Advanced trends of shale inhibitors for enhanced properties of water-based drilling fluid

Water-based mud (WBM) is an environmentally acceptable drilling fluid. However, it makes shale to be prone to swelling owing to its interaction with active clays. Shale swelling makes drilling to be difficult, so, additives are added to inhibit shale swelling, and improve rheological and filtration properties. The use of conventional additives particularly organic and inorganic compounds are not suitable at extreme conditions of drilling. Other materials like nanomaterials have emerged as promising alternatives used under such conditions. This review aims to highlight in detail the essential types of inhibitors and the evolvement of nanoparticles in enhancing drilling fluid properties.