Incorporation of açaí seed ash as a low-cost chemical additive for water-based drilling fluid for oil Wells.
Açaí seed ash; Chemical characterization; Eco-friendly drilling fluids; Drilling fluid properties
The growing demand for sustainable practices has encouraged the reuse of agro-industrial waste in high value-added applications. In this context, the oil industry has been seeking environmentally friendly alternatives to the additives used in drilling fluids, aiming to reduce environmental impacts and promote the circular economy. At the same time, the açaí (Euterpe oleracea Martius) production chain, widely developed in the Amazon region, generates large volumes of solid waste, mainly the seed, which accounts for about 80% of the fruit. Part of this material is burned for energy generation, resulting in a secondary byproduct — açaí seed ash — which is often discarded without industrial reuse. This study proposes the use of this ash as an alternative additive in water-based drilling fluids, with an environmental focus (eco-friendly drilling fluids), due to its lower environmental impact. As a main methodological step, açaí samples were collected in the city of Óbidos-PA, sieved and separated into particle size ranges of 707–300 µm, 297–149 µm, and 707–149 µm, which were applied to the water-based drilling fluid as a replacement for calcium carbonate in the reference fluid. The açaí seed ash was characterized using different instrumental techniques, including ash content analysis, thermogravimetric analysis, X-ray fluorescence spectroscopy (XRF) for identifying chemical elements, Fourier-transform infrared spectroscopy (FTIR) for verifying functional groups, particle size analysis for particle size distribution, and scanning electron microscopy (SEM) for morphological evaluation. The formulated fluids were subjected to a series of performance tests, including sedimentation resistance tests, rheological analysis, filtrate volume measurement, and filter cake characterization. These tests allowed for the evaluation of the ash's effectiveness as a functional additive. The results showed that the ash exhibited comparable or even superior performance to conventional calcium carbonate, improving parameters such as plastic viscosity, yield point, and filtrate volume. Therefore, the study reinforces the potential of açaí seed ash as a sustainable input for the oil industry, contributing both to the valorization of regional waste and to the advancement of cleaner technologies in well drilling operations.