Incorporação de diferentes sólidos e seus efeitos nas propriedades de fluidos de perfuração olefínicos

Abstract

This paper presents a study on the influence of the joint incorporation of fine solids (bentonite clay, sand, calcium carbonate and sodium chloride) in properties of olefinic drilling fluids. For this purpose, Petrobras gave in a synthetic olefinic fluid with initial density of 9.4 lb / gal. The study was carried out in three stages: the first evaluated the effect of the thermal aging in the properties of the fluids without incorporation of solids; the second stage evaluated the influence of the incorporation of salt (sodium chloride) in the properties of the fluids separating the synthetic fluid in 6 aliquots of 350mL. After dynamic aging the salt was added to proportions of 5, 10 and 15% by volume; and the third stage was to study the influence of the incorporation of the solids together in the properties of the fluids. For the development of the third stage, 28 aliquots of 350 mL of synthetic fluid were separated and, after dynamic aging, the contaminants were added according to an experimental design. To study the influence of these incorporations the following properties were determined: density, plastic viscosity, flow limit, gel strength, electrical stability and volume of filtrate. The results showed that thermal aging influences only the rheological properties and the electrical stability of the fluid. In addition, the incorporated salt acts as a contaminant, since it alters the properties of the fluid, increasing density, plastic viscosity, strength gel and reducing the flow limit, the electrical stability and the volume of filtrate. Finally, it was evidenced that the solids incorporated together, act as contaminants for fluids, since they alter their properties, increasing the values of density, plastic viscosity, flow limit, gel strength and reducing the values of electrical stability and filtrate volume.