(203c) Electrospray Ionization FT-ICR Mass Spectrometry of "Arn'" Naphthenic Acids in Sodium and Calcium Naphthenate Deposits, and Crudes: Extraction and Quantification

Many oilfield operators face flow assurance challenges associated with the deposition of naphthenate solids and formation of sodium soaps in production equipment. Calcium and sodium naphthenates are respectively solid deposits and emulsions formed by the interaction of naphthenic acids with divalent (Ca2+, Mg2+) or monovalent (Na+, K+) ions in produced water. Calcium naphthenate formation, an interfacial phenomenon, is thought to depend largely on tetraprotic naphthenic acids known as ?ARN' acids in the crude, whereas the formation of sodium naphthenate originates from less substituted lower molecular weight naphthenic acids. In the current paper, ?ARN' acids extracted from whole crude oils and naphthenate deposits and soaps are characterized by high resolution FT-ICR mass spectrometry and the results compared and contrasted. We present our first attempts to quantify ARN-type acids in whole crude oils. The high resolution and mass accuracy of FT-ICR MS provides detailed acidic speciation for all crudes and deposits analyzed.