| Resumo : |
This thesis explores the challenges of a potential solution in the plug and abandonment (P&A) process for depleted oil and gas wells. With a focus on the advancing technology that uses thermite reactions to create the plugging material, this study delves into this exothermic reaction's propagation and its numerical model. Therefore, it establishes a comprehensive scientific foundation by integrating theoretical, experimental, and numerical analyses, with the primary goal of gaining an in-depth understanding of the dynamics of a thermite reaction and assessing its effectiveness within the context of well-plugging and abandonment. First, the fundamental thermodynamics principles governing this reaction are explored, allowing for the selection of appropriate reagents and the evaluation of reaction efficiency in terms of energy generation and temperature. A comparative study of various thermite systems highlights the advantages of the 2Al/Fe2O3 thermite, positioning it as a promising candidate for P&A due to its ability to achieve high adiabatic combustion temperatures with minimal gaseous products. Subsequent investigations delve into the kinetics mechanism of this thermite system, revealing a multi-step process. Then, a finite-difference numerical model of the thermite reaction wave propagation is presented, which is capable of predicting temperature levels and energy dissipation and also provides insights into the impact of various parameters on reaction dynamics. Experimental methodologies complement the numerical analysis, revealing the benefits of solvent dilution in enhancing thermal efficiency and controlling reaction rates. Overall, this comprehensive investigation advances our understanding of thermite reactions in P&A operations and contributes to developing more accurate simulations for the sustainable management of oil wells in line with global decarbonization efforts. |