Covalently-Linked Organic Functionalities on Nano-Platelets as a Viscosifier for Oil-Based Muds

Abstract

Organic functionalities have attached with layered materials through weak ionic bonds in traditional viscosifiers. Since the ionic linkages are weaker than the covalent bonds, ionic organic functionalities tend to detach under high temperature, pressure, shears, presence of other stronger ionic groups and repeated exposures toward alkaline or acidic conditions. To overcome these drawbacks of traditional viscosifiers, we have designed a novel viscosifier with covalently-linked organic moieties on layered materials (COLM). The organic functionalities were linked on the nano-platelets through covalent bonding and thus these linkages provide excellent stability compare to ionic interaction. The synthesis of COLM involves facile synthetic routes that have generated synthetic layered materials of high purity and reproducible chemical composition. The rheological properties of oil-based mud (OBM) containing COLM are characterized under high temperature and high pressure. Unprecedented flat rheology was observed when COLM was blended in OBM and compared with traditional organoclay. The temperature dependent viscoelastic behavior (storage modulus, G' and loss modulus, G") of the OBMs were also studied to establish the effectiveness of COLM compare to traditional organoclay.