(Evaluation of polycationic bentonite clays from Paraiba State with additives for application in oil drilling and water-based paints)

Abstract

With the new occurrences of bentonite clays in Paraiba State, there is need for optimizing their rheology in order to make them to fit the requirements of the Brazilian industry, aiming its use in drilling fluids and water based paints. Three clays were used (Chocolate Campos Novos, Chocolate Corredor and Chocobofe Primavera) in order to assess the technological properties for use as thixotropic agent in the formulation of drilling fluids and water based inks; this research deals with the rheology of dispersions of doped clay with MgO and/or Na₂CO₃. The rheological behavior was studied with a viscometer with dispersions of 4.86% and 6.00% (w/w) and with additives ranging from 2% to 3% (w/w) in simple and combined form. The results obtained were compared with the Petrobras, ISO and API specifications. The studied samples showed typical characteristics of bentonite originating from Paraiba State, with the characteristic smectite and kaolinitic clay minerals, and accessories; the rheological analysis showed that the clays studied using Na₂CO₃ showed promising results for technological application in well drilling fluids, and the samples with both additives Na₂CO₃ and MgO exhibited promising results for technological application in water based paints.

Keywords:
bentonite clays; rheological properties; drilling fluids; water based paints