Joel Escobedo

Viscometric Determination of the Onset of Asphaltene Flocculation: A Novel Method

A new technique for the determination of the onset of asphaltene flocculation has been developed through accurate viscosity measurements of a crude oil being diluted with a precipitating agent (n-pentane, n-heptane, n-nonane). This detection method is based on experimental observations of an increase in the viscosity of a crude oil-asphaltene-precipitating agent suspension in which asphaltene particle aggregation occurs. The key point in this development is the phenomenon of asphaltene flocculation induced by the addition of a n-paraffin hydrocarbon (i.e. n-heptane, n-pentane, n-nonane) to crude oil. The onset of asphaltene flocculation is detected graphically, and its location is enhanced by comparison of the analyte curve with a reference system. The reference system was developed using polar and non-precipitating solvents (i.e. toluene, benzene, THF).

Chapter 8 Asphaltene and other Heavy Organic Depositions

Publisher Summary Asphaltene and other heavy organic depositions during production and processing of crude oil present a very serious problem in many areas throughout the world. This chapter discusses the application of modern theoretical and experimental techniques of statistical mechanics and thermodynamics to develop the methods to predict organic deposition during production and processing of crude oil. The parameters governing the precipitation of heavy organic from petroleum fluids are the composition of crude and injection fluid, pressure, and temperature of the reservoir. The chapter discusses a continuous thermodynamic (CT) model in which the theory of heterogeneous polymer solutions is utilized for the predictions of the onset point and amount of organic deposits from petroleum crude. A steric colloidal (SC) model, which is capable of predicting the onset of organic deposition, is also described. A combination of the two models results in a fractal aggregation (FA) model. The chapter also discusses chromatographic methods for the characterization of crude oils and organic deposits from petroleum fluids and presents model predictions of the onsets and amounts of heavy organic deposits along with the experimental results.