Remediation of Naphthenate Stable Emulsion for Malaysian Oilfields

Abstract

Abstract Crude oil production from various fields contains large amounts of naphthenic and carboxylic acids. Combination of formation and injection water with these acids has resulted in the production of stable viscous emulsion which affects oil production to a large extent. Due to the unique properties of different crudes, injection and formation waters a better understanding of the chemistry of the naphthenic acids is of great interest. Interaction of naphthenic acids in crude oil with metal ions such as calcium and sodium leads to the formation of naphthenates. Moreover, the release of CO2 from the crude oil at sufficiently low pressures leads to a corresponding increase in pH which then leads to the formation of soaps. The behavior of naphthenates ranges from soft to hard emulsion which depends on the cation composition of the brine and other contributing factors. This study investigates the effects of a range of parameters on the Naphthenate emulsion formation, including naphthenic acid type, composition of the brine, pH, etc. A pseudo model of synthetic naphthenic acids using commercial mixtures and various types of crude oil and naphthenic acid was utilized to investigate emulsion stability and viscosity. It was concluded that brine chemistry and pH play a major role in the stability and viscosity of the emulsion. Slight variation in the pH with controlled brine composition accelerates the demulsification process.