of calcite minerals in the shales by using a digital image processing technology on a microscopic scale, mapping the heterogeneity to finite element grids, establishing a numerical model which can accurately reflect the micro structure of the shales in combination with a rock fracturing process analysis system RFPA2D-DIP based on a micro structure, implementing uniaxial compression numerical tests on the shales by using the model, and studying the influence of the micro structures of the shales on the compressive strength and destroy modes of the shales under the load in different directions. Therefore, the problem that the stress distribution heterogeneity caused by the own heterogeneity of the shales on a microscopic scale and the local failure caused thereby is rarely involved in the existing studies on the compressive strength and destroy modes of the shales, and the nature of brittle failure mechanisms of the shales is hard to get can be solved. The method provided by the invention belongs to the field of rock mechanics.

Description

technical field [0001] The invention relates to a new method for digital image-based shale fracture mode in shale gas exploration and development, belonging to the field of rock mechanics. Background technique [0002] Scholars at home and abroad have done a lot of research on the compressive strength and failure mode of shale, especially on the strength, deformation and failure mode of shale under different confining pressures and different dip angles, but these The research is mainly based on the macro-scale failure of shale, and seldom involves the non-uniformity of stress distribution caused by the self-inhomogeneity of shale at the meso-scale and the local failure induced by it. Therefore, it is difficult to obtain the brittle failure mechanism of shale. essence. Contents of the invention [0003] The purpose of the present invention is to provide a digital image-based shale fracture mode analysis method to solve the existing research on shale compressive strength an...

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Problems solved by technology

[0003] The purpose of the present invention is to provide a digital image-based shale fracture mode analysis method to solve the existing research on shale compressive strength and failure mode, which rarely involves the self-inhomogeneity of shale at the mesoscopic scale. The non-uniform stress distribution and the local failure induced by it make it difficult to get the essence of the brittle failure mechanism of shale

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