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ABSTRACT: In order to decrease the emission of CO2 to the atmosphere, people begin to study the underground storage of CO2. In the process of injecting gas, the rock cracking on the action of the gas press is concerned by the people. Aiming at the problems of the fracture and the cracks extending on the action of the gas press, it uses the finite element simulation software of the tension fracture, simulates the process of the rock body injecting gas.
Firstly, based on the elastic mechanics and fracture mechanics theory, it simulates the process of the rock body injecting gas under the ground 100 meter. Because the rock tensile strength is smaller than the compressive strength, the rock body damage on the gas injection is the tensile damage on the action of the tension stress. It cracks on the top and bottom of the injection stomata and the gas press of the injection stomata decreases. Because of the crack the stress is changed around the injection stomata, it forms the stress concentration on the tip of the cracks.
Through the analysis, we can see that it forms the stress concentration on the tip of the cracks in the rock fracture process. These lead the rock cracks extending and the extending direction of the cracks is consistent with the crack type of the classical linear elastic fracture mechanics; the gas fracturing process of the numerical simulation is feasible and it can conclude the more ideal effect. It can provide the theory basis for the engineering practice.
KEYWORDS: Emission of CO2, Gas injection, Rock fracture, Finite element simulation software, Fracture mechanics theory
(ProQuest: ... denotes formulae omitted.)
INTRODUCTION
At present, the human activity make the gas concentrations of the main greenhouse gas reaching the highest level having the record, which the CO2 concentration of in the year of 2000 in the atmosphere increases 31±4% than 1000~1750. According to predicting, the CO2 concentration will reach 540~970 ppm in 2100, the ground average gas temperature will increase1.4~8.5 °C from 1990 to 2100, but the ground temperature will increase 3.9~6.0 °C in 2100 in China. In order to implement the commitment target of Tokyo Protocol some developed country have considered the CO2 geological mothballed as the main methods decreasing...