Comparative study on the structures and properties of organo-montmorillonite and organo-palygorskite in oil-based drilling fluids

Abstract

Abstract This work aims to reveal the differences of structures and properties between organo-montmorillonite (OMt) and organo-palygorskite (OPal) in oil-based drilling fluids. Organoclays are prepared in aqueous solution and characterized by XRD, SEM and TEM. Surfactants can intercalate into the interlayer space of Mt while they coat only on the palygorskite surface. OMt can form “house of cards” structure while OPal forms “haystack” structure. Temperature rising promotes network structure and rheological properties of organoclays in oil. The decline of rheological properties at high temperature is mainly caused by the dissolution of surfactants into oil, instead of thermal decomposition.