Evaluation of the Performance of Mycelial Polysaccharide for Water-Based Drilling Fluids

This study investigates the application and performance evaluation of an eco-friendly mycelial polysaccharide in high-temperature water-based drilling fluids. The polysaccharide was prepared through liquid-solid extraction coupled with enzymatic hydrolysis, followed by comprehensive structural and property characterization using advanced analytical techniques, including Fourier-transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), and gel permeation chromatography (GPC). FTIR analysis confirmed the polysaccharide's molecular structure, revealing a main chain composed of glycosyl units interconnected via glycosidic bonds. Key functional groups included hydroxyl and ether bonds, along with minor carbonyl groups and aromatic ring structures. TGA results demonstrated the polysaccharide's exceptional thermal stability, maintaining structural integrity up to 230 ℃ without significant degradation. Performance evaluations in drilling fluids showed improvements in rheological properties, lubrication efficiency, and shale inhibition. The additive maintained stable rheological performance at high temperatures (up to 180 ℃) and exhibited excellent fluid loss control, significantly reducing filtration volume. Environmental assessments confirmed its superior ecological compatibility, characterized by low biotoxicity, moderate pollution load, and high biodegradability, fully complying with international environmental standards. In summary, this novel polysaccharide offers distinct advantages, including controlled molecular weight, high-temperature resistance, superior lubricity, and excellent ecological sustainability.