Influence of Asphaltene Aggregation and Pressure on Crude Oil Emulsion Stability

My supervisor introduced me to the field of surface and colloid chemistry in 1997, while studying physical chemistry as an undergraduate student at the University of Bergen. Little did I then know that the work would lead me into the petroleum industry, and a struggle with "the good and the bad asphaltenes". As an experimentalist, the work in the laboratory has, more often than not, provided results difficult to interpret. Nevertheless, the work has continued, and in-between the total failures, there has been some near successes, which have resulted in the thesis you are now paging through. During my time as a dr.ing. student I have had the fortune to participate in a project with the acronym FLUCHA II, which stands for Fluid Characterisation at elevated pressures and temperatures. The group has consisted of 3 dr.ing. students and 1 post doc, under the guidance of the enthusiastic and demanding Prof. Sjöblom. The work tasks of the group have covered a number of flow assurance related problems, i.e. Acknowledgements First of all, I would like to express my sincere gratitude to my academic advisor Prof. Johan Sjöblom, for his years of guidance and invaluable encouragement, along with generous hosting when teambuilding throughout this research work. During my three years of work, I have enjoyed the opportunity of working with several fellow graduate students and postdoctoral associates, which have provided intellectual assistance and an enjoyable working environment. I am also grateful to all my co-authors, whom I have had the fruitful pleasure of collaborating with. I would also like to acknowledge the FLUCHA II program financed by the Research Council of Norway and the oil industry. Statoil ASA is especially thanked for providing office space and access to laboratory equipment. Finally, I wholeheartedly thank Helene and my parents for their love and support, without which this work would never have been completed. ii Abstract Abstract Water-in-crude oil emulsions stabilised by various surface-active components are one of the major problems in relation to petroleum production. This thesis presents results from high-pressure separation experiments on "live" crude oil and model oil emulsions, as well as studies of interactions between various indigenous stabilising materials in crude oil. A high-pressure separation rig was used to study the influence of gas and gas bubbles on the separation of water-in-crude oil emulsions. The results were interpreted as a flotation effect from rising gas bubbles, which led to increased …