On the use of an agro waste, Miscanthus x. Giganteus, as filtrate reducer for water-based drilling fluids

During drilling operations, the influx of liquids to the producing zones can cause wellbore instability problems and decrease the well's productivity. Different additives are used as filtrate reducers in water-based drilling fluids (WBFs). The growing need of more sustainable drilling operations motivates the incorporation of residues and waste in WBFs formulations. This study reports the evaluation of Miscanthus x. Giganteous (MxG) fines as filtrate reducers in WBFs, promoting the valorization of this agro waste. MxG was characterized by FTIR, and the spectra exhibited characteristic bands of its major constituents. The MxG size reduction was performed by grinding and sieving it through #100, 200 and 325 mesh screens, and the particle size distribution was obtained by optical microscopy. TGA results showed that the sieved MxG grass fines exhibited thermal stability in the range for use in deep and ultra-deep wells, and the degradation profiles were dependent on the average particle size. The filtration properties of all WBFs studied were well described by Darcy's law, allowing the determination of the spurt loss volume. The filtration performance of the WBFs was significantly improved when the average particle size of the MxG fines decreased, exhibiting comparable or superior results than other materials obtained by more complex, solvent-dependent, expensive and time-consuming processes described in literature.