Análise do impacto da adição de sólidos às propriedades de emulsões olefínicas usadas em fluidos de perfuração.

Abstract

This work aims to develop olefin inverse emulsions used in drilling fluids and to know and evaluate the influence of the addition of solids (clay, calcium carbonate and sand) on their physical properties. For this, inverse emulsions (water in oil - w/o) were used, in which linear olefin composes the continuous phase and saturated sodium chloride brine constitutes the dispersed phase. The parameters related to the preparation and formulation conditions of the emulsions (stirring speed, emulsification time, emulsifier content and lime content) were defined by tests performed in the first stage of this study, based on an experimental design, considering the analysis of microscopic images, rheological behavior and the separated volume of emulsions in gravitational separation tests, aiming to obtain emulsions with better stability and physical properties, suitable for application in drilling fluids. The analysis of the results of the first stage allowed to select two emulsion formulations, whose properties demonstrated compatibility with the operational requirements. In the second stage of the study, the selected emulsion formulations were added with different contents (5, 10, and 15%) of clay, calcium carbonate and sand. The added solids emulsions were characterized for their properties before and after dynamic aging. The results demonstrated that the properties required for application of olefin emulsions to drilling fluids are obtained by applying high emulsification speeds and adding lime contents higher than 5g, considering 350 mL volume. In addition, among the added solids, clay has presented the greatest influence on emulsion properties, resulting in decreased olefin and emulsifier volumes separated in the gravitational separation test and an increase in consistency index. The increase in clay concentration and dynamic aging intensified the impacts caused by the addition of this type of solid.