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Title: Asphaltene deposition: A thermodynamic-colloidal model

Thesis/Dissertation ·
OSTI ID:7025759

Asphaltene deposition during petroleum production and processing is a very serious problem in many areas throughout the world. This dissertation concerns the development of a thermodynamic-colloidal model for predicting the onset of flocculation of asphaltenes in oil mixtures due to either changes in temperature, pressure, and composition or electrical phenomena. Given one experimental onset point for a crude oil, the model can predict the onset of asphaltene flocculation of the same oil with any other solvent or oil mixture, at any pressure and composition including that of the original reservoir fluid. The resin critical chemical potential is introduced as a property of each crude oil related to its asphaltene flocculation tendency and being only a function of temperature and of the nature of the asphaltene-resin micelles. For those oil mixtures from which flocculation is caused simply by flow, as apparently in primary oil production, the model can make predictions as to the velocity ranges where asphaltene flocculation can be avoided. Both the static and dynamic parts of the model are tested with the available experimental data on the onset of asphaltene flocculation and the results are encouraging. Furthermore, a simple, rapid, and precise method for determining the resin content of a crude utilizing high performance liquid chromatography was proposed and tested. Gel permeation chromatography was utilized to determine the molecular weight distributions of asphaltenes and resins derived from two different crude oils. A functional relationship has been demonstrated to exist between the asphaltene number average molecular weight (relative to polystyrene) and the carbon number of the paraffin flocculant used to separate the asphaltenes from the crude.

Research Organization:
Illinois Univ., Chicago, IL (USA)
OSTI ID:
7025759
Resource Relation:
Other Information: Thesis (Ph. D.)
Country of Publication:
United States
Language:
English