Effects Of Xanthan Gum And Bentonite On The Performance Of A Microemulsion-Based Drilling Fluid

Microemulsion-based drilling fluids are a new technology that aims to substitute water and oil-based drilling fluid, for featuring high lubricity, stability, low toxicity, low cost and less fluid loss. This paper studies the viscosifying action of xanthan gum and bentonite in a microemulsion-based drilling fluid, composed by an aqueous solution of glycerin, vegetable oil and a nonionic surfactant, through rheological tests. From the results, it could be concluded that the xanthan gum has a higher viscosifying action, since the drilling fluid added with a smaller amount of this biopolymer presented a higher apparent and plastic viscosity, gel strength and shear limit. The two viscosifiers attributed pseudoplasticity to the drilling fluids and the rheological model that better adjusted to the presented behaviors was the Herschel-Bulkley model.