Avaliação do volume de filtrado e formação do reboco de fluidos de perfuração microemulsionados

Abstract

Drilling fluids play key roles in the activity of building a well such as: cooling and lubricating the drill, cleaning the debris from the well, stabilizing the pressures in the well walls, forming a low permeability film, among other functions that are indispensable. In view of the studies and environmental impacts caused by non-aqueous drilling fluids, this work aimed to formulate

drilling fluids using a microemulsion composed of pine oil, NP-100 surfactant and water- glycerin (1:1 in mass) and analyze the influence that the concentrations of surfactant and

vegetable oil have on the filtration properties of these formulated fluids. 12 drilling fluids were formulated, and for each composition, 300 g of microemulsion was prepared and the additives were subsequently added under intense agitation and regular time intervals. The factorial experimental design (2k + 4 central points + star configuration) was executed in order to evaluate the behavior of the filtrate volume and the mud cake thickness as a function of the surfactant and oil concentrations. It was possible to verify that these drilling fluids performed well in the filtration tests. The mud cake showed low permeability, in the range of 0.26 x 10-2 to 2.69 x 10-2 mD, and a desirable thickness, between 0.40 and 1.24 mm. The empirical models were obtained and it was found that the best working point has a composition of 45% surfactant, 5% oily phase and 50% aqueous phase.