Influência da população de partículas no processo de sedimentação em fluido newtoniano

Abstract

With the increasing number of wells reaching the abandonment phase, attention to this stage has intensified. Currently, the primary method of abandonment involves pumping Portland cement and other auxiliary materials into the well to fill it and prevent gas or oil leaks. However, cement presents some issues that may result in cracks under unforeseen pressures. Faced with the limitations of cement, bentonite has emerged as a viable alternative due to its mechanical and chemical characteristics. When used in wellbore closure, bentonite forms an impermeable barrier and adapts to the environment due to its density and plasticity. However, the use of bentonite can lead to premature plugging in deeper oil and gas wells, especially when premature hydration occurs, causing plug formation before reaching the well’s bottom. The objective of this study was to analyze the behavior of particle groups of different sizes and specific masses sedimenting in water, particularly bentonite pellets, which have practical application potential. The study aimed to investigate the influence of the number of particles, along with the shape factor and mass ratio, on the trajectory and sedimentation velocity. To achieve this, various tests with different geometries and particle quantities were conducted, using glass spheres, resin spheres, resin cylinders, and bentonite pellets with different particle concentrations. After conducting the experiments, it was possible to conclude that increasing the number of particles in sedimentation resulted in greater contact between them, with some tending to move towards the tank wall. The mass ratio influenced the trajectory and velocity, with particles having a higher mass ratio experiencing less impact due to the need for greater forces to displace them. Sphericity emerged as a crucial factor, affecting speeds and trajectories. Long particles exhibited lateral alignment, whereas nonspherical ones, such as bentonite, remained in contact for a longer duration during kissing, highlighting the importance of adhesive properties. These findings underscore the complexity of particle behavior and its relevance, especially in the oil and gas industry, suggesting the need for further studies to optimize processes related to sedimentation in fluid media.