Rheological aspects of xanthan gum: Governing factors and applications in water-based drilling fluids and enhanced oil recovery.

In the context of a low-carbon future, green, sustainable, and environmentally friendly oilfield development methods have become urgent priorities. The application of bio-based materials in water-based drilling fluids (WBDFs) and enhanced oil recovery (EOR) is emerging as a key strategy for driving sustainable development. Xanthan gum (XG), a natural polysaccharide, has gained significant attention due to its non-toxic, biodegradable, renewable, and environmentally friendly characteristics. Its shear-thinning rheological properties make it particularly suitable for oilfield development. This review summarizes the production, modification, and chemical structure of XG, focusing on key factors influencing the rheological behavior of its aqueous solutions, including shear rate, shear stress, concentration, pH, salinity, temperature, time, and polysaccharide interactions. Additionally, recent advances in XG's application in WBDFs and EOR are discussed. Although XG's viscosity stability and recovery under high-temperature and long-duration conditions present challenges, these issues have been largely addressed through increased salinity and chemical modifications. Finally, this review highlights key future research directions, such as exploring the structure-rheology relationship of XG, polysaccharide interactions, the rheological behavior and sustainability of XG derivatives, and its economic feasibility in oilfield development. These insights aim to improve XG's adaptability to harsh oilfield conditions and guide its use in similar environments.