Research on the Chemistry of Emulsifiers for Nonaqueous Drilling Fluids

Abstract

Abstract High-performance nonaqueous fluids (HP NAF) are complex engineering systems. The emulsifier is the backbone of any NAF; therefore, highest return on investment is likely to come from the development of emulsifier chemistry. The objective of the present research is to improve the knowledge of different reactions that occur during synthesis of an emulsifier and investigate how the different products of the synthesis impact emulsifier performance in a NAF. Creating a new emulsifier is a one-step process of C18 amine condensation and various cyclic anhydrides. Reaction time and temperature was varied in this work to generate different reaction products, and analytical techniques, such as 1H nuclear magnetic resonance (NMR), 13C NMR, Fourier transform infrared spectroscopy (FTIR), and gel permeation chromatography were used to investigate the mechanism of the chemical reaction and for reaction process optimization. The reaction is a simple formation of a monoamide between the amine and the cyclic anhydride; however, secondary reactions are possible that decrease the emulsifier performance. The monoamide that forms initially can be transformed into other species under elevated temperatures, which no longer function as emulsifiers. This paper presents the performance of a new emulsifier in a HP NAF and provides a systematic insight into various chemical transformations that are possible when attempting to use this amide-formation reaction to create an emulsifier. Development of structure-activity relationships for chemical components of emulsifiers and a systematic knowledge of invert emulsion performance will improve the comprehension of emulsifier performance in an HP NAF. This knowledge can be applied to improve emulsion stability and rheology of a drilling fluid.