Dynamic Characteristics of Liquid CO2 Phase Change Fracturing, Using Experimental Technique

Abstract

The study of the shock pressure is the premise to analyze the rock disintegration mechanism of liquid CO2 phase change fracturing. In order to obtain the phase-changing shock pressure, the relative dynamic signals are detected. These signals include both dynamic strain and stress: the strain is about the dynamic response of the liquid CO2 storage tube, while the stress refers to the phase-changing shock pressure. These signals are obtained by a series of dynamic tests. In addition, the force analysis of the storage tube was conducted, and its crack propagation form was determined based on the dynamic fracturing mechanics, then the tube’s dynamic characteristics and macroscopic failure were comprehensively analyzed. Under the experimental conditions in this paper, the failure mechanism of the storage tube was obtained as follows: the failure of the storage tube undergoes three states: elastic deformation, plastic deformation, and full plastic limit state; the strain response and fracturing of the tube are inhomogeneous: showing 5 distinct regions. Moreover, the phase-changing shock stress distributes unevenly; similar but opposite to the tube fracturing, namely, the stress value is larger in the ends than the middle, while the middle part of the tube is damaged most seriously.