A thermal study of a new oil well plugging &amp; abandonment operation

Magalhães, Elisan dos Santos; Lemos, Marcelo J. S. de

doi:10.1016/j.ijthermalsci.2020.106421

Cited by 20 publications

(10 citation statements)

References 22 publications

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“…Already in the 21st century, we have studies of new applications of thermite in challenging environments such as welding in deep-water [15] and in space [16], well sealing and abandonment as patented by Skjold [17], and fabrication of lunar physical assets [18]. Recently, thermite reactions have been applied to develop a game change technology for plug and abandonment of depleted oil wells, which uses the released heat with the purpose of melting the production tubing and permanently close the borehole [19,20].…”

Section: Introductionmentioning

confidence: 99%

Detailed Numerical Modeling and Simulation of Fe₂O₃−Al Thermite Reaction

Souza

Lemos

2021

Propellants Explo Pyrotec

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A thermite reaction is a self-propagating exothermic reaction with many practical applications in welding processes, material synthesis, pyrotechnic and initiator technologies. Motivated by the above-mentioned, the present study involves modeling and simulation of common hematite-aluminum thermite reaction with the aim of predicting temperature levels and radial burning speeds in a thin disk ignited at the center. Balance equations of species and energy conservation were solved in one dimension space by applying a finite difference method, considering no species transport and a one-step mechanism. The Arrhenius equation was adopted to model the kinetics rate. Phase change and temperature dependence of the thermochemical properties were also considered. Analyses of spatial and temporal meshes revealed that numerical results were independent of the grid used. Predictions show that the ignition procedure affects the formation of the reaction-front, higher temperatures, and longer ignition zones can start the self-sustained reaction earlier. However, once the reaction wave is established, its velocity and peak temperature are the same, independent of the initial temperature profile. Simulations herein also show that an increase of the activation energy and decrease of the pre-exponential factor slows down the reaction speed considerably, impacting on accurate prediction of reactionwave velocity. Further, the activation energy influences the burning velocity much more drastically than the pre-exponential factor. The maximum temperature observed in the model is around the melting temperature of alumina (2327 K), which is in agreement with the experimental results reported in the literature.

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Section: Introductionmentioning

confidence: 99%

Detailed Numerical Modeling and Simulation of Fe₂O₃−Al Thermite Reaction

Souza

Lemos

2021

Propellants Explo Pyrotec

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“…After this first commercial application, the advantages of thermite rail welding spread across Germany and around the world [2]. Then, thermite gained important applications as the aluminothermic production of metals and alloys [3], self-propagating high-temperature synthesis (SHS) of ceramics and composite materials [4], and also applications in challenging environments such as welding in space [5], well sealing and abandonment [6][7][8], and fabrication of lunar physical assets [9]. With the development of nanotechnology, nano-thermite has emerged in the last two decades and has been widely investigated for applications in propulsive systems [10] and joining [11].…”

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confidence: 99%

“…The processes involved are complex and accounts for phase changes, species decomposition, diffusion, fluidized particle motion, droplet collision, among other phenomena that are difficult to measure experimentally in such a fast and high-temperature reaction. Therefore, the objective of this contribution is to shed some light on the complex mechanisms of thermite reactions via thermodynamics analysis, not entirely accounted for in [15] and approximated by a constant heat generation model in [7] or by a prescribed time-varying heat flux in [17]. It is also important to emphasize that in references [7] and [17] the porous thermite mixture zone where the exothermal reaction takes place was not included.…”

mentioning

confidence: 99%

“…Therefore, the objective of this contribution is to shed some light on the complex mechanisms of thermite reactions via thermodynamics analysis, not entirely accounted for in [15] and approximated by a constant heat generation model in [7] or by a prescribed time-varying heat flux in [17]. It is also important to emphasize that in references [7] and [17] the porous thermite mixture zone where the exothermal reaction takes place was not included. Instead, the heat release rate was assumed as mentioned above, namely a given constant heat generation in [7] or a prescribed transient heat flux in [17].…”

mentioning

confidence: 99%

“…It is also important to emphasize that in references [7] and [17] the porous thermite mixture zone where the exothermal reaction takes place was not included. Instead, the heat release rate was assumed as mentioned above, namely a given constant heat generation in [7] or a prescribed transient heat flux in [17]. For the interested reader, treatment of combustion in porous material can be found in [18] based on the mathematical model presented in [19].…”

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confidence: 99%

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Thermodynamics of thermite reactions for a new thermal plug and abandonment process

Souza

Lemos

Kawachi

2021

Continuum Mech. Thermodyn.

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Thermites are powerful energetic materials able to release large amounts of energy in a selfpropagating reaction. They have been widely applied in rail welding, pyrotechnics, and material synthesis, as they are highly exothermic. In recent years, there has been an increased interest on applying a thermite reaction in the plug and abandonment of wells due to the possibility of reducing the high cost of this process. However, some primary studies are required to understand these energetic materials and to select the most efficient thermite mixtures to be applied in a plug and abandonment scenario. Although they do not react as simple condensed-phase reactions because of all the complex physicochemical mechanisms involved, they can be characterized and understood by simple principles of thermodynamics. As so, this research presents the importance of the Gibbs free energy concept to determine the candidates of a thermite reaction, in addition to showing how important characteristics of these reactions such as adiabatic temperature and heat released can be calculated using thermodynamic principles. Lastly, the minimization of Gibbs free energy method for determining the final products of a reaction, considering chemical equilibrium, is presented and applied to predict the final products, as a function of temperature, for some of the most powerful thermite mixtures. The conclusion is that, although the 2Al-Fe 2 O 3 thermite reaction has the lower mass and volumetric heat of combustion in comparison with the 2Al-3CuO and 3Be-Fe 2 O 3 thermites, it can reach the highest adiabatic temperature observed due to the lower gaseous mass fraction in the products, which means fewer heat losses due to phase changes. So, the thermite mixture 2Al-Fe 2 O 3 is a promising candidate for the plug and abandonment of mature oil wells. KeywordsThermite • Aluminothermic reactions • Gibbs free energy • Thermodynamics Latin symbols a Chemical activity C p Heat capacity at constant pressure G Gibbs free energy H Enthalpy m Mass n Number of mols Communicated by Andreas Öchsner.

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