Novel Amphiphilic Comb-Like Polymers: Synthesis, Characterization, and Their Properties as Viscosifying and Filtration Additives for Drilling Fluids

Abstract

Novel amphiphilic comb-like polymers (CPASA), used as viscosifying and filtration loss additives for low-solid water-based drilling fluids under high temperature and salinity conditions, were prepared from acrylamide, sodium 4-styrenesulfonate, and allyl polyethylene glycol ether with toluylene-end groups via inverse microemulsion polymerization. The chemical structure was characterized by Fourier transform infrared spectroscopy (FTIR) and hydrogen nuclear magnetic resonance (¹H-NMR). The thermal stability, aqueous solution properties, and drilling fluid properties were evaluated. Results showed that the comb-like polymers exhibited dramatic enhancement in their thermal- and salt-resistant properties because of the steric hindrance and intermolecular associations of the side-chains. The rheological properties, filtration properties, and negative Zeta potentials of both fresh-water drilling fluid and saturated salt-water drilling fluid were greatly improved by the addition of CPASA before and after thermal aging tests, which were ascribed to the steric hindrance of its comb-like conformation, the strong electrical double layer force of clay particles, and the stable mud network formed by CPASA and clay particles in drilling fluid.

Keywords:

• amphiphilic
• comb-like polymer
• drilling fluid
• synthesis
• thermal-resistance
• salt-resistance
• viscosifying

Funding

The authors are grateful for financial support by National 863 Program of China (2012AA091502), the National Science and Technology Major Project of the Ministry of Science and Technology of China (2011ZX05021-004), Oil Shale Exploration and Development Project (OSR-04-07), Research of Deep Well Bore Stability Foundation (Sinoprobe-09-05-05).