Simulation method for deformation-fragmentation of quasi-brittle material under action of supercritical CO2

Abstract

The invention discloses a simulation method for deformation-fragmentation of a quasi-brittle material under the action of supercritical CO2. The simulation method comprises the following steps: carrying out statistics on natural fracture distribution in a coal rock mass, determining geometric parameters, and writing a fracture generation program; establishing a numerical calculation model, dividing entity units, embedding fracture units at the junctions of the natural fractures and the entity units, and automatically generating a set; sequentially constructing a mechanical constitutive relationship reflecting coal rock matrix plastic deformation, non-through crack mixed fracture and separation / extrusion / compression-shear friction of contact surfaces among blocks after complete fracture of the coal rock; determining an evolution law of coal rock mechanical parameters along with supercritical CO2 action time, inputting material parameters and setting initial conditions; and setting an increment step size, an output parameter, a crack unit failure and a state variable at a contact pair activation moment. The invention provides an effective simulation tool for the leakproofness evolution of the cover layer under the CO2 corrosion and complex stress coupling action under the CO2 geological sequestration condition.

Description

technical field [0001] The present invention relates to CO 2 Technical field of geological storage and carbon emission reduction, specifically related to a supercritical CO 2 Simulation method for deformation-fracture of quasi-brittle materials under action. Background technique [0002] CCUS (Carbon Capture, Utilization and Storage, carbon capture, utilization and storage) technology is to reduce CO in the process of fossil energy power generation and industrial production. 2 The key technology for emissions is also the bottom-line technology for my country to achieve carbon neutrality. CO 2 Geological storage is the core component of CCUS technology, which determines the development potential and direction of CCUS technology. CO 2 The key to long-term safe storage is no leakage in a limited geological reservoir environment, and the core element is CO 2 Deformation-fragmentation mechanical properties change characteristics of caprock under long-term action and deep st...

AI Technical Summary

Problems solved by technology

However, the fractures in the caprock are randomly distributed, and the in-situ stress, CO 2 Under the joint influence of injection pressure, the above-mentioned complete coal rock mass and fractures are often subjected to complex stresses, resulting in complex response processes such as plastic deformation, mixed fracture modes, separation / extrusion / shear friction; more importantly, supercritical CO 2 It will corrode the quartz, calcite, clay minerals and other components in the rock, resulting in a decrease in its strength, fracture energy, and shear mechanical properties

Ignoring these two factors will seriously affect the CO 2 Accuracy of Numerical Simulation Results for Geological Storage

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