Synthesis of an Eco-Friendly Xylooligosaccharides and Its Mechanistic Evaluation in Water-Based Drilling Fluids

This study investigates the preparation and application mechanism of Xylooligosaccharides (XOS), an environmentally friendly oligosaccharide additive derived from black fungus in water-based drilling fluids (WBFs). The distinctive molecular characteristics of XOS are revealed through Fourier-transform infrared spectroscopy. Thermogravimetric analysis confirms its stability at temperatures below 150 °C. In terms of performance enhancement, incorporating XOS improves rheological properties and filtration efficiency. Elevated XOS concentrations increase viscosity, diminish fluid loss, suppress clay hydration, and enhance cohesive strength, especially at higher temperatures. Additionally, incorporating XOS prompts the formation of a lubricating layer on particle surfaces, facilitating improved interaction between particles and the surrounding fluid. This layer substantially reduces friction coefficients, thereby significantly boosting the lubrication efficiency of the drilling fluid. At the microstructural level, the incorporation of XOS leads to noticeable microstructural refinement in the matrix mud cake, resulting in a smoother particle distribution due to interactions between XOS and particles. Mechanistically, introducing XOS results in a significant shift in the distribution of clay particle sizes. This phenomenon can be attributed to XOS’s ability to create a stable hydration film within the WBFs. As a result, this film mitigates particle aggregation, leading to a reduction in particle size. XOS emerges as a versatile and sustainable oligosaccharide inhibitor, effectively optimizing the performance of WBFs. Its diverse contributions to lubrication, inhibition, and microstructure refinement position XOS as a promising solution for efficiently extracting oil and gas resource.