The growing global concern about the environment associated with academic and government efforts are enabling a number of alternatives for sustainable development. Within this perspective one can include the search for value-added products using waste from renewable energy sources, such as those from the production of biodiesel. The rapid development of biodiesel production in Brazil directly affected the supply of glycerin and therefore the sector is seeking a market that can absorb this waste. Thus, with the increasing search for environmentally friendly products, formulation of a drilling fluid using a co-product of biodiesel production to replace the n-paraffin is of great importance to the oil industry for meeting the requirement of environmental regulation and, in addition, considerably reducing the cost of raw materials. In this context, the aim of this study was to characterize different glycerins to evaluate their potential as basis for drilling fluids for oil wells and gas. The glycerins were stable under the conditions evaluated without phase separation and precipitation of solids, exhibited good rheological profile and low value of interface tension. The results indicate a strong possibility of use of these glycerins as basis for drilling fluids and applicability by the oil industry.

O trabalho objetivou avaliar xantanas produzidas por Xanthomonas arboricola pv pruni como viscosificante de fluido para aplicação na perfuração de poços de petróleo, comparando-as com três amostras comerciais utilizadas para este fim. Para isto, a viscosidade de soluções aquosas e salinas (NaCl, KCl e CaCl2) das diferentes xantanas, em distintas temperaturas (25, 45, 65 e 80 ºC), foi determinada em reômetro. Os parâmetros reológicos índice de consistência (K) e o índice de fluxo (n) foram obtidos pelo ajuste do modelo de Ostwald-de-Waelle. A força gel (G0, G10 e G30) foi determinada em viscosímetro, e a concentração de sais monovalentes (sódio e potássio) e divalentes (cálcio e magnésio) foi determinada em fotômetro de chama e em espectrômetro de absorção atômica, respectivamente. De uma forma geral, os resultados obtidos neste estudo mostram que as xantanas produzidas pelo patovar pruni, Xp 106-600 e Xp 115-600, por conterem baixa concentração de sais, apresentaram potencial para aplicação em fluido de perfuração de poços de petróleo, quando utilizada solução salina. Já os polímeros comerciais apresentaram melhores resultados quando utilizados em solução aquosa, pois continham alta concentração de sais.

The aim of this work was to evaluate xanthans produced by Xanthomonas arboricola pv pruni to be used for increasing the viscosity of fluids applied in the perforation of oil wells, which were compared with three commercial samples. In order to do that, the viscosity of aqueous and saline solutions (NaCl, KCl and CaCl2) from different xanthans, at different temperatures (25, 45, 65 and 80 ºC), was determined in a rheometer. The rheological parameters consistency index (K) and flow behaviour index (n) were obtained by adjusting the data with the Ostwald-de-Waelle model. Gel strength (G0, G10 e G30) was determined in a viscometer, and the concentration of monovalent (sodium and potassium) and divalent salts (calcium and magnesium) was determined in flame photometer and in atomic absorption spectrometer, respectively. Taken together, the results obtained in this study showed that xanthans produced by patovar pruni, Xp 106-600 and Xp 115-600, are promising for fluids used in oil well perforation with saline solutions, because they have low concentration of salts. As for the commercial polymers, they presented the best results when used in aqueous solution, because they had high salt concentrations.