Improving HPHT Stability of Water Based Drilling Fluids

Abstract

Abstract A new method is discussed to improve the HPHT stability of conventional rheology modifiers and fluid loss polymers used in water-based drilling fluids. The method exploits the interactions of polysaccharides (e.g. xanthan gum, scleroglucan), cellulosics (e.g. CMC, PAC) and starches with polyglycols. Polymer and polyglycols were found to associate by inter-molecular hydrogen bonding and hydrophobic interactions. This association / complexation was found to stabilize the polymers at higher temperatures. Our laboratory findings are validated by field observations in the Kakap field in Indonesia that show improved HPHT stability when adding polyglycols to water-based drilling fluid formulations.