B41oa oil and Gas Processing Section a flow Assurance Heriot-Watt University

4.1.1 Importance of Asphaltenes in Emulsion Stability 
During the recovery, treatment and transportation of crude oil, the problem of 
emulsion formation can arise. As mentioned, surface active agents can 
partially stabilise any emulsions that are formed; the degree of stabilisation 
depends on the type of emulsifier that is present and its concentration. 
Asphaltenes are large polyaromatic hydrocarbons that consist of condensed 
aromatic rings – these compounds also contain hydrophilic functional groups 
and it is the presence of these functional groups that renders asphaltenes 
surface-active (and causes them to be effective emulsion-stabilisers). 
Thus, the formation of asphaltenes within reservoir systems causes major 
operational issues. It follows, therefore, that the inhibition and/or removal of 
asphaltenes is important to the oil industry. 
4.1.2 De-emulsification 
De-emulsification involves the breaking down emulsions into its individual 
components. There are a number of methods that can be used to de-emulsify 
emulsions, including: 
•
Thermal methods. 
•
Physical methods. 
•
Chemical methods. 
•
Electrical methods. 

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TOPIC 4: Asphaltenes 
 
 
 
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Thermal, electrical and physical methods generally don’t give a high degree of 
de-emulsification – thus, they often need to be used in combination with each 
other. When using the thermal approach care is needed to prevent both 
asphaltene and wax deposition – see Section B, Topic 3B for more details. 
Chemical methods are often used and where appropriate are be both effective 
and efficient. However, the chosen chemical treatment must be tailored to 
exactly match the type of crude oil being processed. 
Ultrafiltration has been suggested as a possible approach to de-emulsification. 
However, it is still in the early stages of research and is not yet commercially 
available. 

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TOPIC 4: Asphaltenes 
 
 
 
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