AMORIM, L. V.; http://lattes.cnpq.br/7209301206982076; AMORIM, Luciana Viana.
Résumé:
The development of this work was motivated by the constant search to
improve the Theological behavior of bentonite clays dispersions from Boa Vista,
state of Paraiba (major deposit of clay in South America), and the challenge to
salve the frequent problems related to contamination of drilling fluids during
drilling well operations. The main objectives of this work are: identify the causes
of the poor rheological behavior of bentonite clays from Boa Vista, PB using
electrodialysis and to evaluate the action of cellulose based polymeric additives
to protect and recover the rheological and the water loss properties of bentonite
clays dispersions contaminated by calcium and magnesium chlorides. For this
purpose, three samples of natural bentonite clays and four commercial samples
Paraiba state were selected. The natural bentonite clays were transformed into
sodium bentonite by addition of concentrated Na2C03 solution. The rheological
properties and the water loss value of bentonite clays dispersions prepared with
4.86% w/w and after several treatment conditions (thermal treatment, dialysis,
electrodialysis, degradation, protection and recovery treatments) were obtained
according to Petrobras standards. The results show that: i) the electrodialysis
can be a valuable tool to identify the factors that dictate the rheological behavior
of bentonite clay dispersions, after the cations exchange process; ii) the
rheological properties and the water loss value are strongly dependent on
bentonite/polymer interaction, which depends on the viscosity degree and the
polymer chain length and iii) the different behaviors of dispersions, after
protecting and recovery treatments, are useful to optimize drilling fluids
applications.
