DESENVOLVIMENTO DE UM FLUIDO DE PERFURAÇÃO BASE ÓLEO VEGETAL PARA SER UTILIZADO NA PERFURAÇÃO DE POÇOS DE PETRÓLEO

Abstract

Drilling fluids are fluids used in oil wells, in the drilling step, which act assisting in the whole process. The specifications for a fluid are: to be chemically stable; to facilitate the separation of gravel on the surface; to keep solids suspended when at rest; to leave the walls of the wells stable; to be inert in relation to damage to producing rocks; to be pumpable; to have a good cost-benefit ratio; to be mildly corrosive and abrasive to the drilling system equipments; to accept any physical and chemical treatment; to facilitate geological interpretations of the material removed from the well. The objective of this work is to obtain a drilling fluid based on microemulsions, which are systems with higher stability and constituted of water, oil and nonionic surfactant. To choose the best point of the microemulsion, ternary diagrams were made, with several points in different proportions of water, oil and surfactant, from titration, identifying all possible Winsor regions, being the region of WIV, to which form Microemulsion and chosen for the development of fluid. The drilling fluids can be based on water, oil or gas and, recently, the synthetic fluids are being widely used. In this work, the developed fluid is based on oil, that is, there is a greater amount of oil in the microemulsion. The fluid rheology was performed in the Fann Viscosimeter, model 35A, with the R1B1 configuration. Filtrate volume tests were also made in order to ensure the stability of the well and prevent invasion to rock formations. The results for the gels, plastic viscosity, apparent and yield limit are in the specifications of the standard PETROBRAS N-2604, based on the API Spec 13A, the American Petroleum Institute, as well as the specific mass. According to the results of the rheological and filtration tests, it was concluded that a microemulsion drilling fluid based on vegetable oil was obtained, which with the more detailed study can be used in drilling wells, with fluid 1 (60% surfactant , 30% oily phase and 10% aqueous phase), due to the good rheology and low filtrate volume.