The continuous exploration of oil wells has increased the demand for plug and abandonment procedures. Current techniques used for well plugging involve the cementing process, which is extremely expensive and difficult to perform. Aiming to overcome these challenges, a new approach in this area has been investigated. This novel technology, named here as Thermal Plug and Abandonment (TP&A), proposes a chemical mixture that would be introduced through the production tube or the steel casing. Then, this mixture is ignited and the exothermic reaction generates enough heat to melt the wellbore components. After the cooling stage, the solidified mass composed by these components and the products of the reaction will serve as a seal to plug the well. Under such circumstances, this work aims to investigate this new technology assuming a thermite mixture that is introduced through the steel casing. For that, a numerical analysis is employed to investigate the heat conduction and the phase change through the oil well structure, which is modelled as a two-dimensional axisymmetric domain. The heat generated by the reaction is approached as a spatial and time-dependent heat flux profile that was estimated based on experiments found in literature. The thermal behavior is assessed to discover if the heat generated by the reaction is enough to form a plug composed by all components found in an oil well environment. It was found that temperatures are high enough to melt most part of the steel and a significant amount of the cement layer. The investigation also found that temperatures heavily drop through the cement layer, which avoids any notable melting of the cap rock. Finally, the heat fluxes’ profiles were increased, and it was found that a TP&A procedure that accounts for a seal composed by only the thermite products and the melted steel layer might be a more practical approach.

油井的不断勘探增加了对堵塞和废弃程序的需求。当前用于封井的技术涉及固井过程，该过程极其昂贵且难以实施。为了克服这些挑战，已经研究了该领域的一种新方法。这种新技术在这里被称为热插拔和废弃 (TP&A)，它提出了一种化学混合物，可以通过生产管或钢套管引入。然后，这种混合物被点燃，放热反应产生足够的热量来熔化井眼部件。在冷却阶段之后，由这些组分和反应产物组成的固化块将用作封堵井的密封件。在这样的情况下，这项工作旨在研究这项新技术，假设通过钢壳引入铝热剂混合物。为此，采用数值分析来研究通过油井结构的热传导和相变，将其建模为二维轴对称域。反应产生的热量被视为空间和时间相关的热通量分布，该分布是根据文献中发现的实验估计的。评估热行为以发现反应产生的热量是否足以形成由油井环境中发现的所有组分组成的塞子。发现温度高到足以熔化大部分钢和大量的水泥层。调查还发现，水泥层的温度急剧下降，这避免了盖层的任何显着熔化。最后，增加了热通量的分布，并且发现仅由铝热剂产品和熔化的钢层组成的密封的 TP&A 程序可能是更实用的方法。