Estudo da estabilidade da suspensão constituinte do fluido Br- Mul/Petrobras

Abstract

Non-newtonian fluids sediments have been subject in various industrial operations, such as the prospecting process of petroleum and natural gas. When oil wells are not in operation, the gravitational separation between solid and liquid occurs and despite the great relevance there are few information about this subject and that new legislation requires to evaluate the true state of these wells after some time, it is noted that there is little information about the subject in the technical literature. In this context, the main objective of this work was to experimentally obtain information about fluid dynamics stability of the oil well drilling fluid Br-Mul for a period of one year. According to the company that provided the fluid, it is designed to not to settle down and present pseudoplasticity with time dependence. However, when leaving the fluid stand for some period it is noted the separation process. Therefore, it was studied the dynamic separation of a set of micrometer particles belonging to the fluid itself. Monitoring the volumetric solids concentration for different positions of the test vessel over time during the sedimentation phenomenon was conducted by a technique which is considered a differential in laboratories studying the separation processes: Attenuation Technique of Gamma Ray. This technique allows the volumetric solids concentration monitoration without removing fluid samples. During the sedimentation test, it was possible to verify the formation of the region without particle, observed by many researchers. Tests in the laboratory also evaluate the rheology of the fluid and allowed to observe the pseudoplastic behavior expected for it. In this work was also calculated the sedimentation velocity of fluid particles, porous medium permeability and, it is proposed a constitutive equation for solids pressure. In this way, it was possible to contribute to the understanding of the present conditions in the oil wells that are filled with this suspension.