WorldOil

Understanding naphthenate salt issues in oil production

Various naphthenic acids are present in nearly all crude oils in different forms. Problems occur when the naphthenic acids come in contact with high-pH connate waters. The problems start at the oil-water interface and can cause organic deposition, impede oil-water separation and ultimately lead to poor water quality. This article reviews the characterization of, problems caused by and remediation of naphthenate salt issues in the upstream environment, drawing information from direct experience and literature. INTRODUCTION Crude oil is a complex mixture of 10,000-100,000 distinct compounds.1 Typically, the components are organized into the well-known fractions of Saturates, Aromatics, Resins and Asphaltenes (SARA). Included in these fractions are oil-soluble naphthenic acids. At reservoir conditions, the acids are contained in the oil phase and demonstrate low interfacial activity.2 As the pressure cascades up through the flowline and ultimately into the topside separation equipment, depressurization occurs.