Characterization of Sodium Emulsion Soaps Formed from Production Fluids of Kutei Basin, Indonesia

Abstract

Crude oils, produced waters, and emulsions retrieved from the Kutei Basin of Indonesia have been examined by a variety of analytical techniques to understand soap-formation mechanisms and origins of reactants. Crude oils contain long-chain, n-alkanoic or slightly branched monocarboxylic acids, which primarily have a landplant origin. Although the crude oils may contain up >1000 ppmw of carboxylic acids, the total acid number (TAN) is anomalously low (∼0.5 mg KOH/g, on average). Traces of mononaphthenic, bicyclonaphthenic, alkyl benzoic, diprotic, and tetraprotic acids are detected in some Kutei Basin oils. The oils and acids therein are significantly different from oils that have a marine algal origin, which, in certain areas of the world, contain high TAN values and concentrations of naphthenic acids synthesized by microbial biodegradation. The naphthenic acids combine with calcium in produced waters to form calcium naphthenates. Produced waters are enriched in sodium bicarbonate (NaHCO 3 ), as a result of the decarboxylation of volatile fatty acids. When the pH of produced water exceeds a value of ∼6.2, NaHCO 3 reacts with the carboxylic acids in a saponificationlike reaction to form interfacial sodium carboxylate soap emulsions. These emulsions may be stabilized by formation flour (reservoir formation of fine particulates of rock, such as quartz sand, silts, and aluminum silicate clays (for example, allophanes)), scale/corrosion debris, and high-molecular-weight acids. The Kutei Basin soap emulsions are resolved by heating and treatment with relatively high dosages of acid demulsifiers.

Metal Ion Interactions with Crude Oil Components: Specificity of Ca2+ Binding to Naphthenic Acid at an Oil/Water Interface

“…The total acidity of the crude oil depends on its source, and oil-specific measures are often required to reduce potential damage when processing the highest acidity crudes (typically total acid number [TAN] values in excess of approximately 0.8 mg KOH/g) [10]. Naphthenic acids also exhibit specific interactions with calcium in certain oilfields, where Ca 2+ coordination leads to precipitation and deposition of naphthenate-rich scale [11].…”

Oilfield metal naphthenate formation and mitigation measures: a review

“…Some potassium carboxylate emulsion soaps have occurred in a West African field, but calcium carboxylates are rare (Runham and Smith 2009). From field observations, sodium carboxylate soap problems are associated with higher concentrations of bicarbonate ion because they form tight emulsions which are stabilized by interfacial sodium carboxylate-bicarbonate complexes (Gallup and Curiale 2007;Shepherd et al 2006). This highly stable emulsion increases fluid viscosity which can reduce production rate (Turner and Smith, 2005).…”

“…Copious chemical injection is usually required to achieve success using any of these methods. Though acetic acid is by far the most common, other organic acids including formic acid, citric acid, glycolic acid, sulphonic acid, myristic acid and lauric acid have been applied in the field (Nichols et al 2014;Gallup and Curiale 2007;Vindstad et al 2003;Gallup et al 2002). More aggressive options such as phosphoric acid or hydrochloric acid injection have been adopted in cases where organic acids gave unsatisfactory results (Nichols et al 2014;Vindstad et al 2003;Gallup et al 2005).…”

Comprehensive study of a heavy fuel oil spill : modeling and analytical approaches to understanding environmental weathering

“…[60] Naphthenic acids form ionic bonds with ions in the environment to form naphthenates. The naphthenic acids within our samples are consistent with sodium naphthenates, monoprotic carboxylic acids characterized by low DBEs and ranging from 15-35 carbon atoms.…”