Inhibition of asphaltene precipitation in Brazilian crude oils using new oil soluble amphiphiles

Asphaltene and resins are heavy fractions of petroleum responsible for serious problems during petroleum production. These problems include the formation of organic deposits in oil reservoirs; wells, transport pipelines and equipment, and can significantly increase the production operational costs. The nature and behavior of asphaltene in crude oils is complex and changes in temperature, pressure and composition of crude oils during production can result in precipitation of asphaltene components. Potential solutions for these problems include physical removal of deposits, solvent washes and treatment with dispersant agents. The use of soluble amphiphile oils provides the most practical and economical solution for deposits treatment. In this work, the inhibitory capacity of a number of new chemical additives to asphaltene precipitation was examined in three types of Brazilian crude oils. Low molar mass ethoxylated nonylphenols, vegetable oils (coconut essential oil, sweet almond, andiroba and sandalwood oil) and organic acids (linoleic, caprylic and palmytic) displayed highest capacity to inhibit asphaltene deposition. The dissolution capacity of some additives was evaluated for two asphaltenic deposits in aliphatic solvents. The remarkable solubilization effect displayed by dodecylbenzenesulfonic acid, confirmed the importance of acid-base interactions in this process. The results also revealed distinct mechanisms for asphaltene solubilization/dispersion in aliphatic solvents and inhibition of asphaltene precipitation in crude oils. (c) 2006 Elsevier B.V. All rights reserved.