The exploration, production, transportation and refining of petroleum often pose
great technical and environmental challenges to the oil and gas industry. It is
therefore extremely important to reliably predict and control fluid behaviour, in
order to optimize production cost and for purposes of potential environmental
pollution in the oil and gas operational activities. The investigations in this work
focuses upon North Sea crude oils. In view of the fact that the North Sea crude oils
are derived from the same source rock (Kimmeridge), they would be expected to
have the same chemistry, but however, they tend to behave differently. The
objectives of the research were to develop a better understanding of the effect of
temperature and time on evaporation rate and its role in modifying the rate of
weathering of North Sea crude oils on seawater. In this research, the chemistry of
the oils was investigated to see the relationship to their emulsification behaviour. In
the first part of this thesis, the weathering behaviour of four North Sea crude oils
were investigated, in particular the evaporation, using a novel evaporation method.
It was observed that the rate of evaporation varied between the North Sea oils.
Evaporation of emulsified oil differed to unemulsified oil. North Sea crude oils of
different states of weathering were emulsified and their viscosities and water
contents measured. The four oils produced emulsion types of different viscosities
and states of stability. The effects of degree of weathering of oils on emulsion states
were assessed. The chemistry of the four North Sea crudes was investigated using a
range of analytical techniques. The oils were fractionated by SARA analysis to
produce saturates, aliphatic, resins and asphaltene fractions, prior to chemical
analyses, using a range of analytical techniques (The crude oils were fractionated
and the fractions analyzed for their chemical compositions). The compositions of
the four crude oils differed to one another. From these analyses, a number of
parameters were selected to characterize the oils. These were polarity, aromaticity
and alkyl side chain. These data were used in a modeling study. The asphaltenes
from the North Sea crudes investigated were substituted into both synthetic and
model oils to study the effect on emulsification. It was observed that the asphaltenes
had an effect on the emulsification behaviour. The behavior of modeled asphaltene
structures based on the chemical characterization data was found to correlate with
the emulsification behavior of the North Sea crudes investigatedAkwa Ibom State University of Technology (AKUTECH
