Estudo da Atapulgita como viscosificante para fluido de perfuração aquoso salgado

Abstract

Drilling fluids are essential for the drilling of an oil well as they cool and clean the drill, direct the cuttings to the surface and other functions. In the fluids are added some agents with specific functions to perform a drilling safely and inexpensively. More and more studies are being carried out to find cheaper additives that promote drilling efficiency. This work compared a saline aqueous fluid (polymer-viscous) used in industry with an aqueous fluid viscosified with the atapulgite clay. In the fluid with atapulgite its concentration and that of sodium chloride (NaCl) were varied. Measurements of specific gravity, apparent viscosity, plastic viscosity, flow limit, API filtrate and pH of the fluid were made according to the API standard. The results showed that the fluids with atapulgite, in higher concentration, did not suffer much interference of the NaCl in the rheological results. However, the fluids with lower concentration of atapulgite suffered more interference and only obtained good rheological results when they had low concentration of NaCl. In addition to good results in rheological properties, fluids with higher concentrations of atapulgite had good results in the API filtration test, because the filtrate volume was lower.