Fluidos de perfuração aquosos: a contribuição da goma xantana e carboximetilcelulose no controle de filtrado

This study aimed mainly to evaluate the influence of xanthan gum (XG) and carboxymethylcellulose (CMC) in the filtration process of water-based drilling fluids, considering the conformational changes suffered by the polyelectrolyte with the addition of sodium chloride (NaCl) in different concentrations (0.17, 0.34 and 0.51 mol.L-1). It was also evaluated the behavior of the fluid by the addition of calcium carbonate (CaCO3) in pure water and in brine. Seeking a better understanding of the interaction between the polymers used and CaCO3, polymer adsorption analyzes were performed using a depletion method, which yielded a higher percentage of adsorption of Xanthan Gum in this material (29%), which can justify the formation of a thin and waterproof filter cake for drilling fluids containing this polymer. However, the best values of apparent viscosity (20 and 24 mPa.s) and volume of filtrate (8.0 and 8.1 mL) were obtained for the systems consisting of xanthan gum, CMC and CaCO3, in NaCl aqueous solutions concentrations of 0.34 and 0.51 mol.L-1, respectively. The values can be related to the presence of CMC that increases the apparent viscosity and reduces the volume of filtrate. In addition, the CaCO3 added acts as a bridging agent, promoting the formation of a less permeable filter cake

Este trabalho objetiva avaliar a influencia da goma xantana e carboximetilcelulose (CMC) no processo de filtração dos fluidos de perfuração base água, considerando as mudanças conformacionais sofridas pelos polieletrólitos com a adição do sal (NaCl) em diferente concentrações (0,17; 0,34 e 0,51). Foi também avaliado o comportamento do fluido com a adição do carbonato de cálcio (CaCO3). Procurando um melhor entendimento entre os polímeros utilizado e o CaCO3, as analises de adsorção polimérica foram realizadas por meio de um método de depleção. A maior porcentagem de adsorção da Goma Xantana neste material pode justificar a formação de um reboco fino e impermeável para fluidos de perfuração que contenham esse polímero.