Polysaccharide derivative as an additive in Olefin-Based drilling fluid

• Carboxymethylcellulose was hydrophobically modified with dodecylamine (CMC-DDA) • The materials had intermediate solubility in polar and non-polar solvents. • The viscosity values of the CMC-DDA were higher than the CMC in water and brine. • CMC-DDA improved drilling fluid properties compared to a commercial additive. The search for drilling fluids of low environmental impact and high performance has increased and became of utmost importance over the years. In this study, a hydrophobically modified polysaccharide was obtained from the reaction of carboxymethylcellulose (CMC) with dodecylamine (DDA) in water and evaluated as a new green additive in an olefin-based fluid. FTIR and 1 H NMR spectra revealed the presence of amide groups on the CMA-DDA derivative, demonstrating that the reaction was successful. Unlike the polysaccharide precursor, the product showed turbidity in water, due to association between hydrophobic groups inserted onto CMC chains. The formation of polymer aggregates in water was confirmed by DLS. The rheological measurements in water and saline medium also corroborated to DLS data, as the viscosity of the derivative was higher than that of CMC. Confocal microscopy indicated that the hydrophobically modified CMC contributes to the inverse emulsion stability. CMC-DDA behaved as an efficient rheological modifier on olefin-based drilling fluids, besides of contributing to reduce filtrate loss under high temperature and high pressure (HTHP) conditions.